- implemented -Wunused-label
[cparser] / parser.c
index f63c266..c769d34 100644 (file)
--- a/parser.c
+++ b/parser.c
@@ -4,20 +4,23 @@
 #include <stdarg.h>
 #include <stdbool.h>
 
+#include "diagnostic.h"
+#include "format_check.h"
 #include "parser.h"
 #include "lexer.h"
 #include "token_t.h"
+#include "types.h"
 #include "type_t.h"
 #include "type_hash.h"
 #include "ast_t.h"
+#include "lang_features.h"
+#include "warning.h"
 #include "adt/bitfiddle.h"
 #include "adt/error.h"
 #include "adt/array.h"
 
 //#define PRINT_TOKENS
-//#define ABORT_ON_ERROR
 #define MAX_LOOKAHEAD 2
-//#define STRICT_C99
 
 typedef struct {
        declaration_t *old_declaration;
@@ -30,37 +33,33 @@ struct declaration_specifiers_t {
        source_position_t  source_position;
        unsigned char      storage_class;
        bool               is_inline;
+       decl_modifiers_t   decl_modifiers;
        type_t            *type;
 };
 
 typedef declaration_t* (*parsed_declaration_func) (declaration_t *declaration);
 
-static token_t         token;
-static token_t         lookahead_buffer[MAX_LOOKAHEAD];
-static int             lookahead_bufpos;
-static stack_entry_t  *environment_stack = NULL;
-static stack_entry_t  *label_stack       = NULL;
-static context_t      *global_context    = NULL;
-static context_t      *context           = NULL;
-static declaration_t  *last_declaration  = NULL;
-static declaration_t  *current_function  = NULL;
+static token_t             token;
+static token_t             lookahead_buffer[MAX_LOOKAHEAD];
+static int                 lookahead_bufpos;
+static stack_entry_t      *environment_stack = NULL;
+static stack_entry_t      *label_stack       = NULL;
+static scope_t            *global_scope      = NULL;
+static scope_t            *scope             = NULL;
+static declaration_t      *last_declaration  = NULL;
+static declaration_t      *current_function  = NULL;
+static switch_statement_t *current_switch    = NULL;
+static statement_t        *current_loop      = NULL;
+static goto_statement_t   *goto_first        = NULL;
+static goto_statement_t   *goto_last         = NULL;
+static label_statement_t  *label_first       = NULL;
+static label_statement_t  *label_last        = NULL;
 static struct obstack  temp_obst;
-static bool            found_error;
-
-static type_t         *type_int         = NULL;
-static type_t         *type_long_double = NULL;
-static type_t         *type_double      = NULL;
-static type_t         *type_float       = NULL;
-static type_t         *type_char        = NULL;
-static type_t         *type_string      = NULL;
-static type_t         *type_void        = NULL;
-static type_t         *type_void_ptr    = NULL;
-static type_t         *type_valist      = NULL;
-
-type_t *type_size_t      = NULL;
-type_t *type_ptrdiff_t   = NULL;
-type_t *type_wchar_t     = NULL;
-type_t *type_wchar_t_ptr = NULL;
+
+/** The current source position. */
+#define HERE token.source_position
+
+static type_t *type_valist;
 
 static statement_t *parse_compound_statement(void);
 static statement_t *parse_statement(void);
@@ -87,7 +86,8 @@ static void semantic_comparison(binary_expression_t *expression);
        case T_const:           \
        case T_restrict:        \
        case T_volatile:        \
-       case T_inline:
+       case T_inline:          \
+       case T_forceinline:
 
 #ifdef PROVIDE_COMPLEX
 #define COMPLEX_SPECIFIERS  \
@@ -127,6 +127,10 @@ static void semantic_comparison(binary_expression_t *expression);
        TYPE_QUALIFIERS         \
        TYPE_SPECIFIERS
 
+/**
+ * Allocate an AST node with given size and
+ * initialize all fields with zero.
+ */
 static void *allocate_ast_zero(size_t size)
 {
        void *res = allocate_ast(size);
@@ -134,7 +138,19 @@ static void *allocate_ast_zero(size_t size)
        return res;
 }
 
-static size_t get_statement_struct_size(statement_type_t type)
+static declaration_t *allocate_declaration_zero(void)
+{
+       declaration_t *declaration = allocate_ast_zero(sizeof(*allocate_declaration_zero()));
+       declaration->type = type_error_type;
+       return declaration;
+}
+
+/**
+ * Returns the size of a statement node.
+ *
+ * @param kind  the statement kind
+ */
+static size_t get_statement_struct_size(statement_kind_t kind)
 {
        static const size_t sizes[] = {
                [STATEMENT_COMPOUND]    = sizeof(compound_statement_t),
@@ -153,22 +169,30 @@ static size_t get_statement_struct_size(statement_type_t type)
                [STATEMENT_FOR]         = sizeof(for_statement_t),
                [STATEMENT_ASM]         = sizeof(asm_statement_t)
        };
-       assert(type <= sizeof(sizes) / sizeof(sizes[0]));
-       assert(sizes[type] != 0);
-       return sizes[type];
+       assert(kind <= sizeof(sizes) / sizeof(sizes[0]));
+       assert(sizes[kind] != 0);
+       return sizes[kind];
 }
 
-static statement_t *allocate_statement_zero(statement_type_t type)
+/**
+ * Allocate a statement node of given kind and initialize all
+ * fields with zero.
+ */
+static statement_t *allocate_statement_zero(statement_kind_t kind)
 {
-       size_t       size = get_statement_struct_size(type);
+       size_t       size = get_statement_struct_size(kind);
        statement_t *res  = allocate_ast_zero(size);
 
-       res->base.type = type;
+       res->base.kind = kind;
        return res;
 }
 
-
-static size_t get_expression_struct_size(expression_type_t type)
+/**
+ * Returns the size of an expression node.
+ *
+ * @param kind  the expression kind
+ */
+static size_t get_expression_struct_size(expression_kind_t kind)
 {
        static const size_t sizes[] = {
                [EXPR_INVALID]             = sizeof(expression_base_t),
@@ -187,35 +211,48 @@ static size_t get_expression_struct_size(expression_type_t type)
                [EXPR_FUNCTION]            = sizeof(string_literal_expression_t),
                [EXPR_PRETTY_FUNCTION]     = sizeof(string_literal_expression_t),
                [EXPR_BUILTIN_SYMBOL]      = sizeof(builtin_symbol_expression_t),
+               [EXPR_BUILTIN_CONSTANT_P]  = sizeof(builtin_constant_expression_t),
+               [EXPR_BUILTIN_PREFETCH]    = sizeof(builtin_prefetch_expression_t),
                [EXPR_OFFSETOF]            = sizeof(offsetof_expression_t),
                [EXPR_VA_START]            = sizeof(va_start_expression_t),
                [EXPR_VA_ARG]              = sizeof(va_arg_expression_t),
                [EXPR_STATEMENT]           = sizeof(statement_expression_t),
        };
-       if(type >= EXPR_UNARY_FIRST && type <= EXPR_UNARY_LAST) {
+       if(kind >= EXPR_UNARY_FIRST && kind <= EXPR_UNARY_LAST) {
                return sizes[EXPR_UNARY_FIRST];
        }
-       if(type >= EXPR_BINARY_FIRST && type <= EXPR_BINARY_LAST) {
+       if(kind >= EXPR_BINARY_FIRST && kind <= EXPR_BINARY_LAST) {
                return sizes[EXPR_BINARY_FIRST];
        }
-       assert(type <= sizeof(sizes) / sizeof(sizes[0]));
-       assert(sizes[type] != 0);
-       return sizes[type];
+       assert(kind <= sizeof(sizes) / sizeof(sizes[0]));
+       assert(sizes[kind] != 0);
+       return sizes[kind];
 }
 
-static expression_t *allocate_expression_zero(expression_type_t type)
+/**
+ * Allocate an expression node of given kind and initialize all
+ * fields with zero.
+ */
+static expression_t *allocate_expression_zero(expression_kind_t kind)
 {
-       size_t        size = get_expression_struct_size(type);
+       size_t        size = get_expression_struct_size(kind);
        expression_t *res  = allocate_ast_zero(size);
 
-       res->base.type = type;
+       res->base.kind     = kind;
+       res->base.datatype = type_error_type;
        return res;
 }
 
-static size_t get_type_struct_size(type_type_t type)
+/**
+ * Returns the size of a type node.
+ *
+ * @param kind  the type kind
+ */
+static size_t get_type_struct_size(type_kind_t kind)
 {
        static const size_t sizes[] = {
                [TYPE_ATOMIC]          = sizeof(atomic_type_t),
+               [TYPE_BITFIELD]        = sizeof(bitfield_type_t),
                [TYPE_COMPOUND_STRUCT] = sizeof(compound_type_t),
                [TYPE_COMPOUND_UNION]  = sizeof(compound_type_t),
                [TYPE_ENUM]            = sizeof(enum_type_t),
@@ -227,22 +264,31 @@ static size_t get_type_struct_size(type_type_t type)
                [TYPE_TYPEOF]          = sizeof(typeof_type_t),
        };
        assert(sizeof(sizes) / sizeof(sizes[0]) == (int) TYPE_TYPEOF + 1);
-       assert(type <= TYPE_TYPEOF);
-       assert(sizes[type] != 0);
-       return sizes[type];
+       assert(kind <= TYPE_TYPEOF);
+       assert(sizes[kind] != 0);
+       return sizes[kind];
 }
 
-static type_t *allocate_type_zero(type_type_t type)
+/**
+ * Allocate a type node of given kind and initialize all
+ * fields with zero.
+ */
+static type_t *allocate_type_zero(type_kind_t kind)
 {
-       size_t  size = get_type_struct_size(type);
+       size_t  size = get_type_struct_size(kind);
        type_t *res  = obstack_alloc(type_obst, size);
        memset(res, 0, size);
 
-       res->base.type = type;
+       res->base.kind = kind;
        return res;
 }
 
-static size_t get_initializer_size(initializer_type_t type)
+/**
+ * Returns the size of an initializer node.
+ *
+ * @param kind  the initializer kind
+ */
+static size_t get_initializer_size(initializer_kind_t kind)
 {
        static const size_t sizes[] = {
                [INITIALIZER_VALUE]       = sizeof(initializer_value_t),
@@ -250,39 +296,51 @@ static size_t get_initializer_size(initializer_type_t type)
                [INITIALIZER_WIDE_STRING] = sizeof(initializer_wide_string_t),
                [INITIALIZER_LIST]        = sizeof(initializer_list_t)
        };
-       assert(type < sizeof(sizes) / sizeof(*sizes));
-       assert(sizes[type] != 0);
-       return sizes[type];
+       assert(kind < sizeof(sizes) / sizeof(*sizes));
+       assert(sizes[kind] != 0);
+       return sizes[kind];
 }
 
-static initializer_t *allocate_initializer(initializer_type_t type)
+/**
+ * Allocate an initializer node of given kind and initialize all
+ * fields with zero.
+ */
+static initializer_t *allocate_initializer_zero(initializer_kind_t kind)
 {
-       initializer_t *result = allocate_ast_zero(get_initializer_size(type));
-       result->type          = type;
+       initializer_t *result = allocate_ast_zero(get_initializer_size(kind));
+       result->kind          = kind;
 
        return result;
 }
 
+/**
+ * Free a type from the type obstack.
+ */
 static void free_type(void *type)
 {
        obstack_free(type_obst, type);
 }
 
 /**
- * returns the top element of the environment stack
+ * Returns the index of the top element of the environment stack.
  */
 static size_t environment_top(void)
 {
        return ARR_LEN(environment_stack);
 }
 
+/**
+ * Returns the index of the top element of the label stack.
+ */
 static size_t label_top(void)
 {
        return ARR_LEN(label_stack);
 }
 
 
-
+/**
+ * Return the next token.
+ */
 static inline void next_token(void)
 {
        token                              = lookahead_buffer[lookahead_bufpos];
@@ -297,6 +355,9 @@ static inline void next_token(void)
 #endif
 }
 
+/**
+ * Return the next token with a given lookahead.
+ */
 static inline const token_t *look_ahead(int num)
 {
        assert(num > 0 && num <= MAX_LOOKAHEAD);
@@ -306,121 +367,41 @@ static inline const token_t *look_ahead(int num)
 
 #define eat(token_type)  do { assert(token.type == token_type); next_token(); } while(0)
 
-static void error(void)
-{
-       found_error = true;
-#ifdef ABORT_ON_ERROR
-       abort();
-#endif
-}
-
-static void parser_print_prefix_pos(const source_position_t source_position)
-{
-    fputs(source_position.input_name, stderr);
-    fputc(':', stderr);
-    fprintf(stderr, "%u", source_position.linenr);
-    fputs(": ", stderr);
-}
-
-static void parser_print_error_prefix_pos(
-               const source_position_t source_position)
-{
-       parser_print_prefix_pos(source_position);
-       fputs("error: ", stderr);
-       error();
-}
-
-static void parser_print_error_prefix(void)
-{
-       parser_print_error_prefix_pos(token.source_position);
-}
-
-static void parse_error(const char *message)
-{
-       parser_print_error_prefix();
-       fprintf(stderr, "parse error: %s\n", message);
-}
-
-static void parser_print_warning_prefix_pos(
-               const source_position_t source_position)
-{
-       parser_print_prefix_pos(source_position);
-       fputs("warning: ", stderr);
-}
-
-static void parser_print_warning_prefix(void)
-{
-       parser_print_warning_prefix_pos(token.source_position);
-}
-
-static void parse_warning_pos(const source_position_t source_position,
-                              const char *const message)
-{
-       parser_print_prefix_pos(source_position);
-       fprintf(stderr, "warning: %s\n", message);
-}
-
-static void parse_warning(const char *message)
-{
-       parse_warning_pos(token.source_position, message);
-}
-
+/**
+ * Report a parse error because an expected token was not found.
+ */
 static void parse_error_expected(const char *message, ...)
 {
-       va_list args;
-       int first = 1;
-
        if(message != NULL) {
-               parser_print_error_prefix();
-               fprintf(stderr, "%s\n", message);
-       }
-       parser_print_error_prefix();
-       fputs("Parse error: got ", stderr);
-       print_token(stderr, &token);
-       fputs(", expected ", stderr);
-
-       va_start(args, message);
-       token_type_t token_type = va_arg(args, token_type_t);
-       while(token_type != 0) {
-               if(first == 1) {
-                       first = 0;
-               } else {
-                       fprintf(stderr, ", ");
-               }
-               print_token_type(stderr, token_type);
-               token_type = va_arg(args, token_type_t);
+               errorf(HERE, "%s", message);
        }
-       va_end(args);
-       fprintf(stderr, "\n");
-}
-
-static void print_type_quoted(type_t *type)
-{
-       fputc('\'', stderr);
-       print_type(type);
-       fputc('\'', stderr);
+       va_list ap;
+       va_start(ap, message);
+       errorf(HERE, "got '%K', expected %#k", &token, &ap, ", ");
+       va_end(ap);
 }
 
+/**
+ * Report a type error.
+ */
 static void type_error(const char *msg, const source_position_t source_position,
                        type_t *type)
 {
-       parser_print_error_prefix_pos(source_position);
-       fprintf(stderr, "%s, but found type ", msg);
-       print_type_quoted(type);
-       fputc('\n', stderr);
+       errorf(source_position, "%s, but found type '%T'", msg, type);
 }
 
+/**
+ * Report an incompatible type.
+ */
 static void type_error_incompatible(const char *msg,
                const source_position_t source_position, type_t *type1, type_t *type2)
 {
-       parser_print_error_prefix_pos(source_position);
-       fprintf(stderr, "%s, incompatible types: ", msg);
-       print_type_quoted(type1);
-       fprintf(stderr, " - ");
-       print_type_quoted(type2);
-       fprintf(stderr, ")\n");
+       errorf(source_position, "%s, incompatible types: '%T' - '%T'", msg, type1, type2);
 }
 
+/**
+ * Eat an complete block, ie. '{ ... }'.
+ */
 static void eat_block(void)
 {
        if(token.type == '{')
@@ -438,6 +419,9 @@ static void eat_block(void)
        eat('}');
 }
 
+/**
+ * Eat a statement until an ';' token.
+ */
 static void eat_statement(void)
 {
        while(token.type != ';') {
@@ -454,6 +438,9 @@ static void eat_statement(void)
        eat(';');
 }
 
+/**
+ * Eat a parenthesed term, ie. '( ... )'.
+ */
 static void eat_paren(void)
 {
        if(token.type == '(')
@@ -502,11 +489,11 @@ static void eat_paren(void)
     }                                              \
     next_token();
 
-static void set_context(context_t *new_context)
+static void set_scope(scope_t *new_scope)
 {
-       context = new_context;
+       scope = new_scope;
 
-       last_declaration = new_context->declarations;
+       last_declaration = new_scope->declarations;
        if(last_declaration != NULL) {
                while(last_declaration->next != NULL) {
                        last_declaration = last_declaration->next;
@@ -515,25 +502,10 @@ static void set_context(context_t *new_context)
 }
 
 /**
- * called when we find a 2nd declarator for an identifier we already have a
- * declarator for
+ * Search a symbol in a given namespace and returns its declaration or
+ * NULL if this symbol was not found.
  */
-static bool is_compatible_declaration(declaration_t *declaration,
-                                      declaration_t *previous)
-{
-       /* happens for K&R style function parameters */
-       if(previous->type == NULL) {
-               previous->type = declaration->type;
-               return true;
-       }
-
-       type_t *type1 = skip_typeref(declaration->type);
-       type_t *type2 = skip_typeref(previous->type);
-
-       return types_compatible(type1, type2);
-}
-
-static declaration_t *get_declaration(symbol_t *symbol, namespace_t namespc)
+static declaration_t *get_declaration(const symbol_t *const symbol, const namespace_t namespc)
 {
        declaration_t *declaration = symbol->declaration;
        for( ; declaration != NULL; declaration = declaration->symbol_next) {
@@ -544,105 +516,15 @@ static declaration_t *get_declaration(symbol_t *symbol, namespace_t namespc)
        return NULL;
 }
 
-static const char *get_namespace_prefix(namespace_t namespc)
-{
-       switch(namespc) {
-       case NAMESPACE_NORMAL:
-               return "";
-       case NAMESPACE_UNION:
-               return "union ";
-       case NAMESPACE_STRUCT:
-               return "struct ";
-       case NAMESPACE_ENUM:
-               return "enum ";
-       case NAMESPACE_LABEL:
-               return "label ";
-       }
-       panic("invalid namespace found");
-}
-
 /**
  * pushs an environment_entry on the environment stack and links the
  * corresponding symbol to the new entry
  */
-static declaration_t *stack_push(stack_entry_t **stack_ptr,
-                                 declaration_t *declaration,
-                                 context_t *parent_context)
+static void stack_push(stack_entry_t **stack_ptr, declaration_t *declaration)
 {
        symbol_t    *symbol    = declaration->symbol;
        namespace_t  namespc = (namespace_t)declaration->namespc;
 
-       /* a declaration should be only pushed once */
-       declaration->parent_context = parent_context;
-
-       declaration_t *previous_declaration = get_declaration(symbol, namespc);
-       assert(declaration != previous_declaration);
-       if(previous_declaration != NULL
-                       && previous_declaration->parent_context == context) {
-               if(!is_compatible_declaration(declaration, previous_declaration)) {
-                       parser_print_error_prefix_pos(declaration->source_position);
-                       fprintf(stderr, "definition of symbol '%s%s' with type ",
-                                       get_namespace_prefix(namespc), symbol->string);
-                       print_type_quoted(declaration->type);
-                       fputc('\n', stderr);
-                       parser_print_error_prefix_pos(
-                                       previous_declaration->source_position);
-                       fprintf(stderr, "is incompatible with previous declaration "
-                                       "of type ");
-                       print_type_quoted(previous_declaration->type);
-                       fputc('\n', stderr);
-               } else {
-                       unsigned old_storage_class = previous_declaration->storage_class;
-                       unsigned new_storage_class = declaration->storage_class;
-                       if (current_function == NULL) {
-                               if (old_storage_class != STORAGE_CLASS_STATIC &&
-                                   new_storage_class == STORAGE_CLASS_STATIC) {
-                                       parser_print_error_prefix_pos(declaration->source_position);
-                                       fprintf(stderr,
-                                               "static declaration of '%s' follows non-static declaration\n",
-                                               symbol->string);
-                                       parser_print_error_prefix_pos(previous_declaration->source_position);
-                                       fprintf(stderr, "previous declaration of '%s' was here\n",
-                                               symbol->string);
-                               } else {
-                                       if (old_storage_class == STORAGE_CLASS_EXTERN) {
-                                               if (new_storage_class == STORAGE_CLASS_NONE) {
-                                                       previous_declaration->storage_class = STORAGE_CLASS_NONE;
-                                               }
-                                       } else {
-                                               parser_print_warning_prefix_pos(declaration->source_position);
-                                               fprintf(stderr, "redundant declaration for '%s'\n",
-                                                                               symbol->string);
-                                               parser_print_warning_prefix_pos(previous_declaration->source_position);
-                                               fprintf(stderr, "previous declaration of '%s' was here\n",
-                                                                               symbol->string);
-                                       }
-                               }
-                       } else {
-                               if (old_storage_class == STORAGE_CLASS_EXTERN &&
-                                               new_storage_class == STORAGE_CLASS_EXTERN) {
-                                       parser_print_warning_prefix_pos(declaration->source_position);
-                                       fprintf(stderr, "redundant extern declaration for '%s'\n",
-                                               symbol->string);
-                                       parser_print_warning_prefix_pos(previous_declaration->source_position);
-                                       fprintf(stderr, "previous declaration of '%s' was here\n",
-                                               symbol->string);
-                               } else {
-                                       parser_print_error_prefix_pos(declaration->source_position);
-                                       if (old_storage_class == new_storage_class) {
-                                               fprintf(stderr, "redeclaration of '%s'\n", symbol->string);
-                                       } else {
-                                               fprintf(stderr, "redeclaration of '%s' with different linkage\n", symbol->string);
-                                       }
-                                       parser_print_error_prefix_pos(previous_declaration->source_position);
-                                       fprintf(stderr, "previous declaration of '%s' was here\n",
-                                               symbol->string);
-                               }
-                       }
-               }
-               return previous_declaration;
-       }
-
        /* remember old declaration */
        stack_entry_t entry;
        entry.symbol          = symbol;
@@ -673,19 +555,19 @@ static declaration_t *stack_push(stack_entry_t **stack_ptr,
                        iter_last->symbol_next = declaration;
                }
        }
-
-       return declaration;
 }
 
-static declaration_t *environment_push(declaration_t *declaration)
+static void environment_push(declaration_t *declaration)
 {
        assert(declaration->source_position.input_name != NULL);
-       return stack_push(&environment_stack, declaration, context);
+       assert(declaration->parent_scope != NULL);
+       stack_push(&environment_stack, declaration);
 }
 
-static declaration_t *label_push(declaration_t *declaration)
+static void label_push(declaration_t *declaration)
 {
-       return stack_push(&label_stack, declaration, &current_function->context);
+       declaration->parent_scope = &current_function->scope;
+       stack_push(&label_stack, declaration);
 }
 
 /**
@@ -752,26 +634,33 @@ static int get_rank(const type_t *type)
        assert(!is_typeref(type));
        /* The C-standard allows promoting to int or unsigned int (see Â§ 7.2.2
         * and esp. footnote 108). However we can't fold constants (yet), so we
-        * can't decide wether unsigned int is possible, while int always works.
+        * can't decide whether unsigned int is possible, while int always works.
         * (unsigned int would be preferable when possible... for stuff like
         *  struct { enum { ... } bla : 4; } ) */
-       if(type->type == TYPE_ENUM)
+       if(type->kind == TYPE_ENUM)
                return ATOMIC_TYPE_INT;
 
-       assert(type->type == TYPE_ATOMIC);
-       const atomic_type_t *atomic_type = &type->atomic;
-       atomic_type_type_t   atype       = atomic_type->atype;
-       return atype;
+       assert(type->kind == TYPE_ATOMIC);
+       return type->atomic.akind;
 }
 
 static type_t *promote_integer(type_t *type)
 {
+       if(type->kind == TYPE_BITFIELD)
+               type = type->bitfield.base;
+
        if(get_rank(type) < ATOMIC_TYPE_INT)
                type = type_int;
 
        return type;
 }
 
+/**
+ * Create a cast expression.
+ *
+ * @param expression  the expression to cast
+ * @param dest_type   the destination type
+ */
 static expression_t *create_cast_expression(expression_t *expression,
                                             type_t *dest_type)
 {
@@ -783,17 +672,20 @@ static expression_t *create_cast_expression(expression_t *expression,
        return cast;
 }
 
+/**
+ * Check if a given expression represents the 0 pointer constant.
+ */
 static bool is_null_pointer_constant(const expression_t *expression)
 {
        /* skip void* cast */
-       if(expression->type == EXPR_UNARY_CAST
-                       || expression->type == EXPR_UNARY_CAST_IMPLICIT) {
+       if(expression->kind == EXPR_UNARY_CAST
+                       || expression->kind == EXPR_UNARY_CAST_IMPLICIT) {
                expression = expression->unary.value;
        }
 
        /* TODO: not correct yet, should be any constant integer expression
         * which evaluates to 0 */
-       if (expression->type != EXPR_CONST)
+       if (expression->kind != EXPR_CONST)
                return false;
 
        type_t *const type = skip_typeref(expression->base.datatype);
@@ -803,117 +695,49 @@ static bool is_null_pointer_constant(const expression_t *expression)
        return expression->conste.v.int_value == 0;
 }
 
+/**
+ * Create an implicit cast expression.
+ *
+ * @param expression  the expression to cast
+ * @param dest_type   the destination type
+ */
 static expression_t *create_implicit_cast(expression_t *expression,
                                           type_t *dest_type)
 {
-       type_t *source_type = expression->base.datatype;
-
-       if(source_type == NULL)
-               return expression;
-
-       source_type = skip_typeref(source_type);
-       dest_type   = skip_typeref(dest_type);
+       type_t *const source_type = expression->base.datatype;
 
-       if(source_type == dest_type)
+       if (source_type == dest_type)
                return expression;
 
-       switch (dest_type->type) {
-               case TYPE_ENUM:
-                       /* TODO warning for implicitly converting to enum */
-               case TYPE_ATOMIC:
-                       if (source_type->type != TYPE_ATOMIC &&
-                                       source_type->type != TYPE_ENUM) {
-                               panic("casting of non-atomic types not implemented yet");
-                       }
-
-                       if(is_type_floating(dest_type) && !is_type_scalar(source_type)) {
-                               type_error_incompatible("can't cast types",
-                                               expression->base.source_position, source_type,
-                                               dest_type);
-                               return expression;
-                       }
-
-                       return create_cast_expression(expression, dest_type);
-
-               case TYPE_POINTER:
-                       switch (source_type->type) {
-                               case TYPE_ATOMIC:
-                                       if (is_null_pointer_constant(expression)) {
-                                               return create_cast_expression(expression, dest_type);
-                                       }
-                                       break;
-
-                               case TYPE_POINTER:
-                                       if (pointers_compatible(source_type, dest_type)) {
-                                               return create_cast_expression(expression, dest_type);
-                                       }
-                                       break;
-
-                               case TYPE_ARRAY: {
-                                       array_type_t   *array_type   = &source_type->array;
-                                       pointer_type_t *pointer_type = &dest_type->pointer;
-                                       if (types_compatible(array_type->element_type,
-                                                                                pointer_type->points_to)) {
-                                               return create_cast_expression(expression, dest_type);
-                                       }
-                                       break;
-                               }
-
-                               default:
-                                       panic("casting of non-atomic types not implemented yet");
-                       }
-
-                       type_error_incompatible("can't implicitly cast types",
-                                       expression->base.source_position, source_type, dest_type);
-                       return expression;
-
-               default:
-                       panic("casting of non-atomic types not implemented yet");
-       }
+       return create_cast_expression(expression, dest_type);
 }
 
 /** Implements the rules from Â§ 6.5.16.1 */
-static void semantic_assign(type_t *orig_type_left, expression_t **right,
+static type_t *semantic_assign(type_t *orig_type_left,
+                            const expression_t *const right,
                             const char *context)
 {
-       type_t *orig_type_right = (*right)->base.datatype;
-
-       if(orig_type_right == NULL)
-               return;
-
-       type_t *const type_left  = skip_typeref(orig_type_left);
-       type_t *const type_right = skip_typeref(orig_type_right);
+       type_t *const orig_type_right = right->base.datatype;
+       type_t *const type_left       = skip_typeref(orig_type_left);
+       type_t *const type_right      = skip_typeref(orig_type_right);
 
        if ((is_type_arithmetic(type_left) && is_type_arithmetic(type_right)) ||
-           (is_type_pointer(type_left) && is_null_pointer_constant(*right)) ||
+           (is_type_pointer(type_left) && is_null_pointer_constant(right)) ||
            (is_type_atomic(type_left, ATOMIC_TYPE_BOOL)
                && is_type_pointer(type_right))) {
-               *right = create_implicit_cast(*right, type_left);
-               return;
+               return orig_type_left;
        }
 
        if (is_type_pointer(type_left) && is_type_pointer(type_right)) {
-               pointer_type_t *pointer_type_left  = &type_left->pointer;
-               pointer_type_t *pointer_type_right = &type_right->pointer;
-               type_t         *points_to_left     = pointer_type_left->points_to;
-               type_t         *points_to_right    = pointer_type_right->points_to;
-
-               points_to_left  = skip_typeref(points_to_left);
-               points_to_right = skip_typeref(points_to_right);
+               type_t *points_to_left  = skip_typeref(type_left->pointer.points_to);
+               type_t *points_to_right = skip_typeref(type_right->pointer.points_to);
 
                /* the left type has all qualifiers from the right type */
                unsigned missing_qualifiers
                        = points_to_right->base.qualifiers & ~points_to_left->base.qualifiers;
                if(missing_qualifiers != 0) {
-                       parser_print_error_prefix();
-                       fprintf(stderr, "destination type ");
-                       print_type_quoted(type_left);
-                       fprintf(stderr, " in %s from type ", context);
-                       print_type_quoted(type_right);
-                       fprintf(stderr, " lacks qualifiers '");
-                       print_type_qualifiers(missing_qualifiers);
-                       fprintf(stderr, "' in pointed-to type\n");
-                       return;
+                       errorf(HERE, "destination type '%T' in %s from type '%T' lacks qualifiers '%Q' in pointed-to type", type_left, context, type_right, missing_qualifiers);
+                       return orig_type_left;
                }
 
                points_to_left  = get_unqualified_type(points_to_left);
@@ -922,34 +746,39 @@ static void semantic_assign(type_t *orig_type_left, expression_t **right,
                if(!is_type_atomic(points_to_left, ATOMIC_TYPE_VOID)
                                && !is_type_atomic(points_to_right, ATOMIC_TYPE_VOID)
                                && !types_compatible(points_to_left, points_to_right)) {
-                       goto incompatible_assign_types;
+                       return NULL;
                }
 
-               *right = create_implicit_cast(*right, type_left);
-               return;
+               return orig_type_left;
        }
 
-       if (is_type_compound(type_left)
-                       && types_compatible(type_left, type_right)) {
-               *right = create_implicit_cast(*right, type_left);
-               return;
+       if (is_type_compound(type_left)  && is_type_compound(type_right)) {
+               type_t *const unqual_type_left  = get_unqualified_type(type_left);
+               type_t *const unqual_type_right = get_unqualified_type(type_right);
+               if (types_compatible(unqual_type_left, unqual_type_right)) {
+                       return orig_type_left;
+               }
        }
 
-incompatible_assign_types:
-       /* TODO: improve error message */
-       parser_print_error_prefix();
-       fprintf(stderr, "incompatible types in %s\n", context);
-       parser_print_error_prefix();
-       print_type_quoted(orig_type_left);
-       fputs(" <- ", stderr);
-       print_type_quoted(orig_type_right);
-       fputs("\n", stderr);
+       if (!is_type_valid(type_left))
+               return type_left;
+
+       if (!is_type_valid(type_right))
+               return orig_type_right;
+
+       return NULL;
 }
 
 static expression_t *parse_constant_expression(void)
 {
        /* start parsing at precedence 7 (conditional expression) */
-       return parse_sub_expression(7);
+       expression_t *result = parse_sub_expression(7);
+
+       if(!is_constant_expression(result)) {
+               errorf(result->base.source_position, "expression '%E' is not constant\n", result);
+       }
+
+       return result;
 }
 
 static expression_t *parse_assignment_expression(void)
@@ -960,9 +789,9 @@ static expression_t *parse_assignment_expression(void)
 
 static type_t *make_global_typedef(const char *name, type_t *type)
 {
-       symbol_t *symbol       = symbol_table_insert(name);
+       symbol_t *const symbol       = symbol_table_insert(name);
 
-       declaration_t *declaration   = allocate_ast_zero(sizeof(declaration[0]));
+       declaration_t *const declaration = allocate_declaration_zero();
        declaration->namespc         = NAMESPACE_NORMAL;
        declaration->storage_class   = STORAGE_CLASS_TYPEDEF;
        declaration->type            = type;
@@ -977,15 +806,15 @@ static type_t *make_global_typedef(const char *name, type_t *type)
        return typedef_type;
 }
 
-static const char *parse_string_literals(void)
+static string_t parse_string_literals(void)
 {
        assert(token.type == T_STRING_LITERAL);
-       const char *result = token.v.string;
+       string_t result = token.v.string;
 
        next_token();
 
-       while(token.type == T_STRING_LITERAL) {
-               result = concat_strings(result, token.v.string);
+       while (token.type == T_STRING_LITERAL) {
+               result = concat_strings(&result, &token.v.string);
                next_token();
        }
 
@@ -1004,7 +833,7 @@ static void parse_attributes(void)
                        while(depth > 0) {
                                switch(token.type) {
                                case T_EOF:
-                                       parse_error("EOF while parsing attribute");
+                                       errorf(HERE, "EOF while parsing attribute");
                                        break;
                                case '(':
                                        next_token();
@@ -1088,13 +917,13 @@ static designator_t *parse_designation(void)
 #endif
 
 static initializer_t *initializer_from_string(array_type_t *type,
-                                              const char *string)
+                                              const string_t *const string)
 {
        /* TODO: check len vs. size of array type */
        (void) type;
 
-       initializer_t *initializer = allocate_initializer(INITIALIZER_STRING);
-       initializer->string.string = string;
+       initializer_t *initializer = allocate_initializer_zero(INITIALIZER_STRING);
+       initializer->string.string = *string;
 
        return initializer;
 }
@@ -1106,7 +935,7 @@ static initializer_t *initializer_from_wide_string(array_type_t *const type,
        (void) type;
 
        initializer_t *const initializer =
-               allocate_initializer(INITIALIZER_WIDE_STRING);
+               allocate_initializer_zero(INITIALIZER_WIDE_STRING);
        initializer->wide_string.string = *string;
 
        return initializer;
@@ -1119,16 +948,16 @@ static initializer_t *initializer_from_expression(type_t *type,
 
        /* Â§ 6.7.8.14/15 char array may be initialized by string literals */
        type_t *const expr_type = expression->base.datatype;
-       if (is_type_array(type) && expr_type->type == TYPE_POINTER) {
-               array_type_t *const array_type     = &type->array;
-               type_t       *const element_type   = skip_typeref(array_type->element_type);
+       if (is_type_array(type) && expr_type->kind == TYPE_POINTER) {
+               array_type_t *const array_type   = &type->array;
+               type_t       *const element_type = skip_typeref(array_type->element_type);
 
-               if (element_type->type == TYPE_ATOMIC) {
-                       switch (expression->type) {
+               if (element_type->kind == TYPE_ATOMIC) {
+                       switch (expression->kind) {
                                case EXPR_STRING_LITERAL:
-                                       if (element_type->atomic.atype == ATOMIC_TYPE_CHAR) {
+                                       if (element_type->atomic.akind == ATOMIC_TYPE_CHAR) {
                                                return initializer_from_string(array_type,
-                                                       expression->string.value);
+                                                       &expression->string.value);
                                        }
 
                                case EXPR_WIDE_STRING_LITERAL: {
@@ -1139,55 +968,67 @@ static initializer_t *initializer_from_expression(type_t *type,
                                        }
                                }
 
-                               default: break;
+                               default:
+                                       break;
                        }
                }
        }
 
-       type_t *expression_type = skip_typeref(expression->base.datatype);
-       if(is_type_scalar(type) || types_compatible(type, expression_type)) {
-               semantic_assign(type, &expression, "initializer");
-
-               initializer_t *result = allocate_initializer(INITIALIZER_VALUE);
-               result->value.value   = expression;
+       type_t *const res_type = semantic_assign(type, expression, "initializer");
+       if (res_type == NULL)
+               return NULL;
 
-               return result;
-       }
+       initializer_t *const result = allocate_initializer_zero(INITIALIZER_VALUE);
+       result->value.value = create_implicit_cast(expression, res_type);
 
-       return NULL;
+       return result;
 }
 
 static initializer_t *parse_sub_initializer(type_t *type,
-                                            expression_t *expression,
-                                            type_t *expression_type);
+                                            expression_t *expression);
 
 static initializer_t *parse_sub_initializer_elem(type_t *type)
 {
        if(token.type == '{') {
-               return parse_sub_initializer(type, NULL, NULL);
+               return parse_sub_initializer(type, NULL);
        }
 
-       expression_t *expression      = parse_assignment_expression();
-       type_t       *expression_type = skip_typeref(expression->base.datatype);
-
-       return parse_sub_initializer(type, expression, expression_type);
+       expression_t *expression = parse_assignment_expression();
+       return parse_sub_initializer(type, expression);
 }
 
 static bool had_initializer_brace_warning;
 
+static void skip_designator(void)
+{
+       while(1) {
+               if(token.type == '.') {
+                       next_token();
+                       if(token.type == T_IDENTIFIER)
+                               next_token();
+               } else if(token.type == '[') {
+                       next_token();
+                       parse_constant_expression();
+                       if(token.type == ']')
+                               next_token();
+               } else {
+                       break;
+               }
+       }
+}
+
 static initializer_t *parse_sub_initializer(type_t *type,
-                                            expression_t *expression,
-                                            type_t *expression_type)
+                                            expression_t *expression)
 {
        if(is_type_scalar(type)) {
                /* there might be extra {} hierarchies */
                if(token.type == '{') {
                        next_token();
                        if(!had_initializer_brace_warning) {
-                               parse_warning("braces around scalar initializer");
+                               warningf(HERE, "braces around scalar initializer");
                                had_initializer_brace_warning = true;
                        }
-                       initializer_t *result = parse_sub_initializer(type, NULL, NULL);
+                       initializer_t *result = parse_sub_initializer(type, NULL);
                        if(token.type == ',') {
                                next_token();
                                /* TODO: warn about excessive elements */
@@ -1202,7 +1043,7 @@ static initializer_t *parse_sub_initializer(type_t *type,
                return initializer_from_expression(type, expression);
        }
 
-       /* does the expression match the currently looked at object to initalize */
+       /* does the expression match the currently looked at object to initialize */
        if(expression != NULL) {
                initializer_t *result = initializer_from_expression(type, expression);
                if(result != NULL)
@@ -1219,17 +1060,21 @@ static initializer_t *parse_sub_initializer(type_t *type,
        initializer_t  *result = NULL;
        initializer_t **elems;
        if(is_type_array(type)) {
-               array_type_t *array_type   = &type->array;
-               type_t       *element_type = array_type->element_type;
-               element_type               = skip_typeref(element_type);
+               if(token.type == '.') {
+                       errorf(HERE,
+                              "compound designator in initializer for array type '%T'",
+                              type);
+                       skip_designator();
+               }
+
+               type_t *const element_type = skip_typeref(type->array.element_type);
 
                initializer_t *sub;
                had_initializer_brace_warning = false;
                if(expression == NULL) {
                        sub = parse_sub_initializer_elem(element_type);
                } else {
-                       sub = parse_sub_initializer(element_type, expression,
-                                                   expression_type);
+                       sub = parse_sub_initializer(element_type, expression);
                }
 
                /* didn't match the subtypes -> try the parent type */
@@ -1251,7 +1096,7 @@ static initializer_t *parse_sub_initializer(type_t *type,
                        sub = parse_sub_initializer_elem(element_type);
                        if(sub == NULL) {
                                /* TODO error, do nicer cleanup */
-                               parse_error("member initializer didn't match");
+                               errorf(HERE, "member initializer didn't match");
                                DEL_ARR_F(elems);
                                return NULL;
                        }
@@ -1259,10 +1104,16 @@ static initializer_t *parse_sub_initializer(type_t *type,
                }
        } else {
                assert(is_type_compound(type));
-               compound_type_t *compound_type = &type->compound;
-               context_t       *context       = &compound_type->declaration->context;
+               scope_t *const scope = &type->compound.declaration->scope;
 
-               declaration_t *first = context->declarations;
+               if(token.type == '[') {
+                       errorf(HERE,
+                              "array designator in initializer for compound type '%T'",
+                              type);
+                       skip_designator();
+               }
+
+               declaration_t *first = scope->declarations;
                if(first == NULL)
                        return NULL;
                type_t *first_type = first->type;
@@ -1273,7 +1124,7 @@ static initializer_t *parse_sub_initializer(type_t *type,
                if(expression == NULL) {
                        sub = parse_sub_initializer_elem(first_type);
                } else {
-                       sub = parse_sub_initializer(first_type, expression,expression_type);
+                       sub = parse_sub_initializer(first_type, expression);
                }
 
                /* didn't match the subtypes -> try our parent type */
@@ -1303,8 +1154,8 @@ static initializer_t *parse_sub_initializer(type_t *type,
 
                        sub = parse_sub_initializer_elem(iter_type);
                        if(sub == NULL) {
-                               /* TODO error, do nicer cleanup*/
-                               parse_error("member initializer didn't match");
+                               /* TODO error, do nicer cleanup */
+                               errorf(HERE, "member initializer didn't match");
                                DEL_ARR_F(elems);
                                return NULL;
                        }
@@ -1317,7 +1168,7 @@ static initializer_t *parse_sub_initializer(type_t *type,
 
        initializer_list_t *init = allocate_ast_zero(sizeof(init[0]) + elems_size);
 
-       init->initializer.type = INITIALIZER_LIST;
+       init->initializer.kind = INITIALIZER_LIST;
        init->len              = len;
        memcpy(init->initializers, elems, elems_size);
        DEL_ARR_F(elems);
@@ -1332,24 +1183,19 @@ static initializer_t *parse_sub_initializer(type_t *type,
        return result;
 }
 
-static initializer_t *parse_initializer(type_t *type)
+static initializer_t *parse_initializer(type_t *const orig_type)
 {
        initializer_t *result;
 
-       type = skip_typeref(type);
+       type_t *const type = skip_typeref(orig_type);
 
        if(token.type != '{') {
                expression_t  *expression  = parse_assignment_expression();
                initializer_t *initializer = initializer_from_expression(type, expression);
                if(initializer == NULL) {
-                       parser_print_error_prefix();
-                       fprintf(stderr, "initializer expression '");
-                       print_expression(expression);
-                       fprintf(stderr, "', type ");
-                       print_type_quoted(expression->base.datatype);
-                       fprintf(stderr, " is incompatible with type ");
-                       print_type_quoted(type);
-                       fprintf(stderr, "\n");
+                       errorf(HERE,
+                               "initializer expression '%E' of type '%T' is incompatible with type '%T'",
+                               expression, expression->base.datatype, orig_type);
                }
                return initializer;
        }
@@ -1367,13 +1213,13 @@ static initializer_t *parse_initializer(type_t *type)
                expect('}');
                return result;
        } else {
-               result = parse_sub_initializer(type, NULL, NULL);
+               result = parse_sub_initializer(type, NULL);
        }
 
        return result;
 }
 
-
+static declaration_t *append_declaration(declaration_t *declaration);
 
 static declaration_t *parse_compound_type_specifier(bool is_struct)
 {
@@ -1413,63 +1259,62 @@ static declaration_t *parse_compound_type_specifier(bool is_struct)
        }
 
        if(declaration == NULL) {
-               declaration = allocate_ast_zero(sizeof(declaration[0]));
-
-               if(is_struct) {
-                       declaration->namespc = NAMESPACE_STRUCT;
-               } else {
-                       declaration->namespc = NAMESPACE_UNION;
-               }
+               declaration = allocate_declaration_zero();
+               declaration->namespc         =
+                       (is_struct ? NAMESPACE_STRUCT : NAMESPACE_UNION);
                declaration->source_position = token.source_position;
                declaration->symbol          = symbol;
-               record_declaration(declaration);
+               declaration->parent_scope  = scope;
+               if (symbol != NULL) {
+                       environment_push(declaration);
+               }
+               append_declaration(declaration);
        }
 
        if(token.type == '{') {
                if(declaration->init.is_defined) {
                        assert(symbol != NULL);
-                       parser_print_error_prefix();
-                       fprintf(stderr, "multiple definition of %s %s\n",
-                                       is_struct ? "struct" : "union", symbol->string);
-                       declaration->context.declarations = NULL;
+                       errorf(HERE, "multiple definition of '%s %Y'",
+                              is_struct ? "struct" : "union", symbol);
+                       declaration->scope.declarations = NULL;
                }
                declaration->init.is_defined = true;
 
-               int         top          = environment_top();
-               context_t  *last_context = context;
-               set_context(&declaration->context);
+               int       top        = environment_top();
+               scope_t  *last_scope = scope;
+               set_scope(&declaration->scope);
 
                parse_compound_type_entries();
                parse_attributes();
 
-               assert(context == &declaration->context);
-               set_context(last_context);
+               assert(scope == &declaration->scope);
+               set_scope(last_scope);
                environment_pop_to(top);
        }
 
        return declaration;
 }
 
-static void parse_enum_entries(enum_type_t *const enum_type)
+static void parse_enum_entries(type_t *const enum_type)
 {
        eat('{');
 
        if(token.type == '}') {
                next_token();
-               parse_error("empty enum not allowed");
+               errorf(HERE, "empty enum not allowed");
                return;
        }
 
        do {
-               declaration_t *entry = allocate_ast_zero(sizeof(entry[0]));
-
                if(token.type != T_IDENTIFIER) {
                        parse_error_expected("while parsing enum entry", T_IDENTIFIER, 0);
                        eat_block();
                        return;
                }
+
+               declaration_t *const entry = allocate_declaration_zero();
                entry->storage_class   = STORAGE_CLASS_ENUM_ENTRY;
-               entry->type            = (type_t*) enum_type;
+               entry->type            = enum_type;
                entry->symbol          = token.v.symbol;
                entry->source_position = token.source_position;
                next_token();
@@ -1513,11 +1358,11 @@ static type_t *parse_enum_specifier(void)
        }
 
        if(declaration == NULL) {
-               declaration = allocate_ast_zero(sizeof(declaration[0]));
-
-               declaration->namespc       = NAMESPACE_ENUM;
+               declaration = allocate_declaration_zero();
+               declaration->namespc         = NAMESPACE_ENUM;
                declaration->source_position = token.source_position;
                declaration->symbol          = symbol;
+               declaration->parent_scope  = scope;
        }
 
        type_t *const type      = allocate_type_zero(TYPE_ENUM);
@@ -1525,14 +1370,15 @@ static type_t *parse_enum_specifier(void)
 
        if(token.type == '{') {
                if(declaration->init.is_defined) {
-                       parser_print_error_prefix();
-                       fprintf(stderr, "multiple definitions of enum %s\n",
-                               symbol->string);
+                       errorf(HERE, "multiple definitions of enum %Y", symbol);
                }
-               record_declaration(declaration);
+               if (symbol != NULL) {
+                       environment_push(declaration);
+               }
+               append_declaration(declaration);
                declaration->init.is_defined = 1;
 
-               parse_enum_entries(&type->enumt);
+               parse_enum_entries(type);
                parse_attributes();
        }
 
@@ -1661,8 +1507,7 @@ static void parse_declaration_specifiers(declaration_specifiers_t *specifiers)
 #define MATCH_STORAGE_CLASS(token, class)                                \
                case token:                                                      \
                        if(specifiers->storage_class != STORAGE_CLASS_NONE) {        \
-                               parse_error("multiple storage classes in declaration "   \
-                                           "specifiers");                               \
+                               errorf(HERE, "multiple storage classes in declaration specifiers"); \
                        }                                                            \
                        specifiers->storage_class = class;                           \
                        next_token();                                                \
@@ -1689,7 +1534,7 @@ static void parse_declaration_specifiers(declaration_specifiers_t *specifiers)
                                        break;
 
                                default:
-                                       parse_error("multiple storage classes in declaration specifiers");
+                                       errorf(HERE, "multiple storage classes in declaration specifiers");
                                        break;
                        }
                        next_token();
@@ -1716,7 +1561,7 @@ static void parse_declaration_specifiers(declaration_specifiers_t *specifiers)
                case token:                                                     \
                        next_token();                                               \
                        if(type_specifiers & specifier) {                           \
-                               parse_error("multiple " name " type specifiers given"); \
+                               errorf(HERE, "multiple " name " type specifiers given"); \
                        } else {                                                    \
                                type_specifiers |= specifier;                           \
                        }                                                           \
@@ -1735,6 +1580,10 @@ static void parse_declaration_specifiers(declaration_specifiers_t *specifiers)
                MATCH_SPECIFIER(T__Complex,   SPECIFIER_COMPLEX,   "_Complex")
                MATCH_SPECIFIER(T__Imaginary, SPECIFIER_IMAGINARY, "_Imaginary")
 #endif
+               case T_forceinline:
+                       /* only in microsoft mode */
+                       specifiers->decl_modifiers |= DM_FORCEINLINE;
+
                case T_inline:
                        next_token();
                        specifiers->is_inline = true;
@@ -1743,7 +1592,7 @@ static void parse_declaration_specifiers(declaration_specifiers_t *specifiers)
                case T_long:
                        next_token();
                        if(type_specifiers & SPECIFIER_LONG_LONG) {
-                               parse_error("multiple type specifiers given");
+                               errorf(HERE, "multiple type specifiers given");
                        } else if(type_specifiers & SPECIFIER_LONG) {
                                type_specifiers |= SPECIFIER_LONG_LONG;
                        } else {
@@ -1751,7 +1600,7 @@ static void parse_declaration_specifiers(declaration_specifiers_t *specifiers)
                        }
                        break;
 
-               /* TODO: if type != NULL for the following rules should issue
+               /* TODO: if is_type_valid(type) for the following rules should issue
                 * an error */
                case T_struct: {
                        type = allocate_type_zero(TYPE_COMPOUND_STRUCT);
@@ -1801,7 +1650,7 @@ static void parse_declaration_specifiers(declaration_specifiers_t *specifiers)
 finish_specifiers:
 
        if(type == NULL) {
-               atomic_type_type_t atomic_type;
+               atomic_type_kind_t atomic_type;
 
                /* match valid basic types */
                switch(type_specifiers) {
@@ -1893,30 +1742,32 @@ finish_specifiers:
                default:
                        /* invalid specifier combination, give an error message */
                        if(type_specifiers == 0) {
-#ifndef STRICT_C99
-                               parse_warning("no type specifiers in declaration, using int");
-                               atomic_type = ATOMIC_TYPE_INT;
-                               break;
-#else
-                               parse_error("no type specifiers given in declaration");
-#endif
+                               if (! strict_mode) {
+                                       if (warning.implicit_int) {
+                                               warningf(HERE, "no type specifiers in declaration, using 'int'");
+                                       }
+                                       atomic_type = ATOMIC_TYPE_INT;
+                                       break;
+                               } else {
+                                       errorf(HERE, "no type specifiers given in declaration");
+                               }
                        } else if((type_specifiers & SPECIFIER_SIGNED) &&
                                  (type_specifiers & SPECIFIER_UNSIGNED)) {
-                               parse_error("signed and unsigned specifiers gives");
+                               errorf(HERE, "signed and unsigned specifiers gives");
                        } else if(type_specifiers & (SPECIFIER_SIGNED | SPECIFIER_UNSIGNED)) {
-                               parse_error("only integer types can be signed or unsigned");
+                               errorf(HERE, "only integer types can be signed or unsigned");
                        } else {
-                               parse_error("multiple datatypes in declaration");
+                               errorf(HERE, "multiple datatypes in declaration");
                        }
                        atomic_type = ATOMIC_TYPE_INVALID;
                }
 
                type               = allocate_type_zero(TYPE_ATOMIC);
-               type->atomic.atype = atomic_type;
+               type->atomic.akind = atomic_type;
                newtype            = 1;
        } else {
                if(type_specifiers != 0) {
-                       parse_error("multiple datatypes in declaration");
+                       errorf(HERE, "multiple datatypes in declaration");
                }
        }
 
@@ -1952,8 +1803,7 @@ static declaration_t *parse_identifier_list(void)
        declaration_t *declarations     = NULL;
        declaration_t *last_declaration = NULL;
        do {
-               declaration_t *declaration = allocate_ast_zero(sizeof(declaration[0]));
-
+               declaration_t *const declaration = allocate_declaration_zero();
                declaration->source_position = token.source_position;
                declaration->symbol          = token.v.symbol;
                next_token();
@@ -1978,22 +1828,19 @@ static void semantic_parameter(declaration_t *declaration)
        /* TODO: improve error messages */
 
        if(declaration->storage_class == STORAGE_CLASS_TYPEDEF) {
-               parse_error("typedef not allowed in parameter list");
+               errorf(HERE, "typedef not allowed in parameter list");
        } else if(declaration->storage_class != STORAGE_CLASS_NONE
                        && declaration->storage_class != STORAGE_CLASS_REGISTER) {
-               parse_error("parameter may only have none or register storage class");
+               errorf(HERE, "parameter may only have none or register storage class");
        }
 
-       type_t *orig_type = declaration->type;
-       if(orig_type == NULL)
-               return;
-       type_t *type = skip_typeref(orig_type);
+       type_t *const orig_type = declaration->type;
+       type_t *      type      = skip_typeref(orig_type);
 
-       /* Array as last part of a paramter type is just syntactic sugar.  Turn it
+       /* Array as last part of a parameter type is just syntactic sugar.  Turn it
         * into a pointer. Â§ 6.7.5.3 (7) */
        if (is_type_array(type)) {
-               const array_type_t *arr_type     = &type->array;
-               type_t             *element_type = arr_type->element_type;
+               type_t *const element_type = type->array.element_type;
 
                type = make_pointer_type(element_type, type->base.qualifiers);
 
@@ -2001,11 +1848,8 @@ static void semantic_parameter(declaration_t *declaration)
        }
 
        if(is_type_incomplete(type)) {
-               parser_print_error_prefix();
-               fprintf(stderr, "incomplete type (");
-               print_type_quoted(orig_type);
-               fprintf(stderr, ") not allowed for parameter '%s'\n",
-                       declaration->symbol->string);
+               errorf(HERE, "incomplete type ('%T') not allowed for parameter '%Y'",
+                      orig_type, declaration->symbol);
        }
 }
 
@@ -2016,7 +1860,7 @@ static declaration_t *parse_parameter(void)
 
        parse_declaration_specifiers(&specifiers);
 
-       declaration_t *declaration = parse_declarator(&specifiers, true);
+       declaration_t *declaration = parse_declarator(&specifiers, /*may_be_abstract=*/true);
 
        semantic_parameter(declaration);
 
@@ -2178,7 +2022,7 @@ static construct_type_t *parse_function_declarator(declaration_t *declaration)
 
        declaration_t *parameters = parse_parameters(&type->function);
        if(declaration != NULL) {
-               declaration->context.declarations = parameters;
+               declaration->scope.declarations = parameters;
        }
 
        construct_function_type_t *construct_function_type =
@@ -2221,7 +2065,7 @@ static construct_type_t *parse_inner_declarator(declaration_t *declaration,
        switch(token.type) {
        case T_IDENTIFIER:
                if(declaration == NULL) {
-                       parse_error("no identifier expected in typename");
+                       errorf(HERE, "no identifier expected in typename");
                } else {
                        declaration->symbol          = token.v.symbol;
                        declaration->source_position = token.source_position;
@@ -2306,7 +2150,16 @@ static type_t *construct_declarator_type(construct_type_t *construct_list,
 
                        function_type->function.return_type = type;
 
-                       type = function_type;
+                       type_t *skipped_return_type = skip_typeref(type);
+                       if (is_type_function(skipped_return_type)) {
+                               errorf(HERE, "function returning function is not allowed");
+                               type = type_error_type;
+                       } else if (is_type_array(skipped_return_type)) {
+                               errorf(HERE, "function returning array is not allowed");
+                               type = type_error_type;
+                       } else {
+                               type = function_type;
+                       }
                        break;
                }
 
@@ -2330,7 +2183,13 @@ static type_t *construct_declarator_type(construct_type_t *construct_list,
                        array_type->array.is_variable  = parsed_array->is_variable;
                        array_type->array.size         = parsed_array->size;
 
-                       type = array_type;
+                       type_t *skipped_type = skip_typeref(type);
+                       if (is_type_atomic(skipped_type, ATOMIC_TYPE_VOID)) {
+                               errorf(HERE, "array of void is not allowed");
+                               type = type_error_type;
+                       } else {
+                               type = array_type;
+                       }
                        break;
                }
                }
@@ -2352,13 +2211,14 @@ static type_t *construct_declarator_type(construct_type_t *construct_list,
 static declaration_t *parse_declarator(
                const declaration_specifiers_t *specifiers, bool may_be_abstract)
 {
-       type_t        *type        = specifiers->type;
-       declaration_t *declaration = allocate_ast_zero(sizeof(declaration[0]));
-       declaration->storage_class = specifiers->storage_class;
-       declaration->is_inline     = specifiers->is_inline;
+       declaration_t *const declaration = allocate_declaration_zero();
+       declaration->storage_class  = specifiers->storage_class;
+       declaration->modifiers      = specifiers->decl_modifiers;
+       declaration->is_inline      = specifiers->is_inline;
 
        construct_type_t *construct_type
                = parse_inner_declarator(declaration, may_be_abstract);
+       type_t *const type = specifiers->type;
        declaration->type = construct_declarator_type(construct_type, type);
 
        if(construct_type != NULL) {
@@ -2380,47 +2240,219 @@ static type_t *parse_abstract_declarator(type_t *base_type)
        return result;
 }
 
-static declaration_t *record_declaration(declaration_t *declaration)
+static declaration_t *append_declaration(declaration_t* const declaration)
 {
-       assert(declaration->parent_context == NULL);
-       assert(context != NULL);
-
-       symbol_t *symbol = declaration->symbol;
-       if(symbol != NULL) {
-               declaration_t *alias = environment_push(declaration);
-               if(alias != declaration)
-                       return alias;
-       } else {
-               declaration->parent_context = context;
-       }
-
-       if(last_declaration != NULL) {
+       if (last_declaration != NULL) {
                last_declaration->next = declaration;
        } else {
-               context->declarations = declaration;
+               scope->declarations = declaration;
        }
        last_declaration = declaration;
-
        return declaration;
 }
 
-static void parser_error_multiple_definition(declaration_t *declaration,
-               const source_position_t source_position)
-{
-       parser_print_error_prefix_pos(source_position);
-       fprintf(stderr, "multiple definition of symbol '%s'\n",
-               declaration->symbol->string);
-       parser_print_error_prefix_pos(declaration->source_position);
-       fprintf(stderr, "this is the location of the previous definition.\n");
-}
-
-static bool is_declaration_specifier(const token_t *token,
-                                     bool only_type_specifiers)
+/**
+ * Check if the declaration of main is suspicious.  main should be a
+ * function with external linkage, returning int, taking either zero
+ * arguments, two, or three arguments of appropriate types, ie.
+ *
+ * int main([ int argc, char **argv [, char **env ] ]).
+ *
+ * @param decl    the declaration to check
+ * @param type    the function type of the declaration
+ */
+static void check_type_of_main(const declaration_t *const decl, const function_type_t *const func_type)
 {
-       switch(token->type) {
-               TYPE_SPECIFIERS
-                       return true;
-               case T_IDENTIFIER:
+       if (decl->storage_class == STORAGE_CLASS_STATIC) {
+               warningf(decl->source_position, "'main' is normally a non-static function");
+       }
+       if (skip_typeref(func_type->return_type) != type_int) {
+               warningf(decl->source_position, "return type of 'main' should be 'int', but is '%T'", func_type->return_type);
+       }
+       const function_parameter_t *parm = func_type->parameters;
+       if (parm != NULL) {
+               type_t *const first_type = parm->type;
+               if (!types_compatible(skip_typeref(first_type), type_int)) {
+                       warningf(decl->source_position, "first argument of 'main' should be 'int', but is '%T'", first_type);
+               }
+               parm = parm->next;
+               if (parm != NULL) {
+                       type_t *const second_type = parm->type;
+                       if (!types_compatible(skip_typeref(second_type), type_char_ptr_ptr)) {
+                               warningf(decl->source_position, "second argument of 'main' should be 'char**', but is '%T'", second_type);
+                       }
+                       parm = parm->next;
+                       if (parm != NULL) {
+                               type_t *const third_type = parm->type;
+                               if (!types_compatible(skip_typeref(third_type), type_char_ptr_ptr)) {
+                                       warningf(decl->source_position, "third argument of 'main' should be 'char**', but is '%T'", third_type);
+                               }
+                               parm = parm->next;
+                               if (parm != NULL) {
+                                       warningf(decl->source_position, "'main' takes only zero, two or three arguments");
+                               }
+                       }
+               } else {
+                       warningf(decl->source_position, "'main' takes only zero, two or three arguments");
+               }
+       }
+}
+
+/**
+ * Check if a symbol is the equal to "main".
+ */
+static bool is_sym_main(const symbol_t *const sym)
+{
+       return strcmp(sym->string, "main") == 0;
+}
+
+static declaration_t *internal_record_declaration(
+       declaration_t *const declaration,
+       const bool is_function_definition)
+{
+       const symbol_t *const symbol  = declaration->symbol;
+       const namespace_t     namespc = (namespace_t)declaration->namespc;
+
+       type_t       *const orig_type = declaration->type;
+       const type_t *const type      = skip_typeref(orig_type);
+       if (is_type_function(type) &&
+                       type->function.unspecified_parameters &&
+                       warning.strict_prototypes) {
+               warningf(declaration->source_position,
+                        "function declaration '%#T' is not a prototype",
+                        orig_type, declaration->symbol);
+       }
+
+       if (is_function_definition && warning.main && is_sym_main(symbol)) {
+               check_type_of_main(declaration, &type->function);
+       }
+
+       declaration_t *const previous_declaration = get_declaration(symbol, namespc);
+       assert(declaration != previous_declaration);
+       if (previous_declaration != NULL) {
+               if (previous_declaration->parent_scope == scope) {
+                       /* can happen for K&R style declarations */
+                       if(previous_declaration->type == NULL) {
+                               previous_declaration->type = declaration->type;
+                       }
+
+                       const type_t *const prev_type = skip_typeref(previous_declaration->type);
+                       if (!types_compatible(type, prev_type)) {
+                               errorf(declaration->source_position,
+                                       "declaration '%#T' is incompatible with previous declaration '%#T'",
+                                       orig_type, symbol, previous_declaration->type, symbol);
+                               errorf(previous_declaration->source_position, "previous declaration of '%Y' was here", symbol);
+                       } else {
+                               unsigned old_storage_class = previous_declaration->storage_class;
+                               unsigned new_storage_class = declaration->storage_class;
+
+                               /* pretend no storage class means extern for function declarations
+                                * (except if the previous declaration is neither none nor extern) */
+                               if (is_type_function(type)) {
+                                       switch (old_storage_class) {
+                                               case STORAGE_CLASS_NONE:
+                                                       old_storage_class = STORAGE_CLASS_EXTERN;
+
+                                               case STORAGE_CLASS_EXTERN:
+                                                       if (is_function_definition) {
+                                                               if (warning.missing_prototypes &&
+                                                                   prev_type->function.unspecified_parameters &&
+                                                                   !is_sym_main(symbol)) {
+                                                                       warningf(declaration->source_position, "no previous prototype for '%#T'", orig_type, symbol);
+                                                               }
+                                                       } else if (new_storage_class == STORAGE_CLASS_NONE) {
+                                                               new_storage_class = STORAGE_CLASS_EXTERN;
+                                                       }
+                                                       break;
+
+                                               default: break;
+                                       }
+                               }
+
+                               if (old_storage_class == STORAGE_CLASS_EXTERN &&
+                                               new_storage_class == STORAGE_CLASS_EXTERN) {
+warn_redundant_declaration:
+                                       if (warning.redundant_decls) {
+                                               warningf(declaration->source_position, "redundant declaration for '%Y'", symbol);
+                                               warningf(previous_declaration->source_position, "previous declaration of '%Y' was here", symbol);
+                                       }
+                               } else if (current_function == NULL) {
+                                       if (old_storage_class != STORAGE_CLASS_STATIC &&
+                                                       new_storage_class == STORAGE_CLASS_STATIC) {
+                                               errorf(declaration->source_position, "static declaration of '%Y' follows non-static declaration", symbol);
+                                               errorf(previous_declaration->source_position, "previous declaration of '%Y' was here", symbol);
+                                       } else {
+                                               if (old_storage_class != STORAGE_CLASS_EXTERN && !is_function_definition) {
+                                                       goto warn_redundant_declaration;
+                                               }
+                                               if (new_storage_class == STORAGE_CLASS_NONE) {
+                                                       previous_declaration->storage_class = STORAGE_CLASS_NONE;
+                                               }
+                                       }
+                               } else {
+                                       if (old_storage_class == new_storage_class) {
+                                               errorf(declaration->source_position, "redeclaration of '%Y'", symbol);
+                                       } else {
+                                               errorf(declaration->source_position, "redeclaration of '%Y' with different linkage", symbol);
+                                       }
+                                       errorf(previous_declaration->source_position, "previous declaration of '%Y' was here", symbol);
+                               }
+                       }
+                       return previous_declaration;
+               }
+       } else if (is_function_definition) {
+               if (declaration->storage_class != STORAGE_CLASS_STATIC) {
+                       if (warning.missing_prototypes && !is_sym_main(symbol)) {
+                               warningf(declaration->source_position, "no previous prototype for '%#T'", orig_type, symbol);
+                       } else if (warning.missing_declarations && !is_sym_main(symbol)) {
+                               warningf(declaration->source_position, "no previous declaration for '%#T'", orig_type, symbol);
+                       }
+               }
+       } else if (warning.missing_declarations &&
+           scope == global_scope &&
+           !is_type_function(type) && (
+             declaration->storage_class == STORAGE_CLASS_NONE ||
+             declaration->storage_class == STORAGE_CLASS_THREAD
+           )) {
+               warningf(declaration->source_position, "no previous declaration for '%#T'", orig_type, symbol);
+       }
+
+       assert(declaration->parent_scope == NULL);
+       assert(declaration->symbol != NULL);
+       assert(scope != NULL);
+
+       declaration->parent_scope = scope;
+
+       environment_push(declaration);
+       return append_declaration(declaration);
+}
+
+static declaration_t *record_declaration(declaration_t *declaration)
+{
+       return internal_record_declaration(declaration, false);
+}
+
+static declaration_t *record_function_definition(declaration_t *declaration)
+{
+       return internal_record_declaration(declaration, true);
+}
+
+static void parser_error_multiple_definition(declaration_t *declaration,
+               const source_position_t source_position)
+{
+       errorf(source_position, "multiple definition of symbol '%Y'",
+              declaration->symbol);
+       errorf(declaration->source_position,
+              "this is the location of the previous definition.");
+}
+
+static bool is_declaration_specifier(const token_t *token,
+                                     bool only_type_specifiers)
+{
+       switch(token->type) {
+               TYPE_SPECIFIERS
+                       return true;
+               case T_IDENTIFIER:
                        return is_typedef_symbol(token->v.symbol);
 
                case T___extension__:
@@ -2438,9 +2470,7 @@ static void parse_init_declarator_rest(declaration_t *declaration)
        eat('=');
 
        type_t *orig_type = declaration->type;
-       type_t *type      = NULL;
-       if(orig_type != NULL)
-               type = skip_typeref(orig_type);
+       type_t *type      = type = skip_typeref(orig_type);
 
        if(declaration->init.initializer != NULL) {
                parser_error_multiple_definition(declaration, token.source_position);
@@ -2448,9 +2478,9 @@ static void parse_init_declarator_rest(declaration_t *declaration)
 
        initializer_t *initializer = parse_initializer(type);
 
-       /* Â§ 6.7.5 (22)  array intializers for arrays with unknown size determine
+       /* Â§ 6.7.5 (22)  array initializers for arrays with unknown size determine
         * the array type size */
-       if(type != NULL && is_type_array(type) && initializer != NULL) {
+       if(is_type_array(type) && initializer != NULL) {
                array_type_t *array_type = &type->array;
 
                if(array_type->size == NULL) {
@@ -2458,22 +2488,19 @@ static void parse_init_declarator_rest(declaration_t *declaration)
 
                        cnst->base.datatype = type_size_t;
 
-                       switch (initializer->type) {
+                       switch (initializer->kind) {
                                case INITIALIZER_LIST: {
-                                       initializer_list_t *const list = &initializer->list;
-                                       cnst->conste.v.int_value = list->len;
+                                       cnst->conste.v.int_value = initializer->list.len;
                                        break;
                                }
 
                                case INITIALIZER_STRING: {
-                                       initializer_string_t *const string = &initializer->string;
-                                       cnst->conste.v.int_value = strlen(string->string) + 1;
+                                       cnst->conste.v.int_value = initializer->string.string.size;
                                        break;
                                }
 
                                case INITIALIZER_WIDE_STRING: {
-                                       initializer_wide_string_t *const string = &initializer->wide_string;
-                                       cnst->conste.v.int_value = string->string.size;
+                                       cnst->conste.v.int_value = initializer->wide_string.string.size;
                                        break;
                                }
 
@@ -2485,12 +2512,10 @@ static void parse_init_declarator_rest(declaration_t *declaration)
                }
        }
 
-       if(type != NULL && is_type_function(type)) {
-               parser_print_error_prefix_pos(declaration->source_position);
-               fprintf(stderr, "initializers not allowed for function types at "
-                               "declator '%s' (type ", declaration->symbol->string);
-               print_type_quoted(orig_type);
-               fprintf(stderr, ")\n");
+       if(is_type_function(type)) {
+               errorf(declaration->source_position,
+                      "initializers not allowed for function types at declator '%Y' (type '%T')",
+                      declaration->symbol, orig_type);
        } else {
                declaration->init.initializer = initializer;
        }
@@ -2503,25 +2528,21 @@ static void parse_anonymous_declaration_rest(
 {
        eat(';');
 
-       declaration_t *declaration = allocate_ast_zero(sizeof(declaration[0]));
-
+       declaration_t *const declaration = allocate_declaration_zero();
        declaration->type            = specifiers->type;
        declaration->storage_class   = specifiers->storage_class;
        declaration->source_position = specifiers->source_position;
 
        if (declaration->storage_class != STORAGE_CLASS_NONE) {
-               parse_warning_pos(declaration->source_position,
-                               "useless storage class in empty declaration");
+               warningf(declaration->source_position, "useless storage class in empty declaration");
        }
 
        type_t *type = declaration->type;
-       switch (type->type) {
+       switch (type->kind) {
                case TYPE_COMPOUND_STRUCT:
                case TYPE_COMPOUND_UNION: {
-                       const compound_type_t *compound_type = &type->compound;
-                       if (compound_type->declaration->symbol == NULL) {
-                               parse_warning_pos(declaration->source_position,
-                                               "unnamed struct/union that defines no instances");
+                       if (type->compound.declaration->symbol == NULL) {
+                               warningf(declaration->source_position, "unnamed struct/union that defines no instances");
                        }
                        break;
                }
@@ -2530,8 +2551,7 @@ static void parse_anonymous_declaration_rest(
                        break;
 
                default:
-                       parse_warning_pos(declaration->source_position,
-                                         "empty declaration");
+                       warningf(declaration->source_position, "empty declaration");
                        break;
        }
 
@@ -2548,10 +2568,11 @@ static void parse_declaration_rest(declaration_t *ndeclaration,
                type_t *orig_type = declaration->type;
                type_t *type      = skip_typeref(orig_type);
 
-               if(type->type != TYPE_FUNCTION && declaration->is_inline) {
-                       parser_print_warning_prefix_pos(declaration->source_position);
-                       fprintf(stderr, "variable '%s' declared 'inline'\n",
-                                       declaration->symbol->string);
+               if (type->kind != TYPE_FUNCTION &&
+                   declaration->is_inline &&
+                   is_type_valid(type)) {
+                       warningf(declaration->source_position,
+                                "variable '%Y' declared 'inline'\n", declaration->symbol);
                }
 
                if(token.type == '=') {
@@ -2562,18 +2583,39 @@ static void parse_declaration_rest(declaration_t *ndeclaration,
                        break;
                eat(',');
 
-               ndeclaration = parse_declarator(specifiers, false);
+               ndeclaration = parse_declarator(specifiers, /*may_be_abstract=*/false);
        }
        expect_void(';');
 }
 
 static declaration_t *finished_kr_declaration(declaration_t *declaration)
 {
-       /* TODO: check that it was actually a parameter that gets a type */
+       symbol_t *symbol  = declaration->symbol;
+       if(symbol == NULL) {
+               errorf(HERE, "anonymous declaration not valid as function parameter");
+               return declaration;
+       }
+       namespace_t namespc = (namespace_t) declaration->namespc;
+       if(namespc != NAMESPACE_NORMAL) {
+               return record_declaration(declaration);
+       }
+
+       declaration_t *previous_declaration = get_declaration(symbol, namespc);
+       if(previous_declaration == NULL ||
+                       previous_declaration->parent_scope != scope) {
+               errorf(HERE, "expected declaration of a function parameter, found '%Y'",
+                      symbol);
+               return declaration;
+       }
 
-       /* we should have a declaration for the parameter in the current
-        * scope */
-       return record_declaration(declaration);
+       if(previous_declaration->type == NULL) {
+               previous_declaration->type           = declaration->type;
+               previous_declaration->storage_class  = declaration->storage_class;
+               previous_declaration->parent_scope = scope;
+               return previous_declaration;
+       } else {
+               return record_declaration(declaration);
+       }
 }
 
 static void parse_declaration(parsed_declaration_func finished_declaration)
@@ -2585,7 +2627,7 @@ static void parse_declaration(parsed_declaration_func finished_declaration)
        if(token.type == ';') {
                parse_anonymous_declaration_rest(&specifiers, finished_declaration);
        } else {
-               declaration_t *declaration = parse_declarator(&specifiers, false);
+               declaration_t *declaration = parse_declarator(&specifiers, /*may_be_abstract=*/false);
                parse_declaration_rest(declaration, &specifiers, finished_declaration);
        }
 }
@@ -2600,12 +2642,14 @@ static void parse_kr_declaration_list(declaration_t *declaration)
                return;
 
        /* push function parameters */
-       int         top          = environment_top();
-       context_t  *last_context = context;
-       set_context(&declaration->context);
+       int       top        = environment_top();
+       scope_t  *last_scope = scope;
+       set_scope(&declaration->scope);
 
-       declaration_t *parameter = declaration->context.declarations;
+       declaration_t *parameter = declaration->scope.declarations;
        for( ; parameter != NULL; parameter = parameter->next) {
+               assert(parameter->parent_scope == NULL);
+               parameter->parent_scope = scope;
                environment_push(parameter);
        }
 
@@ -2615,8 +2659,8 @@ static void parse_kr_declaration_list(declaration_t *declaration)
        }
 
        /* pop function parameters */
-       assert(context == &declaration->context);
-       set_context(last_context);
+       assert(scope == &declaration->scope);
+       set_scope(last_scope);
        environment_pop_to(top);
 
        /* update function type */
@@ -2626,22 +2670,22 @@ static void parse_kr_declaration_list(declaration_t *declaration)
        function_parameter_t *parameters     = NULL;
        function_parameter_t *last_parameter = NULL;
 
-       declaration_t *parameter_declaration = declaration->context.declarations;
+       declaration_t *parameter_declaration = declaration->scope.declarations;
        for( ; parameter_declaration != NULL;
                        parameter_declaration = parameter_declaration->next) {
                type_t *parameter_type = parameter_declaration->type;
                if(parameter_type == NULL) {
-#ifdef STRICT_C99
-                       parser_print_error_prefix();
-                       fprintf(stderr, "no type specified for function parameter '%s'\n",
-                               parameter_declaration->symbol->string);
-#else
-                       parser_print_warning_prefix();
-                       fprintf(stderr, "no type specified for function parameter '%s', "
-                               "using int\n", parameter_declaration->symbol->string);
-                       parameter_type              = type_int;
-                       parameter_declaration->type = parameter_type;
-#endif
+                       if (strict_mode) {
+                               errorf(HERE, "no type specified for function parameter '%Y'",
+                                      parameter_declaration->symbol);
+                       } else {
+                               if (warning.implicit_int) {
+                                       warningf(HERE, "no type specified for function parameter '%Y', using 'int'",
+                                               parameter_declaration->symbol);
+                               }
+                               parameter_type              = type_int;
+                               parameter_declaration->type = parameter_type;
+                       }
                }
 
                semantic_parameter(parameter_declaration);
@@ -2669,6 +2713,53 @@ static void parse_kr_declaration_list(declaration_t *declaration)
        declaration->type = type;
 }
 
+/**
+ * Check if all labels are defined in the current function.
+ * Check if all labels are used in the current function.
+ */
+static void check_labels(void)
+{
+       bool first_err = true;
+       for (const goto_statement_t *goto_statement = goto_first;
+           goto_statement != NULL;
+           goto_statement = goto_statement->next) {
+               declaration_t *label = goto_statement->label;
+
+               label->used = true;
+               if (label->source_position.input_name == NULL) {
+                       if (first_err) {
+                               first_err = false;
+                               diagnosticf("%s: In function '%Y':\n",
+                                       current_function->source_position.input_name,
+                                       current_function->symbol);
+                       }
+                       errorf(goto_statement->statement.source_position,
+                               "label '%Y' used but not defined", label->symbol);
+                }
+       }
+       goto_first = goto_last = NULL;
+
+       if (warning.unused_label) {
+               for (const label_statement_t *label_statement = label_first;
+                        label_statement != NULL;
+                        label_statement = label_statement->next) {
+                       const declaration_t *label = label_statement->label;
+
+                       if (! label->used) {
+                               if (first_err) {
+                                       first_err = false;
+                                       diagnosticf("%s: In function '%Y':\n",
+                                               current_function->source_position.input_name,
+                                               current_function->symbol);
+                               }
+                               warningf(label_statement->statement.source_position,
+                                       "label '%Y' defined but not used", label->symbol);
+                       }
+               }
+       }
+       label_first = label_last = NULL;
+}
+
 static void parse_external_declaration(void)
 {
        /* function-definitions and declarations both start with declaration
@@ -2679,12 +2770,12 @@ static void parse_external_declaration(void)
 
        /* must be a declaration */
        if(token.type == ';') {
-               parse_anonymous_declaration_rest(&specifiers, record_declaration);
+               parse_anonymous_declaration_rest(&specifiers, append_declaration);
                return;
        }
 
        /* declarator is common to both function-definitions and declarations */
-       declaration_t *ndeclaration = parse_declarator(&specifiers, false);
+       declaration_t *ndeclaration = parse_declarator(&specifiers, /*may_be_abstract=*/false);
 
        /* must be a declaration */
        if(token.type == ',' || token.type == '=' || token.type == ';') {
@@ -2702,18 +2793,14 @@ static void parse_external_declaration(void)
        }
 
        type_t *type = ndeclaration->type;
-       if(type == NULL) {
-               eat_block();
-               return;
-       }
 
        /* note that we don't skip typerefs: the standard doesn't allow them here
         * (so we can't use is_type_function here) */
-       if(type->type != TYPE_FUNCTION) {
-               parser_print_error_prefix();
-               fprintf(stderr, "declarator '");
-               print_type_ext(type, ndeclaration->symbol, NULL);
-               fprintf(stderr, "' has a body but is not a function type.\n");
+       if(type->kind != TYPE_FUNCTION) {
+               if (is_type_valid(type)) {
+                       errorf(HERE, "declarator '%#T' has a body but is not a function type",
+                              type, ndeclaration->symbol);
+               }
                eat_block();
                return;
        }
@@ -2731,20 +2818,25 @@ static void parse_external_declaration(void)
                ndeclaration->type = type;
        }
 
-       declaration_t *declaration = record_declaration(ndeclaration);
+       declaration_t *const declaration = record_function_definition(ndeclaration);
        if(ndeclaration != declaration) {
-               memcpy(&declaration->context, &ndeclaration->context,
-                               sizeof(declaration->context));
+               declaration->scope = ndeclaration->scope;
        }
        type = skip_typeref(declaration->type);
 
-       /* push function parameters and switch context */
-       int         top          = environment_top();
-       context_t  *last_context = context;
-       set_context(&declaration->context);
+       /* push function parameters and switch scope */
+       int       top        = environment_top();
+       scope_t  *last_scope = scope;
+       set_scope(&declaration->scope);
 
-       declaration_t *parameter = declaration->context.declarations;
+       declaration_t *parameter = declaration->scope.declarations;
        for( ; parameter != NULL; parameter = parameter->next) {
+               if(parameter->parent_scope == &ndeclaration->scope) {
+                       parameter->parent_scope = scope;
+               }
+               assert(parameter->parent_scope == NULL
+                               || parameter->parent_scope == scope);
+               parameter->parent_scope = scope;
                environment_push(parameter);
        }
 
@@ -2759,6 +2851,7 @@ static void parse_external_declaration(void)
                current_function                    = declaration;
 
                declaration->init.statement = parse_compound_statement();
+               check_labels();
 
                assert(current_function == declaration);
                current_function = old_current_function;
@@ -2766,31 +2859,52 @@ static void parse_external_declaration(void)
        }
 
 end_of_parse_external_declaration:
-       assert(context == &declaration->context);
-       set_context(last_context);
+       assert(scope == &declaration->scope);
+       set_scope(last_scope);
        environment_pop_to(top);
 }
 
+static type_t *make_bitfield_type(type_t *base, expression_t *size)
+{
+       type_t *type        = allocate_type_zero(TYPE_BITFIELD);
+       type->bitfield.base = base;
+       type->bitfield.size = size;
+
+       return type;
+}
+
 static void parse_struct_declarators(const declaration_specifiers_t *specifiers)
 {
+       /* TODO: check constraints for struct declarations (in specifiers) */
        while(1) {
+               declaration_t *declaration;
+
                if(token.type == ':') {
                        next_token();
-                       parse_constant_expression();
-                       /* TODO (bitfields) */
-               } else {
-                       declaration_t *declaration = parse_declarator(specifiers, true);
 
-                       /* TODO: check constraints for struct declarations */
-                       /* TODO: check for doubled fields */
-                       record_declaration(declaration);
+                       type_t *base_type = specifiers->type;
+                       expression_t *size = parse_constant_expression();
+
+                       type_t *type = make_bitfield_type(base_type, size);
+
+                       declaration = allocate_declaration_zero();
+                       declaration->namespc         = NAMESPACE_NORMAL;
+                       declaration->storage_class   = STORAGE_CLASS_NONE;
+                       declaration->source_position = token.source_position;
+                       declaration->modifiers       = specifiers->decl_modifiers;
+                       declaration->type            = type;
+               } else {
+                       declaration = parse_declarator(specifiers,/*may_be_abstract=*/true);
 
                        if(token.type == ':') {
                                next_token();
-                               parse_constant_expression();
-                               /* TODO (bitfields) */
+                               expression_t *size = parse_constant_expression();
+
+                               type_t *type = make_bitfield_type(declaration->type, size);
+                               declaration->type = type;
                        }
                }
+               record_declaration(declaration);
 
                if(token.type != ',')
                        break;
@@ -2811,7 +2925,7 @@ static void parse_compound_type_entries(void)
                parse_struct_declarators(&specifiers);
        }
        if(token.type == T_EOF) {
-               parse_error("EOF while parsing struct");
+               errorf(HERE, "EOF while parsing struct");
        }
        next_token();
 }
@@ -2825,7 +2939,7 @@ static type_t *parse_typename(void)
                /* TODO: improve error message, user does probably not know what a
                 * storage class is...
                 */
-               parse_error("typename may not have a storage class");
+               errorf(HERE, "typename may not have a storage class");
        }
 
        type_t *result = parse_abstract_declarator(specifiers.type);
@@ -2850,6 +2964,9 @@ struct expression_parser_function_t {
 
 expression_parser_function_t expression_parsers[T_LAST_TOKEN];
 
+/**
+ * Creates a new invalid expression.
+ */
 static expression_t *create_invalid_expression(void)
 {
        expression_t *expression         = allocate_expression_zero(EXPR_INVALID);
@@ -2857,18 +2974,23 @@ static expression_t *create_invalid_expression(void)
        return expression;
 }
 
+/**
+ * Prints an error message if an expression was expected but not read
+ */
 static expression_t *expected_expression_error(void)
 {
-       parser_print_error_prefix();
-       fprintf(stderr, "expected expression, got token ");
-       print_token(stderr, &token);
-       fprintf(stderr, "\n");
-
+       /* skip the error message if the error token was read */
+       if (token.type != T_ERROR) {
+               errorf(HERE, "expected expression, got token '%K'", &token);
+       }
        next_token();
 
        return create_invalid_expression();
 }
 
+/**
+ * Parse a string constant.
+ */
 static expression_t *parse_string_const(void)
 {
        expression_t *cnst  = allocate_expression_zero(EXPR_STRING_LITERAL);
@@ -2878,6 +3000,9 @@ static expression_t *parse_string_const(void)
        return cnst;
 }
 
+/**
+ * Parse a wide string constant.
+ */
 static expression_t *parse_wide_string_const(void)
 {
        expression_t *const cnst = allocate_expression_zero(EXPR_WIDE_STRING_LITERAL);
@@ -2887,6 +3012,9 @@ static expression_t *parse_wide_string_const(void)
        return cnst;
 }
 
+/**
+ * Parse an integer constant.
+ */
 static expression_t *parse_int_const(void)
 {
        expression_t *cnst       = allocate_expression_zero(EXPR_CONST);
@@ -2898,6 +3026,9 @@ static expression_t *parse_int_const(void)
        return cnst;
 }
 
+/**
+ * Parse a float constant.
+ */
 static expression_t *parse_float_const(void)
 {
        expression_t *cnst         = allocate_expression_zero(EXPR_CONST);
@@ -2921,30 +3052,34 @@ static declaration_t *create_implicit_function(symbol_t *symbol,
                free_type(ntype);
        }
 
-       declaration_t *declaration = allocate_ast_zero(sizeof(declaration[0]));
-
+       declaration_t *const declaration = allocate_declaration_zero();
        declaration->storage_class   = STORAGE_CLASS_EXTERN;
        declaration->type            = type;
        declaration->symbol          = symbol;
        declaration->source_position = source_position;
+       declaration->parent_scope  = global_scope;
 
-       /* prepend the implicit definition to the global context
-        * this is safe since the symbol wasn't declared as anything else yet
-        */
-       assert(symbol->declaration == NULL);
-
-       context_t *last_context = context;
-       context = global_context;
+       scope_t *old_scope = scope;
+       set_scope(global_scope);
 
        environment_push(declaration);
-       declaration->next     = context->declarations;
-       context->declarations = declaration;
+       /* prepends the declaration to the global declarations list */
+       declaration->next   = scope->declarations;
+       scope->declarations = declaration;
 
-       context = last_context;
+       assert(scope == global_scope);
+       set_scope(old_scope);
 
        return declaration;
 }
 
+/**
+ * Creates a return_type (func)(argument_type) function type if not
+ * already exists.
+ *
+ * @param return_type    the return type
+ * @param argument_type  the argument type
+ */
 static type_t *make_function_1_type(type_t *return_type, type_t *argument_type)
 {
        function_parameter_t *parameter
@@ -2964,6 +3099,11 @@ static type_t *make_function_1_type(type_t *return_type, type_t *argument_type)
        return result;
 }
 
+/**
+ * Creates a function type for some function like builtins.
+ *
+ * @param symbol   the symbol describing the builtin
+ */
 static type_t *get_builtin_symbol_type(symbol_t *symbol)
 {
        switch(symbol->ID) {
@@ -2983,13 +3123,12 @@ static type_t *get_builtin_symbol_type(symbol_t *symbol)
 }
 
 /**
- * performs automatic type cast as described in Â§ 6.3.2.1
+ * Performs automatic type cast as described in Â§ 6.3.2.1.
+ *
+ * @param orig_type  the original type
  */
 static type_t *automatic_type_conversion(type_t *orig_type)
 {
-       if(orig_type == NULL)
-               return NULL;
-
        type_t *type = skip_typeref(orig_type);
        if(is_type_array(type)) {
                array_type_t *array_type   = &type->array;
@@ -3012,42 +3151,30 @@ static type_t *automatic_type_conversion(type_t *orig_type)
  */
 type_t *revert_automatic_type_conversion(const expression_t *expression)
 {
-       if(expression->base.datatype == NULL)
-               return NULL;
+       switch (expression->kind) {
+               case EXPR_REFERENCE: return expression->reference.declaration->type;
+               case EXPR_SELECT:    return expression->select.compound_entry->type;
 
-       switch(expression->type) {
-       case EXPR_REFERENCE: {
-               const reference_expression_t *ref = &expression->reference;
-               return ref->declaration->type;
-       }
-       case EXPR_SELECT: {
-               const select_expression_t *select = &expression->select;
-               return select->compound_entry->type;
-       }
-       case EXPR_UNARY_DEREFERENCE: {
-               expression_t   *value        = expression->unary.value;
-               type_t         *type         = skip_typeref(value->base.datatype);
-               pointer_type_t *pointer_type = &type->pointer;
+               case EXPR_UNARY_DEREFERENCE: {
+                       const expression_t *const value = expression->unary.value;
+                       type_t             *const type  = skip_typeref(value->base.datatype);
+                       assert(is_type_pointer(type));
+                       return type->pointer.points_to;
+               }
 
-               return pointer_type->points_to;
-       }
-       case EXPR_BUILTIN_SYMBOL: {
-               const builtin_symbol_expression_t *builtin
-                       = &expression->builtin_symbol;
-               return get_builtin_symbol_type(builtin->symbol);
-       }
-       case EXPR_ARRAY_ACCESS: {
-               const array_access_expression_t *array_access
-                       = &expression->array_access;
-               const expression_t *array_ref = array_access->array_ref;
-               type_t *type_left  = skip_typeref(array_ref->base.datatype);
-               assert(is_type_pointer(type_left));
-               pointer_type_t *pointer_type = &type_left->pointer;
-               return pointer_type->points_to;
-       }
+               case EXPR_BUILTIN_SYMBOL:
+                       return get_builtin_symbol_type(expression->builtin_symbol.symbol);
 
-       default:
-               break;
+               case EXPR_ARRAY_ACCESS: {
+                       const expression_t *const array_ref = expression->array_access.array_ref;
+                       type_t             *const type_left = skip_typeref(array_ref->base.datatype);
+                       if (!is_type_valid(type_left))
+                               return type_left;
+                       assert(is_type_pointer(type_left));
+                       return type_left->pointer.points_to;
+               }
+
+               default: break;
        }
 
        return expression->base.datatype;
@@ -3066,25 +3193,23 @@ static expression_t *parse_reference(void)
        next_token();
 
        if(declaration == NULL) {
-#ifndef STRICT_C99
-               /* an implicitly defined function */
-               if(token.type == '(') {
-                       parser_print_prefix_pos(token.source_position);
-                       fprintf(stderr, "warning: implicit declaration of function '%s'\n",
-                               ref->symbol->string);
+               if (! strict_mode && token.type == '(') {
+                       /* an implicitly defined function */
+                       if (warning.implicit_function_declaration) {
+                               warningf(HERE, "implicit declaration of function '%Y'",
+                                       ref->symbol);
+                       }
 
                        declaration = create_implicit_function(ref->symbol,
                                                               source_position);
-               } else
-#endif
-               {
-                       parser_print_error_prefix();
-                       fprintf(stderr, "unknown symbol '%s' found.\n", ref->symbol->string);
+               } else {
+                       errorf(HERE, "unknown symbol '%Y' found.", ref->symbol);
                        return expression;
                }
        }
 
-       type_t *type = declaration->type;
+       type_t *type         = declaration->type;
+
        /* we always do the auto-type conversions; the & and sizeof parser contains
         * code to revert this! */
        type = automatic_type_conversion(type);
@@ -3125,31 +3250,24 @@ static expression_t *parse_statement_expression(void)
 {
        expression_t *expression = allocate_expression_zero(EXPR_STATEMENT);
 
-       statement_t *statement          = parse_compound_statement();
-       expression->statement.statement = statement;
-       if(statement == NULL) {
-               expect(')');
-               return NULL;
-       }
+       statement_t *statement           = parse_compound_statement();
+       expression->statement.statement  = statement;
+       expression->base.source_position = statement->base.source_position;
 
-       assert(statement->type == STATEMENT_COMPOUND);
-       compound_statement_t *compound_statement = &statement->compound;
-
-       /* find last statement and use it's type */
-       const statement_t *last_statement = NULL;
-       const statement_t *iter           = compound_statement->statements;
-       for( ; iter != NULL; iter = iter->base.next) {
-               last_statement = iter;
-       }
+       /* find last statement and use its type */
+       type_t *type = type_void;
+       const statement_t *stmt = statement->compound.statements;
+       if (stmt != NULL) {
+               while (stmt->base.next != NULL)
+                       stmt = stmt->base.next;
 
-       if(last_statement->type == STATEMENT_EXPRESSION) {
-               const expression_statement_t *expression_statement
-                       = &last_statement->expression;
-               expression->base.datatype
-                       = expression_statement->expression->base.datatype;
+               if (stmt->kind == STATEMENT_EXPRESSION) {
+                       type = stmt->expression.expression->base.datatype;
+               }
        } else {
-               expression->base.datatype = type_void;
+               warningf(expression->base.source_position, "empty statement expression ({})");
        }
+       expression->base.datatype = type;
 
        expect(')');
 
@@ -3162,7 +3280,7 @@ static expression_t *parse_brace_expression(void)
 
        switch(token.type) {
        case '{':
-               /* gcc extension: a stement expression */
+               /* gcc extension: a statement expression */
                return parse_statement_expression();
 
        TYPE_QUALIFIERS
@@ -3186,15 +3304,14 @@ static expression_t *parse_function_keyword(void)
        /* TODO */
 
        if (current_function == NULL) {
-               parse_error("'__func__' used outside of a function");
+               errorf(HERE, "'__func__' used outside of a function");
        }
 
        string_literal_expression_t *expression
                = allocate_ast_zero(sizeof(expression[0]));
 
-       expression->expression.type     = EXPR_FUNCTION;
+       expression->expression.kind     = EXPR_FUNCTION;
        expression->expression.datatype = type_string;
-       expression->value               = "TODO: FUNCTION";
 
        return (expression_t*) expression;
 }
@@ -3204,12 +3321,15 @@ static expression_t *parse_pretty_function_keyword(void)
        eat(T___PRETTY_FUNCTION__);
        /* TODO */
 
+       if (current_function == NULL) {
+               errorf(HERE, "'__PRETTY_FUNCTION__' used outside of a function");
+       }
+
        string_literal_expression_t *expression
                = allocate_ast_zero(sizeof(expression[0]));
 
-       expression->expression.type     = EXPR_PRETTY_FUNCTION;
+       expression->expression.kind     = EXPR_PRETTY_FUNCTION;
        expression->expression.datatype = type_string;
-       expression->value               = "TODO: PRETTY FUNCTION";
 
        return (expression_t*) expression;
 }
@@ -3291,18 +3411,16 @@ static expression_t *parse_va_start(void)
        expression->va_starte.ap = parse_assignment_expression();
        expect(',');
        expression_t *const expr = parse_assignment_expression();
-       if (expr->type == EXPR_REFERENCE) {
+       if (expr->kind == EXPR_REFERENCE) {
                declaration_t *const decl = expr->reference.declaration;
-               if (decl->parent_context == &current_function->context &&
+               if (decl->parent_scope == &current_function->scope &&
                    decl->next == NULL) {
                        expression->va_starte.parameter = decl;
                        expect(')');
                        return expression;
                }
        }
-       parser_print_error_prefix_pos(expr->base.source_position);
-       fprintf(stderr, "second argument of 'va_start' must be last parameter "
-                       "of the current function\n");
+       errorf(expr->base.source_position, "second argument of 'va_start' must be last parameter of the current function");
 
        return create_invalid_expression();
 }
@@ -3338,6 +3456,42 @@ static expression_t *parse_builtin_symbol(void)
        return expression;
 }
 
+static expression_t *parse_builtin_constant(void)
+{
+       eat(T___builtin_constant_p);
+
+       expression_t *expression = allocate_expression_zero(EXPR_BUILTIN_CONSTANT_P);
+
+       expect('(');
+       expression->builtin_constant.value = parse_assignment_expression();
+       expect(')');
+       expression->base.datatype = type_int;
+
+       return expression;
+}
+
+static expression_t *parse_builtin_prefetch(void)
+{
+       eat(T___builtin_prefetch);
+
+       expression_t *expression = allocate_expression_zero(EXPR_BUILTIN_PREFETCH);
+
+       expect('(');
+       expression->builtin_prefetch.adr = parse_assignment_expression();
+       if (token.type == ',') {
+               next_token();
+               expression->builtin_prefetch.rw = parse_assignment_expression();
+       }
+       if (token.type == ',') {
+               next_token();
+               expression->builtin_prefetch.locality = parse_assignment_expression();
+       }
+       expect(')');
+       expression->base.datatype = type_void;
+
+       return expression;
+}
+
 static expression_t *parse_compare_builtin(void)
 {
        expression_t *expression;
@@ -3373,16 +3527,16 @@ static expression_t *parse_compare_builtin(void)
        expression->binary.right = parse_assignment_expression();
        expect(')');
 
-       type_t *orig_type_left  = expression->binary.left->base.datatype;
-       type_t *orig_type_right = expression->binary.right->base.datatype;
-       if(orig_type_left == NULL || orig_type_right == NULL)
-               return expression;
+       type_t *const orig_type_left  = expression->binary.left->base.datatype;
+       type_t *const orig_type_right = expression->binary.right->base.datatype;
 
-       type_t *type_left  = skip_typeref(orig_type_left);
-       type_t *type_right = skip_typeref(orig_type_right);
+       type_t *const type_left  = skip_typeref(orig_type_left);
+       type_t *const type_right = skip_typeref(orig_type_right);
        if(!is_type_floating(type_left) && !is_type_floating(type_right)) {
-               type_error_incompatible("invalid operands in comparison",
-                                       token.source_position, type_left, type_right);
+               if (is_type_valid(type_left) && is_type_valid(type_right)) {
+                       type_error_incompatible("invalid operands in comparison",
+                               token.source_position, orig_type_left, orig_type_right);
+               }
        } else {
                semantic_comparison(&expression->binary);
        }
@@ -3390,6 +3544,52 @@ static expression_t *parse_compare_builtin(void)
        return expression;
 }
 
+static expression_t *parse_builtin_expect(void)
+{
+       eat(T___builtin_expect);
+
+       expression_t *expression
+               = allocate_expression_zero(EXPR_BINARY_BUILTIN_EXPECT);
+
+       expect('(');
+       expression->binary.left = parse_assignment_expression();
+       expect(',');
+       expression->binary.right = parse_constant_expression();
+       expect(')');
+
+       expression->base.datatype = expression->binary.left->base.datatype;
+
+       return expression;
+}
+
+static expression_t *parse_assume(void) {
+       eat(T_assume);
+
+       expression_t *expression
+               = allocate_expression_zero(EXPR_UNARY_ASSUME);
+
+       expect('(');
+       expression->unary.value = parse_assignment_expression();
+       expect(')');
+
+       expression->base.datatype = type_void;
+       return expression;
+}
+
+static expression_t *parse_alignof(void) {
+       eat(T___alignof__);
+
+       expression_t *expression
+               = allocate_expression_zero(EXPR_ALIGNOF);
+
+       expect('(');
+       expression->alignofe.type = parse_typename();
+       expect(')');
+
+       expression->base.datatype = type_size_t;
+       return expression;
+}
+
 static expression_t *parse_primary_expression(void)
 {
        switch(token.type) {
@@ -3397,7 +3597,7 @@ static expression_t *parse_primary_expression(void)
                return parse_int_const();
        case T_FLOATINGPOINT:
                return parse_float_const();
-       case T_STRING_LITERAL: /* TODO merge */
+       case T_STRING_LITERAL:
                return parse_string_const();
        case T_WIDE_STRING_LITERAL:
                return parse_wide_string_const();
@@ -3414,9 +3614,10 @@ static expression_t *parse_primary_expression(void)
                return parse_va_start();
        case T___builtin_va_arg:
                return parse_va_arg();
+       case T___builtin_expect:
+               return parse_builtin_expect();
        case T___builtin_nanf:
        case T___builtin_alloca:
-       case T___builtin_expect:
        case T___builtin_va_end:
                return parse_builtin_symbol();
        case T___builtin_isgreater:
@@ -3426,20 +3627,39 @@ static expression_t *parse_primary_expression(void)
        case T___builtin_islessgreater:
        case T___builtin_isunordered:
                return parse_compare_builtin();
+       case T___builtin_constant_p:
+               return parse_builtin_constant();
+       case T___builtin_prefetch:
+               return parse_builtin_prefetch();
+       case T___alignof__:
+               return parse_alignof();
+       case T_assume:
+               return parse_assume();
 
        case '(':
                return parse_brace_expression();
        }
 
-       parser_print_error_prefix();
-       fprintf(stderr, "unexpected token ");
-       print_token(stderr, &token);
-       fprintf(stderr, "\n");
+       errorf(HERE, "unexpected token '%K'", &token);
        eat_statement();
 
        return create_invalid_expression();
 }
 
+/**
+ * Check if the expression has the character type and issue a warning then.
+ */
+static void check_for_char_index_type(const expression_t *expression) {
+       type_t       *const type      = expression->base.datatype;
+       const type_t *const base_type = skip_typeref(type);
+
+       if (is_type_atomic(base_type, ATOMIC_TYPE_CHAR) &&
+                       warning.char_subscripts) {
+               warningf(expression->base.source_position,
+                       "array subscript has type '%T'", type);
+       }
+}
+
 static expression_t *parse_array_expression(unsigned precedence,
                                             expression_t *left)
 {
@@ -3452,38 +3672,34 @@ static expression_t *parse_array_expression(unsigned precedence,
        array_access_expression_t *array_access
                = allocate_ast_zero(sizeof(array_access[0]));
 
-       array_access->expression.type = EXPR_ARRAY_ACCESS;
-
-       type_t *type_left   = left->base.datatype;
-       type_t *type_inside = inside->base.datatype;
-       type_t *return_type = NULL;
-
-       if(type_left != NULL && type_inside != NULL) {
-               type_left   = skip_typeref(type_left);
-               type_inside = skip_typeref(type_inside);
-
-               if(is_type_pointer(type_left)) {
-                       pointer_type_t *pointer = &type_left->pointer;
-                       return_type             = pointer->points_to;
-                       array_access->array_ref = left;
-                       array_access->index     = inside;
-               } else if(is_type_pointer(type_inside)) {
-                       pointer_type_t *pointer = &type_inside->pointer;
-                       return_type             = pointer->points_to;
-                       array_access->array_ref = inside;
-                       array_access->index     = left;
-                       array_access->flipped   = true;
-               } else {
-                       parser_print_error_prefix();
-                       fprintf(stderr, "array access on object with non-pointer types ");
-                       print_type_quoted(type_left);
-                       fprintf(stderr, ", ");
-                       print_type_quoted(type_inside);
-                       fprintf(stderr, "\n");
-               }
-       } else {
+       array_access->expression.kind = EXPR_ARRAY_ACCESS;
+
+       type_t *const orig_type_left   = left->base.datatype;
+       type_t *const orig_type_inside = inside->base.datatype;
+
+       type_t *const type_left   = skip_typeref(orig_type_left);
+       type_t *const type_inside = skip_typeref(orig_type_inside);
+
+       type_t *return_type;
+       if (is_type_pointer(type_left)) {
+               return_type             = type_left->pointer.points_to;
                array_access->array_ref = left;
                array_access->index     = inside;
+               check_for_char_index_type(inside);
+       } else if (is_type_pointer(type_inside)) {
+               return_type             = type_inside->pointer.points_to;
+               array_access->array_ref = inside;
+               array_access->index     = left;
+               array_access->flipped   = true;
+               check_for_char_index_type(left);
+       } else {
+               if (is_type_valid(type_left) && is_type_valid(type_inside)) {
+                       errorf(HERE,
+                               "array access on object with non-pointer types '%T', '%T'",
+                               orig_type_left, orig_type_inside);
+               }
+               return_type             = type_error_type;
+               array_access->array_ref = create_invalid_expression();
        }
 
        if(token.type != ']') {
@@ -3504,7 +3720,7 @@ static expression_t *parse_sizeof(unsigned precedence)
 
        sizeof_expression_t *sizeof_expression
                = allocate_ast_zero(sizeof(sizeof_expression[0]));
-       sizeof_expression->expression.type     = EXPR_SIZEOF;
+       sizeof_expression->expression.kind     = EXPR_SIZEOF;
        sizeof_expression->expression.datatype = type_size_t;
 
        if(token.type == '(' && is_declaration_specifier(look_ahead(1), true)) {
@@ -3542,58 +3758,46 @@ static expression_t *parse_select_expression(unsigned precedence,
        select->select.symbol = symbol;
        next_token();
 
-       type_t *orig_type = compound->base.datatype;
-       if(orig_type == NULL)
-               return create_invalid_expression();
-
-       type_t *type = skip_typeref(orig_type);
+       type_t *const orig_type = compound->base.datatype;
+       type_t *const type      = skip_typeref(orig_type);
 
        type_t *type_left = type;
        if(is_pointer) {
-               if(type->type != TYPE_POINTER) {
-                       parser_print_error_prefix();
-                       fprintf(stderr, "left hand side of '->' is not a pointer, but ");
-                       print_type_quoted(orig_type);
-                       fputc('\n', stderr);
+               if (!is_type_pointer(type)) {
+                       if (is_type_valid(type)) {
+                               errorf(HERE, "left hand side of '->' is not a pointer, but '%T'", orig_type);
+                       }
                        return create_invalid_expression();
                }
-               pointer_type_t *pointer_type = &type->pointer;
-               type_left                    = pointer_type->points_to;
+               type_left = type->pointer.points_to;
        }
        type_left = skip_typeref(type_left);
 
-       if(type_left->type != TYPE_COMPOUND_STRUCT
-                       && type_left->type != TYPE_COMPOUND_UNION) {
-               parser_print_error_prefix();
-               fprintf(stderr, "request for member '%s' in something not a struct or "
-                       "union, but ", symbol->string);
-               print_type_quoted(type_left);
-               fputc('\n', stderr);
+       if (type_left->kind != TYPE_COMPOUND_STRUCT &&
+           type_left->kind != TYPE_COMPOUND_UNION) {
+               if (is_type_valid(type_left)) {
+                       errorf(HERE, "request for member '%Y' in something not a struct or "
+                              "union, but '%T'", symbol, type_left);
+               }
                return create_invalid_expression();
        }
 
-       compound_type_t *compound_type = &type_left->compound;
-       declaration_t   *declaration   = compound_type->declaration;
+       declaration_t *const declaration = type_left->compound.declaration;
 
        if(!declaration->init.is_defined) {
-               parser_print_error_prefix();
-               fprintf(stderr, "request for member '%s' of incomplete type ",
-                       symbol->string);
-               print_type_quoted(type_left);
-               fputc('\n', stderr);
+               errorf(HERE, "request for member '%Y' of incomplete type '%T'",
+                      symbol, type_left);
                return create_invalid_expression();
        }
 
-       declaration_t *iter = declaration->context.declarations;
+       declaration_t *iter = declaration->scope.declarations;
        for( ; iter != NULL; iter = iter->next) {
                if(iter->symbol == symbol) {
                        break;
                }
        }
        if(iter == NULL) {
-               parser_print_error_prefix();
-               print_type_quoted(type_left);
-               fprintf(stderr, " has no member named '%s'\n", symbol->string);
+               errorf(HERE, "'%T' has no member named '%Y'", orig_type, symbol);
                return create_invalid_expression();
        }
 
@@ -3603,46 +3807,50 @@ static expression_t *parse_select_expression(unsigned precedence,
 
        select->select.compound_entry = iter;
        select->base.datatype         = expression_type;
+
+       if(expression_type->kind == TYPE_BITFIELD) {
+               expression_t *extract
+                       = allocate_expression_zero(EXPR_UNARY_BITFIELD_EXTRACT);
+               extract->unary.value   = select;
+               extract->base.datatype = expression_type->bitfield.base;
+
+               return extract;
+       }
+
        return select;
 }
 
+/**
+ * Parse a call expression, ie. expression '( ... )'.
+ *
+ * @param expression  the function address
+ */
 static expression_t *parse_call_expression(unsigned precedence,
                                            expression_t *expression)
 {
        (void) precedence;
        expression_t *result = allocate_expression_zero(EXPR_CALL);
 
-       call_expression_t *call  = &result->call;
-       call->function           = expression;
+       call_expression_t *call = &result->call;
+       call->function          = expression;
 
-       function_type_t *function_type = NULL;
-       type_t          *orig_type     = expression->base.datatype;
-       if(orig_type != NULL) {
-               type_t *type  = skip_typeref(orig_type);
+       type_t *const orig_type = expression->base.datatype;
+       type_t *const type      = skip_typeref(orig_type);
 
-               if(is_type_pointer(type)) {
-                       pointer_type_t *pointer_type = &type->pointer;
-
-                       type = skip_typeref(pointer_type->points_to);
+       function_type_t *function_type = NULL;
+       if (is_type_pointer(type)) {
+               type_t *const to_type = skip_typeref(type->pointer.points_to);
 
-                       if (is_type_function(type)) {
-                               function_type             = &type->function;
-                               call->expression.datatype = function_type->return_type;
-                       }
-               }
-               if(function_type == NULL) {
-                       parser_print_error_prefix();
-                       fputs("called object '", stderr);
-                       print_expression(expression);
-                       fputs("' (type ", stderr);
-                       print_type_quoted(orig_type);
-                       fputs(") is not a pointer to a function\n", stderr);
-
-                       function_type             = NULL;
-                       call->expression.datatype = NULL;
+               if (is_type_function(to_type)) {
+                       function_type             = &to_type->function;
+                       call->expression.datatype = function_type->return_type;
                }
        }
 
+       if (function_type == NULL && is_type_valid(type)) {
+               errorf(HERE, "called object '%E' (type '%T') is not a pointer to a function", expression, orig_type);
+       }
+
        /* parse arguments */
        eat('(');
 
@@ -3673,32 +3881,31 @@ static expression_t *parse_call_expression(unsigned precedence,
                for( ; parameter != NULL && argument != NULL;
                                parameter = parameter->next, argument = argument->next) {
                        type_t *expected_type = parameter->type;
-                       /* TODO report context in error messages */
-                       argument->expression = create_implicit_cast(argument->expression,
-                                                                   expected_type);
+                       /* TODO report scope in error messages */
+                       expression_t *const arg_expr = argument->expression;
+                       type_t       *const res_type = semantic_assign(expected_type, arg_expr, "function call");
+                       if (res_type == NULL) {
+                               /* TODO improve error message */
+                               errorf(arg_expr->base.source_position,
+                                       "Cannot call function with argument '%E' of type '%T' where type '%T' is expected",
+                                       arg_expr, arg_expr->base.datatype, expected_type);
+                       } else {
+                               argument->expression = create_implicit_cast(argument->expression, expected_type);
+                       }
                }
                /* too few parameters */
                if(parameter != NULL) {
-                       parser_print_error_prefix();
-                       fprintf(stderr, "too few arguments to function '");
-                       print_expression(expression);
-                       fprintf(stderr, "'\n");
+                       errorf(HERE, "too few arguments to function '%E'", expression);
                } else if(argument != NULL) {
                        /* too many parameters */
                        if(!function_type->variadic
                                        && !function_type->unspecified_parameters) {
-                               parser_print_error_prefix();
-                               fprintf(stderr, "too many arguments to function '");
-                               print_expression(expression);
-                               fprintf(stderr, "'\n");
+                               errorf(HERE, "too many arguments to function '%E'", expression);
                        } else {
                                /* do default promotion */
                                for( ; argument != NULL; argument = argument->next) {
                                        type_t *type = argument->expression->base.datatype;
 
-                                       if(type == NULL)
-                                               continue;
-
                                        type = skip_typeref(type);
                                        if(is_type_integer(type)) {
                                                type = promote_integer(type);
@@ -3709,7 +3916,11 @@ static expression_t *parse_call_expression(unsigned precedence,
                                        argument->expression
                                                = create_implicit_cast(argument->expression, type);
                                }
+
+                               check_format(&result->call);
                        }
+               } else {
+                       check_format(&result->call);
                }
        }
 
@@ -3720,17 +3931,17 @@ static type_t *semantic_arithmetic(type_t *type_left, type_t *type_right);
 
 static bool same_compound_type(const type_t *type1, const type_t *type2)
 {
-       if(!is_type_compound(type1))
-               return false;
-       if(type1->type != type2->type)
-               return false;
-
-       const compound_type_t *compound1 = &type1->compound;
-       const compound_type_t *compound2 = &type2->compound;
-
-       return compound1->declaration == compound2->declaration;
+       return
+               is_type_compound(type1) &&
+               type1->kind == type2->kind &&
+               type1->compound.declaration == type2->compound.declaration;
 }
 
+/**
+ * Parse a conditional expression, ie. 'expression ? ... : ...'.
+ *
+ * @param expression  the conditional expression
+ */
 static expression_t *parse_conditional_expression(unsigned precedence,
                                                   expression_t *expression)
 {
@@ -3742,13 +3953,11 @@ static expression_t *parse_conditional_expression(unsigned precedence,
        conditional->condition = expression;
 
        /* 6.5.15.2 */
-       type_t *condition_type_orig = expression->base.datatype;
-       if(condition_type_orig != NULL) {
-               type_t *condition_type = skip_typeref(condition_type_orig);
-               if(condition_type != NULL && !is_type_scalar(condition_type)) {
-                       type_error("expected a scalar type in conditional condition",
-                                  expression->base.source_position, condition_type_orig);
-               }
+       type_t *const condition_type_orig = expression->base.datatype;
+       type_t *const condition_type      = skip_typeref(condition_type_orig);
+       if (!is_type_scalar(condition_type) && is_type_valid(condition_type)) {
+               type_error("expected a scalar type in conditional condition",
+                          expression->base.source_position, condition_type_orig);
        }
 
        expression_t *true_expression = parse_expression();
@@ -3758,16 +3967,13 @@ static expression_t *parse_conditional_expression(unsigned precedence,
        conditional->true_expression  = true_expression;
        conditional->false_expression = false_expression;
 
-       type_t *orig_true_type  = true_expression->base.datatype;
-       type_t *orig_false_type = false_expression->base.datatype;
-       if(orig_true_type == NULL || orig_false_type == NULL)
-               return result;
-
-       type_t *true_type  = skip_typeref(orig_true_type);
-       type_t *false_type = skip_typeref(orig_false_type);
+       type_t *const orig_true_type  = true_expression->base.datatype;
+       type_t *const orig_false_type = false_expression->base.datatype;
+       type_t *const true_type       = skip_typeref(orig_true_type);
+       type_t *const false_type      = skip_typeref(orig_false_type);
 
        /* 6.5.15.3 */
-       type_t *result_type = NULL;
+       type_t *result_type;
        if (is_type_arithmetic(true_type) && is_type_arithmetic(false_type)) {
                result_type = semantic_arithmetic(true_type, false_type);
 
@@ -3777,9 +3983,10 @@ static expression_t *parse_conditional_expression(unsigned precedence,
                conditional->true_expression     = true_expression;
                conditional->false_expression    = false_expression;
                conditional->expression.datatype = result_type;
-       } else if (same_compound_type(true_type, false_type)
-                       || (is_type_atomic(true_type, ATOMIC_TYPE_VOID) &&
-                               is_type_atomic(false_type, ATOMIC_TYPE_VOID))) {
+       } else if (same_compound_type(true_type, false_type) || (
+           is_type_atomic(true_type, ATOMIC_TYPE_VOID) &&
+           is_type_atomic(false_type, ATOMIC_TYPE_VOID)
+               )) {
                /* just take 1 of the 2 types */
                result_type = true_type;
        } else if (is_type_pointer(true_type) && is_type_pointer(false_type)
@@ -3788,22 +3995,29 @@ static expression_t *parse_conditional_expression(unsigned precedence,
                result_type = true_type;
        } else {
                /* TODO */
-               type_error_incompatible("while parsing conditional",
-                                       expression->base.source_position, true_type,
-                                       false_type);
+               if (is_type_valid(true_type) && is_type_valid(false_type)) {
+                       type_error_incompatible("while parsing conditional",
+                                               expression->base.source_position, true_type,
+                                               false_type);
+               }
+               result_type = type_error_type;
        }
 
        conditional->expression.datatype = result_type;
        return result;
 }
 
+/**
+ * Parse an extension expression.
+ */
 static expression_t *parse_extension(unsigned precedence)
 {
        eat(T___extension__);
 
        /* TODO enable extensions */
-
-       return parse_sub_expression(precedence);
+       expression_t *expression = parse_sub_expression(precedence);
+       /* TODO disable extensions */
+       return expression;
 }
 
 static expression_t *parse_builtin_classify_type(const unsigned precedence)
@@ -3823,15 +4037,14 @@ static expression_t *parse_builtin_classify_type(const unsigned precedence)
 
 static void semantic_incdec(unary_expression_t *expression)
 {
-       type_t *orig_type = expression->value->base.datatype;
-       if(orig_type == NULL)
-               return;
-
-       type_t *type = skip_typeref(orig_type);
-       if(!is_type_arithmetic(type) && type->type != TYPE_POINTER) {
-               /* TODO: improve error message */
-               parser_print_error_prefix();
-               fprintf(stderr, "operation needs an arithmetic or pointer type\n");
+       type_t *const orig_type = expression->value->base.datatype;
+       type_t *const type      = skip_typeref(orig_type);
+       /* TODO !is_type_real && !is_type_pointer */
+       if(!is_type_arithmetic(type) && type->kind != TYPE_POINTER) {
+               if (is_type_valid(type)) {
+                       /* TODO: improve error message */
+                       errorf(HERE, "operation needs an arithmetic or pointer type");
+               }
                return;
        }
 
@@ -3840,15 +4053,13 @@ static void semantic_incdec(unary_expression_t *expression)
 
 static void semantic_unexpr_arithmetic(unary_expression_t *expression)
 {
-       type_t *orig_type = expression->value->base.datatype;
-       if(orig_type == NULL)
-               return;
-
-       type_t *type = skip_typeref(orig_type);
+       type_t *const orig_type = expression->value->base.datatype;
+       type_t *const type      = skip_typeref(orig_type);
        if(!is_type_arithmetic(type)) {
-               /* TODO: improve error message */
-               parser_print_error_prefix();
-               fprintf(stderr, "operation needs an arithmetic type\n");
+               if (is_type_valid(type)) {
+                       /* TODO: improve error message */
+                       errorf(HERE, "operation needs an arithmetic type");
+               }
                return;
        }
 
@@ -3857,13 +4068,12 @@ static void semantic_unexpr_arithmetic(unary_expression_t *expression)
 
 static void semantic_unexpr_scalar(unary_expression_t *expression)
 {
-       type_t *orig_type = expression->value->base.datatype;
-       if(orig_type == NULL)
-               return;
-
-       type_t *type = skip_typeref(orig_type);
+       type_t *const orig_type = expression->value->base.datatype;
+       type_t *const type      = skip_typeref(orig_type);
        if (!is_type_scalar(type)) {
-               parse_error("operand of ! must be of scalar type\n");
+               if (is_type_valid(type)) {
+                       errorf(HERE, "operand of ! must be of scalar type");
+               }
                return;
        }
 
@@ -3872,13 +4082,12 @@ static void semantic_unexpr_scalar(unary_expression_t *expression)
 
 static void semantic_unexpr_integer(unary_expression_t *expression)
 {
-       type_t *orig_type = expression->value->base.datatype;
-       if(orig_type == NULL)
-               return;
-
-       type_t *type = skip_typeref(orig_type);
+       type_t *const orig_type = expression->value->base.datatype;
+       type_t *const type      = skip_typeref(orig_type);
        if (!is_type_integer(type)) {
-               parse_error("operand of ~ must be of integer type\n");
+               if (is_type_valid(type)) {
+                       errorf(HERE, "operand of ~ must be of integer type");
+               }
                return;
        }
 
@@ -3887,39 +4096,40 @@ static void semantic_unexpr_integer(unary_expression_t *expression)
 
 static void semantic_dereference(unary_expression_t *expression)
 {
-       type_t *orig_type = expression->value->base.datatype;
-       if(orig_type == NULL)
-               return;
-
-       type_t *type = skip_typeref(orig_type);
+       type_t *const orig_type = expression->value->base.datatype;
+       type_t *const type      = skip_typeref(orig_type);
        if(!is_type_pointer(type)) {
-               parser_print_error_prefix();
-               fputs("Unary '*' needs pointer or arrray type, but type ", stderr);
-               print_type_quoted(orig_type);
-               fputs(" given.\n", stderr);
+               if (is_type_valid(type)) {
+                       errorf(HERE, "Unary '*' needs pointer or arrray type, but type '%T' given", orig_type);
+               }
                return;
        }
 
-       pointer_type_t *pointer_type = &type->pointer;
-       type_t         *result_type  = pointer_type->points_to;
-
+       type_t *result_type = type->pointer.points_to;
        result_type = automatic_type_conversion(result_type);
        expression->expression.datatype = result_type;
 }
 
+/**
+ * Check the semantic of the address taken expression.
+ */
 static void semantic_take_addr(unary_expression_t *expression)
 {
        expression_t *value  = expression->value;
        value->base.datatype = revert_automatic_type_conversion(value);
 
        type_t *orig_type = value->base.datatype;
-       if(orig_type == NULL)
+       if(!is_type_valid(orig_type))
                return;
 
-       if(value->type == EXPR_REFERENCE) {
-               reference_expression_t *reference   = (reference_expression_t*) value;
-               declaration_t          *declaration = reference->declaration;
+       if(value->kind == EXPR_REFERENCE) {
+               declaration_t *const declaration = value->reference.declaration;
                if(declaration != NULL) {
+                       if (declaration->storage_class == STORAGE_CLASS_REGISTER) {
+                               errorf(expression->expression.source_position,
+                                       "address of register variable '%Y' requested",
+                                       declaration->symbol);
+                       }
                        declaration->address_taken = 1;
                }
        }
@@ -3931,13 +4141,14 @@ static void semantic_take_addr(unary_expression_t *expression)
 static expression_t *parse_##unexpression_type(unsigned precedence)            \
 {                                                                              \
        eat(token_type);                                                           \
-                                                                               \
+                                                                                  \
        expression_t *unary_expression                                             \
                = allocate_expression_zero(unexpression_type);                         \
+       unary_expression->base.source_position = HERE;                             \
        unary_expression->unary.value = parse_sub_expression(precedence);          \
                                                                                   \
        sfunc(&unary_expression->unary);                                           \
-                                                                               \
+                                                                                  \
        return unary_expression;                                                   \
 }
 
@@ -4020,23 +4231,23 @@ static type_t *semantic_arithmetic(type_t *type_left, type_t *type_right)
        }
 }
 
+/**
+ * Check the semantic restrictions for a binary expression.
+ */
 static void semantic_binexpr_arithmetic(binary_expression_t *expression)
 {
-       expression_t *left       = expression->left;
-       expression_t *right      = expression->right;
-       type_t       *orig_type_left  = left->base.datatype;
-       type_t       *orig_type_right = right->base.datatype;
-
-       if(orig_type_left == NULL || orig_type_right == NULL)
-               return;
-
-       type_t *type_left  = skip_typeref(orig_type_left);
-       type_t *type_right = skip_typeref(orig_type_right);
+       expression_t *const left            = expression->left;
+       expression_t *const right           = expression->right;
+       type_t       *const orig_type_left  = left->base.datatype;
+       type_t       *const orig_type_right = right->base.datatype;
+       type_t       *const type_left       = skip_typeref(orig_type_left);
+       type_t       *const type_right      = skip_typeref(orig_type_right);
 
        if(!is_type_arithmetic(type_left) || !is_type_arithmetic(type_right)) {
                /* TODO: improve error message */
-               parser_print_error_prefix();
-               fprintf(stderr, "operation needs arithmetic types\n");
+               if (is_type_valid(type_left) && is_type_valid(type_right)) {
+                       errorf(HERE, "operation needs arithmetic types");
+               }
                return;
        }
 
@@ -4048,21 +4259,18 @@ static void semantic_binexpr_arithmetic(binary_expression_t *expression)
 
 static void semantic_shift_op(binary_expression_t *expression)
 {
-       expression_t *left       = expression->left;
-       expression_t *right      = expression->right;
-       type_t       *orig_type_left  = left->base.datatype;
-       type_t       *orig_type_right = right->base.datatype;
-
-       if(orig_type_left == NULL || orig_type_right == NULL)
-               return;
-
-       type_t *type_left  = skip_typeref(orig_type_left);
-       type_t *type_right = skip_typeref(orig_type_right);
+       expression_t *const left            = expression->left;
+       expression_t *const right           = expression->right;
+       type_t       *const orig_type_left  = left->base.datatype;
+       type_t       *const orig_type_right = right->base.datatype;
+       type_t       *      type_left       = skip_typeref(orig_type_left);
+       type_t       *      type_right      = skip_typeref(orig_type_right);
 
        if(!is_type_integer(type_left) || !is_type_integer(type_right)) {
                /* TODO: improve error message */
-               parser_print_error_prefix();
-               fprintf(stderr, "operation needs integer types\n");
+               if (is_type_valid(type_left) && is_type_valid(type_right)) {
+                       errorf(HERE, "operation needs integer types");
+               }
                return;
        }
 
@@ -4076,16 +4284,12 @@ static void semantic_shift_op(binary_expression_t *expression)
 
 static void semantic_add(binary_expression_t *expression)
 {
-       expression_t *left            = expression->left;
-       expression_t *right           = expression->right;
-       type_t       *orig_type_left  = left->base.datatype;
-       type_t       *orig_type_right = right->base.datatype;
-
-       if(orig_type_left == NULL || orig_type_right == NULL)
-               return;
-
-       type_t *type_left  = skip_typeref(orig_type_left);
-       type_t *type_right = skip_typeref(orig_type_right);
+       expression_t *const left            = expression->left;
+       expression_t *const right           = expression->right;
+       type_t       *const orig_type_left  = left->base.datatype;
+       type_t       *const orig_type_right = right->base.datatype;
+       type_t       *const type_left       = skip_typeref(orig_type_left);
+       type_t       *const type_right      = skip_typeref(orig_type_right);
 
        /* Â§ 5.6.5 */
        if(is_type_arithmetic(type_left) && is_type_arithmetic(type_right)) {
@@ -4098,28 +4302,19 @@ static void semantic_add(binary_expression_t *expression)
                expression->expression.datatype = type_left;
        } else if(is_type_pointer(type_right) && is_type_integer(type_left)) {
                expression->expression.datatype = type_right;
-       } else {
-               parser_print_error_prefix();
-               fprintf(stderr, "invalid operands to binary + (");
-               print_type_quoted(orig_type_left);
-               fprintf(stderr, ", ");
-               print_type_quoted(orig_type_right);
-               fprintf(stderr, ")\n");
+       } else if (is_type_valid(type_left) && is_type_valid(type_right)) {
+               errorf(HERE, "invalid operands to binary + ('%T', '%T')", orig_type_left, orig_type_right);
        }
 }
 
 static void semantic_sub(binary_expression_t *expression)
 {
-       expression_t *left            = expression->left;
-       expression_t *right           = expression->right;
-       type_t       *orig_type_left  = left->base.datatype;
-       type_t       *orig_type_right = right->base.datatype;
-
-       if(orig_type_left == NULL || orig_type_right == NULL)
-               return;
-
-       type_t       *type_left       = skip_typeref(orig_type_left);
-       type_t       *type_right      = skip_typeref(orig_type_right);
+       expression_t *const left            = expression->left;
+       expression_t *const right           = expression->right;
+       type_t       *const orig_type_left  = left->base.datatype;
+       type_t       *const orig_type_right = right->base.datatype;
+       type_t       *const type_left       = skip_typeref(orig_type_left);
+       type_t       *const type_right      = skip_typeref(orig_type_right);
 
        /* Â§ 5.6.5 */
        if(is_type_arithmetic(type_left) && is_type_arithmetic(type_right)) {
@@ -4132,25 +4327,20 @@ static void semantic_sub(binary_expression_t *expression)
                expression->expression.datatype = type_left;
        } else if(is_type_pointer(type_left) && is_type_pointer(type_right)) {
                if(!pointers_compatible(type_left, type_right)) {
-                       parser_print_error_prefix();
-                       fprintf(stderr, "pointers to incompatible objects to binary - (");
-                       print_type_quoted(orig_type_left);
-                       fprintf(stderr, ", ");
-                       print_type_quoted(orig_type_right);
-                       fprintf(stderr, ")\n");
+                       errorf(HERE, "pointers to incompatible objects to binary '-' ('%T', '%T')", orig_type_left, orig_type_right);
                } else {
                        expression->expression.datatype = type_ptrdiff_t;
                }
-       } else {
-               parser_print_error_prefix();
-               fprintf(stderr, "invalid operands to binary - (");
-               print_type_quoted(orig_type_left);
-               fprintf(stderr, ", ");
-               print_type_quoted(orig_type_right);
-               fprintf(stderr, ")\n");
+       } else if (is_type_valid(type_left) && is_type_valid(type_right)) {
+               errorf(HERE, "invalid operands to binary '-' ('%T', '%T')", orig_type_left, orig_type_right);
        }
 }
 
+/**
+ * Check the semantics of comparison expressions.
+ *
+ * @param expression   The expression to check.
+ */
 static void semantic_comparison(binary_expression_t *expression)
 {
        expression_t *left            = expression->left;
@@ -4158,9 +4348,6 @@ static void semantic_comparison(binary_expression_t *expression)
        type_t       *orig_type_left  = left->base.datatype;
        type_t       *orig_type_right = right->base.datatype;
 
-       if(orig_type_left == NULL || orig_type_right == NULL)
-               return;
-
        type_t *type_left  = skip_typeref(orig_type_left);
        type_t *type_right = skip_typeref(orig_type_right);
 
@@ -4170,15 +4357,23 @@ static void semantic_comparison(binary_expression_t *expression)
                expression->left  = create_implicit_cast(left, arithmetic_type);
                expression->right = create_implicit_cast(right, arithmetic_type);
                expression->expression.datatype = arithmetic_type;
+               if (warning.float_equal &&
+                   (expression->expression.kind == EXPR_BINARY_EQUAL ||
+                    expression->expression.kind == EXPR_BINARY_NOTEQUAL) &&
+                   is_type_floating(arithmetic_type)) {
+                       warningf(expression->expression.source_position,
+                                "comparing floating point with == or != is unsafe");
+               }
        } else if (is_type_pointer(type_left) && is_type_pointer(type_right)) {
                /* TODO check compatibility */
        } else if (is_type_pointer(type_left)) {
                expression->right = create_implicit_cast(right, type_left);
        } else if (is_type_pointer(type_right)) {
                expression->left = create_implicit_cast(left, type_right);
-       } else {
+       } else if (is_type_valid(type_left) && is_type_valid(type_right)) {
                type_error_incompatible("invalid operands in comparison",
-                                       token.source_position, type_left, type_right);
+                                       expression->expression.source_position,
+                                       type_left, type_right);
        }
        expression->expression.datatype = type_int;
 }
@@ -4190,23 +4385,21 @@ static void semantic_arithmetic_assign(binary_expression_t *expression)
        type_t       *orig_type_left  = left->base.datatype;
        type_t       *orig_type_right = right->base.datatype;
 
-       if(orig_type_left == NULL || orig_type_right == NULL)
-               return;
-
        type_t *type_left  = skip_typeref(orig_type_left);
        type_t *type_right = skip_typeref(orig_type_right);
 
        if(!is_type_arithmetic(type_left) || !is_type_arithmetic(type_right)) {
                /* TODO: improve error message */
-               parser_print_error_prefix();
-               fprintf(stderr, "operation needs arithmetic types\n");
+               if (is_type_valid(type_left) && is_type_valid(type_right)) {
+                       errorf(HERE, "operation needs arithmetic types");
+               }
                return;
        }
 
        /* combined instructions are tricky. We can't create an implicit cast on
         * the left side, because we need the uncasted form for the store.
         * The ast2firm pass has to know that left_type must be right_type
-        * for the arithmeitc operation and create a cast by itself */
+        * for the arithmetic operation and create a cast by itself */
        type_t *arithmetic_type = semantic_arithmetic(type_left, type_right);
        expression->right       = create_implicit_cast(right, arithmetic_type);
        expression->expression.datatype = type_left;
@@ -4214,122 +4407,226 @@ static void semantic_arithmetic_assign(binary_expression_t *expression)
 
 static void semantic_arithmetic_addsubb_assign(binary_expression_t *expression)
 {
-       expression_t *left            = expression->left;
-       expression_t *right           = expression->right;
-       type_t       *orig_type_left  = left->base.datatype;
-       type_t       *orig_type_right = right->base.datatype;
-
-       if(orig_type_left == NULL || orig_type_right == NULL)
-               return;
-
-       type_t *type_left  = skip_typeref(orig_type_left);
-       type_t *type_right = skip_typeref(orig_type_right);
+       expression_t *const left            = expression->left;
+       expression_t *const right           = expression->right;
+       type_t       *const orig_type_left  = left->base.datatype;
+       type_t       *const orig_type_right = right->base.datatype;
+       type_t       *const type_left       = skip_typeref(orig_type_left);
+       type_t       *const type_right      = skip_typeref(orig_type_right);
 
        if (is_type_arithmetic(type_left) && is_type_arithmetic(type_right)) {
                /* combined instructions are tricky. We can't create an implicit cast on
                 * the left side, because we need the uncasted form for the store.
                 * The ast2firm pass has to know that left_type must be right_type
-                * for the arithmeitc operation and create a cast by itself */
+                * for the arithmetic operation and create a cast by itself */
                type_t *const arithmetic_type = semantic_arithmetic(type_left, type_right);
                expression->right = create_implicit_cast(right, arithmetic_type);
                expression->expression.datatype = type_left;
        } else if (is_type_pointer(type_left) && is_type_integer(type_right)) {
                expression->expression.datatype = type_left;
-       } else {
-               parser_print_error_prefix();
-               fputs("Incompatible types ", stderr);
-               print_type_quoted(orig_type_left);
-               fputs(" and ", stderr);
-               print_type_quoted(orig_type_right);
-               fputs(" in assignment\n", stderr);
-               return;
+       } else if (is_type_valid(type_left) && is_type_valid(type_right)) {
+               errorf(HERE, "incompatible types '%T' and '%T' in assignment", orig_type_left, orig_type_right);
        }
 }
 
+/**
+ * Check the semantic restrictions of a logical expression.
+ */
 static void semantic_logical_op(binary_expression_t *expression)
 {
-       expression_t *left            = expression->left;
-       expression_t *right           = expression->right;
-       type_t       *orig_type_left  = left->base.datatype;
-       type_t       *orig_type_right = right->base.datatype;
-
-       if(orig_type_left == NULL || orig_type_right == NULL)
-               return;
-
-       type_t *type_left  = skip_typeref(orig_type_left);
-       type_t *type_right = skip_typeref(orig_type_right);
+       expression_t *const left            = expression->left;
+       expression_t *const right           = expression->right;
+       type_t       *const orig_type_left  = left->base.datatype;
+       type_t       *const orig_type_right = right->base.datatype;
+       type_t       *const type_left       = skip_typeref(orig_type_left);
+       type_t       *const type_right      = skip_typeref(orig_type_right);
 
        if (!is_type_scalar(type_left) || !is_type_scalar(type_right)) {
                /* TODO: improve error message */
-               parser_print_error_prefix();
-               fprintf(stderr, "operation needs scalar types\n");
+               if (is_type_valid(type_left) && is_type_valid(type_right)) {
+                       errorf(HERE, "operation needs scalar types");
+               }
                return;
        }
 
        expression->expression.datatype = type_int;
 }
 
-static bool has_const_fields(type_t *type)
+/**
+ * Checks if a compound type has constant fields.
+ */
+static bool has_const_fields(const compound_type_t *type)
 {
-       (void) type;
+       const scope_t       *scope       = &type->declaration->scope;
+       const declaration_t *declaration = scope->declarations;
+
+       for (; declaration != NULL; declaration = declaration->next) {
+               if (declaration->namespc != NAMESPACE_NORMAL)
+                       continue;
+
+               const type_t *decl_type = skip_typeref(declaration->type);
+               if (decl_type->base.qualifiers & TYPE_QUALIFIER_CONST)
+                       return true;
+       }
        /* TODO */
        return false;
 }
 
+/**
+ * Check the semantic restrictions of a binary assign expression.
+ */
 static void semantic_binexpr_assign(binary_expression_t *expression)
 {
        expression_t *left           = expression->left;
        type_t       *orig_type_left = left->base.datatype;
 
-       if(orig_type_left == NULL)
-               return;
-
        type_t *type_left = revert_automatic_type_conversion(left);
        type_left         = skip_typeref(orig_type_left);
 
        /* must be a modifiable lvalue */
        if (is_type_array(type_left)) {
-               parser_print_error_prefix();
-               fprintf(stderr, "Cannot assign to arrays ('");
-               print_expression(left);
-               fprintf(stderr, "')\n");
+               errorf(HERE, "cannot assign to arrays ('%E')", left);
                return;
        }
        if(type_left->base.qualifiers & TYPE_QUALIFIER_CONST) {
-               parser_print_error_prefix();
-               fprintf(stderr, "assignment to readonly location '");
-               print_expression(left);
-               fprintf(stderr, "' (type ");
-               print_type_quoted(orig_type_left);
-               fprintf(stderr, ")\n");
+               errorf(HERE, "assignment to readonly location '%E' (type '%T')", left,
+                      orig_type_left);
                return;
        }
        if(is_type_incomplete(type_left)) {
-               parser_print_error_prefix();
-               fprintf(stderr, "left-hand side of assignment '");
-               print_expression(left);
-               fprintf(stderr, "' has incomplete type ");
-               print_type_quoted(orig_type_left);
-               fprintf(stderr, "\n");
+               errorf(HERE,
+                      "left-hand side of assignment '%E' has incomplete type '%T'",
+                      left, orig_type_left);
                return;
        }
-       if(is_type_compound(type_left) && has_const_fields(type_left)) {
-               parser_print_error_prefix();
-               fprintf(stderr, "can't assign to '");
-               print_expression(left);
-               fprintf(stderr, "' because compound type ");
-               print_type_quoted(orig_type_left);
-               fprintf(stderr, " has readonly fields\n");
+       if(is_type_compound(type_left) && has_const_fields(&type_left->compound)) {
+               errorf(HERE, "cannot assign to '%E' because compound type '%T' has readonly fields",
+                      left, orig_type_left);
                return;
        }
 
-       semantic_assign(orig_type_left, &expression->right, "assignment");
+       type_t *const res_type = semantic_assign(orig_type_left, expression->right,
+                                                "assignment");
+       if (res_type == NULL) {
+               errorf(expression->expression.source_position,
+                       "cannot assign to '%T' from '%T'",
+                       orig_type_left, expression->right->base.datatype);
+       } else {
+               expression->right = create_implicit_cast(expression->right, res_type);
+       }
 
        expression->expression.datatype = orig_type_left;
 }
 
+static bool expression_has_effect(const expression_t *const expr)
+{
+       switch (expr->kind) {
+               case EXPR_UNKNOWN:                   break;
+               case EXPR_INVALID:                   break;
+               case EXPR_REFERENCE:                 return false;
+               case EXPR_CONST:                     return false;
+               case EXPR_STRING_LITERAL:            return false;
+               case EXPR_WIDE_STRING_LITERAL:       return false;
+               case EXPR_CALL: {
+                       const call_expression_t *const call = &expr->call;
+                       if (call->function->kind != EXPR_BUILTIN_SYMBOL)
+                               return true;
+
+                       switch (call->function->builtin_symbol.symbol->ID) {
+                               case T___builtin_va_end: return true;
+                               default:                 return false;
+                       }
+               }
+               case EXPR_CONDITIONAL: {
+                       const conditional_expression_t *const cond = &expr->conditional;
+                       return
+                               expression_has_effect(cond->true_expression) &&
+                               expression_has_effect(cond->false_expression);
+               }
+               case EXPR_SELECT:                    return false;
+               case EXPR_ARRAY_ACCESS:              return false;
+               case EXPR_SIZEOF:                    return false;
+               case EXPR_CLASSIFY_TYPE:             return false;
+               case EXPR_ALIGNOF:                   return false;
+
+               case EXPR_FUNCTION:                  return false;
+               case EXPR_PRETTY_FUNCTION:           return false;
+               case EXPR_BUILTIN_SYMBOL:            break; /* handled in EXPR_CALL */
+               case EXPR_BUILTIN_CONSTANT_P:        return false;
+               case EXPR_BUILTIN_PREFETCH:          return true;
+               case EXPR_OFFSETOF:                  return false;
+               case EXPR_VA_START:                  return true;
+               case EXPR_VA_ARG:                    return true;
+               case EXPR_STATEMENT:                 return true; // TODO
+
+               case EXPR_UNARY_NEGATE:              return false;
+               case EXPR_UNARY_PLUS:                return false;
+               case EXPR_UNARY_BITWISE_NEGATE:      return false;
+               case EXPR_UNARY_NOT:                 return false;
+               case EXPR_UNARY_DEREFERENCE:         return false;
+               case EXPR_UNARY_TAKE_ADDRESS:        return false;
+               case EXPR_UNARY_POSTFIX_INCREMENT:   return true;
+               case EXPR_UNARY_POSTFIX_DECREMENT:   return true;
+               case EXPR_UNARY_PREFIX_INCREMENT:    return true;
+               case EXPR_UNARY_PREFIX_DECREMENT:    return true;
+               case EXPR_UNARY_CAST:
+                       return is_type_atomic(expr->base.datatype, ATOMIC_TYPE_VOID);
+               case EXPR_UNARY_CAST_IMPLICIT:       return true;
+               case EXPR_UNARY_ASSUME:              return true;
+               case EXPR_UNARY_BITFIELD_EXTRACT:    return false;
+
+               case EXPR_BINARY_ADD:                return false;
+               case EXPR_BINARY_SUB:                return false;
+               case EXPR_BINARY_MUL:                return false;
+               case EXPR_BINARY_DIV:                return false;
+               case EXPR_BINARY_MOD:                return false;
+               case EXPR_BINARY_EQUAL:              return false;
+               case EXPR_BINARY_NOTEQUAL:           return false;
+               case EXPR_BINARY_LESS:               return false;
+               case EXPR_BINARY_LESSEQUAL:          return false;
+               case EXPR_BINARY_GREATER:            return false;
+               case EXPR_BINARY_GREATEREQUAL:       return false;
+               case EXPR_BINARY_BITWISE_AND:        return false;
+               case EXPR_BINARY_BITWISE_OR:         return false;
+               case EXPR_BINARY_BITWISE_XOR:        return false;
+               case EXPR_BINARY_SHIFTLEFT:          return false;
+               case EXPR_BINARY_SHIFTRIGHT:         return false;
+               case EXPR_BINARY_ASSIGN:             return true;
+               case EXPR_BINARY_MUL_ASSIGN:         return true;
+               case EXPR_BINARY_DIV_ASSIGN:         return true;
+               case EXPR_BINARY_MOD_ASSIGN:         return true;
+               case EXPR_BINARY_ADD_ASSIGN:         return true;
+               case EXPR_BINARY_SUB_ASSIGN:         return true;
+               case EXPR_BINARY_SHIFTLEFT_ASSIGN:   return true;
+               case EXPR_BINARY_SHIFTRIGHT_ASSIGN:  return true;
+               case EXPR_BINARY_BITWISE_AND_ASSIGN: return true;
+               case EXPR_BINARY_BITWISE_XOR_ASSIGN: return true;
+               case EXPR_BINARY_BITWISE_OR_ASSIGN:  return true;
+               case EXPR_BINARY_LOGICAL_AND:
+               case EXPR_BINARY_LOGICAL_OR:
+               case EXPR_BINARY_COMMA:
+                       return expression_has_effect(expr->binary.right);
+
+               case EXPR_BINARY_BUILTIN_EXPECT:     return true;
+               case EXPR_BINARY_ISGREATER:          return false;
+               case EXPR_BINARY_ISGREATEREQUAL:     return false;
+               case EXPR_BINARY_ISLESS:             return false;
+               case EXPR_BINARY_ISLESSEQUAL:        return false;
+               case EXPR_BINARY_ISLESSGREATER:      return false;
+               case EXPR_BINARY_ISUNORDERED:        return false;
+       }
+
+       panic("unexpected statement");
+}
+
 static void semantic_comma(binary_expression_t *expression)
 {
+       if (warning.unused_value) {
+               const expression_t *const left = expression->left;
+               if (!expression_has_effect(left)) {
+                       warningf(left->base.source_position, "left-hand operand of comma expression has no effect");
+               }
+       }
        expression->expression.datatype = expression->right->base.datatype;
 }
 
@@ -4436,44 +4733,55 @@ static expression_t *parse_sub_expression(unsigned precedence)
                left = parser->infix_parser(parser->infix_precedence, left);
 
                assert(left != NULL);
-               assert(left->type != EXPR_UNKNOWN);
+               assert(left->kind != EXPR_UNKNOWN);
                left->base.source_position = source_position;
        }
 
        return left;
 }
 
+/**
+ * Parse an expression.
+ */
 static expression_t *parse_expression(void)
 {
        return parse_sub_expression(1);
 }
 
-
-
+/**
+ * Register a parser for a prefix-like operator with given precedence.
+ *
+ * @param parser      the parser function
+ * @param token_type  the token type of the prefix token
+ * @param precedence  the precedence of the operator
+ */
 static void register_expression_parser(parse_expression_function parser,
                                        int token_type, unsigned precedence)
 {
        expression_parser_function_t *entry = &expression_parsers[token_type];
 
        if(entry->parser != NULL) {
-               fprintf(stderr, "for token ");
-               print_token_type(stderr, (token_type_t) token_type);
-               fprintf(stderr, "\n");
+               diagnosticf("for token '%k'\n", (token_type_t)token_type);
                panic("trying to register multiple expression parsers for a token");
        }
        entry->parser     = parser;
        entry->precedence = precedence;
 }
 
+/**
+ * Register a parser for an infix operator with given precedence.
+ *
+ * @param parser      the parser function
+ * @param token_type  the token type of the infix operator
+ * @param precedence  the precedence of the operator
+ */
 static void register_infix_parser(parse_expression_infix_function parser,
                int token_type, unsigned precedence)
 {
        expression_parser_function_t *entry = &expression_parsers[token_type];
 
        if(entry->infix_parser != NULL) {
-               fprintf(stderr, "for token ");
-               print_token_type(stderr, (token_type_t) token_type);
-               fprintf(stderr, "\n");
+               diagnosticf("for token '%k'\n", (token_type_t)token_type);
                panic("trying to register multiple infix expression parsers for a "
                      "token");
        }
@@ -4481,6 +4789,9 @@ static void register_infix_parser(parse_expression_infix_function parser,
        entry->infix_precedence = precedence;
 }
 
+/**
+ * Initialize the expression parsers.
+ */
 static void init_expression_parsers(void)
 {
        memset(&expression_parsers, 0, sizeof(expression_parsers));
@@ -4549,6 +4860,9 @@ static void init_expression_parsers(void)
                                                     T___builtin_classify_type, 25);
 }
 
+/**
+ * Parse a asm statement constraints specification.
+ */
 static asm_constraint_t *parse_asm_constraints(void)
 {
        asm_constraint_t *result = NULL;
@@ -4590,6 +4904,9 @@ static asm_constraint_t *parse_asm_constraints(void)
        return result;
 }
 
+/**
+ * Parse a asm statement clobber specification.
+ */
 static asm_clobber_t *parse_asm_clobbers(void)
 {
        asm_clobber_t *result = NULL;
@@ -4614,6 +4931,9 @@ static asm_clobber_t *parse_asm_clobbers(void)
        return result;
 }
 
+/**
+ * Parse an asm statement.
+ */
 static statement_t *parse_asm_statement(void)
 {
        eat(T_asm);
@@ -4653,6 +4973,9 @@ end_of_asm:
        return statement;
 }
 
+/**
+ * Parse a case statement.
+ */
 static statement_t *parse_case_statement(void)
 {
        eat(T_case);
@@ -4663,11 +4986,48 @@ static statement_t *parse_case_statement(void)
        statement->case_label.expression = parse_expression();
 
        expect(':');
+
+       if (! is_constant_expression(statement->case_label.expression)) {
+               errorf(statement->base.source_position,
+                       "case label does not reduce to an integer constant");
+       } else {
+               /* TODO: check if the case label is already known */
+               if (current_switch != NULL) {
+                       /* link all cases into the switch statement */
+                       if (current_switch->last_case == NULL) {
+                               current_switch->first_case =
+                               current_switch->last_case  = &statement->case_label;
+                       } else {
+                               current_switch->last_case->next = &statement->case_label;
+                       }
+               } else {
+                       errorf(statement->base.source_position,
+                               "case label not within a switch statement");
+               }
+       }
        statement->case_label.label_statement = parse_statement();
 
        return statement;
 }
 
+/**
+ * Finds an existing default label of a switch statement.
+ */
+static case_label_statement_t *
+find_default_label(const switch_statement_t *statement)
+{
+       for (case_label_statement_t *label = statement->first_case;
+            label != NULL;
+                label = label->next) {
+               if (label->expression == NULL)
+                       return label;
+       }
+       return NULL;
+}
+
+/**
+ * Parse a default statement.
+ */
 static statement_t *parse_default_statement(void)
 {
        eat(T_default);
@@ -4677,11 +5037,33 @@ static statement_t *parse_default_statement(void)
        statement->base.source_position = token.source_position;
 
        expect(':');
+       if (current_switch != NULL) {
+               const case_label_statement_t *def_label = find_default_label(current_switch);
+               if (def_label != NULL) {
+                       errorf(HERE, "multiple default labels in one switch");
+                       errorf(def_label->statement.source_position,
+                               "this is the first default label");
+               } else {
+                       /* link all cases into the switch statement */
+                       if (current_switch->last_case == NULL) {
+                               current_switch->first_case =
+                                       current_switch->last_case  = &statement->case_label;
+                       } else {
+                               current_switch->last_case->next = &statement->case_label;
+                       }
+               }
+       } else {
+               errorf(statement->base.source_position,
+                       "'default' label not within a switch statement");
+       }
        statement->label.label_statement = parse_statement();
 
        return statement;
 }
 
+/**
+ * Return the declaration for a given label symbol or create a new one.
+ */
 static declaration_t *get_label(symbol_t *symbol)
 {
        declaration_t *candidate = get_declaration(symbol, NAMESPACE_LABEL);
@@ -4689,12 +5071,12 @@ static declaration_t *get_label(symbol_t *symbol)
        /* if we found a label in the same function, then we already created the
         * declaration */
        if(candidate != NULL
-                       && candidate->parent_context == &current_function->context) {
+                       && candidate->parent_scope == &current_function->scope) {
                return candidate;
        }
 
        /* otherwise we need to create a new one */
-       declaration_t *declaration = allocate_ast_zero(sizeof(declaration[0]));
+       declaration_t *const declaration = allocate_declaration_zero();
        declaration->namespc       = NAMESPACE_LABEL;
        declaration->symbol        = symbol;
 
@@ -4703,6 +5085,9 @@ static declaration_t *get_label(symbol_t *symbol)
        return declaration;
 }
 
+/**
+ * Parse a label statement.
+ */
 static statement_t *parse_label_statement(void)
 {
        assert(token.type == T_IDENTIFIER);
@@ -4714,39 +5099,55 @@ static statement_t *parse_label_statement(void)
        /* if source position is already set then the label is defined twice,
         * otherwise it was just mentioned in a goto so far */
        if(label->source_position.input_name != NULL) {
-               parser_print_error_prefix();
-               fprintf(stderr, "duplicate label '%s'\n", symbol->string);
-               parser_print_error_prefix_pos(label->source_position);
-               fprintf(stderr, "previous definition of '%s' was here\n",
-                       symbol->string);
+               errorf(HERE, "duplicate label '%Y'", symbol);
+               errorf(label->source_position, "previous definition of '%Y' was here",
+                      symbol);
        } else {
                label->source_position = token.source_position;
        }
 
        label_statement_t *label_statement = allocate_ast_zero(sizeof(label[0]));
 
-       label_statement->statement.type            = STATEMENT_LABEL;
+       label_statement->statement.kind            = STATEMENT_LABEL;
        label_statement->statement.source_position = token.source_position;
        label_statement->label                     = label;
 
-       expect(':');
+       eat(':');
 
        if(token.type == '}') {
-               parse_error("label at end of compound statement");
+               /* TODO only warn? */
+               errorf(HERE, "label at end of compound statement");
                return (statement_t*) label_statement;
        } else {
-               label_statement->label_statement = parse_statement();
+               if (token.type == ';') {
+                       /* eat an empty statement here, to avoid the warning about an empty
+                        * after a label.  label:; is commonly used to have a label before
+                        * a }. */
+                       next_token();
+               } else {
+                       label_statement->label_statement = parse_statement();
+               }
+       }
+
+       /* remember the labels's in a list for later checking */
+       if (label_last == NULL) {
+               label_first = label_last = label_statement;
+       } else {
+               label_last->next = label_statement;
        }
 
        return (statement_t*) label_statement;
 }
 
+/**
+ * Parse an if statement.
+ */
 static statement_t *parse_if(void)
 {
        eat(T_if);
 
        if_statement_t *statement = allocate_ast_zero(sizeof(statement[0]));
-       statement->statement.type            = STATEMENT_IF;
+       statement->statement.kind            = STATEMENT_IF;
        statement->statement.source_position = token.source_position;
 
        expect('(');
@@ -4762,47 +5163,82 @@ static statement_t *parse_if(void)
        return (statement_t*) statement;
 }
 
+/**
+ * Parse a switch statement.
+ */
 static statement_t *parse_switch(void)
 {
        eat(T_switch);
 
        switch_statement_t *statement = allocate_ast_zero(sizeof(statement[0]));
-       statement->statement.type            = STATEMENT_SWITCH;
+       statement->statement.kind            = STATEMENT_SWITCH;
        statement->statement.source_position = token.source_position;
 
        expect('(');
-       statement->expression = parse_expression();
+       expression_t *const expr = parse_expression();
+       type_t       *      type = skip_typeref(expr->base.datatype);
+       if (is_type_integer(type)) {
+               type = promote_integer(type);
+       } else if (is_type_valid(type)) {
+               errorf(expr->base.source_position, "switch quantity is not an integer, but '%T'", type);
+               type = type_error_type;
+       }
+       statement->expression = create_implicit_cast(expr, type);
        expect(')');
+
+       switch_statement_t *rem = current_switch;
+       current_switch  = statement;
        statement->body = parse_statement();
+       current_switch  = rem;
+
+       if (warning.switch_default && find_default_label(statement) == NULL) {
+               warningf(statement->statement.source_position, "switch has no default case");
+       }
 
        return (statement_t*) statement;
 }
 
+static statement_t *parse_loop_body(statement_t *const loop)
+{
+       statement_t *const rem = current_loop;
+       current_loop = loop;
+       statement_t *const body = parse_statement();
+       current_loop = rem;
+       return body;
+}
+
+/**
+ * Parse a while statement.
+ */
 static statement_t *parse_while(void)
 {
        eat(T_while);
 
        while_statement_t *statement = allocate_ast_zero(sizeof(statement[0]));
-       statement->statement.type            = STATEMENT_WHILE;
+       statement->statement.kind            = STATEMENT_WHILE;
        statement->statement.source_position = token.source_position;
 
        expect('(');
        statement->condition = parse_expression();
        expect(')');
-       statement->body = parse_statement();
+
+       statement->body = parse_loop_body((statement_t*)statement);
 
        return (statement_t*) statement;
 }
 
+/**
+ * Parse a do statement.
+ */
 static statement_t *parse_do(void)
 {
        eat(T_do);
 
        do_while_statement_t *statement = allocate_ast_zero(sizeof(statement[0]));
-       statement->statement.type            = STATEMENT_DO_WHILE;
+       statement->statement.kind            = STATEMENT_DO_WHILE;
        statement->statement.source_position = token.source_position;
 
-       statement->body = parse_statement();
+       statement->body = parse_loop_body((statement_t*)statement);
        expect(T_while);
        expect('(');
        statement->condition = parse_expression();
@@ -4812,19 +5248,22 @@ static statement_t *parse_do(void)
        return (statement_t*) statement;
 }
 
+/**
+ * Parse a for statement.
+ */
 static statement_t *parse_for(void)
 {
        eat(T_for);
 
        for_statement_t *statement = allocate_ast_zero(sizeof(statement[0]));
-       statement->statement.type            = STATEMENT_FOR;
+       statement->statement.kind            = STATEMENT_FOR;
        statement->statement.source_position = token.source_position;
 
        expect('(');
 
-       int         top          = environment_top();
-       context_t  *last_context = context;
-       set_context(&statement->context);
+       int      top        = environment_top();
+       scope_t *last_scope = scope;
+       set_scope(&statement->scope);
 
        if(token.type != ';') {
                if(is_declaration_specifier(&token, false)) {
@@ -4845,15 +5284,18 @@ static statement_t *parse_for(void)
                statement->step = parse_expression();
        }
        expect(')');
-       statement->body = parse_statement();
+       statement->body = parse_loop_body((statement_t*)statement);
 
-       assert(context == &statement->context);
-       set_context(last_context);
+       assert(scope == &statement->scope);
+       set_scope(last_scope);
        environment_pop_to(top);
 
        return (statement_t*) statement;
 }
 
+/**
+ * Parse a goto statement.
+ */
 static statement_t *parse_goto(void)
 {
        eat(T_goto);
@@ -4870,82 +5312,150 @@ static statement_t *parse_goto(void)
 
        goto_statement_t *statement = allocate_ast_zero(sizeof(statement[0]));
 
-       statement->statement.type            = STATEMENT_GOTO;
+       statement->statement.kind            = STATEMENT_GOTO;
        statement->statement.source_position = token.source_position;
 
        statement->label = label;
 
+       /* remember the goto's in a list for later checking */
+       if (goto_last == NULL) {
+               goto_first = goto_last = statement;
+       } else {
+               goto_last->next = statement;
+       }
+
        expect(';');
 
        return (statement_t*) statement;
 }
 
+/**
+ * Parse a continue statement.
+ */
 static statement_t *parse_continue(void)
 {
+       statement_t *statement;
+       if (current_loop == NULL) {
+               errorf(HERE, "continue statement not within loop");
+               statement = NULL;
+       } else {
+               statement = allocate_statement_zero(STATEMENT_CONTINUE);
+
+               statement->base.source_position = token.source_position;
+       }
+
        eat(T_continue);
        expect(';');
 
-       statement_t *statement          = allocate_ast_zero(sizeof(statement[0]));
-       statement->type                 = STATEMENT_CONTINUE;
-       statement->base.source_position = token.source_position;
-
        return statement;
 }
 
+/**
+ * Parse a break statement.
+ */
 static statement_t *parse_break(void)
 {
+       statement_t *statement;
+       if (current_switch == NULL && current_loop == NULL) {
+               errorf(HERE, "break statement not within loop or switch");
+               statement = NULL;
+       } else {
+               statement = allocate_statement_zero(STATEMENT_BREAK);
+
+               statement->base.source_position = token.source_position;
+       }
+
        eat(T_break);
        expect(';');
 
-       statement_t *statement          = allocate_ast_zero(sizeof(statement[0]));
-       statement->type                 = STATEMENT_BREAK;
-       statement->base.source_position = token.source_position;
-
        return statement;
 }
 
+/**
+ * Check if a given declaration represents a local variable.
+ */
+static bool is_local_var_declaration(const declaration_t *declaration) {
+       switch ((storage_class_tag_t) declaration->storage_class) {
+       case STORAGE_CLASS_NONE:
+       case STORAGE_CLASS_AUTO:
+       case STORAGE_CLASS_REGISTER: {
+               const type_t *type = skip_typeref(declaration->type);
+               if(is_type_function(type)) {
+                       return false;
+               } else {
+                       return true;
+               }
+       }
+       default:
+               return false;
+       }
+}
+
+/**
+ * Check if a given expression represents a local variable.
+ */
+static bool is_local_variable(const expression_t *expression)
+{
+       if (expression->base.kind != EXPR_REFERENCE) {
+               return false;
+       }
+       const declaration_t *declaration = expression->reference.declaration;
+       return is_local_var_declaration(declaration);
+}
+
+/**
+ * Parse a return statement.
+ */
 static statement_t *parse_return(void)
 {
        eat(T_return);
 
        return_statement_t *statement = allocate_ast_zero(sizeof(statement[0]));
 
-       statement->statement.type            = STATEMENT_RETURN;
+       statement->statement.kind            = STATEMENT_RETURN;
        statement->statement.source_position = token.source_position;
 
-       assert(is_type_function(current_function->type));
-       function_type_t *function_type = &current_function->type->function;
-       type_t          *return_type   = function_type->return_type;
-
        expression_t *return_value = NULL;
        if(token.type != ';') {
                return_value = parse_expression();
        }
        expect(';');
 
-       if(return_type == NULL)
-               return (statement_t*) statement;
-       if(return_value != NULL && return_value->base.datatype == NULL)
-               return (statement_t*) statement;
-
-       return_type = skip_typeref(return_type);
+       const type_t *const func_type = current_function->type;
+       assert(is_type_function(func_type));
+       type_t *const return_type = skip_typeref(func_type->function.return_type);
 
        if(return_value != NULL) {
                type_t *return_value_type = skip_typeref(return_value->base.datatype);
 
                if(is_type_atomic(return_type, ATOMIC_TYPE_VOID)
                                && !is_type_atomic(return_value_type, ATOMIC_TYPE_VOID)) {
-                       parse_warning("'return' with a value, in function returning void");
+                       warningf(statement->statement.source_position,
+                               "'return' with a value, in function returning void");
                        return_value = NULL;
                } else {
-                       if(return_type != NULL) {
-                               semantic_assign(return_type, &return_value, "'return'");
+                       type_t *const res_type = semantic_assign(return_type,
+                               return_value, "'return'");
+                       if (res_type == NULL) {
+                               errorf(statement->statement.source_position,
+                                       "cannot return something of type '%T' in function returning '%T'",
+                                       return_value->base.datatype, return_type);
+                       } else {
+                               return_value = create_implicit_cast(return_value, res_type);
+                       }
+               }
+               /* check for returning address of a local var */
+               if (return_value->base.kind == EXPR_UNARY_TAKE_ADDRESS) {
+                       const expression_t *expression = return_value->unary.value;
+                       if (is_local_variable(expression)) {
+                               warningf(statement->statement.source_position,
+                                       "function returns address of local variable");
                        }
                }
        } else {
                if(!is_type_atomic(return_type, ATOMIC_TYPE_VOID)) {
-                       parse_warning("'return' without value, in function returning "
-                                     "non-void");
+                       warningf(statement->statement.source_position,
+                               "'return' without value, in function returning non-void");
                }
        }
        statement->return_value = return_value;
@@ -4953,6 +5463,9 @@ static statement_t *parse_return(void)
        return (statement_t*) statement;
 }
 
+/**
+ * Parse a declaration statement.
+ */
 static statement_t *parse_declaration_statement(void)
 {
        statement_t *statement = allocate_statement_zero(STATEMENT_DECLARATION);
@@ -4963,7 +5476,7 @@ static statement_t *parse_declaration_statement(void)
        parse_declaration(record_declaration);
 
        if(before == NULL) {
-               statement->declaration.declarations_begin = context->declarations;
+               statement->declaration.declarations_begin = scope->declarations;
        } else {
                statement->declaration.declarations_begin = before->next;
        }
@@ -4972,18 +5485,29 @@ static statement_t *parse_declaration_statement(void)
        return statement;
 }
 
+/**
+ * Parse an expression statement, ie. expr ';'.
+ */
 static statement_t *parse_expression_statement(void)
 {
        statement_t *statement = allocate_statement_zero(STATEMENT_EXPRESSION);
 
        statement->base.source_position  = token.source_position;
-       statement->expression.expression = parse_expression();
+       expression_t *const expr         = parse_expression();
+       statement->expression.expression = expr;
+
+       if (warning.unused_value  && !expression_has_effect(expr)) {
+               warningf(expr->base.source_position, "statement has no effect");
+       }
 
        expect(';');
 
        return statement;
 }
 
+/**
+ * Parse a statement.
+ */
 static statement_t *parse_statement(void)
 {
        statement_t   *statement = NULL;
@@ -5043,6 +5567,9 @@ static statement_t *parse_statement(void)
                break;
 
        case ';':
+               if (warning.empty_statement) {
+                       warningf(HERE, "statement is empty");
+               }
                next_token();
                statement = NULL;
                break;
@@ -5085,18 +5612,21 @@ static statement_t *parse_statement(void)
        return statement;
 }
 
+/**
+ * Parse a compound statement.
+ */
 static statement_t *parse_compound_statement(void)
 {
-       compound_statement_t *compound_statement
+       compound_statement_t *const compound_statement
                = allocate_ast_zero(sizeof(compound_statement[0]));
-       compound_statement->statement.type            = STATEMENT_COMPOUND;
+       compound_statement->statement.kind            = STATEMENT_COMPOUND;
        compound_statement->statement.source_position = token.source_position;
 
        eat('{');
 
-       int        top          = environment_top();
-       context_t *last_context = context;
-       set_context(&compound_statement->context);
+       int      top        = environment_top();
+       scope_t *last_scope = scope;
+       set_scope(&compound_statement->scope);
 
        statement_t *last_statement = NULL;
 
@@ -5117,61 +5647,86 @@ static statement_t *parse_compound_statement(void)
                last_statement = statement;
        }
 
-       if(token.type != '}') {
-               parser_print_error_prefix_pos(
-                               compound_statement->statement.source_position);
-               fprintf(stderr, "end of file while looking for closing '}'\n");
+       if(token.type == '}') {
+               next_token();
+       } else {
+               errorf(compound_statement->statement.source_position, "end of file while looking for closing '}'");
        }
-       next_token();
 
-       assert(context == &compound_statement->context);
-       set_context(last_context);
+       assert(scope == &compound_statement->scope);
+       set_scope(last_scope);
        environment_pop_to(top);
 
        return (statement_t*) compound_statement;
 }
 
-static void initialize_builtins(void)
+/**
+ * Initialize builtin types.
+ */
+static void initialize_builtin_types(void)
 {
-       type_wchar_t     = make_global_typedef("__WCHAR_TYPE__", type_int);
-       type_wchar_t_ptr = make_pointer_type(type_wchar_t, TYPE_QUALIFIER_NONE);
-       type_size_t      = make_global_typedef("__SIZE_TYPE__",
-                       make_atomic_type(ATOMIC_TYPE_ULONG, TYPE_QUALIFIER_NONE));
-       type_ptrdiff_t   = make_global_typedef("__PTRDIFF_TYPE__",
-                       make_atomic_type(ATOMIC_TYPE_LONG, TYPE_QUALIFIER_NONE));
+       type_intmax_t    = make_global_typedef("__intmax_t__",      type_long_long);
+       type_size_t      = make_global_typedef("__SIZE_TYPE__",     type_unsigned_long);
+       type_ssize_t     = make_global_typedef("__SSIZE_TYPE__",    type_long);
+       type_ptrdiff_t   = make_global_typedef("__PTRDIFF_TYPE__",  type_long);
+       type_uintmax_t   = make_global_typedef("__uintmax_t__",     type_unsigned_long_long);
+       type_uptrdiff_t  = make_global_typedef("__UPTRDIFF_TYPE__", type_unsigned_long);
+       type_wchar_t     = make_global_typedef("__WCHAR_TYPE__",    type_int);
+       type_wint_t      = make_global_typedef("__WINT_TYPE__",     type_int);
+
+       type_intmax_t_ptr  = make_pointer_type(type_intmax_t,  TYPE_QUALIFIER_NONE);
+       type_ptrdiff_t_ptr = make_pointer_type(type_ptrdiff_t, TYPE_QUALIFIER_NONE);
+       type_ssize_t_ptr   = make_pointer_type(type_ssize_t,   TYPE_QUALIFIER_NONE);
+       type_wchar_t_ptr   = make_pointer_type(type_wchar_t,   TYPE_QUALIFIER_NONE);
 }
 
+/**
+ * Parse a translation unit.
+ */
 static translation_unit_t *parse_translation_unit(void)
 {
        translation_unit_t *unit = allocate_ast_zero(sizeof(unit[0]));
 
-       assert(global_context == NULL);
-       global_context = &unit->context;
+       assert(global_scope == NULL);
+       global_scope = &unit->scope;
 
-       assert(context == NULL);
-       set_context(&unit->context);
+       assert(scope == NULL);
+       set_scope(&unit->scope);
 
-       initialize_builtins();
+       initialize_builtin_types();
 
        while(token.type != T_EOF) {
-               parse_external_declaration();
+               if (token.type == ';') {
+                       /* TODO error in strict mode */
+                       warningf(HERE, "stray ';' outside of function");
+                       next_token();
+               } else {
+                       parse_external_declaration();
+               }
        }
 
-       assert(context == &unit->context);
-       context          = NULL;
+       assert(scope == &unit->scope);
+       scope          = NULL;
        last_declaration = NULL;
 
-       assert(global_context == &unit->context);
-       global_context = NULL;
+       assert(global_scope == &unit->scope);
+       global_scope = NULL;
 
        return unit;
 }
 
+/**
+ * Parse the input.
+ *
+ * @return  the translation unit or NULL if errors occurred.
+ */
 translation_unit_t *parse(void)
 {
        environment_stack = NEW_ARR_F(stack_entry_t, 0);
        label_stack       = NEW_ARR_F(stack_entry_t, 0);
-       found_error       = false;
+       diagnostic_count  = 0;
+       error_count       = 0;
+       warning_count     = 0;
 
        type_set_output(stderr);
        ast_set_output(stderr);
@@ -5185,32 +5740,27 @@ translation_unit_t *parse(void)
        DEL_ARR_F(environment_stack);
        DEL_ARR_F(label_stack);
 
-       if(found_error)
+       if(error_count > 0)
                return NULL;
 
        return unit;
 }
 
+/**
+ * Initialize the parser.
+ */
 void init_parser(void)
 {
        init_expression_parsers();
        obstack_init(&temp_obst);
 
-       type_int         = make_atomic_type(ATOMIC_TYPE_INT, TYPE_QUALIFIER_NONE);
-       type_long_double = make_atomic_type(ATOMIC_TYPE_LONG_DOUBLE,
-                                           TYPE_QUALIFIER_NONE);
-       type_double      = make_atomic_type(ATOMIC_TYPE_DOUBLE,
-                                           TYPE_QUALIFIER_NONE);
-       type_float       = make_atomic_type(ATOMIC_TYPE_FLOAT, TYPE_QUALIFIER_NONE);
-       type_char        = make_atomic_type(ATOMIC_TYPE_CHAR, TYPE_QUALIFIER_NONE);
-       type_void        = make_atomic_type(ATOMIC_TYPE_VOID, TYPE_QUALIFIER_NONE);
-       type_void_ptr    = make_pointer_type(type_void, TYPE_QUALIFIER_NONE);
-       type_string      = make_pointer_type(type_char, TYPE_QUALIFIER_NONE);
-
        symbol_t *const va_list_sym = symbol_table_insert("__builtin_va_list");
        type_valist = create_builtin_type(va_list_sym, type_void_ptr);
 }
 
+/**
+ * Terminate the parser.
+ */
 void exit_parser(void)
 {
        obstack_free(&temp_obst, NULL);