&& and || accept scalar types, not only arithmetic types.
[cparser] / parser.c
index c33c112..560fa4d 100644 (file)
--- a/parser.c
+++ b/parser.c
@@ -208,12 +208,18 @@ static void parser_print_warning_prefix_pos(
        fputs("warning: ", stderr);
 }
 
-static void parse_warning(const char *message)
+static void parse_warning_pos(const source_position_t source_position,
+                              const char *const message)
 {
-       parser_print_prefix_pos(token.source_position);
+       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);
+}
+
 static void parse_error_expected(const char *message, ...)
 {
        va_list args;
@@ -243,14 +249,20 @@ static void parse_error_expected(const char *message, ...)
        fprintf(stderr, "\n");
 }
 
+static void print_type_quoted(type_t *type)
+{
+       fputc('\'', stderr);
+       print_type(type);
+       fputc('\'', stderr);
+}
+
 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(type);
+       print_type_quoted(type);
        fputc('\n', stderr);
-       error();
 }
 
 static void type_error_incompatible(const char *msg,
@@ -258,11 +270,10 @@ static void type_error_incompatible(const char *msg,
 {
        parser_print_error_prefix_pos(source_position);
        fprintf(stderr, "%s, incompatible types: ", msg);
-       print_type(type1);
+       print_type_quoted(type1);
        fprintf(stderr, " - ");
-       print_type(type2);
+       print_type_quoted(type2);
        fprintf(stderr, ")\n");
-       error();
 }
 
 static void eat_block(void)
@@ -398,7 +409,7 @@ static declaration_t *stack_push(stack_entry_t **stack_ptr,
                                  context_t *parent_context)
 {
        symbol_t    *symbol    = declaration->symbol;
-       namespace_t  namespace = declaration->namespace;
+       namespace_t  namespace = (namespace_t)declaration->namespace;
 
        /* a declaration should be only pushed once */
        assert(declaration->parent_context == NULL);
@@ -412,15 +423,62 @@ static declaration_t *stack_push(stack_entry_t **stack_ptr,
                        parser_print_error_prefix_pos(declaration->source_position);
                        fprintf(stderr, "definition of symbol %s%s with type ",
                                        get_namespace_prefix(namespace), symbol->string);
-                       error();
-                       print_type(declaration->type);
+                       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(previous_declaration->type);
+                       print_type_quoted(previous_declaration->type);
                        fputc('\n', stderr);
+               } else {
+                       const storage_class_t old_storage = previous_declaration->storage_class;
+                       const storage_class_t new_storage = declaration->storage_class;
+                       if (current_function == NULL) {
+                               if (old_storage != STORAGE_CLASS_STATIC &&
+                                   new_storage == 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 == STORAGE_CLASS_EXTERN) {
+                                               if (new_storage == 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 == STORAGE_CLASS_EXTERN &&
+                                               new_storage == 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 == new_storage) {
+                                               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;
        }
@@ -430,7 +488,7 @@ static declaration_t *stack_push(stack_entry_t **stack_ptr,
        entry.symbol          = symbol;
        entry.old_declaration = symbol->declaration;
        entry.namespace       = namespace;
-       ARR_APP1(*stack_ptr, entry);
+       ARR_APP1(stack_entry_t, *stack_ptr, entry);
 
        /* replace/add declaration into declaration list of the symbol */
        if(symbol->declaration == NULL) {
@@ -488,7 +546,7 @@ static void stack_pop_to(stack_entry_t **stack_ptr, size_t new_top)
 
                declaration_t *old_declaration = entry->old_declaration;
                symbol_t      *symbol          = entry->symbol;
-               namespace_t    namespace       = entry->namespace;
+               namespace_t    namespace       = (namespace_t)entry->namespace;
 
                /* replace/remove declaration */
                declaration_t *declaration = symbol->declaration;
@@ -498,20 +556,20 @@ static void stack_pop_to(stack_entry_t **stack_ptr, size_t new_top)
                                symbol->declaration = declaration->symbol_next;
                        } else {
                                symbol->declaration = old_declaration;
-                               assert(old_declaration->symbol_next ==
-                                      declaration->symbol_next);
                        }
                } else {
-                       for(; declaration != NULL; declaration = declaration->symbol_next) {
-                               declaration_t *symbol_next = declaration->symbol_next;
-                               if(symbol_next->namespace == namespace) {
-                                       declaration->symbol_next = old_declaration;
-                                       assert(old_declaration->symbol_next
-                                               == symbol_next->symbol_next);
+                       declaration_t *iter_last = declaration;
+                       declaration_t *iter      = declaration->symbol_next;
+                       for( ; iter != NULL; iter_last = iter, iter = iter->symbol_next) {
+                               /* replace an entry? */
+                               if(iter->namespace == namespace) {
+                                       assert(iter_last != NULL);
+                                       iter_last->symbol_next = old_declaration;
+                                       old_declaration->symbol_next = iter->symbol_next;
                                        break;
                                }
                        }
-                       assert(declaration != NULL);
+                       assert(iter != NULL);
                }
        }
 
@@ -566,6 +624,17 @@ static expression_t *create_cast_expression(expression_t *expression,
        return (expression_t*) cast;
 }
 
+static bool is_null_expression(const expression_t *const expr)
+{
+       if (expr->type != EXPR_CONST) return false;
+
+       type_t *const type = skip_typeref(expr->datatype);
+       if (!is_type_integer(type)) return false;
+
+       const const_t *const const_expr = (const const_t*)expr;
+       return const_expr->v.int_value == 0;
+}
+
 static expression_t *create_implicit_cast(expression_t *expression,
                                           type_t *dest_type)
 {
@@ -596,26 +665,36 @@ static expression_t *create_implicit_cast(expression_t *expression,
        if(dest_type->type == TYPE_POINTER) {
                pointer_type_t *pointer_type
                        = (pointer_type_t*) dest_type;
-               if(source_type->type == TYPE_POINTER) {
-                       if(!pointers_compatible(source_type, dest_type)) {
-                               type_error_incompatible("can't implicitely cast types",
-                                               expression->source_position,
-                                               source_type, dest_type);
-                           return expression;
-                       } else {
-                               return create_cast_expression(expression, dest_type);
-                       }
-               } else if(source_type->type == TYPE_ARRAY) {
-                       array_type_t *array_type = (array_type_t*) source_type;
-                       if(!types_compatible(array_type->element_type,
-                                            pointer_type->points_to)) {
-                               type_error_incompatible("can't implicitely cast types",
-                                               expression->source_position,
-                                               source_type, dest_type);
-                           return expression;
+               switch (source_type->type) {
+                       case TYPE_ATOMIC:
+                               if (is_null_expression(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 *const array_type = (array_type_t*) source_type;
+                               if (types_compatible(array_type->element_type,
+                                                                                                                pointer_type->points_to)) {
+                                       return create_cast_expression(expression, dest_type);
+                               }
+                               break;
                        }
-                       return create_cast_expression(expression, dest_type);
+
+                       default:
+                               panic("casting of non-atomic types not implemented yet");
                }
+
+               type_error_incompatible("can't implicitely cast types",
+                                                                                                               expression->source_position,
+                                                                                                               source_type, dest_type);
+               return expression;
        }
 
        panic("casting of non-atomic types not implemented yet");
@@ -629,24 +708,23 @@ static void semantic_assign(type_t *orig_type_left, expression_t **right,
        if(orig_type_right == NULL)
                return;
 
-       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(type_left == type_right) {
                /* fine */
-       } else if(is_type_arithmetic(type_left) && is_type_arithmetic(type_right)) {
+       } else if ((is_type_arithmetic(type_left) && is_type_arithmetic(type_right)) ||
+                  (type_left->type == TYPE_POINTER && is_null_expression(*right)) ||
+                  (type_left->type == TYPE_POINTER && type_right->type == TYPE_POINTER)) {
                *right = create_implicit_cast(*right, type_left);
-       } else if(type_left->type == TYPE_POINTER
-                       && type_right->type == TYPE_POINTER) {
-               /* TODO */
        } else {
                /* TODO: improve error message */
                parser_print_error_prefix();
                fprintf(stderr, "incompatible types in %s\n", context);
                parser_print_error_prefix();
-               print_type(type_left);
+               print_type_quoted(type_left);
                fputs(" <- ", stderr);
-               print_type(type_right);
+               print_type_quoted(type_right);
                fputs("\n", stderr);
        }
 
@@ -762,7 +840,7 @@ static designator_t *parse_designation(void)
                        designator = allocate_ast_zero(sizeof(designator[0]));
                        next_token();
                        if(token.type != T_IDENTIFIER) {
-                               parse_error_expected("problem while parsing designator",
+                               parse_error_expected("while parsing designator",
                                                     T_IDENTIFIER, 0);
                                return NULL;
                        }
@@ -831,8 +909,7 @@ static initializer_t *parse_initializer_list(type_t *type)
                        break;
 
                if(token.type != ',') {
-                       parse_error_expected("problem while parsing initializer list",
-                                            ',', '}', 0);
+                       parse_error_expected("while parsing initializer list", ',', '}', 0);
                        eat_block();
                        return result;
                }
@@ -869,10 +946,10 @@ static declaration_t *parse_compound_type_specifier(bool is_struct)
                }
        } else if(token.type != '{') {
                if(is_struct) {
-                       parse_error_expected("problem while parsing struct type specifier",
+                       parse_error_expected("while parsing struct type specifier",
                                             T_IDENTIFIER, '{', 0);
                } else {
-                       parse_error_expected("problem while parsing union type specifier",
+                       parse_error_expected("while parsing union type specifier",
                                             T_IDENTIFIER, '{', 0);
                }
 
@@ -889,6 +966,7 @@ static declaration_t *parse_compound_type_specifier(bool is_struct)
                }
                declaration->source_position = token.source_position;
                declaration->symbol          = symbol;
+               record_declaration(declaration);
        }
 
        if(token.type == '{') {
@@ -899,7 +977,6 @@ static declaration_t *parse_compound_type_specifier(bool is_struct)
                                        is_struct ? "struct" : "union", symbol->string);
                        declaration->context.declarations = NULL;
                }
-               record_declaration(declaration);
                declaration->init.is_defined = true;
 
                int         top          = environment_top();
@@ -931,8 +1008,7 @@ static void parse_enum_entries(void)
                declaration_t *entry = allocate_ast_zero(sizeof(entry[0]));
 
                if(token.type != T_IDENTIFIER) {
-                       parse_error_expected("problem while parsing enum entry",
-                                            T_IDENTIFIER, 0);
+                       parse_error_expected("while parsing enum entry", T_IDENTIFIER, 0);
                        eat_block();
                        return;
                }
@@ -969,7 +1045,7 @@ static declaration_t *parse_enum_specifier(void)
 
                declaration = get_declaration(symbol, NAMESPACE_ENUM);
        } else if(token.type != '{') {
-               parse_error_expected("problem while parsing enum type specifier",
+               parse_error_expected("while parsing enum type specifier",
                                     T_IDENTIFIER, '{', 0);
                return NULL;
        } else {
@@ -1378,7 +1454,7 @@ finish_specifiers:
                }
        }
 
-       type->qualifiers = type_qualifiers;
+       type->qualifiers = (type_qualifier_t)type_qualifiers;
 
        type_t *result = typehash_insert(type);
        if(newtype && result != (type_t*) type) {
@@ -1388,9 +1464,9 @@ finish_specifiers:
        specifiers->type = result;
 }
 
-static type_qualifier_t parse_type_qualifiers(void)
+static unsigned parse_type_qualifiers(void)
 {
-       type_qualifier_t type_qualifiers = 0;
+       unsigned type_qualifiers = TYPE_QUALIFIER_NONE;
 
        while(true) {
                switch(token.type) {
@@ -1409,8 +1485,8 @@ static void parse_identifier_list(void)
 {
        while(true) {
                if(token.type != T_IDENTIFIER) {
-                       parse_error_expected("problem while parsing parameter identifier "
-                                            "list", T_IDENTIFIER, 0);
+                       parse_error_expected("while parsing parameter identifier list",
+                                            T_IDENTIFIER, 0);
                        return;
                }
                next_token();
@@ -1647,8 +1723,7 @@ static construct_type_t *parse_inner_declarator(declaration_t *declaration,
        default:
                if(may_be_abstract)
                        break;
-               parse_error_expected("problem while parsing declarator", T_IDENTIFIER,
-                                    '(', 0);
+               parse_error_expected("while parsing declarator", T_IDENTIFIER, '(', 0);
        }
 
        while(true) {
@@ -1807,7 +1882,6 @@ static void parser_error_multiple_definition(declaration_t *previous,
        parser_print_error_prefix_pos(previous->source_position);
        fprintf(stderr, "this is the location of the previous "
                "definition.\n");
-       error();
 }
 
 static void parse_init_declarators(const declaration_specifiers_t *specifiers)
@@ -1943,6 +2017,29 @@ static void parse_declaration(void)
        parse_declaration_specifiers(&specifiers);
 
        if(token.type == ';') {
+               if (specifiers.storage_class != STORAGE_CLASS_NONE) {
+                       parse_warning_pos(source_position,
+                                         "useless keyword in empty declaration");
+               }
+               switch (specifiers.type->type) {
+                       case TYPE_COMPOUND_STRUCT:
+                       case TYPE_COMPOUND_UNION: {
+                               const compound_type_t *const comp_type =
+                                       (const compound_type_t*)specifiers.type;
+                               if (comp_type->declaration->symbol == NULL) {
+                                       parse_warning_pos(source_position,
+                                                                                                               "unnamed struct/union that defines no instances");
+                               }
+                               break;
+                       }
+
+                       case TYPE_ENUM: break;
+
+                       default:
+                               parse_warning_pos(source_position, "empty declaration");
+                               break;
+               }
+
                next_token();
 
                declaration_t *declaration = allocate_ast_zero(sizeof(declaration[0]));
@@ -1990,6 +2087,14 @@ struct expression_parser_function_t {
 
 expression_parser_function_t expression_parsers[T_LAST_TOKEN];
 
+static expression_t *make_invalid_expression(void)
+{
+       expression_t *expression    = allocate_ast_zero(sizeof(expression[0]));
+       expression->type            = EXPR_INVALID;
+       expression->source_position = token.source_position;
+       return expression;
+}
+
 static expression_t *expected_expression_error(void)
 {
        parser_print_error_prefix();
@@ -1997,11 +2102,9 @@ static expression_t *expected_expression_error(void)
        print_token(stderr, & token);
        fprintf(stderr, "\n");
 
-       expression_t *expression = allocate_ast_zero(sizeof(expression[0]));
-       expression->type = EXPR_INVALID;
        next_token();
 
-       return expression;
+       return make_invalid_expression();
 }
 
 static expression_t *parse_string_const(void)
@@ -2238,7 +2341,7 @@ static designator_t *parse_designator(void)
        designator_t *result = allocate_ast_zero(sizeof(result[0]));
 
        if(token.type != T_IDENTIFIER) {
-               parse_error_expected("problem while parsing member designator",
+               parse_error_expected("while parsing member designator",
                                     T_IDENTIFIER, 0);
                eat_brace();
                return NULL;
@@ -2251,8 +2354,8 @@ static designator_t *parse_designator(void)
                if(token.type == '.') {
                        next_token();
                        if(token.type != T_IDENTIFIER) {
-                               parse_error_expected("problem while parsing member designator",
-                                       T_IDENTIFIER, 0);
+                               parse_error_expected("while parsing member designator",
+                                                    T_IDENTIFIER, 0);
                                eat_brace();
                                return NULL;
                        }
@@ -2367,11 +2470,7 @@ static expression_t *parse_primary_expression(void)
        fprintf(stderr, "\n");
        eat_statement();
 
-       expression_t *expression = allocate_ast_zero(sizeof(expression[0]));
-       expression->type     = EXPR_INVALID;
-       expression->datatype = type_void;
-
-       return expression;
+       return make_invalid_expression();
 }
 
 static expression_t *parse_array_expression(unsigned precedence,
@@ -2399,7 +2498,7 @@ static expression_t *parse_array_expression(unsigned precedence,
                } else {
                        parser_print_error_prefix();
                        fprintf(stderr, "array access on object with non-pointer type ");
-                       print_type(type);
+                       print_type_quoted(type);
                        fprintf(stderr, "\n");
                }
        }
@@ -2458,8 +2557,9 @@ static expression_t *parse_select_expression(unsigned precedence,
                                              expression_t *compound)
 {
        (void) precedence;
-
        assert(token.type == '.' || token.type == T_MINUSGREATER);
+
+       bool is_pointer = (token.type == T_MINUSGREATER);
        next_token();
 
        select_expression_t *select = allocate_ast_zero(sizeof(select[0]));
@@ -2467,15 +2567,69 @@ static expression_t *parse_select_expression(unsigned precedence,
        select->expression.type = EXPR_SELECT;
        select->compound        = compound;
 
-       /* TODO: datatype */
-
        if(token.type != T_IDENTIFIER) {
-               parse_error_expected("Problem while parsing select", T_IDENTIFIER, 0);
+               parse_error_expected("while parsing select", T_IDENTIFIER, 0);
                return (expression_t*) select;
        }
-       select->symbol = token.v.symbol;
+       symbol_t *symbol = token.v.symbol;
+       select->symbol   = symbol;
        next_token();
 
+       type_t *type = compound->datatype;
+       if(type == NULL)
+               return make_invalid_expression();
+
+       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(type);
+                       fputc('\n', stderr);
+                       return make_invalid_expression();
+               }
+               pointer_type_t *pointer_type = (pointer_type_t*) type;
+               type_left                    = pointer_type->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);
+               return make_invalid_expression();
+       }
+
+       compound_type_t *compound_type = (compound_type_t*) type_left;
+       declaration_t   *declaration   = compound_type->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);
+               return make_invalid_expression();
+       }
+
+       declaration_t *iter = declaration->context.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 memeber named '%s'\n", symbol->string);
+               return make_invalid_expression();
+       }
+
+       select->compound_entry      = iter;
+       select->expression.datatype = iter->type;
        return (expression_t*) select;
 }
 
@@ -2495,7 +2649,7 @@ static expression_t *parse_call_expression(unsigned precedence,
                fputs("called object '", stderr);
                print_expression(expression);
                fputs("' (type ", stderr);
-               print_type(type);
+               print_type_quoted(type);
                fputs("is not a function\n", stderr);
 
                function_type             = NULL;
@@ -2597,7 +2751,7 @@ static expression_t *parse_conditional_expression(unsigned precedence,
        /* 6.5.15.2 */
        type_t *condition_type = conditional->condition->datatype;
        if(condition_type != NULL) {
-               if(!is_type_scalar(condition_type)) {
+               if(!is_type_scalar(skip_typeref(condition_type))) {
                        type_error("expected a scalar type", expression->source_position,
                                   condition_type);
                }
@@ -2614,27 +2768,33 @@ static expression_t *parse_conditional_expression(unsigned precedence,
        if(false_type == NULL)
                return (expression_t*) conditional;
 
+       type_t *const skipped_true_type  = skip_typeref(true_type);
+       type_t *const skipped_false_type = skip_typeref(false_type);
+
        /* 6.5.15.3 */
-       if(true_type == false_type) {
-               conditional->expression.datatype = true_type;
-       } else if(is_type_arithmetic(true_type) && is_type_arithmetic(false_type)) {
-               type_t *result = get_type_after_conversion(true_type, false_type);
+       if (skipped_true_type == skipped_false_type) {
+               conditional->expression.datatype = skipped_true_type;
+       } else if (is_type_arithmetic(skipped_true_type) &&
+                  is_type_arithmetic(skipped_false_type)) {
+               type_t *const result = get_type_after_conversion(skipped_true_type,
+                                                                skipped_false_type);
                /* TODO: create implicit convs if necessary */
                conditional->expression.datatype = result;
-       } else if(true_type->type == TYPE_POINTER &&
-                 false_type->type == TYPE_POINTER &&
+       } else if (skipped_true_type->type == TYPE_POINTER &&
+                  skipped_false_type->type == TYPE_POINTER &&
                          true /* TODO compatible points_to types */) {
                /* TODO */
-       } else if(/* (is_null_ptr_const(true_type) && false_type->type == TYPE_POINTER)
-              || (is_null_ptr_const(false_type) &&
-                  true_type->type == TYPE_POINTER) TODO*/ false) {
+       } else if(/* (is_null_ptr_const(skipped_true_type) &&
+                     skipped_false_type->type == TYPE_POINTER)
+              || (is_null_ptr_const(skipped_false_type) &&
+                  skipped_true_type->type == TYPE_POINTER) TODO*/ false) {
                /* TODO */
        } else if(/* 1 is pointer to object type, other is void* */ false) {
                /* TODO */
        } else {
-               type_error_incompatible("problem while parsing conditional",
+               type_error_incompatible("while parsing conditional",
                                        expression->source_position, true_type,
-                                       false_type);
+                                       skipped_false_type);
        }
 
        return (expression_t*) conditional;
@@ -2707,6 +2867,15 @@ static void semantic_take_addr(unary_expression_t *expression)
        if(orig_type == NULL)
                return;
 
+       expression_t *value = expression->value;
+       if(value->type == EXPR_REFERENCE) {
+               reference_expression_t *reference   = (reference_expression_t*) value;
+               declaration_t          *declaration = reference->declaration;
+               if(declaration != NULL) {
+                       declaration->address_taken = 1;
+               }
+       }
+
        expression->expression.datatype = make_pointer_type(orig_type, 0);
 }
 
@@ -2879,9 +3048,9 @@ static void semantic_add(binary_expression_t *expression)
        } else {
                parser_print_error_prefix();
                fprintf(stderr, "invalid operands to binary + (");
-               print_type(orig_type_left);
+               print_type_quoted(orig_type_left);
                fprintf(stderr, ", ");
-               print_type(orig_type_right);
+               print_type_quoted(orig_type_right);
                fprintf(stderr, ")\n");
        }
 }
@@ -2913,9 +3082,9 @@ static void semantic_sub(binary_expression_t *expression)
                if(!pointers_compatible(type_left, type_right)) {
                        parser_print_error_prefix();
                        fprintf(stderr, "pointers to incompatible objects to binary - (");
-                       print_type(orig_type_left);
+                       print_type_quoted(orig_type_left);
                        fprintf(stderr, ", ");
-                       print_type(orig_type_right);
+                       print_type_quoted(orig_type_right);
                        fprintf(stderr, ")\n");
                } else {
                        expression->expression.datatype = type_ptrdiff_t;
@@ -2923,9 +3092,9 @@ static void semantic_sub(binary_expression_t *expression)
        } else {
                parser_print_error_prefix();
                fprintf(stderr, "invalid operands to binary - (");
-               print_type(orig_type_left);
+               print_type_quoted(orig_type_left);
                fprintf(stderr, ", ");
-               print_type(orig_type_right);
+               print_type_quoted(orig_type_right);
                fprintf(stderr, ")\n");
        }
 }
@@ -2949,6 +3118,17 @@ 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;
+       } else if (type_left->type  == TYPE_POINTER &&
+                  type_right->type == TYPE_POINTER) {
+               /* TODO check compatibility */
+       } else if (type_left->type == TYPE_POINTER) {
+               expression->right = create_implicit_cast(right, type_left);
+       } else if (type_right->type == TYPE_POINTER) {
+               expression->left = create_implicit_cast(left, type_right);
+       } else {
+               type_error_incompatible("invalid operands in comparison",
+                                       expression->expression.source_position,
+                                       type_left, type_right);
        }
        expression->expression.datatype = type_int;
 }
@@ -2995,10 +3175,10 @@ static void semantic_logical_op(binary_expression_t *expression)
        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)) {
+       if (!is_type_scalar(type_left) || !is_type_scalar(type_right)) {
                /* TODO: improve error message */
                parser_print_error_prefix();
-               fprintf(stderr, "operation needs arithmetic types\n");
+               fprintf(stderr, "operation needs scalar types\n");
                return;
        }
 
@@ -3120,7 +3300,7 @@ static expression_t *parse_sub_expression(unsigned precedence)
                left = parser->infix_parser(parser->infix_precedence, left);
 
                assert(left != NULL);
-               assert(left->type != EXPR_INVALID);
+               assert(left->type != EXPR_UNKNOWN);
                left->source_position = source_position;
        }