+type_t *make_reference_type(type_t *refers_to);
+type_t *make_based_pointer_type(type_t *points_to,
+ type_qualifiers_t qualifiers, variable_t *variable);
+type_t *make_array_type(type_t *element_type, size_t size,
+ type_qualifiers_t qualifiers);
+
+type_t *duplicate_type(const type_t *type);
+type_t *identify_new_type(type_t *type);
+
+static inline bool is_typeref(const type_t *type)
+{
+ return type->kind == TYPE_TYPEDEF || type->kind == TYPE_TYPEOF;
+}
+
+static inline bool is_type_atomic(const type_t *type, atomic_type_kind_t atype)
+{
+ assert(!is_typeref(type));
+
+ if(type->kind != TYPE_ATOMIC)
+ return false;
+ const atomic_type_t *atomic_type = &type->atomic;
+
+ return atomic_type->akind == atype;
+}
+
+static inline bool is_type_pointer(const type_t *type)
+{
+ assert(!is_typeref(type));
+ return type->kind == TYPE_POINTER;
+}
+
+static inline bool is_type_reference(const type_t *type)
+{
+ assert(!is_typeref(type));
+ return type->kind == TYPE_REFERENCE;
+}
+
+static inline bool is_type_array(const type_t *type)
+{
+ assert(!is_typeref(type));
+ return type->kind == TYPE_ARRAY;
+}
+
+static inline bool is_type_function(const type_t *type)
+{
+ assert(!is_typeref(type));
+ return type->kind == TYPE_FUNCTION;
+}
+
+static inline bool is_type_union(const type_t *type)
+{
+ assert(!is_typeref(type));
+ return type->kind == TYPE_COMPOUND_UNION;
+}
+
+static inline bool is_type_struct(const type_t *type)
+{
+ assert(!is_typeref(type));
+ return type->kind == TYPE_COMPOUND_STRUCT;
+}
+
+static inline bool is_type_builtin(const type_t *type)
+{
+ assert(!is_typeref(type));
+ return type->kind == TYPE_BUILTIN;
+}
+
+static inline bool is_type_compound(const type_t *type)
+{
+ assert(!is_typeref(type));
+ return type->kind == TYPE_COMPOUND_STRUCT
+ || type->kind == TYPE_COMPOUND_UNION;
+}
+
+static inline bool is_type_valid(const type_t *type)
+{
+ assert(!is_typeref(type));
+ return type->kind != TYPE_ERROR;
+}
+
+/**
+ * Allocate a type node of given kind and initialize all
+ * fields with zero.
+ *
+ * @param kind type kind to allocate
+ */
+type_t *allocate_type_zero(type_kind_t kind);
+
+/**
+ * Creates a return_type (func)(void) function type if not
+ * already exists.
+ *
+ * @param return_type the return type
+ */
+type_t *make_function_0_type(type_t *return_type);
+
+/**
+ * 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
+ */
+type_t *make_function_1_type(type_t *return_type, type_t *argument_type1);
+
+
+/**
+ * Creates a return_type (func)(argument_type1,argument_type2) function type
+ * if not already exists.
+ */
+type_t *make_function_2_type(type_t *return_type, type_t *argument_type1,
+ type_t *argument_type2);
+
+/**
+ * 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
+ */
+type_t *make_function_1_type_variadic(type_t *return_type, type_t *argument_type);
+
+/**
+ * Create a function type with n parameters
+ */
+type_t *make_function_type(type_t *return_type, int n_types,
+ type_t *const *argument_types,
+ decl_modifiers_t modifiers);