It turns out I'd already found lookup_and_check_tag's control flow
confusing, and had refactored it on the modules branch. For instance,
it continually checks 'if (decl &&$ condition)' before finally getting
to 'else if (!decl)'. why not just check !decl first and be done?
Well, it is done thusly.
gcc/cp/
* decl.c (lookup_and_check_tag): Refactor.
pushed to trunk
nathan
--
Nathan Sidwell
diff --git i/gcc/cp/decl.c w/gcc/cp/decl.c
index 14742c115ad..d2a8d4012ab 100644
--- i/gcc/cp/decl.c
+++ w/gcc/cp/decl.c
@@ -14885,71 +14885,73 @@ lookup_and_check_tag (enum tag_types tag_code, tree name,
else
decl = lookup_elaborated_type (name, how);
- if (decl
- && (DECL_CLASS_TEMPLATE_P (decl)
- /* If scope is TAG_how::CURRENT_ONLY we're defining a class,
- so ignore a template template parameter. */
- || (how != TAG_how::CURRENT_ONLY
- && DECL_TEMPLATE_TEMPLATE_PARM_P (decl))))
- decl = DECL_TEMPLATE_RESULT (decl);
-
- if (decl && TREE_CODE (decl) == TYPE_DECL)
- {
- /* Look for invalid nested type:
- class C {
- class C {};
- }; */
- if (how == TAG_how::CURRENT_ONLY && DECL_SELF_REFERENCE_P (decl))
- {
- error ("%qD has the same name as the class in which it is "
- "declared", decl);
- return error_mark_node;
- }
-
- /* Two cases we need to consider when deciding if a class
- template is allowed as an elaborated type specifier:
- 1. It is a self reference to its own class.
- 2. It comes with a template header.
- For example:
-
- template <class T> class C {
- class C *c1; // DECL_SELF_REFERENCE_P is true
- class D;
- };
- template <class U> class C; // template_header_p is true
- template <class T> class C<T>::D {
- class C *c2; // DECL_SELF_REFERENCE_P is true
- }; */
-
- tree t = check_elaborated_type_specifier (tag_code,
- decl,
- template_header_p
- | DECL_SELF_REFERENCE_P (decl));
- if (template_header_p && t && CLASS_TYPE_P (t)
- && (!CLASSTYPE_TEMPLATE_INFO (t)
- || (!PRIMARY_TEMPLATE_P (CLASSTYPE_TI_TEMPLATE (t)))))
- {
- error ("%qT is not a template", t);
- inform (location_of (t), "previous declaration here");
- if (TYPE_CLASS_SCOPE_P (t)
- && CLASSTYPE_TEMPLATE_INFO (TYPE_CONTEXT (t)))
- inform (input_location,
- "perhaps you want to explicitly add %<%T::%>",
- TYPE_CONTEXT (t));
- t = error_mark_node;
- }
+ if (!decl)
+ /* We found nothing. */
+ return NULL_TREE;
- return t;
- }
- else if (decl && TREE_CODE (decl) == TREE_LIST)
+ if (TREE_CODE (decl) == TREE_LIST)
{
error ("reference to %qD is ambiguous", name);
print_candidates (decl);
return error_mark_node;
}
- else
+
+ if (DECL_CLASS_TEMPLATE_P (decl)
+ /* If scope is TAG_how::CURRENT_ONLY we're defining a class,
+ so ignore a template template parameter. */
+ || (how != TAG_how::CURRENT_ONLY && DECL_TEMPLATE_TEMPLATE_PARM_P (decl)))
+ decl = DECL_TEMPLATE_RESULT (decl);
+
+ if (TREE_CODE (decl) != TYPE_DECL)
+ /* Found not-a-type. */
return NULL_TREE;
+
+ /* Look for invalid nested type:
+ class C {
+ class C {};
+ }; */
+ if (how == TAG_how::CURRENT_ONLY && DECL_SELF_REFERENCE_P (decl))
+ {
+ error ("%qD has the same name as the class in which it is "
+ "declared", decl);
+ return error_mark_node;
+ }
+
+ /* Two cases we need to consider when deciding if a class
+ template is allowed as an elaborated type specifier:
+ 1. It is a self reference to its own class.
+ 2. It comes with a template header.
+
+ For example:
+
+ template <class T> class C {
+ class C *c1; // DECL_SELF_REFERENCE_P is true
+ class D;
+ };
+ template <class U> class C; // template_header_p is true
+ template <class T> class C<T>::D {
+ class C *c2; // DECL_SELF_REFERENCE_P is true
+ }; */
+
+ tree t = check_elaborated_type_specifier (tag_code, decl,
+ template_header_p
+ | DECL_SELF_REFERENCE_P (decl));
+ if (template_header_p && t && CLASS_TYPE_P (t)
+ && (!CLASSTYPE_TEMPLATE_INFO (t)
+ || (!PRIMARY_TEMPLATE_P (CLASSTYPE_TI_TEMPLATE (t)))))
+ {
+ error ("%qT is not a template", t);
+ inform (location_of (t), "previous declaration here");
+ if (TYPE_CLASS_SCOPE_P (t)
+ && CLASSTYPE_TEMPLATE_INFO (TYPE_CONTEXT (t)))
+ inform (input_location,
+ "perhaps you want to explicitly add %<%T::%>",
+ TYPE_CONTEXT (t));
+ return error_mark_node;
+ }
+
+ return t;
}
/* Get the struct, enum or union (TAG_CODE says which) with tag NAME.
