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c++: Member template function lookup failure [PR94799]

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My earlier patch for this PR, r11-86, broke pybind11.  That patch
changed cp_parser_class_name to also consider the object expression
scope (parser->context->object_type) to fix parsing of

  p->template A<T>::foo(); // consider p's scope too

Here we reject

  b.operator typename B<T>::type();

because 'typename_p' in cp_parser_class_name uses 'scope', which means
that 'typename_p' will be true for the example above.  Then we create
a TYPENAME_TYPE via make_typename_type, which fails when tsubsting it;
the code basically created 'typename B::B' and then we complain that there
is no member named 'B' in 'A<int>'.  So, when deciding if we should
create a TYPENAME_TYPE, don't consider the object_type scope, like we
did pre-r11-86.

gcc/cp/ChangeLog:

	PR c++/94799
	* parser.c (cp_parser_class_name): Use parser->scope when
	setting typename_p.

gcc/testsuite/ChangeLog:

	PR c++/94799
	* g++.dg/template/lookup16.C: New test.
This commit is contained in:
Marek Polacek 2020-10-19 18:13:42 -04:00
parent 43cb72263f
commit 323dd42552
2 changed files with 29 additions and 7 deletions
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13
gcc/cp/parser.c
View File

@ -23794,13 +23794,10 @@ cp_parser_class_name (cp_parser *parser,
bool enum_ok)
{
tree decl;
tree scope;
bool typename_p;
cp_token *token;
tree identifier = NULL_TREE;
/* All class-names start with an identifier. */
token = cp_lexer_peek_token (parser->lexer);
cp_token *token = cp_lexer_peek_token (parser->lexer);
if (token->type != CPP_NAME && token->type != CPP_TEMPLATE_ID)
{
cp_parser_error (parser, "expected class-name");
@ -23816,14 +23813,16 @@ cp_parser_class_name (cp_parser *parser,
where we first want to look up A<T>::a in the class of the object
expression, as per [basic.lookup.classref]. */
scope = parser->scope ? parser->scope : parser->context->object_type;
tree scope = parser->scope ? parser->scope : parser->context->object_type;
if (scope == error_mark_node)
return error_mark_node;
/* Any name names a type if we're following the `typename' keyword
in a qualified name where the enclosing scope is type-dependent. */
typename_p = (typename_keyword_p && scope && TYPE_P (scope)
&& dependent_type_p (scope));
const bool typename_p = (typename_keyword_p
&& parser->scope
&& TYPE_P (parser->scope)
&& dependent_type_p (parser->scope));
/* Handle the common case (an identifier, but not a template-id)
efficiently. */
if (token->type == CPP_NAME

23
gcc/testsuite/g++.dg/template/lookup16.C Normal file
View File

@ -0,0 +1,23 @@
// PR c++/94799
// { dg-do compile { target c++11 } }
template <typename> struct A {
typedef int type;
operator int();
};
template <typename T> using B = A<T>;
template <typename T> typename B<T>::type foo(B<T> b)
{
auto r1 = b.operator typename A<T>::type();
auto r2 = b.operator typename A<T>::template A<T>::type();
auto r3 = b.operator typename B<T>::type();
auto r4 = b.operator typename B<T>::template A<T>::type();
return r1 + r2 + r3 + r4;
}
void bar()
{
foo(A<int>());
}