On 10/5/20 7:07 PM, Marek Polacek wrote:
I was notified that our P0634R3 (Down with typename) implementation has
a flaw: when we have an out-of-class member function definition, we
still required 'typename' for its parameters. For example here:
template <typename T> struct S {
int simple(T::type);
};
template <typename T>
int S<T>::simple(/* typename */T::type) { return 0; }
the 'typename' isn't necessary per [temp.res]/5.2.4. We have a qualified
name here ("S<T>::simple") so we know it's already been declared so we
can look it up to see if it's a function template or a variable
template.
In this case, the P0634R3 code in cp_parser_direct_declarator wasn't
looking into uninstantiated templates and didn't find the member
function 'simple' -- cp_parser_lookup_name returned a SCOPE_REF which
means that the qualifying scope was dependent. With this fix, we find
the BASELINK for 'simple', don't clear CP_PARSER_FLAGS_TYPENAME_OPTIONAL
from the flags, and the typename is implicitly assumed.
Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
OK.
gcc/cp/ChangeLog:
PR c++/97297
* parser.c (cp_parser_direct_declarator): When checking if a
name is a function template declaration for the P0634R3 case,
look in uninstantiated templates too.
gcc/testsuite/ChangeLog:
PR c++/97297
* g++.dg/cpp2a/typename18.C: New test.
---
gcc/cp/parser.c | 10 ++++++++--
gcc/testsuite/g++.dg/cpp2a/typename18.C | 21 +++++++++++++++++++++
2 files changed, 29 insertions(+), 2 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/cpp2a/typename18.C
diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
index cb4422764ed..2002c05fdb5 100644
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -21788,8 +21788,14 @@ cp_parser_direct_declarator (cp_parser* parser,
templates, assume S::p to name a type. Otherwise,
don't. */
tree decl
- = cp_parser_lookup_name_simple (parser, unqualified_name,
- token->location);
+ = cp_parser_lookup_name (parser, unqualified_name,
+ none_type,
+ /*is_template=*/false,
+ /*is_namespace=*/false,
+ /*check_dependency=*/false,
+ /*ambiguous_decls=*/NULL,
+ token->location);
+
if (!is_overloaded_fn (decl)
/* Allow
template<typename T>
diff --git a/gcc/testsuite/g++.dg/cpp2a/typename18.C
b/gcc/testsuite/g++.dg/cpp2a/typename18.C
new file mode 100644
index 00000000000..99468661491
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp2a/typename18.C
@@ -0,0 +1,21 @@
+// PR c++/97297
+// { dg-do compile { target c++20 } }
+
+template <typename T>
+struct S {
+ int simple(T::type);
+
+ template <typename U>
+ int member(U::type);
+};
+
+template <typename T>
+int S<T>::simple(T::type) {
+ return 1;
+}
+
+template <typename T>
+template <typename U>
+int S<T>::member(U::type) {
+ return 2;
+}
base-commit: ea6da7f50fe2adc3a09fc10a3f437902c40ebff9
