On Thu, 21 Jan 2021, Patrick Palka wrote:
> Here at parse time finish_qualified_id_expr adds an implicit 'this->' to
> the expression tmp::integral<T> (because it's type-dependent, and also
> current_class_ptr is set) within the trailing return type, and later
> during substitution we can't resolve the 'this' since
> tsubst_function_type does inject_this_parm only for non-static member
> functions which tmp::func is not.
>
> It seems the root of the problem is that we set current_class_ptr when
> parsing the signature of a static member function. Since explicit uses
> of 'this' are already not allowed in this context, we probably shouldn't
> be doing inject_this_parm either.
>
> Bootstrapped and regtested on x64_64-pc-linux-gnu, does this look OK for
> trunk?
>
> gcc/cp/ChangeLog:
>
> PR c++/97399
> * parser.c (cp_parser_init_declarator): If the storage class
> specifier is sc_static, pass true for static_p to
> cp_parser_declarator.
> (cp_parser_direct_declarator): Don't do inject_this_parm when
> the member function is static.
>
> gcc/testsuite/ChangeLog:
>
> PR c++/88548
> PR c++/97399
> * g++.dg/cpp0x/this2.C: New test.
> * g++.dg/template/pr97399a.C: New test.
> * g++.dg/template/pr97399b.C: New test.
> ---
> gcc/cp/parser.c | 5 +++--
> gcc/testsuite/g++.dg/cpp0x/this2.C | 8 ++++++++
> gcc/testsuite/g++.dg/template/pr97399a.C | 11 +++++++++++
> gcc/testsuite/g++.dg/template/pr97399b.C | 11 +++++++++++
> 4 files changed, 33 insertions(+), 2 deletions(-)
> create mode 100644 gcc/testsuite/g++.dg/cpp0x/this2.C
> create mode 100644 gcc/testsuite/g++.dg/template/pr97399a.C
> create mode 100644 gcc/testsuite/g++.dg/template/pr97399b.C
>
> diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
> index 48437f23175..18cf9888632 100644
> --- a/gcc/cp/parser.c
> +++ b/gcc/cp/parser.c
> @@ -21413,6 +21413,7 @@ cp_parser_init_declarator (cp_parser* parser,
> bool is_non_constant_init;
> int ctor_dtor_or_conv_p;
> bool friend_p = cp_parser_friend_p (decl_specifiers);
> + bool static_p = decl_specifiers->storage_class == sc_static;
> tree pushed_scope = NULL_TREE;
> bool range_for_decl_p = false;
> bool saved_default_arg_ok_p = parser->default_arg_ok_p;
> @@ -21446,7 +21447,7 @@ cp_parser_init_declarator (cp_parser* parser,
> = cp_parser_declarator (parser, CP_PARSER_DECLARATOR_NAMED,
> flags, &ctor_dtor_or_conv_p,
> /*parenthesized_p=*/NULL,
> - member_p, friend_p, /*static_p=*/false);
> + member_p, friend_p, static_p);
> /* Gather up the deferred checks. */
> stop_deferring_access_checks ();
I should note that the above parser change is needed so that we properly
communicate static-ness to cp_parser_direct_declarator when parsing a
member function template.
>
> @@ -22122,7 +22123,7 @@ cp_parser_direct_declarator (cp_parser* parser,
>
> tree save_ccp = current_class_ptr;
> tree save_ccr = current_class_ref;
> - if (memfn)
> + if (memfn && !static_p)
> /* DR 1207: 'this' is in scope after the cv-quals. */
> inject_this_parameter (current_class_type, cv_quals);
>
> diff --git a/gcc/testsuite/g++.dg/cpp0x/this2.C
> b/gcc/testsuite/g++.dg/cpp0x/this2.C
> new file mode 100644
> index 00000000000..3781bc5efec
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/cpp0x/this2.C
> @@ -0,0 +1,8 @@
> +// PR c++/88548
> +// { dg-do compile { target c++11 } }
> +
> +struct S {
> + int a;
> + template <class> static auto m1 ()
> + -> decltype(this->a) { return 0; }; // { dg-error "'this'" }
> +};
> diff --git a/gcc/testsuite/g++.dg/template/pr97399a.C
> b/gcc/testsuite/g++.dg/template/pr97399a.C
> new file mode 100644
> index 00000000000..3713dbde6e0
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/template/pr97399a.C
> @@ -0,0 +1,11 @@
> +// PR c++/97399
> +// { dg-do compile { target c++11 } }
> +
> +template <bool> struct enable_if_t {};
> +struct tmp {
> + template <class T> static constexpr bool is_integral();
> + template <class T> static auto func()
> + -> enable_if_t<tmp::is_integral<T>()>;
> +};
> +template <class> constexpr bool tmp::is_integral() { return true; }
> +int main() { tmp::func<int>(); }
> diff --git a/gcc/testsuite/g++.dg/template/pr97399b.C
> b/gcc/testsuite/g++.dg/template/pr97399b.C
> new file mode 100644
> index 00000000000..9196c985834
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/template/pr97399b.C
> @@ -0,0 +1,11 @@
> +// PR c++/97399
> +// { dg-do compile { target c++11 } }
> +
> +template <bool> struct enable_if_t {};
> +struct tmp {
> + template <class T> constexpr bool is_integral(); // non-static
> + template <class T> static auto func()
> + -> enable_if_t<tmp::is_integral<T>()>; // { dg-error "without object" }
> +};
> +template <class> constexpr bool tmp::is_integral() { return true; }
> +int main() { tmp::func<int>(); } // { dg-error "no match" }
> --
> 2.30.0.155.g66e871b664
>
>
