Hi,
On 21 Dec 2024, at 17:35, Simon Martin wrote:
> When erroring out due to an incomplete type, we add a contextual note
> about the type. However, when the error is suppressed by
> -Wno-template-body, the note remains, making the compiler output quite
> puzzling.
>
> This patch makes sure the note is suppressed if we're processing a
> template declaration body with -Wno-template-body.
>
> Successfully tested on x86_64-pc-linux-gnu.
Ping.
Thanks! Simon
>
> PR c++/118163
>
> gcc/cp/ChangeLog:
>
> * cp-tree.h (get_current_template): Declare.
> * error.cc (get_current_template): Make non static.
> * typeck2.cc (cxx_incomplete_type_inform): Suppress note when
> parsing a template declaration with -Wno-template-body.
>
> gcc/testsuite/ChangeLog:
>
> * g++.dg/diagnostic/incomplete-type-2.C: New test.
> * g++.dg/diagnostic/incomplete-type-2a.C: New test.
>
> ---
> gcc/cp/cp-tree.h | 1 +
> gcc/cp/error.cc | 2 +-
> gcc/cp/typeck2.cc | 6 ++++++
> gcc/testsuite/g++.dg/diagnostic/incomplete-type-2.C | 7 +++++++
> .../g++.dg/diagnostic/incomplete-type-2a.C | 13
> +++++++++++++
> 5 files changed, 28 insertions(+), 1 deletion(-)
> create mode 100644
> gcc/testsuite/g++.dg/diagnostic/incomplete-type-2.C
> create mode 100644
> gcc/testsuite/g++.dg/diagnostic/incomplete-type-2a.C
>
> diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
> index 6de8f64b5ee..52f954b63d9 100644
> --- a/gcc/cp/cp-tree.h
> +++ b/gcc/cp/cp-tree.h
> @@ -7297,6 +7297,7 @@ struct decl_location_traits
> typedef hash_map<tree, location_t, decl_location_traits>
> erroneous_templates_t;
> extern GTY((cache)) erroneous_templates_t *erroneous_templates;
>
> +extern tree get_current_template ();
> extern bool cp_seen_error ();
> #define seen_error() cp_seen_error ()
>
> diff --git a/gcc/cp/error.cc b/gcc/cp/error.cc
> index 8c0644fba7e..7fd03dd6d12 100644
> --- a/gcc/cp/error.cc
> +++ b/gcc/cp/error.cc
> @@ -197,7 +197,7 @@ class cxx_format_postprocessor : public
> format_postprocessor
> /* Return the in-scope template that's currently being parsed, or
> NULL_TREE otherwise. */
>
> -static tree
> +tree
> get_current_template ()
> {
> if (scope_chain && in_template_context && !current_instantiation
> ())
> diff --git a/gcc/cp/typeck2.cc b/gcc/cp/typeck2.cc
> index fce687e83b3..505c143dae7 100644
> --- a/gcc/cp/typeck2.cc
> +++ b/gcc/cp/typeck2.cc
> @@ -273,6 +273,12 @@ cxx_incomplete_type_inform (const_tree type)
> if (!TYPE_MAIN_DECL (type))
> return;
>
> + /* When processing a template declaration body, the error generated
> by the
> + caller (if any) might have been suppressed by
> -Wno-template-body. If that
> + is the case, suppress the inform as well. */
> + if (!warn_template_body && get_current_template ())
> + return;
> +
> location_t loc = DECL_SOURCE_LOCATION (TYPE_MAIN_DECL (type));
> tree ptype = strip_top_quals (CONST_CAST_TREE (type));
>
> diff --git a/gcc/testsuite/g++.dg/diagnostic/incomplete-type-2.C
> b/gcc/testsuite/g++.dg/diagnostic/incomplete-type-2.C
> new file mode 100644
> index 00000000000..e2fb20a4ae8
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/diagnostic/incomplete-type-2.C
> @@ -0,0 +1,7 @@
> +// PR c++/118163
> +// { dg-do "compile" }
> +
> +template<class T>
> +struct S { // { dg-note "until the closing brace" }
> + S s; // { dg-error "has incomplete type" }
> +};
> diff --git a/gcc/testsuite/g++.dg/diagnostic/incomplete-type-2a.C
> b/gcc/testsuite/g++.dg/diagnostic/incomplete-type-2a.C
> new file mode 100644
> index 00000000000..d13021d0b68
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/diagnostic/incomplete-type-2a.C
> @@ -0,0 +1,13 @@
> +// PR c++/118163
> +// { dg-do "compile" }
> +// { dg-additional-options "-Wno-template-body" }
> +
> +template<class T>
> +struct S { // { dg-bogus "until the closing brace" }
> + S s; // { dg-bogus "has incomplete type" }
> +};
> +
> +// Check that we don't suppress errors outside of the body.
> +struct forward_decl; // { dg-note "forward declaration" }
> +template<class T>
> +void foo (forward_decl) {} // { dg-error "has incomplete type" }
> --
> 2.44.0
