Hi,
On Fri May 9, 2025 at 5:37 PM CEST, Simon Martin wrote:
> Several gcc_assert through the C++ front-end involve seen_error (), that
> does not take into account errors that were turned into warnings due to
> -fpermissive or -Wtemplate-body.
>
> Running the full C++ testsuite when forcing the use of -fpermissive
> leads to ICEs for 6 tests (see list in ticket); one could consider those
> as reject-valid cases.
>
> This patch keeps track of whether we tried to emit an error (whether it
> was eventually output as such or not) and uses this in seen_error.
>
> Successfully tested on x86_64-pc-linux-gnu.
Friendly ping.
Thanks!
Simon
> PR c++/118388
>
> gcc/cp/ChangeLog:
>
> * error.cc (seen_error_raw): New counter to keep track of errors
> including those downgraded to warnings.
> (cp_seen_error): Take downgraded errors into account.
> * typeck2.cc (merge_exception_specifiers): Use seen_error
> instead of errorcount.
>
> gcc/testsuite/ChangeLog:
>
> * g++.dg/cpp0x/lambda/lambda-ice5-fpermissive.C: New test.
> * g++.dg/cpp0x/noexcept128-fpermissive.C: New test.
>
> ---
> gcc/cp/error.cc | 54 +++++++++----------
> gcc/cp/typeck2.cc | 2 +-
> .../cpp0x/lambda/lambda-ice5-fpermissive.C | 14 +++++
> .../g++.dg/cpp0x/noexcept128-fpermissive.C | 21 ++++++++
> 4 files changed, 63 insertions(+), 28 deletions(-)
> create mode 100644
> gcc/testsuite/g++.dg/cpp0x/lambda/lambda-ice5-fpermissive.C
> create mode 100644 gcc/testsuite/g++.dg/cpp0x/noexcept128-fpermissive.C
>
> diff --git a/gcc/cp/error.cc b/gcc/cp/error.cc
> index 75bf7dcef62..78ecafb0e02 100644
> --- a/gcc/cp/error.cc
> +++ b/gcc/cp/error.cc
> @@ -215,6 +215,11 @@ get_current_template ()
>
> erroneous_templates_t *erroneous_templates;
>
> +/* SEEN_ERROR_RAW will be true if we tried to emit an error message,
> regardless
> + of whether it was actually output or downgraded to a warning. */
> +
> +bool seen_error_raw = false;
> +
> /* Callback function diagnostic_context::m_adjust_diagnostic_info.
>
> Errors issued when parsing a template are automatically treated like
> @@ -227,40 +232,35 @@ cp_adjust_diagnostic_info (diagnostic_context *context,
> diagnostic_info *diagnostic)
> {
> if (diagnostic->kind == DK_ERROR)
> - if (tree tmpl = get_current_template ())
> - {
> - diagnostic->option_id = OPT_Wtemplate_body;
> -
> - if (context->m_permissive)
> - diagnostic->kind = DK_WARNING;
> -
> - bool existed;
> - location_t &error_loc
> - = hash_map_safe_get_or_insert<true> (erroneous_templates,
> - tmpl, &existed);
> - if (!existed)
> - /* Remember that this template had a parse-time error so
> - that we'll ensure a hard error has been issued upon
> - its instantiation. */
> - error_loc = diagnostic->richloc->get_loc ();
> - }
> + {
> + seen_error_raw = true;
> + if (tree tmpl = get_current_template ())
> + {
> + diagnostic->option_id = OPT_Wtemplate_body;
> +
> + if (context->m_permissive)
> + diagnostic->kind = DK_WARNING;
> +
> + bool existed;
> + location_t &error_loc
> + = hash_map_safe_get_or_insert<true> (erroneous_templates,
> + tmpl, &existed);
> + if (!existed)
> + /* Remember that this template had a parse-time error so
> + that we'll ensure a hard error has been issued upon
> + its instantiation. */
> + error_loc = diagnostic->richloc->get_loc ();
> + }
> + }
> }
>
> /* A generalization of seen_error which also returns true if we've
> - permissively downgraded an error to a warning inside a template. */
> + permissively downgraded an error to a warning. */
>
> bool
> cp_seen_error ()
> {
> - if ((seen_error) ())
> - return true;
> -
> - if (erroneous_templates)
> - if (tree tmpl = get_current_template ())
> - if (erroneous_templates->get (tmpl))
> - return true;
> -
> - return false;
> + return (seen_error) () || seen_error_raw;
> }
>
> /* CONTEXT->printer is a basic pretty printer that was constructed
> diff --git a/gcc/cp/typeck2.cc b/gcc/cp/typeck2.cc
> index 45edd180173..a2d230461c4 100644
> --- a/gcc/cp/typeck2.cc
> +++ b/gcc/cp/typeck2.cc
> @@ -2726,7 +2726,7 @@ merge_exception_specifiers (tree list, tree add)
> return add;
> noex = TREE_PURPOSE (list);
> gcc_checking_assert (!TREE_PURPOSE (add)
> - || errorcount || !flag_exceptions
> + || seen_error () || !flag_exceptions
> || cp_tree_equal (noex, TREE_PURPOSE (add)));
>
> /* Combine the dynamic-exception-specifiers, if any. */
> diff --git a/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-ice5-fpermissive.C
> b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-ice5-fpermissive.C
> new file mode 100644
> index 00000000000..11300ad23e0
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-ice5-fpermissive.C
> @@ -0,0 +1,14 @@
> +// PR c++/118388
> +// { dg-do compile { target c++11 } }
> +// { dg-additional-options "-fpermissive" }
> +
> +template<int> int foo()
> +{
> + [] (void i) { return 0; } (0); // { dg-warning "incomplete|invalid|no
> match" }
> + return 0;
> +}
> +
> +void bar()
> +{
> + foo<0>();
> +}
> diff --git a/gcc/testsuite/g++.dg/cpp0x/noexcept128-fpermissive.C
> b/gcc/testsuite/g++.dg/cpp0x/noexcept128-fpermissive.C
> new file mode 100644
> index 00000000000..dfc9629cb06
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/cpp0x/noexcept128-fpermissive.C
> @@ -0,0 +1,21 @@
> +// PR c++/118388
> +// { dg-do compile { target c++11 } }
> +// { dg-additional-options "-fpermissive" }
> +
> +template<typename T>
> +struct traits
> +{
> + static constexpr bool foo() { return sizeof(T) > 1; }
> + static constexpr bool bar() { return sizeof(T) > 1; }
> +};
> +
> +template<typename T>
> +struct X
> +{
> + X& operator=(X&&) noexcept(traits<T>::foo());
> +};
> +
> +template<typename T>
> + X<T>&
> + X<T>::operator=(X&&) noexcept(traits<T>::foo() && traits<T>::bar()) // {
> dg-warning "different exception" }
> + { return *this; }
> --
> 2.44.0
