[Bug c++/96363] bogus error with multiple constrained partial specialization forward declarations
cvs-commit at gcc dot gnu.org
gcc-bugzilla@gcc.gnu.org
Thu May 26 13:43:29 GMT 2022
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96363
--- Comment #4 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Patrick Palka <ppalka@gcc.gnu.org>:
https://gcc.gnu.org/g:97dc78d705a90c1ae83c78a7f2e24942cc3a6257
commit r13-779-g97dc78d705a90c1ae83c78a7f2e24942cc3a6257
Author: Patrick Palka <ppalka@redhat.com>
Date: Thu May 26 09:43:14 2022 -0400
c++: constrained partial spec forward decl [PR96363]
Here during cp_parser_single_declaration for #2, we were calling
associate_classtype_constraints for TPL<T> (the primary template type)
before maybe_process_partial_specialization could get a chance to
notice that we're in fact declaring a distinct constrained partial
spec and not redeclaring the primary template. This caused us to
emit a bogus error about differing constraints b/t the primary template
and #2's constraints. This patch fixes this by moving the call to
associate_classtype_constraints after the call to shadow_tag (which
calls maybe_process_partial_specialization) and adjusting shadow_tag to
use the return value of m_p_p_s.
Moreover, if we later try to define a constrained partial specialization
that's been declared earlier (as in the third testcase), then
maybe_new_partial_specialization correctly notices it's a redeclaration
and returns NULL_TREE. But in this case we also need to update TYPE to
point to the redeclared partial spec (it'll otherwise continue pointing
to the primary template type, eventually leading to a bogus error).
PR c++/96363
gcc/cp/ChangeLog:
* decl.cc (shadow_tag): Use the return value of
maybe_process_partial_specialization.
* parser.cc (cp_parser_single_declaration): Call shadow_tag
before associate_classtype_constraints.
* pt.cc (maybe_new_partial_specialization): Change return type
to bool. Take 'type' argument by mutable reference. Set 'type'
to point to the correct constrained specialization when
appropriate.
(maybe_process_partial_specialization): Adjust accordingly.
gcc/testsuite/ChangeLog:
* g++.dg/cpp2a/concepts-partial-spec12.C: New test.
* g++.dg/cpp2a/concepts-partial-spec12a.C: New test.
* g++.dg/cpp2a/concepts-partial-spec13.C: New test.
More information about the Gcc-bugs
mailing list