c++: Update TYPE_FIELDS of variant types if cp_parser_late_parsing_default_args etc. modify it [PR98533]

The following testcases ICE during type verification, because TYPE_FIELDS
of e.g. S RECORD_TYPE in pr119123.C is different from TYPE_FIELDS of const S.
Various decls are added to S's TYPE_FIELDS first, then finish_struct
indirectly calls fixup_type_variants to sync the variant copies.
But later on cp_parser_class_specifier calls
cp_parser_late_parsing_default_args and that apparently adds a lambda
type (from default argument) to TYPE_FIELDS of S.
Dunno if that is right or not, assuming it is right, the following
patch fixes it by updating TYPE_FIELDS of variant types if there were
any changes in the various functions cp_parser_class_specifier defers and
calls on the outermost enclosing class.
There was quite a lot of code repetition already before, so the patch
uses a lambda to avoid the repetitions.
To my surprise, in some of the contract testcases (
g++.dg/contracts/contracts-friend1.C
g++.dg/contracts/contracts-nested-class1.C
g++.dg/contracts/contracts-nested-class2.C
g++.dg/contracts/contracts-redecl7.C
g++.dg/contracts/contracts-redecl8.C
) it is actually setting class_type and pushing TRANSLATION_UNIT_DECL
rather than some class types in some cases.

Or should the lambda pushing into the containing class be somehow avoided?

2025-03-06  Jakub Jelinek  <jakub@redhat.com>

	PR c++/98533
	PR c++/119123
	* parser.cc (cp_parser_class_specifier): Update TYPE_FIELDS of
	variant types in case cp_parser_late_parsing_default_args etc. change
	TYPE_FIELDS on the main variant.  Add switch_to_class lambda and
	use it to simplify repeated class switching code.

	* g++.dg/cpp0x/pr98533.C: New test.
	* g++.dg/cpp0x/pr119123.C: New test.

0 files changed, 0 insertions, 0 deletions