https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120748
--- Comment #3 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The trunk branch has been updated by Jason Merrill <ja...@gcc.gnu.org>: https://gcc.gnu.org/g:e9549b5ee8496af12bac3ebfa3ec0aa8487fb725 commit r16-1991-ge9549b5ee8496af12bac3ebfa3ec0aa8487fb725 Author: Jason Merrill <ja...@redhat.com> Date: Thu Jul 3 12:05:12 2025 -0400 c++: ICE with 'this' in lambda signature [PR120748] This testcase was crashing from infinite recursion in the diagnostic machinery, trying to print the lambda signature, which referred to the __this capture field in the lambda, which wanted to print the lambda again. But we don't want the signature to refer to the capture field; 'this' in an unevaluated context refers to the 'this' from the enclosing function, not the capture. After fixing that, we still wrongly rejected the B case because THIS_FORBIDDEN is set in a default (template) argument. Since we don't distinguish between THIS_FORBIDDEN being set for a default argument and it being set for a static member function, let's just ignore it if cp_unevaluated_operand; we'll give a better diagnostic for the static memfn case in finish_this_expr. PR c++/120748 gcc/cp/ChangeLog: * lambda.cc (lambda_expr_this_capture): Don't return a FIELD_DECL. * parser.cc (cp_parser_primary_expression): Ignore THIS_FORBIDDEN if cp_unevaluated_operand. gcc/testsuite/ChangeLog: * g++.dg/cpp2a/lambda-targ16.C: New test. * g++.dg/cpp0x/this1.C: Adjust diagnostics.
