https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95999
--- Comment #3 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Roger Sayle <sa...@gcc.gnu.org>: https://gcc.gnu.org/g:bae10419f6e07dbde8e66ff4ff70d050f82ad451 commit r12-7574-gbae10419f6e07dbde8e66ff4ff70d050f82ad451 Author: Roger Sayle <ro...@nextmovesoftware.com> Date: Thu Mar 10 07:41:12 2022 +0000 PR c++/95999: Improved error recovery in enumeration lists. This patch resolves PR c++/95999 which is an ICE-after-error regression in the g++ front-end. When parsing an enumerator list, the C++ parser assumes that cp_parser_constant_expression always returns either an INTEGER_CST or error_mark_node, but in the testcase reported in the PR, it actually returns a VAR_DECL. The usual (but perhaps controversial) design philosophy is that the routine that reports the error normally has a duty to indicate this to the rest of the compiler (via error_mark_node), but here the return value from calling require_rvalue_constant_expression (parser.cc:10666) is ignored. I initially experimented with setting EXPRESSION to error_mark_node here in cp_parser_constant_expression but (perhaps conveniently) that's insufficient to resolve the problem. The simple fix in this patch is to tweak the two places that require INTEGER_CST to treat all other tree types as though they are error_mark_node. 2022-03-10 Roger Sayle <ro...@nextmovesoftware.com> gcc/cp/ChangeLog PR c++/95999 * decl.cc (finish_enum_value_list): If VALUE isn't an INTEGER_CST consider it to be zero (i.e. treat it like error_mark_node). (build_enumerator): Likewise, if PREV_VALUE isn't an INTEGER_CST, set VALUE to error_mark_node. gcc/testsuite/ChangeLog PR c++/95999 * g++.dg/parse/pr95999.C: New test case.
