On 2/21/22 08:17, Roger Sayle wrote:
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 testcase reported in the PR
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.
This patch has been tested on x86_64-pc-linunx-gnu with make bootstrap
and make -k check with no new (unexpected) failures. Ok for mainline?
OK.
2022-02-21 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/pr95999.c: New test case.
Thanks in advance,
Roger
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