https://gcc.gnu.org/bugzilla/show_bug.cgi?id=74762
--- Comment #5 from Manuel López-Ibáñez <manu at gcc dot gnu.org> ---
(In reply to Patrick Palka from comment #1)
> Looks like warn_uninit() suppresses the warning on 'i' because the
> TREE_NO_WARNING flag is set on the ARRAY_REF by the C++ FE (in
> finish_parenthesized_expr(), for an unrelated purpose).
I wonder if a quick work-around for this case in particular is to check for:
if (TREE_CODE (expr) == MODIFY_EXPR)
like the C parser does:
/* A parenthesized expression. */
location_t loc_open_paren = c_parser_peek_token (parser)->location;
c_parser_consume_token (parser);
expr = c_parser_expression (parser);
if (TREE_CODE (expr.value) == MODIFY_EXPR)
TREE_NO_WARNING (expr.value) = 1;
if (expr.original_code != C_MAYBE_CONST_EXPR)
expr.original_code = ERROR_MARK;
/* Don't change EXPR.ORIGINAL_TYPE. */
location_t loc_close_paren = c_parser_peek_token (parser)->location;
set_c_expr_source_range (&expr, loc_open_paren, loc_close_paren);
c_parser_skip_until_found (parser, CPP_CLOSE_PAREN,
"expected %<)%>");
Then the bug will only trigger for code such as ((lhs=rhs)), which is what
TREE_NO_WARNING is trying to avoid warning for.
