We issue bogus -Wparentheses warnings (3 of them!) for this fold expression:
((B && true) || ...) Firstly, issuing a warning for a compiler-generated expression is wrong and secondly, B && true must be wrapped in ( ) otherwise you'll get error: binary expression in operand of fold-expression. Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk? PR c++/94505 - bogus -Wparentheses warning with fold-expression. * pt.c (fold_expression): Add warning_sentinel for -Wparentheses before calling build_x_binary_op. * g++.dg/cpp1z/fold11.C: New test. --- gcc/cp/pt.c | 1 + gcc/testsuite/g++.dg/cpp1z/fold11.C | 12 ++++++++++++ 2 files changed, 13 insertions(+) create mode 100644 gcc/testsuite/g++.dg/cpp1z/fold11.C diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c index 9e39f46a090..5d5941eddb7 100644 --- a/gcc/cp/pt.c +++ b/gcc/cp/pt.c @@ -12356,6 +12356,7 @@ fold_expression (tree t, tree left, tree right, tsubst_flags_t complain) if (FOLD_EXPR_MODIFY_P (t)) return build_x_modify_expr (input_location, left, code, right, complain); + warning_sentinel s(warn_parentheses); switch (code) { case COMPOUND_EXPR: diff --git a/gcc/testsuite/g++.dg/cpp1z/fold11.C b/gcc/testsuite/g++.dg/cpp1z/fold11.C new file mode 100644 index 00000000000..09a30555eee --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp1z/fold11.C @@ -0,0 +1,12 @@ +// PR c++/94505 - bogus -Wparentheses warning with fold-expression. +// { dg-do compile { target c++17 } } +// { dg-options "-Wparentheses" } + +template <bool... B> +bool foo () { + return ((B && true) || ...); // { dg-bogus "suggest parentheses" } +} + +int main () { + foo<true, false, false, true> (); +} base-commit: fc186077486fb6e5453157ad8507c66d0a34017c -- Marek Polacek • Red Hat, Inc. • 300 A St, Boston, MA