catch !x & y brainos

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 3 insertions, 0 deletions

diff --git a/evaluate.c b/evaluate.c
index 2901c1bc..49285841 100644
--- a/evaluate.c
+++ b/evaluate.c
@@ -917,6 +917,9 @@ static struct symbol *evaluate_binop(struct expression *expr)
 			rtype = integer_promotion(rtype);
 		} else {
 			// The rest do usual conversions
+			if (op == '&' && expr->left->type == EXPR_PREOP &&
+			    expr->left->op == '!')
+				warning(expr->pos, "dubious: !x & y");
 			ltype = usual_conversions(op, expr->left, expr->right,
 						  lclass, rclass, ltype, rtype);
 			ctype = rtype = ltype;