Whitelist operator== and operator!= as valid for unused value warnings,
even when overloaded and user-defined. These operators are both more
valuable to warn on (due to likely typos) and extremely unlikely to be
reasonable for use to trigger side-effects.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@137823 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/Expr.cpp b/lib/AST/Expr.cpp
index 5e795be..41fa850 100644
--- a/lib/AST/Expr.cpp
+++ b/lib/AST/Expr.cpp
@@ -1524,8 +1524,21 @@
R2 = cast<ArraySubscriptExpr>(this)->getRHS()->getSourceRange();
return true;
+ case CXXOperatorCallExprClass: {
+ // We warn about operator== and operator!= even when user-defined operator
+ // overloads as there is no reasonable way to define these such that they
+ // have non-trivial, desirable side-effects. See the -Wunused-comparison
+ // warning: these operators are commonly typo'ed, and so warning on them
+ // provides additional value as well. If this list is updated,
+ // DiagnoseUnusedComparison should be as well.
+ const CXXOperatorCallExpr *Op = cast<CXXOperatorCallExpr>(this);
+ if (Op->getOperator() == OO_EqualEqual ||
+ Op->getOperator() == OO_ExclaimEqual)
+ return true;
+
+ // Fallthrough for generic call handling.
+ }
case CallExprClass:
- case CXXOperatorCallExprClass:
case CXXMemberCallExprClass: {
// If this is a direct call, get the callee.
const CallExpr *CE = cast<CallExpr>(this);