From: Argyrios Kyrtzidis <akyrtzi@gmail.com>
Date: Tue, 1 Feb 2011 19:32:59 +0000 (+0000)
Subject: For "if ((a == b))" only warn if 'a' is a modifiable l-value. Caught by John!
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=70f233017bd3091137dcfbc00f6b2baea56edba9;p=clang

For "if ((a == b))" only warn if 'a' is a modifiable l-value. Caught by John!

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@124675 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Sema/SemaExpr.cpp b/lib/Sema/SemaExpr.cpp
index 82771298e0..8448ed8079 100644
--- a/lib/Sema/SemaExpr.cpp
+++ b/lib/Sema/SemaExpr.cpp
@@ -9231,7 +9231,9 @@ void Sema::DiagnoseEqualityWithExtraParens(ParenExpr *parenE) {
   Expr *E = parenE->IgnoreParens();
 
   if (BinaryOperator *opE = dyn_cast<BinaryOperator>(E))
-    if (opE->getOpcode() == BO_EQ) {
+    if (opE->getOpcode() == BO_EQ &&
+        opE->getLHS()->IgnoreParenImpCasts()->isModifiableLvalue(Context)
+                                                           == Expr::MLV_Valid) {
       SourceLocation Loc = opE->getOperatorLoc();
 
       Diag(Loc, diag::warn_equality_with_extra_parens) << E->getSourceRange();
diff --git a/test/SemaCXX/warn-assignment-condition.cpp b/test/SemaCXX/warn-assignment-condition.cpp
index 48cc137dac..6cfab55440 100644
--- a/test/SemaCXX/warn-assignment-condition.cpp
+++ b/test/SemaCXX/warn-assignment-condition.cpp
@@ -109,4 +109,14 @@ void test() {
   if ((x == 5)) {} // expected-warning {{equality comparison with extraneous parentheses}} \
                    // expected-note {{use '=' to turn this equality comparison into an assignment}} \
                    // expected-note {{remove extraneous parentheses around the comparison to silence this warning}}
+  if ((5 == x)) {}
+}
+
+void (*fn)();
+
+void test2() {
+    if ((fn == test2)) {} // expected-warning {{equality comparison with extraneous parentheses}} \
+                          // expected-note {{use '=' to turn this equality comparison into an assignment}} \
+                          // expected-note {{remove extraneous parentheses around the comparison to silence this warning}}
+    if ((test2 == fn)) {}
 }