With invalid overloaded operators, we can get into funny cases where

the overloading of member and non-member functions results in arity
mismatches that don't fit well into our overload-printing scheme. This
only happens for invalid code (which breaks the arity invariants for
these cases), so just suppress the diagnostic rather than inventing
anything new. Fixes <rdar://problem/9222009>.

llvm-svn: 130902

Author: DougGregor

clang/lib/Sema/SemaOverload.cpp

@@ -6676,6 +6676,15 @@ void DiagnoseArityMismatch(Sema &S, OverloadCandidate *Cand,
 
   unsigned MinParams = Fn->getMinRequiredArguments();
 
+  // With invalid overloaded operators, it's possible that we think we
+  // have an arity mismatch when it fact it looks like we have the
+  // right number of arguments, because only overloaded operators have
+  // the weird behavior of overloading member and non-member functions.
+  // Just don't report anything.
+  if (Fn->isInvalidDecl() && 
+      Fn->getDeclName().getNameKind() == DeclarationName::CXXOperatorName)
+    return;
+
   // at least / at most / exactly
   unsigned mode, modeCount;
   if (NumFormalArgs < MinParams) {

clang/test/SemaCXX/overloaded-operator.cpp

@@ -33,7 +33,7 @@ struct A {
 
 A make_A();
 
-bool operator==(A&, Z&); // expected-note 2{{candidate function}}
+bool operator==(A&, Z&); // expected-note 3{{candidate function}}
 
 void h(A a, const A ac, Z z) {
   make_A() == z;
@@ -68,7 +68,7 @@ struct E2 {
 };
 
 // C++ [over.match.oper]p3 - enum restriction.
-float& operator==(E1, E2); 
+float& operator==(E1, E2);  // expected-note{{candidate function}}
 
 void enum_test(Enum1 enum1, Enum2 enum2, E1 e1, E2 e2, Enum1 next_enum1) {
   float &f1 = (e1 == e2);
@@ -85,8 +85,8 @@ class pr5244_foo
   pr5244_foo(char);
 };
 
-bool operator==(const pr5244_foo& s1, const pr5244_foo& s2);
-bool operator==(char c, const pr5244_foo& s);
+bool operator==(const pr5244_foo& s1, const pr5244_foo& s2); // expected-note{{candidate function}}
+bool operator==(char c, const pr5244_foo& s); // expected-note{{candidate function}}
 
 enum pr5244_bar
 {
@@ -399,3 +399,12 @@ namespace rdar9136502 {
     y << x.i; // expected-error{{a bound member function may only be called}}
   }
 }
+
+namespace rdar9222009 {
+class StringRef {
+  inline bool operator==(StringRef LHS, StringRef RHS) { // expected-error{{overloaded 'operator==' must be a binary operator (has 3 parameters)}}
+    return !(LHS == RHS); // expected-error{{invalid operands to binary expression ('rdar9222009::StringRef' and 'rdar9222009::StringRef')}}
+  }
+};
+
+}