[Sema] Don't emit multiple diags for one error

Fixed a bug where we'd emit multiple diagnostics if there was a problem
taking the address of an overloaded template function.

Differential Revision: http://reviews.llvm.org/D13664

llvm-svn: 250078

clang/lib/Sema/SemaOverload.cpp

@@ -9911,6 +9911,7 @@ class AddressOfFunctionResolver {
   bool TargetTypeIsNonStaticMemberFunction;
   bool FoundNonTemplateFunction;
   bool StaticMemberFunctionFromBoundPointer;
+  bool HasComplained;
 
   OverloadExpr::FindResult OvlExprInfo; 
   OverloadExpr *OvlExpr;
@@ -9927,6 +9928,7 @@ class AddressOfFunctionResolver {
             !!TargetType->getAs<MemberPointerType>()),
         FoundNonTemplateFunction(false),
         StaticMemberFunctionFromBoundPointer(false),
+        HasComplained(false),
         OvlExprInfo(OverloadExpr::find(SourceExpr)),
         OvlExpr(OvlExprInfo.Expression),
         FailedCandidates(OvlExpr->getNameLoc()) {
@@ -9977,7 +9979,9 @@ class AddressOfFunctionResolver {
         Matches.size() > 1)
       EliminateSuboptimalCudaMatches();
   }
-
+
+  bool hasComplained() const { return HasComplained; }
+
 private:
   bool isTargetTypeAFunction() const {
     return TargetFunctionType->isFunctionType();
@@ -10057,8 +10061,10 @@ class AddressOfFunctionResolver {
       // now.
       if (S.getLangOpts().CPlusPlus14 &&
           FunDecl->getReturnType()->isUndeducedType() &&
-          S.DeduceReturnType(FunDecl, SourceExpr->getLocStart(), Complain))
+          S.DeduceReturnType(FunDecl, SourceExpr->getLocStart(), Complain)) {
+        HasComplained |= Complain;
         return false;
+      }
 
       QualType ResultTy;
       if (Context.hasSameUnqualifiedType(TargetFunctionType, 
@@ -10140,7 +10146,8 @@ class AddressOfFunctionResolver {
       Matches[0].first = Matches[Result - MatchesCopy.begin()].first;
       Matches[0].second = cast<FunctionDecl>(*Result);
       Matches.resize(1);
-    }
+    } else
+      HasComplained |= Complain;
   }
 
   void EliminateAllTemplateMatches() {
@@ -10261,13 +10268,14 @@ Sema::ResolveAddressOfOverloadedFunction(Expr *AddressOfExpr,
                                      Complain);
   int NumMatches = Resolver.getNumMatches();
   FunctionDecl *Fn = nullptr;
-  if (NumMatches == 0 && Complain) {
+  bool ShouldComplain = Complain && !Resolver.hasComplained();
+  if (NumMatches == 0 && ShouldComplain) {
     if (Resolver.IsInvalidFormOfPointerToMemberFunction())
       Resolver.ComplainIsInvalidFormOfPointerToMemberFunction();
     else
       Resolver.ComplainNoMatchesFound();
   }
-  else if (NumMatches > 1 && Complain)
+  else if (NumMatches > 1 && ShouldComplain)
     Resolver.ComplainMultipleMatchesFound();
   else if (NumMatches == 1) {
     Fn = Resolver.getMatchingFunctionDecl();

clang/test/SemaCXX/addr-of-overloaded-function.cpp

@@ -125,13 +125,9 @@ namespace PR7971 {
 }
 
 namespace PR8033 {
-  template <typename T1, typename T2> int f(T1 *, const T2 *); // expected-note {{candidate function [with T1 = const int, T2 = int]}} \
-  // expected-note{{candidate function}}
-  template <typename T1, typename T2> int f(const T1 *, T2 *); // expected-note {{candidate function [with T1 = int, T2 = const int]}} \
-  // expected-note{{candidate function}}
-  int (*p)(const int *, const int *) = f; // expected-error{{address of overloaded function 'f' is ambiguous}} \
-  // expected-error{{address of overloaded function 'f' is ambiguous}}
-
+  template <typename T1, typename T2> int f(T1 *, const T2 *); // expected-note {{candidate function [with T1 = const int, T2 = int]}}
+  template <typename T1, typename T2> int f(const T1 *, T2 *); // expected-note {{candidate function [with T1 = int, T2 = const int]}}
+  int (*p)(const int *, const int *) = f; // expected-error{{address of overloaded function 'f' is ambiguous}}
 }
 
 namespace PR8196 {