diff --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h
--- a/clang/include/clang/Sema/Sema.h
+++ b/clang/include/clang/Sema/Sema.h
@@ -3011,7 +3011,7 @@
                                  bool CStyle, bool &ObjCLifetimeConversion);
   bool IsFunctionConversion(QualType FromType, QualType ToType,
                             QualType &ResultTy);
-  bool DiagnoseMultipleUserDefinedConversion(Expr *From, QualType ToType);
+  bool DiagnoseAmbiguousUserDefinedConversion(Expr *From, QualType ToType);
   bool isSameOrCompatibleFunctionType(CanQualType Param, CanQualType Arg);
 
   ExprResult PerformMoveOrCopyInitialization(const InitializedEntity &Entity,
diff --git a/clang/lib/Sema/SemaOverload.cpp b/clang/lib/Sema/SemaOverload.cpp
--- a/clang/lib/Sema/SemaOverload.cpp
+++ b/clang/lib/Sema/SemaOverload.cpp
@@ -3606,7 +3606,7 @@
 }
 
 bool
-Sema::DiagnoseMultipleUserDefinedConversion(Expr *From, QualType ToType) {
+Sema::DiagnoseAmbiguousUserDefinedConversion(Expr *From, QualType ToType) {
   ImplicitConversionSequence ICS;
   OverloadCandidateSet CandidateSet(From->getExprLoc(),
                                     OverloadCandidateSet::CSK_Normal);
@@ -5465,7 +5465,7 @@
   if (!ICS.isBad())
     return PerformImplicitConversion(From, Context.BoolTy, ICS, AA_Converting);
 
-  if (!DiagnoseMultipleUserDefinedConversion(From, Context.BoolTy))
+  if (!DiagnoseAmbiguousUserDefinedConversion(From, Context.BoolTy))
     return Diag(From->getBeginLoc(), diag::err_typecheck_bool_condition)
            << From->getType() << From->getSourceRange();
   return ExprError();
@@ -5579,7 +5579,7 @@
     break;
   case ImplicitConversionSequence::AmbiguousConversion:
   case ImplicitConversionSequence::BadConversion:
-    if (!S.DiagnoseMultipleUserDefinedConversion(From, T))
+    if (!S.DiagnoseAmbiguousUserDefinedConversion(From, T))
       return S.Diag(From->getBeginLoc(),
                     diag::err_typecheck_converted_constant_expression)
              << From->getType() << From->getSourceRange() << T;