diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index f399640b3552a..ccd1424e6cf9f 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -9751,6 +9751,8 @@ def err_nsreturns_retained_attribute_mismatch : Error<
   " attributes">;
 def err_nserrordomain_invalid_decl : Error<
   "domain argument %select{|%1 }0does not refer to global constant">;
+def warn_nserrordomain_invalid_decl : Warning<
+  "domain argument %select{|%1 }0does not refer to global constant">;
 def err_nserrordomain_wrong_type : Error<
   "domain argument %0 does not point to an NSString or CFString constant">;
 
diff --git a/clang/lib/Sema/SemaDeclAttr.cpp b/clang/lib/Sema/SemaDeclAttr.cpp
index ca69df6670ecd..8350722737f66 100644
--- a/clang/lib/Sema/SemaDeclAttr.cpp
+++ b/clang/lib/Sema/SemaDeclAttr.cpp
@@ -5545,7 +5545,7 @@ static void handleNSErrorDomain(Sema &S, Decl *D, const ParsedAttr &AL) {
 
   auto *DRE = dyn_cast<DeclRefExpr>(AL.getArgAsExpr(0));
   if (!DRE) {
-    S.Diag(Loc, diag::err_nserrordomain_invalid_decl) << 0;
+    S.Diag(Loc, diag::warn_nserrordomain_invalid_decl) << 0;
     return;
   }
 
diff --git a/clang/test/Sema/ns_error_enum.m b/clang/test/Sema/ns_error_enum.m
index 895f9b8b3356a..d53a3ad400577 100644
--- a/clang/test/Sema/ns_error_enum.m
+++ b/clang/test/Sema/ns_error_enum.m
@@ -74,7 +74,7 @@ typedef NS_ERROR_ENUM(unsigned char, MyErrorEnumInvalid, InvalidDomain) {
 };
 
 typedef NS_ERROR_ENUM(unsigned char, MyErrorEnumInvalid, "domain-string");
-  // expected-error@-1{{domain argument does not refer to global constant}}
+  // expected-warning@-1{{domain argument does not refer to global constant}}
 
 void foo() {}
 typedef NS_ERROR_ENUM(unsigned char, MyErrorEnumInvalidFunction, foo);