diff --git a/clang/lib/Sema/SemaType.cpp b/clang/lib/Sema/SemaType.cpp
--- a/clang/lib/Sema/SemaType.cpp
+++ b/clang/lib/Sema/SemaType.cpp
@@ -3084,12 +3084,16 @@
 static void diagnoseRedundantReturnTypeQualifiers(Sema &S, QualType RetTy,
                                                   Declarator &D,
                                                   unsigned FunctionChunkIndex) {
-  if (D.getTypeObject(FunctionChunkIndex).Fun.hasTrailingReturnType()) {
+  const DeclaratorChunk::FunctionTypeInfo &FTI =
+      D.getTypeObject(FunctionChunkIndex).Fun;
+  if (FTI.hasTrailingReturnType()) {
     // FIXME: TypeSourceInfo doesn't preserve location information for
     // qualifiers.
+    SourceLocation Loc = D.getIdentifierLoc();
+    if (Loc.isInvalid())
+      Loc = FTI.getRParenLoc();
     S.diagnoseIgnoredQualifiers(diag::warn_qual_return_type,
-                                RetTy.getLocalCVRQualifiers(),
-                                D.getIdentifierLoc());
+                                RetTy.getLocalCVRQualifiers(), Loc);
     return;
   }
 
diff --git a/clang/test/SemaCXX/return.cpp b/clang/test/SemaCXX/return.cpp
--- a/clang/test/SemaCXX/return.cpp
+++ b/clang/test/SemaCXX/return.cpp
@@ -65,6 +65,10 @@
     trailing_return_type() -> // expected-warning {{'const' type qualifier on return type has no effect}}
     const int;
 
+auto trailing_return_type_lambda =
+    [](const int &x) -> // expected-warning {{'const' type qualifier on return type has no effect}}
+    const int { return x; };
+
 const int ret_array()[4]; // expected-error {{cannot return array}}
 }