5 files changed, 15 insertions, 6 deletions
diff --git a/clang/lib/Parse/ParseDecl.cpp b/clang/lib/Parse/ParseDecl.cpp
index 01a1657..281cd6d 100644
--- a/clang/lib/Parse/ParseDecl.cpp
+++ b/clang/lib/Parse/ParseDecl.cpp
@@ -6429,6 +6429,7 @@ void Parser::ParseFunctionDeclarator(Declarator &D,
   CachedTokens *ExceptionSpecTokens = nullptr;
   ParsedAttributesWithRange FnAttrs(AttrFactory);
   TypeResult TrailingReturnType;
+  SourceLocation TrailingReturnTypeLoc;
 
   /* LocalEndLoc is the end location for the local FunctionTypeLoc.
      EndLoc is the end location for the function declarator.
@@ -6539,6 +6540,7 @@ void Parser::ParseFunctionDeclarator(Declarator &D,
         SourceRange Range;
         TrailingReturnType =
             ParseTrailingReturnType(Range, D.mayBeFollowedByCXXDirectInit());
+        TrailingReturnTypeLoc = Range.getBegin();
         EndLoc = Range.getEnd();
       }
     } else if (standardAttributesAllowed()) {
@@ -6571,7 +6573,8 @@ void Parser::ParseFunctionDeclarator(Declarator &D,
                     DynamicExceptionRanges.data(), DynamicExceptions.size(),
                     NoexceptExpr.isUsable() ? NoexceptExpr.get() : nullptr,
                     ExceptionSpecTokens, DeclsInPrototype, StartLoc,
-                    LocalEndLoc, D, TrailingReturnType, &DS),
+                    LocalEndLoc, D, TrailingReturnType, TrailingReturnTypeLoc,
+                    &DS),
                 std::move(FnAttrs), EndLoc);
 }
 
diff --git a/clang/lib/Parse/ParseDeclCXX.cpp b/clang/lib/Parse/ParseDeclCXX.cpp
index a903896..6e9eced 100644
--- a/clang/lib/Parse/ParseDeclCXX.cpp
+++ b/clang/lib/Parse/ParseDeclCXX.cpp
@@ -3898,6 +3898,7 @@ void Parser::ParseTrailingRequiresClause(Declarator &D) {
       auto &FunctionChunk = D.getFunctionTypeInfo();
       FunctionChunk.HasTrailingReturnType = TrailingReturnType.isUsable();
       FunctionChunk.TrailingReturnType = TrailingReturnType.get();
+      FunctionChunk.TrailingReturnTypeLoc = Range.getBegin().getRawEncoding();
     } else
       SkipUntil({tok::equal, tok::l_brace, tok::arrow, tok::kw_try, tok::comma},
                 StopAtSemi | StopBeforeMatch);
diff --git a/clang/lib/Parse/ParseExprCXX.cpp b/clang/lib/Parse/ParseExprCXX.cpp
index b225bb7..8181d2a 100644
--- a/clang/lib/Parse/ParseExprCXX.cpp
+++ b/clang/lib/Parse/ParseExprCXX.cpp
@@ -1293,6 +1293,7 @@ ExprResult Parser::ParseLambdaExpressionAfterIntroducer(
   }
 
   TypeResult TrailingReturnType;
+  SourceLocation TrailingReturnTypeLoc;
   if (Tok.is(tok::l_paren)) {
     ParseScope PrototypeScope(this,
                               Scope::FunctionPrototypeScope |
@@ -1379,6 +1380,7 @@ ExprResult Parser::ParseLambdaExpressionAfterIntroducer(
       SourceRange Range;
       TrailingReturnType =
           ParseTrailingReturnType(Range, /*MayBeFollowedByDirectInit*/ false);
+      TrailingReturnTypeLoc = Range.getBegin();
       if (Range.getEnd().isValid())
         DeclEndLoc = Range.getEnd();
     }
@@ -1395,7 +1397,7 @@ ExprResult Parser::ParseLambdaExpressionAfterIntroducer(
                       NoexceptExpr.isUsable() ? NoexceptExpr.get() : nullptr,
                       /*ExceptionSpecTokens*/ nullptr,
                       /*DeclsInPrototype=*/None, LParenLoc, FunLocalRangeEnd, D,
-                      TrailingReturnType, &DS),
+                      TrailingReturnType, TrailingReturnTypeLoc, &DS),
                   std::move(Attr), DeclEndLoc);
 
     // Parse requires-clause[opt].
diff --git a/clang/lib/Sema/DeclSpec.cpp b/clang/lib/Sema/DeclSpec.cpp
index dc37474..b139855 100644
--- a/clang/lib/Sema/DeclSpec.cpp
+++ b/clang/lib/Sema/DeclSpec.cpp
@@ -181,6 +181,8 @@ DeclaratorChunk DeclaratorChunk::getFunction(bool hasProto,
                                              SourceLocation LocalRangeEnd,
                                              Declarator &TheDeclarator,
                                              TypeResult TrailingReturnType,
+                                             SourceLocation
+                                                 TrailingReturnTypeLoc,
                                              DeclSpec *MethodQualifiers) {
   assert(!(MethodQualifiers && MethodQualifiers->getTypeQualifiers() & DeclSpec::TQ_atomic) &&
          "function cannot have _Atomic qualifier");
@@ -210,6 +212,7 @@ DeclaratorChunk DeclaratorChunk::getFunction(bool hasProto,
   I.Fun.HasTrailingReturnType   = TrailingReturnType.isUsable() ||
                                   TrailingReturnType.isInvalid();
   I.Fun.TrailingReturnType      = TrailingReturnType.get();
+  I.Fun.TrailingReturnTypeLoc   = TrailingReturnTypeLoc.getRawEncoding();
   I.Fun.MethodQualifiers        = nullptr;
   I.Fun.QualAttrFactory         = nullptr;
 
diff --git a/clang/lib/Sema/SemaType.cpp b/clang/lib/Sema/SemaType.cpp
index 1ba1869..21aa208 100644
--- a/clang/lib/Sema/SemaType.cpp
+++ b/clang/lib/Sema/SemaType.cpp
@@ -3084,12 +3084,12 @@ void Sema::diagnoseIgnoredQualifiers(unsigned DiagID, unsigned Quals,
 static void diagnoseRedundantReturnTypeQualifiers(Sema &S, QualType RetTy,
                                                   Declarator &D,
                                                   unsigned FunctionChunkIndex) {
-  if (D.getTypeObject(FunctionChunkIndex).Fun.hasTrailingReturnType()) {
-    // FIXME: TypeSourceInfo doesn't preserve location information for
-    // qualifiers.
+  const DeclaratorChunk::FunctionTypeInfo &FTI =
+      D.getTypeObject(FunctionChunkIndex).Fun;
+  if (FTI.hasTrailingReturnType()) {
     S.diagnoseIgnoredQualifiers(diag::warn_qual_return_type,
                                 RetTy.getLocalCVRQualifiers(),
-                                D.getIdentifierLoc());
+                                FTI.getTrailingReturnTypeLoc());
     return;
   }