1 files changed, 19 insertions, 5 deletions

diff --git a/clang/lib/Sema/SemaStmt.cpp b/clang/lib/Sema/SemaStmt.cpp
index b5ff7a30a9e..6d568c4d0b0 100644
--- a/clang/lib/Sema/SemaStmt.cpp
+++ b/clang/lib/Sema/SemaStmt.cpp
@@ -2362,22 +2362,37 @@ Sema::PerformMoveOrCopyInitialization(const InitializedEntity &Entity,
 StmtResult
 Sema::ActOnCapScopeReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) {
   // If this is the first return we've seen, infer the return type.
-  // [expr.prim.lambda]p4 in C++11; block literals follow a superset of those
-  // rules which allows multiple return statements.
+  // [expr.prim.lambda]p4 in C++11; block literals follow the same rules.
   CapturingScopeInfo *CurCap = cast<CapturingScopeInfo>(getCurFunction());
   QualType FnRetType = CurCap->ReturnType;
 
   // For blocks/lambdas with implicit return types, we check each return
   // statement individually, and deduce the common return type when the block
   // or lambda is completed.
-  if (CurCap->HasImplicitReturnType) {
+  if (AutoType *AT =
+          FnRetType.isNull() ? 0 : FnRetType->getContainedAutoType()) {
+    // In C++1y, the return type may involve 'auto'.
+    FunctionDecl *FD = cast<LambdaScopeInfo>(CurCap)->CallOperator;
+    if (CurContext->isDependentContext()) {
+      // C++1y [dcl.spec.auto]p12:
+      //   Return type deduction [...] occurs when the definition is
+      //   instantiated even if the function body contains a return
+      //   statement with a non-type-dependent operand.
+      CurCap->ReturnType = FnRetType = Context.DependentTy;
+    } else if (DeduceFunctionTypeFromReturnExpr(FD, ReturnLoc, RetValExp, AT)) {
+      FD->setInvalidDecl();
+      return StmtError();
+    } else
+      CurCap->ReturnType = FnRetType = FD->getResultType();
+  } else if (CurCap->HasImplicitReturnType) {
+    // FIXME: Fold this into the 'auto' codepath above.
     if (RetValExp && !isa<InitListExpr>(RetValExp)) {
       ExprResult Result = DefaultFunctionArrayLvalueConversion(RetValExp);
       if (Result.isInvalid())
         return StmtError();
       RetValExp = Result.take();
 
-      if (!RetValExp->isTypeDependent())
+      if (!CurContext->isDependentContext())
         FnRetType = RetValExp->getType();
       else
         FnRetType = CurCap->ReturnType = Context.DependentTy;
@@ -2553,7 +2568,6 @@ Sema::ActOnReturnStmt(SourceLocation ReturnLoc, Expr *RetValExp) {
   if (RetValExp && DiagnoseUnexpandedParameterPack(RetValExp))
     return StmtError();
 
-  // FIXME: Unify this and C++1y auto function handling.
   if (isa<CapturingScopeInfo>(getCurFunction()))
     return ActOnCapScopeReturnStmt(ReturnLoc, RetValExp);