Implement most of N3638 (return type deduction for normal functions).

Missing (somewhat ironically) is support for the new deduction rules
in lambda functions, plus PCH support for return type patching.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@181108 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 11 insertions, 4 deletions

diff --git a/lib/Sema/SemaType.cpp b/lib/Sema/SemaType.cpp
index 4bf15f0360..0959f7d66a 100644
--- a/lib/Sema/SemaType.cpp
+++ b/lib/Sema/SemaType.cpp
@@ -2018,6 +2018,8 @@ static QualType GetDeclSpecTypeForDeclarator(TypeProcessingState &state,
   // The TagDecl owned by the DeclSpec.
   TagDecl *OwnedTagDecl = 0;
 
+  bool ContainsPlaceholderType = false;
+
   switch (D.getName().getKind()) {
   case UnqualifiedId::IK_ImplicitSelfParam:
   case UnqualifiedId::IK_OperatorFunctionId:
@@ -2025,6 +2027,7 @@ static QualType GetDeclSpecTypeForDeclarator(TypeProcessingState &state,
   case UnqualifiedId::IK_LiteralOperatorId:
   case UnqualifiedId::IK_TemplateId:
     T = ConvertDeclSpecToType(state);
+    ContainsPlaceholderType = D.getDeclSpec().containsPlaceholderType();
 
     if (!D.isInvalidType() && D.getDeclSpec().isTypeSpecOwned()) {
       OwnedTagDecl = cast<TagDecl>(D.getDeclSpec().getRepAsDecl());
@@ -2048,6 +2051,7 @@ static QualType GetDeclSpecTypeForDeclarator(TypeProcessingState &state,
     // converts to.
     T = SemaRef.GetTypeFromParser(D.getName().ConversionFunctionId,
                                   &ReturnTypeInfo);
+    ContainsPlaceholderType = T->getContainedAutoType();
     break;
   }
 
@@ -2058,7 +2062,7 @@ static QualType GetDeclSpecTypeForDeclarator(TypeProcessingState &state,
   // In C++11, a function declarator using 'auto' must have a trailing return
   // type (this is checked later) and we can skip this. In other languages
   // using auto, we need to check regardless.
-  if (D.getDeclSpec().containsPlaceholderType() &&
+  if (ContainsPlaceholderType &&
       (!SemaRef.getLangOpts().CPlusPlus11 || !D.isFunctionDeclarator())) {
     int Error = -1;
 
@@ -2101,10 +2105,12 @@ static QualType GetDeclSpecTypeForDeclarator(TypeProcessingState &state,
       Error = 10; // Type alias
       break;
     case Declarator::TrailingReturnContext:
-      Error = 11; // Function return type
+      if (!SemaRef.getLangOpts().CPlusPlus1y)
+        Error = 11; // Function return type
       break;
     case Declarator::ConversionIdContext:
-      Error = 12; // conversion-type-id
+      if (!SemaRef.getLangOpts().CPlusPlus1y)
+        Error = 12; // conversion-type-id
       break;
     case Declarator::TypeNameContext:
       Error = 13; // Generic
@@ -2599,7 +2605,8 @@ static TypeSourceInfo *GetFullTypeForDeclarator(TypeProcessingState &state,
         // trailing-return-type is only required if we're declaring a function,
         // and not, for instance, a pointer to a function.
         if (D.getDeclSpec().getTypeSpecType() == DeclSpec::TST_auto &&
-            !FTI.hasTrailingReturnType() && chunkIndex == 0) {
+            !FTI.hasTrailingReturnType() && chunkIndex == 0 &&
+            !S.getLangOpts().CPlusPlus1y) {
           S.Diag(D.getDeclSpec().getTypeSpecTypeLoc(),
                diag::err_auto_missing_trailing_return);
           T = Context.IntTy;