PR0091R3: Implement parsing support for using templates as types.

This change adds a new type node, DeducedTemplateSpecializationType, to
represent a type template name that has been used as a type. This is modeled
around AutoType, and shares a common base class for representing a deduced
placeholder type.

We allow deduced class template types in a few more places than the standard
does: in conditions and for-range-declarators, and in new-type-ids. This is
consistent with GCC and with discussion on the core reflector. This patch
does not yet support deduced class template types being named in typename
specifiers.

llvm-svn: 293207

1 files changed, 6 insertions, 4 deletions

diff --git a/clang/lib/Parse/ParseDecl.cpp b/clang/lib/Parse/ParseDecl.cpp
index 255f27dbfb2..6da61c689eb 100644
--- a/clang/lib/Parse/ParseDecl.cpp
+++ b/clang/lib/Parse/ParseDecl.cpp
@@ -2884,7 +2884,8 @@ void Parser::ParseDeclarationSpecifiers(DeclSpec &DS,
           Actions.getTypeName(*Next.getIdentifierInfo(), Next.getLocation(),
                               getCurScope(), &SS, false, false, nullptr,
                               /*IsCtorOrDtorName=*/false,
-                              /*NonTrivialSourceInfo=*/true);
+                              /*WantNonTrivialSourceInfo=*/true,
+                              isClassTemplateDeductionContext(DSContext));
 
       // If the referenced identifier is not a type, then this declspec is
       // erroneous: We already checked about that it has no type specifier, and
@@ -2998,9 +2999,10 @@ void Parser::ParseDeclarationSpecifiers(DeclSpec &DS,
         continue;
       }
 
-      ParsedType TypeRep =
-        Actions.getTypeName(*Tok.getIdentifierInfo(),
-                            Tok.getLocation(), getCurScope());
+      ParsedType TypeRep = Actions.getTypeName(
+          *Tok.getIdentifierInfo(), Tok.getLocation(), getCurScope(), nullptr,
+          false, false, nullptr, false, false,
+          isClassTemplateDeductionContext(DSContext));
 
       // If this is not a typedef name, don't parse it as part of the declspec,
       // it must be an implicit int or an error.