P0091R3: Implement basic parsing support for C++17 deduction-guides.

We model deduction-guides as functions with a new kind of name that identifies
the template whose deduction they guide; the bulk of this patch is adding the
new name kind. This gives us a clean way to attach an extensible list of guides
to a class template in a way that doesn't require any special handling in AST
files etc (and we're going to need these functions we come to performing
deduction).


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@294266 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 15 insertions, 0 deletions

diff --git a/lib/Sema/SemaDeclCXX.cpp b/lib/Sema/SemaDeclCXX.cpp
index 671d3251a5..49cf8e15ed 100644
--- a/lib/Sema/SemaDeclCXX.cpp
+++ b/lib/Sema/SemaDeclCXX.cpp
@@ -8033,6 +8033,15 @@ Decl *Sema::ActOnConversionDeclarator(CXXConversionDecl *Conversion) {
   return Conversion;
 }
 
+/// Check the validity of a declarator that we parsed for a deduction-guide.
+/// These aren't actually declarators in the grammar, so we need to check that
+/// the user didn't specify any pieces that are not part of the deduction-guide
+/// grammar.
+void Sema::CheckDeductionGuideDeclarator(Declarator &D, QualType &R,
+                                         StorageClass &SC) {
+  // FIXME: Implement
+}
+
 //===----------------------------------------------------------------------===//
 // Namespace Handling
 //===----------------------------------------------------------------------===//
@@ -8613,6 +8622,9 @@ Decl *Sema::ActOnUsingDeclaration(Scope *S,
     Diag(Name.getLocStart(), diag::err_using_decl_template_id)
       << SourceRange(Name.TemplateId->LAngleLoc, Name.TemplateId->RAngleLoc);
     return nullptr;
+
+  case UnqualifiedId::IK_DeductionGuideName:
+    llvm_unreachable("cannot parse qualified deduction guide name");
   }
 
   DeclarationNameInfo TargetNameInfo = GetNameFromUnqualifiedId(Name);
@@ -13747,6 +13759,9 @@ NamedDecl *Sema::ActOnFriendFunctionDecl(Scope *S, Declarator &D,
     case UnqualifiedId::IK_ConversionFunctionId:
       DiagArg = 2;
       break;
+    case UnqualifiedId::IK_DeductionGuideName:
+      DiagArg = 3;
+      break;
     case UnqualifiedId::IK_Identifier:
     case UnqualifiedId::IK_ImplicitSelfParam:
     case UnqualifiedId::IK_LiteralOperatorId: