[c++2a] [concepts] Add rudimentary parsing support for template concept declarations

This patch is a tweak of changyu's patch: https://reviews.llvm.org/D40381. It differs in that the recognition of the 'concept' token is moved into the machinery that recognizes declaration-specifiers - this allows us to leverage the attribute handling machinery more seamlessly.

See the test file to get a sense of the basic parsing that this patch supports. 

There is much more work to be done before concepts are usable...

Thanks Changyu!

llvm-svn: 330794

1 files changed, 7 insertions, 0 deletions

diff --git a/clang/lib/AST/ASTDumper.cpp b/clang/lib/AST/ASTDumper.cpp
index cf512b9bd3f..b0f0c5d0f57 100644
--- a/clang/lib/AST/ASTDumper.cpp
+++ b/clang/lib/AST/ASTDumper.cpp
@@ -466,6 +466,7 @@ namespace  {
                                          bool DumpRefOnly);
     template<typename TemplateDecl>
     void VisitTemplateDecl(const TemplateDecl *D, bool DumpExplicitInst);
+    void VisitConceptDecl(const ConceptDecl *D);
     void VisitFunctionTemplateDecl(const FunctionTemplateDecl *D);
     void VisitClassTemplateDecl(const ClassTemplateDecl *D);
     void VisitClassTemplateSpecializationDecl(
@@ -1577,6 +1578,12 @@ void ASTDumper::VisitTemplateDecl(const TemplateDecl *D,
                                     !D->isCanonicalDecl());
 }
 
+void ASTDumper::VisitConceptDecl(const ConceptDecl *D) {
+  dumpName(D);
+  dumpTemplateParameters(D->getTemplateParameters());
+  dumpStmt(D->getConstraintExpr());
+}
+
 void ASTDumper::VisitFunctionTemplateDecl(const FunctionTemplateDecl *D) {
   // FIXME: We don't add a declaration of a function template specialization
   // to its context when it's explicitly instantiated, so dump explicit