Add an explicit derived class of FunctionDecl to model deduction guides rather
than just treating them as FunctionDecls with a funny name.

No functionality change intended.

llvm-svn: 295491
diff --git a/clang/lib/AST/DeclBase.cpp b/clang/lib/AST/DeclBase.cpp
index 6111aba..cda70c5 100644
--- a/clang/lib/AST/DeclBase.cpp
+++ b/clang/lib/AST/DeclBase.cpp
@@ -619,6 +619,7 @@
 unsigned Decl::getIdentifierNamespaceForKind(Kind DeclKind) {
   switch (DeclKind) {
     case Function:
+    case CXXDeductionGuide:
     case CXXMethod:
     case CXXConstructor:
     case ConstructorUsingShadow: