Switch assert(0/false) llvm_unreachable.

llvm-svn: 140367
diff --git a/clang/lib/Serialization/ASTWriterDecl.cpp b/clang/lib/Serialization/ASTWriterDecl.cpp
index a7468a7..5a5963c 100644
--- a/clang/lib/Serialization/ASTWriterDecl.cpp
+++ b/clang/lib/Serialization/ASTWriterDecl.cpp
@@ -295,7 +295,7 @@
   Record.push_back(D->getIdentifierNamespace());
   Record.push_back(D->getTemplatedKind());
   switch (D->getTemplatedKind()) {
-  default: assert(false && "Unhandled TemplatedKind!");
+  default: llvm_unreachable("Unhandled TemplatedKind!");
     break;
   case FunctionDecl::TK_NonTemplate:
     break;