Switch assert(0/false) llvm_unreachable.

llvm-svn: 140367
diff --git a/clang/lib/AST/ASTImporter.cpp b/clang/lib/AST/ASTImporter.cpp
index c791ba1..55610cb 100644
--- a/clang/lib/AST/ASTImporter.cpp
+++ b/clang/lib/AST/ASTImporter.cpp
@@ -1803,7 +1803,7 @@
     To.setNamedTypeInfo(Importer.Import(FromTInfo));
     return;
   }
-    assert(0 && "Unknown name kind.");
+    llvm_unreachable("Unknown name kind.");
   }
 }