Disallow 'dynamic' as type parameter name

runtime/vm/parser.cc

Index: runtime/vm/parser.cc
===================================================================
--- runtime/vm/parser.cc	(revision 14233)
+++ runtime/vm/parser.cc	(working copy)
@@ -3592,21 +3592,18 @@
     do {
       ConsumeToken();
       SkipMetadata();
-      if (CurrentToken() != Token::kIDENT) {
-        ErrorMsg("type parameter name expected");
-      }
-      String& type_parameter_name = *CurrentLiteral();
       const intptr_t type_parameter_pos = TokenPos();
+      String& type_parameter_name =
+          *ExpectClassIdentifier("type parameter expected");
       // Check for duplicate type parameters.
       for (intptr_t i = 0; i < index; i++) {
         existing_type_parameter ^= type_parameters_array.At(i);
         existing_type_parameter_name = existing_type_parameter.name();
         if (existing_type_parameter_name.Equals(type_parameter_name)) {
-          ErrorMsg("duplicate type parameter '%s'",
+          ErrorMsg(type_parameter_pos, "duplicate type parameter '%s'",
                    type_parameter_name.ToCString());
         }
       }
-      ConsumeToken();
       if (CurrentToken() == Token::kEXTENDS) {
         ConsumeToken();
         // A bound may refer to the owner of the type parameter it applies to,