[clang] [clang] Differentiate between identifier and string EnumArgument (PR #68550)

[Erich Keane via cfe-commits]

================
@@ -274,20 +274,27 @@ class DefaultIntArgument<string name, int default> : IntArgument<name, 1> {
 }
 
 // This argument is more complex, it includes the enumerator type name,
-// a list of strings to accept, and a list of enumerators to map them to.
-class EnumArgument<string name, string type, list<string> values,
+// a list of possible values, and a list of enumerators to map them to.
+class EnumArgument<string name, string type, bit is_string, list<string> values,
----------------
erichkeane wrote:

I think rather than splitting this into doing 2 things, we should instead have an `UnevaluatedStringArgument` type here.

https://github.com/llvm/llvm-project/pull/68550