Make identifiers str (not str8) objects throughout. This affects the parser, various object implementations, and all places that put identifiers into C string literals. In testing, a number of crashes occurred as code would fail when the recursion limit was reached (such as the Unicode interning dictionary having key/value pairs where key is not value). To solve these, I added an overflowed flag, which allows for 50 more recursions after the limit was reached and the exception was raised, and a recursion_critical flag, which indicates that recursion absolutely must be allowed, i.e. that a certain call must not cause a stack overflow exception. There are still some places where both str and str8 are accepted as identifiers; these should eventually be removed.

--- a/Objects/bytesobject.c	Sat Jun 09 16:13:23 2007 +0000
+++ b/Objects/bytesobject.c	Sun Jun 10 09:51:05 2007 +0000
@@ -1078,7 +1078,7 @@
     else if (PyObject_AsCharBuffer(sub_obj, &sub, &sub_len))
         return NULL;
 
-    _adjust_indices(&start, &end, PyString_GET_SIZE(self));
+    _adjust_indices(&start, &end, PyBytes_GET_SIZE(self));
 
     return PyInt_FromSsize_t(
         stringlib_count(str + start, end - start, sub, sub_len)