patch 9.0.1186: imported class does not work when used twice in a line

Problem:    Imported class does not work when used twice in a line.
Solution:   Fix the type parsing.
diff --git a/src/evalvars.c b/src/evalvars.c
index e473e48..8061a50 100644
--- a/src/evalvars.c
+++ b/src/evalvars.c
@@ -3122,8 +3122,12 @@
 	return FAIL;
     if (rettv->v_type == VAR_ANY && *s == '.')
     {
+	char_u *ns = s + 1;
+	s = ns;
+	while (ASCII_ISALNUM(*s) || *s == '_')
+	    ++s;
 	int sid = rettv->vval.v_number;
-	return eval_variable(s + 1, 0, sid, rettv, NULL, 0);
+	return eval_variable(ns, (int)(s - ns), sid, rettv, NULL, 0);
     }
     return OK;
 }