Make ELLIPSIS a separate token. This makes it a syntax error to write ". .    ." for Ellipsis.
diff --git a/Python/ast.c b/Python/ast.c
index d4c8967..8180b42 100644
--- a/Python/ast.c
+++ b/Python/ast.c
@@ -1410,7 +1410,7 @@
         PyArena_AddPyObject(c->c_arena, pynum);
         return Num(pynum, LINENO(n), n->n_col_offset, c->c_arena);
     }
-    case DOT: /* Ellipsis */
+    case ELLIPSIS: /* Ellipsis */
         return Ellipsis(LINENO(n), n->n_col_offset, c->c_arena);
     case LPAR: /* some parenthesized expressions */
         ch = CHILD(n, 1);