Make ELLIPSIS a separate token. This makes it a syntax error to write ". .    ." for Ellipsis.
diff --git a/Lib/compiler/transformer.py b/Lib/compiler/transformer.py
index 79b702c..f07ec97 100644
--- a/Lib/compiler/transformer.py
+++ b/Lib/compiler/transformer.py
@@ -113,7 +113,7 @@
                                token.LBRACE: self.atom_lbrace,
                                token.NUMBER: self.atom_number,
                                token.STRING: self.atom_string,
-                               token.DOT: self.atom_ellipsis,
+                               token.ELLIPSIS: self.atom_ellipsis,
                                token.NAME: self.atom_name,
                                }
         self.encoding = None