Merge 28d2f32 into 9bd4134

psf · Jan 20, 2022 · 9b0487d · 9b0487d
2 parents 9bd4134 + 28d2f32
commit 9b0487d
Showing 1 changed file with 3 additions and 1 deletion.
diff --git a/src/black/__init__.py b/src/black/__init__.py
@@ -1315,7 +1315,9 @@ def assert_equivalent(src: str, dst: str, *, pass_num: int = 1) -> None:
         src_ast = parse_ast(src)
     except Exception as exc:
         raise AssertionError(
-            f"cannot use --safe with this file; failed to parse source file: {exc}"
+            f"cannot use --safe with this file; failed to parse source file AST: {exc}\n"
+            f"This could be caused by running black with an older python version "
+            f"that does not support new syntax used in your source file."
         ) from exc
 
     try: