--strict-equality for None

tyralla · tyralla · commit ccd5179f3f28 · 2025-08-23T23:49:50.000+02:00
I'm curious to see what the Mypy primer thinks of it...
diff --git a/mypy/checkexpr.py b/mypy/checkexpr.py
@@ -3817,7 +3817,7 @@ def dangerous_comparison(
             #
             # TODO: find a way of disabling the check only for types resulted from the expansion.
             return False
-        if isinstance(left, NoneType) or isinstance(right, NoneType):
+        if isinstance(left, NoneType) and isinstance(right, NoneType):
             return False
         if isinstance(left, UnionType) and isinstance(right, UnionType):
             left = remove_optional(left)

Original file line number	Diff line number	Diff line change
`@@ -3817,7 +3817,7 @@ def dangerous_comparison(`
`3817`	`3817`	`#`
`3818`	`3818`	`# TODO: find a way of disabling the check only for types resulted from the expansion.`
`3819`	`3819`	`return False`
`3820`		`- if isinstance(left, NoneType) or isinstance(right, NoneType):`
	`3820`	`+ if isinstance(left, NoneType) and isinstance(right, NoneType):`
`3821`	`3821`	`return False`
`3822`	`3822`	`if isinstance(left, UnionType) and isinstance(right, UnionType):`
`3823`	`3823`	`left = remove_optional(left)`