Fix false positive error on isinstance with type | T

Summary:
When `isinstance(x, type | int)` was used, pyrefly incorrectly reported
an error because the `type` metatype gets canonicalized to
`Type::Type(Any)` inside the union. The `as_class_info` function then
double-wrapped it with `mk_type_form`, producing `Type::Type(Type::Type(Any))`
which `unwrap_class_object_silently` could not handle.

Fix: in `as_class_info`, skip wrapping union members that are already
`Type::Type(...)` to avoid double-wrapping.

fixes #2871

Reviewed By: rchen152

Differential Revision: D98300571

fbshipit-source-id: ae264bdd9a5518baa62cb754ea1646e587b6ab4b

Author: yangdanny97

pyrefly/lib/alt/class/classdef.rs

@@ -150,6 +150,11 @@ impl<'a, Ans: LookupAnswer> AnswersSolver<'a, Ans> {
             }
             Type::Type(box Type::Tuple(_)) => Some(self.instantiate_unbounded_tuple()),
             Type::Type(box Type::Any(a)) => Some((TParams::empty(), a.propagate())),
+            // type[type[Any]] is what we get when `type` appears in an annotation position.
+            // We treat it as type[Any].
+            Type::Type(box ty @ Type::Type(box Type::Any(_))) => {
+                Some((TParams::empty(), ty.clone()))
+            }
             Type::Type(box Type::SpecialForm(SpecialForm::Callable)) => Some((
                 TParams::empty(),
                 self.heap

pyrefly/lib/test/narrow.rs

@@ -727,6 +727,25 @@ def f(x: str | int | None):
     "#,
 );
 
+testcase!(
+    test_isinstance_union_with_type,
+    r#"
+from typing import assert_type
+def f(x: object):
+    if isinstance(x, type | int):
+        assert_type(x, type | int)
+    isinstance(x, type | int)
+    "#,
+);
+
+testcase!(
+    test_issubclass_union_with_type,
+    r#"
+def f(cls: type):
+    issubclass(cls, type | int)
+    "#,
+);
+
 testcase!(
     test_isinstance_of_tuple,
     r#"