From 27b715215972f0526890df3e2d82549c239d75f3 Mon Sep 17 00:00:00 2001
From: Eric Mark Martin <ericmarkmartin@gmail.com>
Date: Mon, 17 Nov 2025 20:45:01 -0500
Subject: [PATCH] some cleanup

---
 .../mdtest/annotations/unsupported_special_forms.md      | 3 ---
 .../resources/mdtest/narrow/type_guards.md               | 7 ++-----
 crates/ty_python_semantic/src/types.rs                   | 3 ++-
 crates/ty_python_semantic/src/types/narrow.rs            | 9 ++++-----
 4 files changed, 8 insertions(+), 14 deletions(-)

diff --git a/crates/ty_python_semantic/resources/mdtest/annotations/unsupported_special_forms.md b/crates/ty_python_semantic/resources/mdtest/annotations/unsupported_special_forms.md
index 6c0947c5e0..50df54b556 100644
--- a/crates/ty_python_semantic/resources/mdtest/annotations/unsupported_special_forms.md
+++ b/crates/ty_python_semantic/resources/mdtest/annotations/unsupported_special_forms.md
@@ -16,9 +16,6 @@ def f(*args: Unpack[Ts]) -> tuple[Unpack[Ts]]:
     reveal_type(args)  # revealed: tuple[@Todo(`Unpack[]` special form), ...]
     return args
 
-def g() -> TypeGuard[int]:
-    return True
-
 def i(callback: Callable[Concatenate[int, P], R_co], *args: P.args, **kwargs: P.kwargs) -> R_co:
     reveal_type(args)  # revealed: P@i.args
     reveal_type(kwargs)  # revealed: P@i.kwargs
diff --git a/crates/ty_python_semantic/resources/mdtest/narrow/type_guards.md b/crates/ty_python_semantic/resources/mdtest/narrow/type_guards.md
index c2a5f8feb6..fdd5a5aee6 100644
--- a/crates/ty_python_semantic/resources/mdtest/narrow/type_guards.md
+++ b/crates/ty_python_semantic/resources/mdtest/narrow/type_guards.md
@@ -12,17 +12,14 @@ from typing_extensions import TypeGuard, TypeIs
 def _(
     a: TypeGuard[str],
     b: TypeIs[str | int],
-    c: TypeGuard[Intersection[complex, Not[int], Not[float]]],
+    c: TypeGuard[bool],
     d: TypeIs[tuple[TypeOf[bytes]]],
     e: TypeGuard,  # error: [invalid-type-form]
     f: TypeIs,  # error: [invalid-type-form]
 ):
     reveal_type(a)  # revealed: TypeGuard[str]
     reveal_type(b)  # revealed: TypeIs[str | int]
-    # not `TypeGuard[complex & ~int & ~float]`: `complex` in argument position
-    # means `complex & int & float` semantically so `Intersection[complex,
-    # Not[int], Not[float]]` means `complex` semantically
-    reveal_type(c)  # revealed: TypeGuard[complex]
+    reveal_type(c)  # revealed: TypeGuard[bool]
     reveal_type(d)  # revealed: TypeIs[tuple[<class 'bytes'>]]
     reveal_type(e)  # revealed: Unknown
     reveal_type(f)  # revealed: Unknown
diff --git a/crates/ty_python_semantic/src/types.rs b/crates/ty_python_semantic/src/types.rs
index 1d6a28b3d1..94f33c07f7 100644
--- a/crates/ty_python_semantic/src/types.rs
+++ b/crates/ty_python_semantic/src/types.rs
@@ -14750,7 +14750,8 @@ impl<'db> TypeGuardType<'db> {
 }
 
 impl<'db> VarianceInferable<'db> for TypeGuardType<'db> {
-    // TODO: comment
+    // `TypeGuard` is covariant in its type parameter. See the `TypeGuard`
+    // section of mdtest/generics/pep695/variance.md for details.
     fn variance_of(self, db: &'db dyn Db, typevar: BoundTypeVarInstance<'db>) -> TypeVarVariance {
         self.return_type(db).variance_of(db, typevar)
     }
diff --git a/crates/ty_python_semantic/src/types/narrow.rs b/crates/ty_python_semantic/src/types/narrow.rs
index b7cdf10e02..f5cf1b4d38 100644
--- a/crates/ty_python_semantic/src/types/narrow.rs
+++ b/crates/ty_python_semantic/src/types/narrow.rs
@@ -288,10 +288,9 @@ impl ClassInfoConstraintFunction {
 /// in the second clobbers the first.
 #[derive(Hash, PartialEq, Debug, Eq, Clone, Copy)]
 struct Conjunction<'db> {
-    /// The intersected constraints (represented as an intersection type)
+    /// The intersected constraints (represented as a type to intersect the guard with)
     constraint: Type<'db>,
-    /// If any constraint in this conjunction is a `TypeGuard`, this is Some and
-    /// contains the union of all `TypeGuard` types in this conjunction
+    /// If any constraint in this conjunction is a `TypeGuard[T]`, this is `Some(T)`
     typeguard: Option<Type<'db>>,
 }
 
@@ -343,10 +342,10 @@ impl<'db> Conjunction<'db> {
 ///
 /// - `f(x) or g(x)` where f returns `TypeIs[A]` and g returns `TypeGuard[B]`
 ///   => `[Conjunction { constraint: A, typeguard: None }, Conjunction { constraint: object, typeguard: Some(B) }]`
-///   => evaluates to `A | B`
+///   => evaluates to `(P & A) | B`, where `P` is our previously-known type
 #[derive(Hash, PartialEq, Debug, Eq, Clone)]
 struct NarrowingConstraint<'db> {
-    /// Disjunctions of conjunctions (DNF)
+    /// Disjunction of conjunctions (DNF)
     disjuncts: SmallVec<[Conjunction<'db>; 4]>,
 }