Recommend running prek against upstream

## Summary

Closes https://github.com/astral-sh/ty/issues/2435.

.devcontainer/post-create.sh

@@ -5,4 +5,4 @@ rustup component add clippy rustfmt
 cargo install cargo-insta
 cargo fetch
 
-pip install maturin pre-commit
+pip install maturin prek

.pre-commit-config.yaml

@@ -21,15 +21,62 @@ exclude: |
   )$
 
 repos:
+  # Priority 0: Read-only hooks; hooks that modify disjoint file types.
   - repo: https://github.com/pre-commit/pre-commit-hooks
     rev: v6.0.0
     hooks:
       - id: check-merge-conflict
+        priority: 0
 
   - repo: https://github.com/abravalheri/validate-pyproject
     rev: v0.24.1
     hooks:
       - id: validate-pyproject
+        priority: 0
+
+  - repo: https://github.com/crate-ci/typos
+    rev: v1.40.0
+    hooks:
+      - id: typos
+        priority: 0
+
+  - repo: local
+    hooks:
+      - id: cargo-fmt
+        name: cargo fmt
+        entry: cargo fmt --
+        language: system
+        types: [rust]
+        pass_filenames: false # This makes it a lot faster
+        priority: 0
+
+  # Prettier
+  - repo: https://github.com/rbubley/mirrors-prettier
+    rev: v3.7.4
+    hooks:
+      - id: prettier
+        types: [yaml]
+        priority: 0
+
+  # zizmor detects security vulnerabilities in GitHub Actions workflows.
+  # Additional configuration for the tool is found in `.github/zizmor.yml`
+  - repo: https://github.com/zizmorcore/zizmor-pre-commit
+    rev: v1.19.0
+    hooks:
+      - id: zizmor
+        priority: 0
+
+  - repo: https://github.com/python-jsonschema/check-jsonschema
+    rev: 0.36.0
+    hooks:
+      - id: check-github-workflows
+        priority: 0
+
+  - repo: https://github.com/shellcheck-py/shellcheck-py
+    rev: v0.11.0.1
+    hooks:
+      - id: shellcheck
+        priority: 0
 
   - repo: https://github.com/executablebooks/mdformat
     rev: 1.0.0
@@ -44,7 +91,20 @@ repos:
             docs/formatter/black\.md
             | docs/\w+\.md
           )$
+        priority: 0
 
+  - repo: https://github.com/astral-sh/ruff-pre-commit
+    rev: v0.14.10
+    hooks:
+      - id: ruff-format
+        priority: 0
+      - id: ruff-check
+        args: [--fix, --exit-non-zero-on-fix]
+        types_or: [python, pyi]
+        require_serial: true
+        priority: 1
+
+  # Priority 1: Second-pass fixers (e.g., markdownlint-fix runs after mdformat).
   - repo: https://github.com/igorshubovych/markdownlint-cli
     rev: v0.47.0
     hooks:
@@ -54,7 +114,9 @@ repos:
             docs/formatter/black\.md
             | docs/\w+\.md
           )$
+        priority: 1
 
+  # Priority 2: blacken-docs runs after markdownlint-fix (both modify markdown).
   - repo: https://github.com/adamchainz/blacken-docs
     rev: 1.20.0
     hooks:
@@ -68,48 +130,7 @@ repos:
           )$
         additional_dependencies:
           - black==25.12.0
-
-  - repo: https://github.com/crate-ci/typos
-    rev: v1.40.0
-    hooks:
-      - id: typos
-
-  - repo: local
-    hooks:
-      - id: cargo-fmt
-        name: cargo fmt
-        entry: cargo fmt --
-        language: system
-        types: [rust]
-        pass_filenames: false # This makes it a lot faster
-
-  - repo: https://github.com/astral-sh/ruff-pre-commit
-    rev: v0.14.10
-    hooks:
-      - id: ruff-format
-      - id: ruff-check
-        args: [--fix, --exit-non-zero-on-fix]
-        types_or: [python, pyi]
-        require_serial: true
-
-  # Prettier
-  - repo: https://github.com/rbubley/mirrors-prettier
-    rev: v3.7.4
-    hooks:
-      - id: prettier
-        types: [yaml]
-
-  # zizmor detects security vulnerabilities in GitHub Actions workflows.
-  # Additional configuration for the tool is found in `.github/zizmor.yml`
-  - repo: https://github.com/zizmorcore/zizmor-pre-commit
-    rev: v1.19.0
-    hooks:
-      - id: zizmor
-
-  - repo: https://github.com/python-jsonschema/check-jsonschema
-    rev: 0.36.0
-    hooks:
-      - id: check-github-workflows
+        priority: 2
 
   # `actionlint` hook, for verifying correct syntax in GitHub Actions workflows.
   # Some additional configuration for `actionlint` can be found in `.github/actionlint.yaml`.
@@ -131,8 +152,4 @@ repos:
           # and checks these with shellcheck. This is arguably its most useful feature,
           # but the integration only works if shellcheck is installed
           - "github.com/wasilibs/go-shellcheck/cmd/shellcheck@v0.11.1"
-
-  - repo: https://github.com/shellcheck-py/shellcheck-py
-    rev: v0.11.0.1
-    hooks:
-      - id: shellcheck
+        priority: 0

CLAUDE.md

@@ -65,6 +65,7 @@ When working on ty, PR titles should start with `[ty]` and be tagged with the `t
 - All changes must be tested. If you're not testing your changes, you're not done.
 - Get your tests to pass. If you didn't run the tests, your code does not work.
 - Follow existing code style. Check neighboring files for patterns.
-- Always run `uvx pre-commit run -a` at the end of a task.
+- Always run `uvx prek run --from-ref @{upstream}` at the end of a task.
 - Avoid writing significant amounts of new code. This is often a sign that we're missing an existing method or mechanism that could help solve the problem. Look for existing utilities first.
 - Avoid falling back to patterns that require `panic!`, `unreachable!`, or `.unwrap()`. Instead, try to encode those constraints in the type system.
+- Prefer let chains (`if let` combined with `&&`) over nested `if let` statements to reduce indentation and improve readability.

CONTRIBUTING.md

@@ -57,8 +57,8 @@ You can optionally install pre-commit hooks to automatically run the validation
 when making a commit:
 
 ```shell
-uv tool install pre-commit
-pre-commit install
+uv tool install prek
+prek install
 ```
 
 We recommend [nextest](https://nexte.st/) to run Ruff's test suite (via `cargo nextest run`),
@@ -85,7 +85,7 @@ and that it passes both the lint and test validation checks:
 ```shell
 cargo clippy --workspace --all-targets --all-features -- -D warnings  # Rust linting
 RUFF_UPDATE_SCHEMA=1 cargo test  # Rust testing and updating ruff.schema.json
-uvx pre-commit run --all-files --show-diff-on-failure  # Rust and Python formatting, Markdown and Python linting, etc.
+uvx prek run -a  # Rust and Python formatting, Markdown and Python linting, etc.
 ```
 
 These checks will run on GitHub Actions when you open your pull request, but running them locally

crates/ty/CONTRIBUTING.md

@@ -38,8 +38,8 @@ You can optionally install pre-commit hooks to automatically run the validation
 when making a commit:
 
 ```shell
-uv tool install pre-commit
-pre-commit install
+uv tool install prek
+prek install
 ```
 
 We recommend [nextest](https://nexte.st/) to run ty's test suite (via `cargo nextest run`),
@@ -66,7 +66,7 @@ and that it passes both the lint and test validation checks:
 ```shell
 cargo clippy --workspace --all-targets --all-features -- -D warnings  # Rust linting
 cargo test  # Rust testing
-uvx pre-commit run --all-files --show-diff-on-failure  # Rust and Python formatting, Markdown and Python linting, etc.
+uvx prek run -a  # Rust and Python formatting, Markdown and Python linting, etc.
 ```
 
 These checks will run on GitHub Actions when you open your pull request, but running them locally

crates/ty_python_semantic/resources/mdtest/decorators/total_ordering.md

@@ -38,6 +38,125 @@ reveal_type(s1 > s2)  # revealed: bool
 reveal_type(s1 >= s2)  # revealed: bool
 ```
 
+## Signature derived from source ordering method
+
+When the source ordering method accepts a broader type (like `object`) for its `other` parameter,
+the synthesized comparison methods should use the same signature. This allows comparisons with types
+other than the class itself:
+
+```py
+from functools import total_ordering
+
+@total_ordering
+class Comparable:
+    def __init__(self, value: int):
+        self.value = value
+
+    def __eq__(self, other: object) -> bool:
+        if isinstance(other, Comparable):
+            return self.value == other.value
+        if isinstance(other, int):
+            return self.value == other
+        return NotImplemented
+
+    def __lt__(self, other: object) -> bool:
+        if isinstance(other, Comparable):
+            return self.value < other.value
+        if isinstance(other, int):
+            return self.value < other
+        return NotImplemented
+
+a = Comparable(10)
+b = Comparable(20)
+
+# Comparisons with the same type work.
+reveal_type(a <= b)  # revealed: bool
+reveal_type(a >= b)  # revealed: bool
+
+# Comparisons with `int` also work because `__lt__` accepts `object`.
+reveal_type(a <= 15)  # revealed: bool
+reveal_type(a >= 5)  # revealed: bool
+```
+
+## Multiple ordering methods with different signatures
+
+When multiple ordering methods are defined with different signatures, the decorator selects a "root"
+method using the priority order: `__lt__` > `__le__` > `__gt__` > `__ge__`. Synthesized methods use
+the signature from the highest-priority method. Methods that are explicitly defined are not
+overridden.
+
+```py
+from functools import total_ordering
+
+@total_ordering
+class MultiSig:
+    def __init__(self, value: int):
+        self.value = value
+
+    def __eq__(self, other: object) -> bool:
+        return True
+    # __lt__ accepts `object` (highest priority, used as root)
+    def __lt__(self, other: object) -> bool:
+        return True
+    # __gt__ only accepts `MultiSig` (not overridden by decorator)
+    def __gt__(self, other: "MultiSig") -> bool:
+        return True
+
+a = MultiSig(10)
+b = MultiSig(20)
+
+# __le__ and __ge__ are synthesized with __lt__'s signature (accepts `object`)
+reveal_type(a <= b)  # revealed: bool
+reveal_type(a <= 15)  # revealed: bool
+reveal_type(a >= b)  # revealed: bool
+reveal_type(a >= 15)  # revealed: bool
+
+# __gt__ keeps its original signature (only accepts MultiSig)
+reveal_type(a > b)  # revealed: bool
+a > 15  # error: [unsupported-operator]
+```
+
+## Overloaded ordering method
+
+When the source ordering method is overloaded, the synthesized comparison methods should preserve
+all overloads:
+
+```py
+from functools import total_ordering
+from typing import overload
+
+@total_ordering
+class Flexible:
+    def __init__(self, value: int):
+        self.value = value
+
+    def __eq__(self, other: object) -> bool:
+        return True
+
+    @overload
+    def __lt__(self, other: "Flexible") -> bool: ...
+    @overload
+    def __lt__(self, other: int) -> bool: ...
+    def __lt__(self, other: "Flexible | int") -> bool:
+        if isinstance(other, Flexible):
+            return self.value < other.value
+        return self.value < other
+
+a = Flexible(10)
+b = Flexible(20)
+
+# Synthesized __le__ preserves overloads from __lt__
+reveal_type(a <= b)  # revealed: bool
+reveal_type(a <= 15)  # revealed: bool
+
+# Synthesized __ge__ also preserves overloads
+reveal_type(a >= b)  # revealed: bool
+reveal_type(a >= 15)  # revealed: bool
+
+# But comparison with an unsupported type should still error
+a <= "string"  # error: [unsupported-operator]
+```
+
 ## Using `__gt__` as the root comparison method
 
 When a class defines `__eq__` and `__gt__`, the decorator synthesizes `__lt__`, `__le__`, and
@@ -127,6 +246,41 @@ reveal_type(c1 > c2)  # revealed: bool
 reveal_type(c1 >= c2)  # revealed: bool
 ```
 
+## Method precedence with inheritance
+
+The decorator always prefers `__lt__` > `__le__` > `__gt__` > `__ge__`, regardless of whether the
+method is defined locally or inherited. In this example, the inherited `__lt__` takes precedence
+over the locally-defined `__gt__`:
+
+```py
+from functools import total_ordering
+from typing import Literal
+
+class Base:
+    def __lt__(self, other: "Base") -> Literal[True]:
+        return True
+
+@total_ordering
+class Child(Base):
+    # __gt__ is defined locally, but __lt__ (inherited) takes precedence
+    def __gt__(self, other: "Child") -> Literal[False]:
+        return False
+
+c1 = Child()
+c2 = Child()
+
+# __lt__ is inherited from Base
+reveal_type(c1 < c2)  # revealed: Literal[True]
+
+# __gt__ is defined locally on Child
+reveal_type(c1 > c2)  # revealed: Literal[False]
+
+# __le__ and __ge__ are synthesized from __lt__ (the highest-priority method),
+# even though __gt__ is defined locally on the class itself
+reveal_type(c1 <= c2)  # revealed: bool
+reveal_type(c1 >= c2)  # revealed: bool
+```
+
 ## Explicitly-defined methods are not overridden
 
 When a class explicitly defines multiple comparison methods, the decorator does not override them.
@@ -245,6 +399,79 @@ n1 <= n2  # error: [unsupported-operator]
 n1 >= n2  # error: [unsupported-operator]
 ```
 
+## Non-bool return type
+
+When the root ordering method returns a non-bool type (like `int`), the synthesized methods return a
+union of that type and `bool`. This is because `@total_ordering` generates methods like:
+
+```python
+def __le__(self, other):
+    return self < other or self == other
+```
+
+If `__lt__` returns `int`, then the synthesized `__le__` could return either `int` (from
+`self < other`) or `bool` (from `self == other`). Since `bool` is a subtype of `int`, the union
+simplifies to `int`:
+
+```py
+from functools import total_ordering
+
+@total_ordering
+class IntReturn:
+    def __init__(self, value: int):
+        self.value = value
+
+    def __eq__(self, other: object) -> bool:
+        if not isinstance(other, IntReturn):
+            return NotImplemented
+        return self.value == other.value
+
+    def __lt__(self, other: "IntReturn") -> int:
+        return self.value - other.value
+
+a = IntReturn(10)
+b = IntReturn(20)
+
+# User-defined __lt__ returns int.
+reveal_type(a < b)  # revealed: int
+
+# Synthesized methods return int (the union int | bool simplifies to int
+# because bool is a subtype of int in Python).
+reveal_type(a <= b)  # revealed: int
+reveal_type(a > b)  # revealed: int
+reveal_type(a >= b)  # revealed: int
+```
+
+When the root method returns a type that is not a supertype of `bool`, the union is preserved:
+
+```py
+from functools import total_ordering
+
+@total_ordering
+class StrReturn:
+    def __init__(self, value: str):
+        self.value = value
+
+    def __eq__(self, other: object) -> bool:
+        if not isinstance(other, StrReturn):
+            return NotImplemented
+        return self.value == other.value
+
+    def __lt__(self, other: "StrReturn") -> str:
+        return self.value
+
+a = StrReturn("a")
+b = StrReturn("b")
+
+# User-defined __lt__ returns str.
+reveal_type(a < b)  # revealed: str
+
+# Synthesized methods return str | bool.
+reveal_type(a <= b)  # revealed: str | bool
+reveal_type(a > b)  # revealed: str | bool
+reveal_type(a >= b)  # revealed: str | bool
+```
+
 ## Function call form
 
 When `total_ordering` is called as a function (not as a decorator), the same validation is

crates/ty_python_semantic/resources/mdtest/generics/pep695/variables.md

@@ -352,16 +352,15 @@ def two_final_constrained[T: (FinalClass, AnotherFinalClass), U: (FinalClass, An
     static_assert(not is_subtype_of(U, T))
 ```
 
-A bound or constrained typevar is not a subtype of itself in a union, since subtyping between a
-TypeVar and an arbitrary other type cannot be guaranteed to be reflexive.
+A bound or constrained typevar is a subtype of itself in a union:
 
 ```py
 def union[T: Base, U: (Base, Unrelated)](t: T, u: U) -> None:
     static_assert(is_assignable_to(T, T | None))
     static_assert(is_assignable_to(U, U | None))
 
-    static_assert(not is_subtype_of(T, T | None))
-    static_assert(not is_subtype_of(U, U | None))
+    static_assert(is_subtype_of(T, T | None))
+    static_assert(is_subtype_of(U, U | None))
 ```
 
 A bound or constrained typevar in a union with a dynamic type is assignable to the typevar:

crates/ty_python_semantic/src/types.rs

@@ -1833,7 +1833,7 @@ impl<'db> Type<'db> {
     ///
     /// This method may have false negatives, but it should not have false positives. It should be
     /// a cheap shallow check, not an exhaustive recursive check.
-    const fn subtyping_is_always_reflexive(self) -> bool {
+    fn subtyping_is_always_reflexive(self) -> bool {
         match self {
             Type::Never
             | Type::FunctionLiteral(..)

crates/ty_python_semantic/src/types/class.rs

@@ -1586,17 +1586,44 @@ impl<'db> ClassLiteral<'db> {
     }
 
     /// Returns `true` if any class in this class's MRO (excluding `object`) defines an ordering
-    /// method (`__lt__`, `__le__`, `__gt__`, `__ge__`). Used by `@total_ordering` validation and
-    /// for synthesizing comparison methods.
+    /// method (`__lt__`, `__le__`, `__gt__`, `__ge__`). Used by `@total_ordering` validation.
     pub(super) fn has_ordering_method_in_mro(
         self,
         db: &'db dyn Db,
         specialization: Option<Specialization<'db>>,
     ) -> bool {
-        self.iter_mro(db, specialization)
-            .filter_map(ClassBase::into_class)
-            .filter(|class| !class.class_literal(db).0.is_known(db, KnownClass::Object))
-            .any(|class| class.class_literal(db).0.has_own_ordering_method(db))
+        self.total_ordering_root_method(db, specialization)
+            .is_some()
+    }
+
+    /// Returns the type of the ordering method used by `@total_ordering`, if any.
+    ///
+    /// Following `functools.total_ordering` precedence, we prefer `__lt__` > `__le__` > `__gt__` >
+    /// `__ge__`, regardless of whether the method is defined locally or inherited.
+    pub(super) fn total_ordering_root_method(
+        self,
+        db: &'db dyn Db,
+        specialization: Option<Specialization<'db>>,
+    ) -> Option<Type<'db>> {
+        const ORDERING_METHODS: [&str; 4] = ["__lt__", "__le__", "__gt__", "__ge__"];
+
+        for name in ORDERING_METHODS {
+            for base in self.iter_mro(db, specialization) {
+                let Some(base_class) = base.into_class() else {
+                    continue;
+                };
+                let (base_literal, base_specialization) = base_class.class_literal(db);
+                if base_literal.is_known(db, KnownClass::Object) {
+                    continue;
+                }
+                let member = class_member(db, base_literal.body_scope(db), name);
+                if let Some(ty) = member.ignore_possibly_undefined() {
+                    return Some(ty.apply_optional_specialization(db, base_specialization));
+                }
+            }
+        }
+
+        None
     }
 
     pub(crate) fn generic_context(self, db: &'db dyn Db) -> Option<GenericContext<'db>> {
@@ -2448,26 +2475,44 @@ impl<'db> ClassLiteral<'db> {
         // ordering method. The decorator requires at least one of __lt__,
         // __le__, __gt__, or __ge__ to be defined (either in this class or
         // inherited from a superclass, excluding `object`).
-        if self.total_ordering(db) && matches!(name, "__lt__" | "__le__" | "__gt__" | "__ge__") {
-            if self.has_ordering_method_in_mro(db, specialization) {
-                let instance_ty =
-                    Type::instance(db, self.apply_optional_specialization(db, specialization));
-
-                let signature = Signature::new(
-                    Parameters::new(
-                        db,
-                        [
-                            Parameter::positional_or_keyword(Name::new_static("self"))
-                                .with_annotated_type(instance_ty),
-                            Parameter::positional_or_keyword(Name::new_static("other"))
-                                .with_annotated_type(instance_ty),
-                        ],
-                    ),
-                    KnownClass::Bool.to_instance(db),
+        //
+        // Only synthesize methods that are not already defined in the MRO.
+        if self.total_ordering(db)
+            && matches!(name, "__lt__" | "__le__" | "__gt__" | "__ge__")
+            && !self
+                .iter_mro(db, specialization)
+                .filter_map(ClassBase::into_class)
+                .filter(|class| !class.class_literal(db).0.is_known(db, KnownClass::Object))
+                .any(|class| {
+                    class_member(db, class.class_literal(db).0.body_scope(db), name)
+                        .ignore_possibly_undefined()
+                        .is_some()
+                })
+            && self.has_ordering_method_in_mro(db, specialization)
+            && let Some(root_method_ty) = self.total_ordering_root_method(db, specialization)
+            && let Some(callables) = root_method_ty.try_upcast_to_callable(db)
+        {
+            let bool_ty = KnownClass::Bool.to_instance(db);
+            let synthesized_callables = callables.map(|callable| {
+                let signatures = CallableSignature::from_overloads(
+                    callable.signatures(db).iter().map(|signature| {
+                        // The generated methods return a union of the root method's return type
+                        // and `bool`. This is because `@total_ordering` synthesizes methods like:
+                        //     def __gt__(self, other): return not (self == other or self < other)
+                        // If `__lt__` returns `int`, then `__gt__` could return `int | bool`.
+                        let return_ty =
+                            UnionType::from_elements(db, [signature.return_ty, bool_ty]);
+                        Signature::new_generic(
+                            signature.generic_context,
+                            signature.parameters().clone(),
+                            return_ty,
+                        )
+                    }),
                 );
+                CallableType::new(db, signatures, CallableTypeKind::FunctionLike)
+            });
 
-                return Some(Type::function_like_callable(db, signature));
-            }
+            return Some(synthesized_callables.into_type(db));
         }
 
         let field_policy = CodeGeneratorKind::from_class(db, self, specialization)?;

crates/ty_python_semantic/src/types/relation.rs

@@ -195,17 +195,6 @@ impl TypeRelation<'_> {
     pub(crate) const fn is_subtyping(self) -> bool {
         matches!(self, TypeRelation::Subtyping)
     }
-
-    pub(crate) const fn can_safely_assume_reflexivity(self, ty: Type) -> bool {
-        match self {
-            TypeRelation::Assignability
-            | TypeRelation::ConstraintSetAssignability
-            | TypeRelation::Redundancy => true,
-            TypeRelation::Subtyping | TypeRelation::SubtypingAssuming(_) => {
-                ty.subtyping_is_always_reflexive()
-            }
-        }
-    }
 }
 
 #[salsa::tracked]
@@ -340,7 +329,7 @@ impl<'db> Type<'db> {
         //
         // Note that we could do a full equivalence check here, but that would be both expensive
         // and unnecessary. This early return is only an optimisation.
-        if relation.can_safely_assume_reflexivity(self) && self == target {
+        if (!relation.is_subtyping() || self.subtyping_is_always_reflexive()) && self == target {
             return ConstraintSet::from(true);
         }
 
@@ -471,38 +460,29 @@ impl<'db> Type<'db> {
                 },
             }),
 
-            // In general, a TypeVar `T` is not redundant with a type `S` unless one of the two conditions is satisfied:
+            // In general, a TypeVar `T` is not a subtype of a type `S` unless one of the two conditions is satisfied:
             // 1. `T` is a bound TypeVar and `T`'s upper bound is a subtype of `S`.
             //    TypeVars without an explicit upper bound are treated as having an implicit upper bound of `object`.
             // 2. `T` is a constrained TypeVar and all of `T`'s constraints are subtypes of `S`.
             //
             // However, there is one exception to this general rule: for any given typevar `T`,
             // `T` will always be a subtype of any union containing `T`.
-            (_, Type::Union(union))
-                if relation.can_safely_assume_reflexivity(self)
+            (Type::TypeVar(bound_typevar), Type::Union(union))
+                if !bound_typevar.is_inferable(db, inferable)
                     && union.elements(db).contains(&self) =>
             {
                 ConstraintSet::from(true)
             }
 
             // A similar rule applies in reverse to intersection types.
-            (Type::Intersection(intersection), _)
-                if relation.can_safely_assume_reflexivity(target)
+            (Type::Intersection(intersection), Type::TypeVar(bound_typevar))
+                if !bound_typevar.is_inferable(db, inferable)
                     && intersection.positive(db).contains(&target) =>
             {
                 ConstraintSet::from(true)
             }
-            (Type::Intersection(intersection), _)
-                if relation.is_assignability()
-                    && intersection.positive(db).iter().any(Type::is_dynamic) =>
-            {
-                // If the intersection contains `Any`/`Unknown`/`@Todo`, it is assignable to any type.
-                // `Any` could materialize to `Never`, `Never & T & ~S` simplifies to `Never` for any
-                // `T` and any `S`, and `Never` is a subtype of all types.
-                ConstraintSet::from(true)
-            }
-            (Type::Intersection(intersection), _)
-                if relation.can_safely_assume_reflexivity(target)
+            (Type::Intersection(intersection), Type::TypeVar(bound_typevar))
+                if !bound_typevar.is_inferable(db, inferable)
                     && intersection.negative(db).contains(&target) =>
             {
                 ConstraintSet::from(false)