diff --git a/crates/ty_python_semantic/resources/mdtest/generics/legacy/functions.md b/crates/ty_python_semantic/resources/mdtest/generics/legacy/functions.md
index 50a5be7058..34c4f04ead 100644
--- a/crates/ty_python_semantic/resources/mdtest/generics/legacy/functions.md
+++ b/crates/ty_python_semantic/resources/mdtest/generics/legacy/functions.md
@@ -530,3 +530,17 @@ age, name = team.employees[0]
 reveal_type(age)  # revealed: Age
 reveal_type(name)  # revealed: Name
 ```
+
+## `~T` is never assignable to `T`
+
+```py
+from typing import TypeVar
+from ty_extensions import Not
+
+T = TypeVar("T")
+
+def f(x: T, y: Not[T]) -> T:
+    x = y  # error: [invalid-assignment]
+    y = x  # error: [invalid-assignment]
+    return x
+```
diff --git a/crates/ty_python_semantic/resources/mdtest/generics/pep695/functions.md b/crates/ty_python_semantic/resources/mdtest/generics/pep695/functions.md
index 1193e91ba5..dd75b2c56a 100644
--- a/crates/ty_python_semantic/resources/mdtest/generics/pep695/functions.md
+++ b/crates/ty_python_semantic/resources/mdtest/generics/pep695/functions.md
@@ -543,3 +543,14 @@ def _(x: int):
 
     reveal_type(C().implicit_self(x))  # revealed: tuple[C, int]
 ```
+
+## `~T` is never assignable to `T`
+
+```py
+from ty_extensions import Not
+
+def f[T](x: T, y: Not[T]) -> T:
+    x = y  # error: [invalid-assignment]
+    y = x  # error: [invalid-assignment]
+    return x
+```
diff --git a/crates/ty_python_semantic/src/types.rs b/crates/ty_python_semantic/src/types.rs
index a9111f3581..916f9471a0 100644
--- a/crates/ty_python_semantic/src/types.rs
+++ b/crates/ty_python_semantic/src/types.rs
@@ -1567,7 +1567,7 @@ impl<'db> Type<'db> {
             (Type::Intersection(intersection), Type::NonInferableTypeVar(_))
                 if intersection.negative(db).contains(&target) =>
             {
-                ConstraintSet::from(true)
+                ConstraintSet::from(false)
             }
 
             // Two identical typevars must always solve to the same type, so they are always