Solve constraints from typevar upper bounds

mypy/constraints.py

@@ -153,7 +153,10 @@ def _infer_constraints(template: Type, actual: Type,
     #     T :> U2", but they are not equivalent to the constraint solver,
     #     which never introduces new Union types (it uses join() instead).
     if isinstance(template, TypeVarType):
-        return [Constraint(template.id, direction, actual)]
+        return [
+            Constraint(template.id, direction, actual),
+            Constraint(template.id, SUBTYPE_OF, template.upper_bound),
+        ]
 
     # Now handle the case of either template or actual being a Union.
     # For a Union to be a subtype of another type, every item of the Union

test-data/unit/check-generic-subtyping.test

@@ -1033,3 +1033,18 @@ x2: X2[str, int]
 reveal_type(iter(x2))  # N: Revealed type is "typing.Iterator[builtins.int]"
 reveal_type([*x2])  # N: Revealed type is "builtins.list[builtins.int]"
 [builtins fixtures/dict.pyi]
+
+
+[case testBoundTypeVarCallable]
+# flags: --strict-optional
+from typing import Callable, Optional, TypeVar
+
+class something: ...
+
+T = TypeVar("T", bound=something)
+
+def raises(opts: Optional[T]) -> T: ...
+def assertRaises(cb: Callable[..., object]) -> None: ...
+
+assertRaises(raises)
+[builtins fixtures/dict.pyi]