diff --git a/mypy/meet.py b/mypy/meet.py index ea2411b8ccc9..b5262f87c0bd 100644 --- a/mypy/meet.py +++ b/mypy/meet.py @@ -553,7 +553,27 @@ def _type_object_overlap(left: Type, right: Type) -> bool: else: return False - if len(left.args) == len(right.args): + if right.type.has_type_var_tuple_type: + # Similar to subtyping, we delegate the heavy lifting to the tuple overlap. + assert right.type.type_var_tuple_prefix is not None + assert right.type.type_var_tuple_suffix is not None + prefix = right.type.type_var_tuple_prefix + suffix = right.type.type_var_tuple_suffix + tvt = right.type.defn.type_vars[prefix] + assert isinstance(tvt, TypeVarTupleType) + fallback = tvt.tuple_fallback + left_prefix, left_middle, left_suffix = split_with_prefix_and_suffix( + left.args, prefix, suffix + ) + right_prefix, right_middle, right_suffix = split_with_prefix_and_suffix( + right.args, prefix, suffix + ) + left_args = left_prefix + (TupleType(list(left_middle), fallback),) + left_suffix + right_args = right_prefix + (TupleType(list(right_middle), fallback),) + right_suffix + else: + left_args = left.args + right_args = right.args + if len(left_args) == len(right_args): # Note: we don't really care about variance here, since the overlapping check # is symmetric and since we want to return 'True' even for partial overlaps. # @@ -570,7 +590,7 @@ def _type_object_overlap(left: Type, right: Type) -> bool: # to contain only instances of B at runtime. if all( _is_overlapping_types(left_arg, right_arg) - for left_arg, right_arg in zip(left.args, right.args) + for left_arg, right_arg in zip(left_args, right_args) ): return True diff --git a/test-data/unit/check-typevar-tuple.test b/test-data/unit/check-typevar-tuple.test index f49e1b3c6613..754151ffb559 100644 --- a/test-data/unit/check-typevar-tuple.test +++ b/test-data/unit/check-typevar-tuple.test @@ -2487,3 +2487,29 @@ class C(Generic[P, R]): c: C[int, str] # E: Can only replace ParamSpec with a parameter types list or another ParamSpec, got "int" reveal_type(c.fn) # N: Revealed type is "def (*Any, **Any)" [builtins fixtures/tuple.pyi] + +[case testTypeVarTupleInstanceOverlap] +# flags: --strict-equality +from typing import TypeVarTuple, Unpack, Generic + +Ts = TypeVarTuple("Ts") + +class Foo(Generic[Unpack[Ts]]): + pass + +x1: Foo[Unpack[tuple[int, ...]]] +y1: Foo[Unpack[tuple[str, ...]]] +x1 is y1 # E: Non-overlapping identity check (left operand type: "Foo[Unpack[Tuple[int, ...]]]", right operand type: "Foo[Unpack[Tuple[str, ...]]]") + +x2: Foo[Unpack[tuple[int, ...]]] +y2: Foo[Unpack[tuple[int, ...]]] +x2 is y2 + +x3: Foo[Unpack[tuple[int, ...]]] +y3: Foo[Unpack[tuple[int, int]]] +x3 is y3 + +x4: Foo[Unpack[tuple[str, ...]]] +y4: Foo[Unpack[tuple[int, int]]] +x4 is y4 # E: Non-overlapping identity check (left operand type: "Foo[Unpack[Tuple[str, ...]]]", right operand type: "Foo[int, int]") +[builtins fixtures/tuple.pyi]