chore(ty): make suppressions ty-native and enforce honesty (leanEthereum#826)

Standardize on ty as the single type checker. Every suppression is now
ty-native (# ty: ignore[code]), load-bearing, and documented, and ty
itself blocks stale or duplicate suppressions going forward.

- Enable the unused-ignore-comment rule, which flags any suppression
  that no longer matches a real diagnostic.
- Remove 23 dead mypy-style # type: ignore comments that ty does not
  need: create_store in the lstar spec (ty raises nothing there) plus
  22 across the test suite and testing framework (frozen-assignment
  tests, abstract instantiation, operator-error paths, mock overrides).
- Convert the genuinely-needed override suppressions to ty-native form
  with the correct rule code (invalid-method-override).
- Document the load-bearing suppressions: the two clock forward
  references forced by the interval/slot import cycle, and the field
  exponentiation override.

ty honors mypy-style # type: ignore comments, so the dead ones were
silently accepted; the new rule surfaces them and keeps the ignore set
honest. just check passes and the affected tests are green.

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Co-authored-by: Thomas Coratger <60488569+tcoratger@users.noreply.github.com>

Author: 3 people

packages/testing/src/consensus_testing/test_fixtures/base.py

@@ -16,7 +16,7 @@ class BaseConsensusFixture(BaseFixture):
 
     # Class-level registry of all consensus fixture formats
     # Override parent's formats to maintain a separate registry
-    formats: ClassVar[dict[str, type["BaseConsensusFixture"]]] = {}  # type: ignore[assignment]
+    formats: ClassVar[dict[str, type["BaseConsensusFixture"]]] = {}
 
     expect_exception: type[Exception] | None = None
     """

packages/testing/src/framework/pytest_plugins/filler.py

@@ -285,7 +285,7 @@ def pytest_collection_modifyitems(config: pytest.Config, items: list[pytest.Item
         return
 
     fork_class = config.test_fork_class
-    layer_module = config.layer_module  # type: ignore[attribute-defined]
+    layer_module = config.layer_module
     registry = layer_module.forks.registry
     verbose = config.getoption("verbose")
     deselected = []
@@ -469,7 +469,7 @@ def base_spec_filler_parametrizer_func(
     ) -> Any:
         """Fixture used to instantiate an auto-fillable fixture object."""
 
-        class FixtureWrapper(fixture_class):  # type: ignore[misc]
+        class FixtureWrapper(fixture_class):
             """Wrapper class that auto-fills and collects fixtures on instantiation."""
 
             def __init__(self, **kwargs: Any) -> None:

pyproject.toml

@@ -89,6 +89,11 @@ python-version = "3.12"
 [tool.ty.src]
 exclude = [".claude/"]
 
+[tool.ty.rules]
+# Flag any suppression comment that no longer matches a real diagnostic.
+# Keeps the ignore set honest as the code evolves and prevents stale or duplicate suppressions.
+unused-ignore-comment = "error"
+
 [tool.ty.terminal]
 error-on-warning = true
 

src/lean_spec/spec/crypto/koalabear.py

@@ -148,6 +148,10 @@ def __rmul__(self, other: Any) -> NoReturn:
         """Reverse multiplication: reject non-Fp left operand to prevent silent int fallback."""
         self._reject(other, "*")
 
+    # The int base declares a three-argument pow with an optional modulus.
+    #
+    # The field already reduces modulo P, so the modulus argument is meaningless here.
+    # Narrowing to the field type is intentional and safe by Liskov substitution.
     def __pow__(self, exponent: int) -> Self:  # ty: ignore[invalid-method-override]
         """Field exponentiation."""
         return type(self)(pow(int(self), exponent, P))

src/lean_spec/spec/forks/lstar/fork_choice.py

@@ -36,7 +36,7 @@
 class ForkChoiceMixin(LstarSpecContract):
     """Fork choice and store maintenance for the lstar fork."""
 
-    def create_store(  # type: ignore[override]  # ty: ignore[invalid-method-override]
+    def create_store(
         self,
         state: SpecStateType,
         anchor_block: SpecBlockType,

src/lean_spec/spec/ssz/collections.py

@@ -216,8 +216,11 @@ def __len__(self) -> int:
         """Return the number of elements in the sequence."""
         return len(self.data)
 
+    # The parent Pydantic model iterates field name and value pairs.
+    # Yielding elements instead is the intended collection behavior.
+    # The narrower element type violates strict Liskov substitution, so it is suppressed.
     @override
-    def __iter__(self) -> Iterator[T]:  # type: ignore[override]
+    def __iter__(self) -> Iterator[T]:  # ty: ignore[invalid-method-override]
         """
         Iterate over the elements.
 

tests/lean_spec/helpers/mocks.py

@@ -28,29 +28,25 @@
 class StoreInterceptingSpec(LstarSpec):
     """Spec stub that forwards consensus calls to the store argument."""
 
-    def on_block(  # type: ignore[override]
-        self, store: Any, signed_block: Any, *args: Any, **kwargs: Any
-    ) -> Any:
+    def on_block(self, store: Any, signed_block: Any, *args: Any, **kwargs: Any) -> Any:
         """Forward to store.on_block."""
         kwargs.pop("scheme", None)
         return store.on_block(signed_block, *args, **kwargs)
 
-    def on_gossip_attestation(  # type: ignore[override]
+    def on_gossip_attestation(
         self, store: Any, signed_attestation: Any, *args: Any, **kwargs: Any
     ) -> Any:
         """Forward to store.on_gossip_attestation."""
         kwargs.pop("scheme", None)
         return store.on_gossip_attestation(signed_attestation, *args, **kwargs)
 
-    def on_gossip_aggregated_attestation(  # type: ignore[override]
+    def on_gossip_aggregated_attestation(
         self, store: Any, signed_attestation: Any, *args: Any, **kwargs: Any
     ) -> Any:
         """Forward to store.on_gossip_aggregated_attestation."""
         return store.on_gossip_aggregated_attestation(signed_attestation, *args, **kwargs)
 
-    def tick_interval(  # type: ignore[override]
-        self, store: Any, has_proposal: bool, is_aggregator: bool = False
-    ) -> Any:
+    def tick_interval(self, store: Any, has_proposal: bool, is_aggregator: bool = False) -> Any:
         """Forward to store.tick_interval."""
         return store.tick_interval(has_proposal, is_aggregator)
 

tests/lean_spec/node/chain/test_service.py

@@ -55,7 +55,7 @@ def __init__(self, emit: list[SignedAggregatedAttestation] | None = None) -> Non
         self.ticks: list[tuple[int, bool, bool]] = []
         self.emit = emit or []
 
-    def tick_interval(  # type: ignore[override]
+    def tick_interval(
         self, store: Store, has_proposal: bool, is_aggregator: bool = False
     ) -> tuple[Store, list[SignedAggregatedAttestation]]:
         """Advance the real store, record the call, then emit at the aggregation interval."""

tests/lean_spec/node/networking/gossipsub/integration/test_mesh_formation.py

@@ -24,7 +24,7 @@
 TOPIC = TopicId("test/mesh")
 
 
-def _all_meshes_in_bounds(network: GossipsubTestNetwork, params, topic: str) -> bool:  # type: ignore[no-untyped-def]
+def _all_meshes_in_bounds(network: GossipsubTestNetwork, params, topic: str) -> bool:
     """Check whether every node's mesh is within [D_low, D_high]."""
     return all(params.d_low <= node.get_mesh_size(topic) <= params.d_high for node in network.nodes)
 

tests/lean_spec/node/networking/service/test_service.py

@@ -144,7 +144,7 @@ async def test_stop_async_iteration_exception_caught(self, peer_id: PeerId) -> N
         sync_service = create_mock_sync_service(peer_id)
         svc = NetworkService(
             sync_service=sync_service,
-            event_source=source,  # type: ignore[arg-type]
+            event_source=source,
             network_name=FORK_DIGEST,
         )
         await svc.run()