Fix typing in `pl.overrides.fairscale` (#10799)

* update typing in fairscale

* [pre-commit.ci] auto fixes from pre-commit.com hooks

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Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

pyproject.toml

@@ -78,7 +78,6 @@ module = [
     "pytorch_lightning.loops.fit_loop",
     "pytorch_lightning.loops.utilities",
     "pytorch_lightning.overrides.distributed",
-    "pytorch_lightning.overrides.fairscale",
     "pytorch_lightning.plugins.environments.lightning_environment",
     "pytorch_lightning.plugins.environments.lsf_environment",
     "pytorch_lightning.plugins.environments.slurm_environment",

pytorch_lightning/overrides/fairscale.py

@@ -11,6 +11,8 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+import torch.nn as nn
+
 import pytorch_lightning as pl
 from pytorch_lightning.overrides.base import _LightningModuleWrapperBase, unwrap_lightning_module
 from pytorch_lightning.utilities import _FAIRSCALE_AVAILABLE
@@ -19,11 +21,11 @@ LightningShardedDataParallel = None
 if _FAIRSCALE_AVAILABLE:
     from fairscale.nn.data_parallel.sharded_ddp import ShardedDataParallel
 
-    class LightningShardedDataParallel(_LightningModuleWrapperBase):
+    class LightningShardedDataParallel(_LightningModuleWrapperBase):  # type: ignore[no-redef]
         # Just do this for later docstrings
         pass
 
-    def unwrap_lightning_module_sharded(wrapped_model) -> "pl.LightningModule":
+    def unwrap_lightning_module_sharded(wrapped_model: nn.Module) -> "pl.LightningModule":
         model = wrapped_model
         if isinstance(model, ShardedDataParallel):
             model = model.module