Error messages for unsupported Trainer attributes

src/pytorch_lightning/core/module.py

@@ -269,6 +269,20 @@ def loggers(self) -> List[Logger]:
         """Reference to the list of loggers in the Trainer."""
         return self.trainer.loggers if self._trainer else []
 
+    @property
+    def use_amp(self) -> bool:
+        raise AttributeError(
+            "`LightningModule.use_amp` was deprecated in v1.6 and is no longer accessible as of v1.8."
+            " Please use `Trainer.amp_backend`.",
+        )
+
+    @use_amp.setter
+    def use_amp(self, use_amp: bool) -> None:
+        raise AttributeError(
+            "`LightningModule.use_amp` was deprecated in v1.6 and is no longer accessible as of v1.8."
+            " Please use `Trainer.amp_backend`.",
+        )
+
     def _call_batch_hook(self, hook_name: str, *args: Any) -> Any:
         if self._trainer:
             datahook_selector = self._trainer._data_connector._datahook_selector

src/pytorch_lightning/trainer/trainer.py

@@ -2143,6 +2143,55 @@ def logged_metrics(self) -> _OUT_DICT:
     def progress_bar_metrics(self) -> _PBAR_DICT:
         return self._logger_connector.progress_bar_metrics
 
+    @property
+    def gpus(self) -> Optional[Union[List[int], str, int]]:
+        raise AttributeError(
+            "`Trainer.gpus` was deprecated in v1.6 and is no longer accessible as of v1.8."
+            " Please use `Trainer.num_devices` or `Trainer.device_ids` to get device information instead."
+        )
+
+    @property
+    def root_gpu(self) -> Optional[int]:
+        raise AttributeError(
+            "`Trainer.root_gpu` was deprecated in v1.6 and is no longer accessible as of v1.8."
+            " Please use `Trainer.strategy.root_device.index` instead."
+        )
+
+    @property
+    def tpu_cores(self) -> int:
+        raise AttributeError(
+            "`Trainer.tpu_cores` was deprecated in v1.6 and is no longer accessible as of v1.8."
+            " Please use `Trainer.num_devices` instead."
+        )
+
+    @property
+    def ipus(self) -> int:
+        raise AttributeError(
+            "`Trainer.ipus` was deprecated in v1.6 and is no longer accessible as of v1.8."
+            " Please use `Trainer.num_devices` instead."
+        )
+
+    @property
+    def num_gpus(self) -> int:
+        raise AttributeError(
+            "`Trainer.num_gpus` was deprecated in v1.6 and is no longer accessible as of v1.8."
+            " Please use `Trainer.num_devices` instead."
+        )
+
+    @property
+    def devices(self) -> int:
+        raise AttributeError(
+            "`Trainer.devices` was deprecated in v1.6 and is no longer accessible as of v1.8."
+            " Please use `Trainer.num_devices` or `Trainer.device_ids` to get device information instead."
+        )
+
+    @property
+    def use_amp(self) -> bool:
+        raise AttributeError(
+            "`Trainer.use_amp` was deprecated in v1.6 and is no longer accessible as of v1.8."
+            " Please use `Trainer.amp_backend`.",
+        )
+
     @property
     def _results(self) -> Optional[_ResultCollection]:
         active_loop = self._active_loop

tests/tests_pytorch/deprecated_api/test_remove_2-0.py

@@ -300,3 +300,33 @@ def test_v2_0_0_deprecated_mc_save_checkpoint():
         match=r"ModelCheckpoint.save_checkpoint\(\)` was deprecated in v1.6 and is no longer supported as of 1.8.",
     ):
         mc.save_checkpoint(trainer)
+
+
+@pytest.mark.parametrize("attribute", ["gpus", "num_gpus", "root_gpu", "devices", "tpu_cores", "ipus"])
+def test_v2_0_0_trainer_unsupported_device_attributes(attribute):
+    trainer = Trainer()
+    with pytest.raises(
+        AttributeError, match=f"`Trainer.{attribute}` was deprecated in v1.6 and is no longer accessible as of v1.8."
+    ):
+        getattr(trainer, attribute)
+
+
+def test_v2_0_0_unsupported_use_amp():
+    trainer = Trainer()
+    with pytest.raises(
+        AttributeError, match=f"`Trainer.use_amp` was deprecated in v1.6 and is no longer accessible as of v1.8."
+    ):
+        _ = trainer.use_amp
+
+    model = BoringModel()
+    with pytest.raises(
+        AttributeError,
+        match=f"`LightningModule.use_amp` was deprecated in v1.6 and is no longer accessible as of v1.8.",
+    ):
+        _ = model.use_amp
+
+    with pytest.raises(
+        AttributeError,
+        match=f"`LightningModule.use_amp` was deprecated in v1.6 and is no longer accessible as of v1.8.",
+    ):
+        model.use_amp = False