Removed redundant type aliases of _device and replaced with torch.types.Device

[alphacrash]

Fixes Issue #152952

cc @jgong5 @mingfeima @XiaobingSuper @sanchitintel @ashokei @jingxu10 @jerryzh168 @Skylion007 @janeyx99 @shink

[pytorch-bot]

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• ✅ login: alphacrash / name: SUD (923df88)

[alphacrash]

@pytorchbot label "topic: not user facing"

[alphacrash]

Based on checks I saw, I removed the unused import and fixed the linting issue using lintrunner -a for the files I have commited.

I am not sure what I can do for bc_linter fail, it would be helpful if I can get some guidance on that.

Saw that issue is marked as closed, do let me know if PR is no longer required, will close it. Thanks!

[Quantum-Kayak]

Thanks for cleaning this up — moving to torch.types.Device improves clarity and reduces redundancy across the codebase. It also makes future refactoring easier by relying on the canonical type directly.

One small note: if _device was used in contexts that might touch backward compatibility tracking, that could be what’s triggering the bc_linterfailure. If you haven't already, might be worth double-checking that this change doesn’t alter any externally visible annotations or serialized schema, especially in __init__.py or module-level exports. If it’s purely internal, a BC note might not be needed — could be flagged for review instead.

Appreciate the attention to detail here. Looks close to ready once the BC issue is clarified.

[alphacrash]

Since the change is intentional, can bc_linter be suppressed?
If not, please do suggest any code changes I can add.

[janeyx99]

@pytorchbot merge

[pytorchmergebot]

Merge started

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[pytorchmergebot]

Merge failed

Reason: 2 jobs have failed, first few of them are: linux-aarch64 / linux-jammy-aarch64-py3.10 / test (default, 3, 3, linux.arm64.m8g.4xlarge), linux-aarch64 / linux-jammy-aarch64-py3.10 / test (default, 2, 3, linux.arm64.m8g.4xlarge)

Details for Dev Infra team

Raised by workflow job

[alphacrash]

I merged the latest main into this branch to fix merge conflicts.
The error from test fail in last merge attempt seems to be some infra issue.

@janeyx99 - Can you please try merge again

[janeyx99]

@pytorchbot merge

[pytorchmergebot]

Merge started

Your change will be merged once all checks pass (ETA 0-4 Hours).

Learn more about merging in the wiki.

Questions? Feedback? Please reach out to the PyTorch DevX Team

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[pytorchmergebot]

Merge failed

Reason: 6 mandatory check(s) failed. The first few are:

• pull / linux-jammy-py3.13-clang12 / test (default, 4, 5, linux.4xlarge)
• pull / linux-jammy-py3.13-clang12 / test (default, 5, 5, linux.4xlarge)
• pull / linux-jammy-py3.13-clang12 / test (default, 1, 5, linux.4xlarge)
• pull / linux-jammy-py3.13-clang12 / test (default, 3, 5, linux.4xlarge)
• pull / linux-jammy-py3.13-clang12 / test (default, 2, 5, linux.4xlarge)

Dig deeper by viewing the failures on hud

Details for Dev Infra team

Raised by workflow job

Failing merge rule: Core Maintainers

[EikanWang]

@pytorchbot rebase

[pytorchmergebot]

@pytorchbot started a rebase job onto refs/remotes/origin/viable/strict. Check the current status here

[pytorchmergebot]

Rebase failed due to Command git -C /home/runner/work/pytorch/pytorch rebase refs/remotes/origin/viable/strict pull/160945/head returned non-zero exit code 1

Rebasing (1/2)
Auto-merging torch/cpu/__init__.py
CONFLICT (content): Merge conflict in torch/cpu/__init__.py
Auto-merging torch/mtia/__init__.py
Auto-merging torch/xpu/__init__.py
CONFLICT (content): Merge conflict in torch/xpu/__init__.py
error: could not apply 7bfdfd64ee0... Removed redundant type aliases of _device
hint: Resolve all conflicts manually, mark them as resolved with
hint: "git add/rm <conflicted_files>", then run "git rebase --continue".
hint: You can instead skip this commit: run "git rebase --skip".
hint: To abort and get back to the state before "git rebase", run "git rebase --abort".
hint: Disable this message with "git config set advice.mergeConflict false"
Could not apply 7bfdfd64ee0... # Removed redundant type aliases of _device

Raised by https://github.com/pytorch/pytorch/actions/runs/18792996465

[EikanWang]

@alphacrash , could you help rebase this PR?

[alphacrash]

@EikanWang, sorry for the delay. Rebased the PR.