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New lint: mem_replace_with_uninit #4511

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merged 1 commit into from
Sep 20, 2019
Merged

New lint: mem_replace_with_uninit #4511

merged 1 commit into from
Sep 20, 2019

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llogiq
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@llogiq llogiq commented Sep 6, 2019

changelog: add mem_replace_uninit lint

This fixes #4485

@flip1995 flip1995 added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties label Sep 6, 2019
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llogiq commented Sep 6, 2019

Seems to be blocked on a rustup.

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mati865 commented Sep 6, 2019

Should work when you retrigger CI, or do rebase.

@llogiq llogiq force-pushed the replace_uninitialized branch 4 times, most recently from 1e6adf7 to 3c1ea68 Compare September 6, 2019 19:22
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Shnatsel commented Sep 6, 2019

There is some potential for false positives here: mem::zeroed() is only dangerous for types where not all possible bit patterns are valid. It's actually fine for numeric types like u8/i8/f32, char, or arrays of them. Not sure about structs. Everything else is dangerous even with mem::zeroed.

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llogiq commented Sep 6, 2019

You're right, that should probably be another lint, because mem::zeroed::<usize>() is not incorrect, just a silly way to say 0.

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Shnatsel commented Sep 6, 2019 •
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mem::zeroed() is the only way to say 0 in a generic context, so people actually use that. However, it is UB when used in a generic context.

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llogiq commented Sep 7, 2019

If the types are all zero-compatible, they should implement Default and use that.

@llogiq llogiq force-pushed the replace_uninitialized branch 2 times, most recently from 1e68ee4 to c6c095a Compare September 7, 2019 06:03
flip1995
flip1995 requested changes Sep 10, 2019
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Can you also run ./util/dev fmt. The only reason CI passes, is because nightly rustfmt is missing since a few days.

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clippy_lints/src/mem_replace.rs Outdated Show resolved Hide resolved
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llogiq commented Sep 13, 2019

@flip1995 can you have another look? The problem was that I tried to match uninitialized() as Path, when it was a Call all along.

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flip1995 requested changes Sep 16, 2019
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@llogiq llogiq force-pushed the replace_uninitialized branch 2 times, most recently from 070e3a7 to b4dee97 Compare September 16, 2019 21:32
flip1995
flip1995 approved these changes Sep 17, 2019
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Thanks, waiting for the rustup.

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@bors r+ rollup

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bors commented Sep 19, 2019

📌 Commit ceeffcb has been approved by flip1995

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llogiq commented Sep 19, 2019

rebased, will r=@flip1995 once travis is happy.

flip1995 added a commit to flip1995/rust-clippy that referenced this pull request Sep 19, 2019
@flip1995
Rollup merge of rust-lang#4511 - rust-lang:replace_uninitialized, r=f…
586f438 
…lip1995

New lint: mem_replace_with_uninit

changelog: add `mem_replace_uninit` lint

This fixes rust-lang#4485
@flip1995 flip1995 mentioned this pull request Sep 19, 2019
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bors commented Sep 19, 2019

⌛ Testing commit ceeffcb with merge 55a4081...

bors added a commit that referenced this pull request Sep 19, 2019
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Auto merge of #4511 - rust-lang:replace_uninitialized, r=flip1995
55a4081 
New lint: mem_replace_with_uninit

changelog: add `mem_replace_uninit` lint

This fixes #4485
@bors bors mentioned this pull request Sep 19, 2019
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flip1995 added a commit to flip1995/rust-clippy that referenced this pull request Sep 19, 2019
@flip1995
Rollup merge of rust-lang#4511 - rust-lang:replace_uninitialized, r=f…
70d5acc 
…lip1995

New lint: mem_replace_with_uninit

changelog: add `mem_replace_uninit` lint

This fixes rust-lang#4485
@flip1995 flip1995 mentioned this pull request Sep 19, 2019
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@bors retry (for queue prio)

bors added a commit that referenced this pull request Sep 19, 2019
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Auto merge of #4553 - flip1995:rollup-0chhiy3, r=flip1995
f84e26d 
Rollup of 4 pull requests

Successful merges:

 - #4511 (New lint: mem_replace_with_uninit)
 - #4535 (New lint: Require `# Safety` section in pub unsafe fn docs)
 - #4539 (Changes cast-lossless to a pedantic lint)
 - #4544 (#4542 remove machine applicable suggestion)

Failed merges:

r? @ghost

changelog: none
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bors commented Sep 19, 2019

⌛ Testing commit ceeffcb with merge 2173797...

bors added a commit that referenced this pull request Sep 19, 2019
@bors
Auto merge of #4511 - rust-lang:replace_uninitialized, r=flip1995
2173797 
New lint: mem_replace_with_uninit

changelog: add `mem_replace_uninit` lint

This fixes #4485
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bors commented Sep 19, 2019

💔 Test failed - checks-travis

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Not all lints defined properly. Please run `util/dev update_lints` to make sure all lints are defined properly.

Your other new lint (the # safety one) got merged first 🤷‍♂

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llogiq commented Sep 20, 2019

@bors retry

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Needs to be reapproved

@bors r+

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bors commented Sep 20, 2019

📌 Commit 8d884c8 has been approved by flip1995

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bors commented Sep 20, 2019

⌛ Testing commit 8d884c8 with merge ca9e4ad...

bors added a commit that referenced this pull request Sep 20, 2019
@bors
Auto merge of #4511 - rust-lang:replace_uninitialized, r=flip1995
ca9e4ad 
New lint: mem_replace_with_uninit

changelog: add `mem_replace_uninit` lint

This fixes #4485
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bors commented Sep 20, 2019

☀️ Test successful - checks-travis, status-appveyor
Approved by: flip1995
Pushing ca9e4ad to master...

@bors bors merged commit 8d884c8 into master Sep 20, 2019
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@flip1995 flip1995 deleted the replace_uninitialized branch October 28, 2019 08:14
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@Shnatsel Shnatsel Shnatsel approved these changes

@flip1995 flip1995 flip1995 approved these changes

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New lint: mem::replace(mem::uninitialized) is dangerous
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@llogiq @mati865 @Shnatsel @flip1995 @bors