End temporary lifetimes being extended by let X: &_ hints
#39066
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arielb1
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r? @eddyb (rust_highfive has picked a reviewer for you, use r? to override) |
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Started a crater run from 27b9e6d to edb3baaa6c0e14481e4a4fa771d57f67f21d5a14. |
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Crater doesn't seem to be done. I asked it to test the crates for those two commits. |
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Hm, actually I don't see a working toolchain, so I asked crater to build those too: |
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@brson yeah I was getting null results for some reason, not sure what went wrong :( |
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Ok, there was a bug in crater. The message broker shutdown at some point and crater never recovered. After starting back up it received the toolchain build complete messages, and I've started the crate builds. |
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Crater says. Only 2 false positives. |
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No positives yay! We should just merge this. @nikomatsakis - since there is nothing on Crater, do you think we can go without a warning? |
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@arielb1 Hmm, interesting! I'm not sure. Can we land it but also include some of this code, so that if you do get an error, we give a nice error message directing you to a tracking issue? How hard would that be? |
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@arielb1 (after all we don't have 100% coverage, crater is still linux only I think, but also outside of crates.io) |
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Added some warnings in a commit - the case that causes new lifetime errors is quite pathological (I added a test), but it exists. |
| expr_span, | ||
| "this expression will be dropped at a different time - see #38603"); | ||
| "this expression used to live longer due to #36082"); |
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we should make a proper tracking issue with an explanation of how to rewrite code to be unambiguous, but this seems good otherwise
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| fn main() { | ||
| let a: &_ = *&&0; |
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what is this test ... testing?
arielb1
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arielb1
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Ready for review. |
arielb1
changed the title
let X: &_ hints
| mc::Categorization::Rvalue(r, or) if r != or => { | ||
| db.note("\ | ||
| before rustc 1.16, this temporary lived longer - see issue #39283 \ | ||
| (https://github.com/rust-lang/rust/issues/39283)"); |
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nice, thanks for writing that up
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@bors r+ |
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📌 Commit 82a2805 has been approved by |
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⌛ Testing commit 82a2805 with merge a1030b2... |
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💔 Test failed - status-travis |
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Strange error on the dist bot - cc @alexcrichton @bors retry |
End temporary lifetimes being extended by `let X: &_` hints cc #39283 r? @nikomatsakis
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☀️ Test successful - status-appveyor, status-travis |
cc #39283
r? @nikomatsakis