rustc: add ReErased to be used by trait selection, MIR and trans. #34012
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r? @Aatch (rust_highfive has picked a reviewer for you, use r? to override) |
| @@ -359,7 +359,8 @@ impl<'cx, 'gcx, 'tcx> ty::fold::TypeFolder<'gcx, 'tcx> for Generalizer<'cx, 'gcx | |||
| ty::ReStatic | | |||
| ty::ReScope(..) | | |||
| ty::ReVar(..) | | |||
| ty::ReFree(..) => { | |||
| ty::ReFree(..) | | |||
| ty::ReErased => { | |||
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probably we ought to map ReErased to ReErased here
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Could this speed up trait selection?
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I am wondering if we can make it an error to try and relate "erased" regions and region variables, kind of like late-bound. This was certainly my hope, but it might cause problems in trans -- certainly we'd have to make this change first. |
| (_, ReEarlyBound(..)) | | ||
| (ReErased, _) | | ||
| (_, ReErased) => { | ||
| bug!("cannot relate region: LUB({:?}, {:?})", a, b); |
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@nikomatsakis Is this what you were talking about?
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@eddyb it's a start; I think we might be able to go a bit further. But probably we should just land this change and I can experiment off-line.
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Seems prudent to kick off a crater run here. I'll do that. |
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@bors r+ |
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📌 Commit bcec7a5 has been approved by |
rustc: add ReErased to be used by trait selection, MIR and trans. `ReErased` replaces `ReStatic` (i.e. `'static`) for erasing regions. Using a distinct lifetime helps prevent accidental mix-ups between the two. It also allows cleaner type printing (see test changes), including in symbol names: ```rust str..pattern..CharSearcher$LT$$u27$static$GT$::drop.30560::h840c2f2afc03bbea // before str..pattern..CharSearcher::drop.30561::h6bd31d2af614377a // after ``` Not that we should be producing symbols this way, but it's still better.
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💔 Test failed - auto-win-gnu-32-opt-rustbuild |
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@bors retry |
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@bors force |
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@bors force |
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💔 Test failed - auto-win-gnu-32-opt-rustbuild |
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@bors retry |
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@bors force |
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@bors force |
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💔 Test failed - auto-win-gnu-32-opt-rustbuild |
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@bors retry |
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@bors force |
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@bors force |
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@bors force |
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@alexcrichton It broke 😢 |
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@bors r- |
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@bors: retry force clean |
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@bors r=nikomatsakis |
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📌 Commit bcec7a5 has been approved by |
rustc: add ReErased to be used by trait selection, MIR and trans. `ReErased` replaces `ReStatic` (i.e. `'static`) for erasing regions. Using a distinct lifetime helps prevent accidental mix-ups between the two. It also allows cleaner type printing (see test changes), including in symbol names: ```rust str..pattern..CharSearcher$LT$$u27$static$GT$::drop.30560::h840c2f2afc03bbea // before str..pattern..CharSearcher::drop.30561::h6bd31d2af614377a // after ``` Not that we should be producing symbols this way, but it's still better.
ReErasedreplacesReStatic(i.e.'static) for erasing regions.Using a distinct lifetime helps prevent accidental mix-ups between the two.
It also allows cleaner type printing (see test changes), including in symbol names:
Not that we should be producing symbols this way, but it's still better.