ICE for async block containing match on empty slice and wildcard #93242
Labels
C-bug
Category: This is a bug.
E-needs-test
Call for participation: An issue has been fixed and does not reproduce, but no test has been added.
glacier
ICE tracked in rust-lang/glacier.
I-ICE
Issue: The compiler panicked, giving an Internal Compilation Error (ICE) ❄️
T-compiler
Relevant to the compiler team, which will review and decide on the PR/issue.
Comments
jix
added
C-bug
|
Interesting. Slightly minimized, seems not to do with pub fn something(path: &[usize]) -> impl Fn() -> usize {
|| match path {
[] => 0,
_ => 1,
}
} |
|
So this definitely has to do with the fact that we only capture the second "length" field of the slice fat-pointer. I'll see if I can come up with a fix! |
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Actually not sure if I'm familiar enough with the pattern match code in MIR to come up with a good fix. @rustbot release-assignment |
Dylan-DPC
added a commit
to Dylan-DPC/rust
that referenced
this issue
Oct 24, 2022
Fake capture closures if typeck results are empty This ICE happens because `closure_min_captures` is empty, the reason it's empty is with the 2021 edition `enable_precise_capture` is set to true, which makes it so that we can't fake capture any information because that result of the `unwrap` is none hence the ICE. Other solution is editing [maybe_read_scrutinee](https://doc.rust-lang.org/nightly/nightly-rustc/src/rustc_typeck/expr_use_visitor.rs.html#453-463) to this since empty slice contains no sub patterns. Fixes rust-lang#93242 ```rust PatKind::Slice(_, ref slice, _) => { if slice.is_none(){ need_to_be_read = true; } } // instead of PatKind::Or(_) | PatKind::Box(_) | PatKind::Slice(..) | PatKind::Ref(..) | PatKind::Wild => {} ```
Dylan-DPC
added a commit
to Dylan-DPC/rust
that referenced
this issue
Oct 24, 2022
Fake capture closures if typeck results are empty This ICE happens because `closure_min_captures` is empty, the reason it's empty is with the 2021 edition `enable_precise_capture` is set to true, which makes it so that we can't fake capture any information because that result of the `unwrap` is none hence the ICE. Other solution is editing [maybe_read_scrutinee](https://doc.rust-lang.org/nightly/nightly-rustc/src/rustc_typeck/expr_use_visitor.rs.html#453-463) to this since empty slice contains no sub patterns. Fixes rust-lang#93242 ```rust PatKind::Slice(_, ref slice, _) => { if slice.is_none(){ need_to_be_read = true; } } // instead of PatKind::Or(_) | PatKind::Box(_) | PatKind::Slice(..) | PatKind::Ref(..) | PatKind::Wild => {} ```
Dylan-DPC
added a commit
to Dylan-DPC/rust
that referenced
this issue
Oct 25, 2022
Fake capture closures if typeck results are empty This ICE happens because `closure_min_captures` is empty, the reason it's empty is with the 2021 edition `enable_precise_capture` is set to true, which makes it so that we can't fake capture any information because that result of the `unwrap` is none hence the ICE. Other solution is editing [maybe_read_scrutinee](https://doc.rust-lang.org/nightly/nightly-rustc/src/rustc_typeck/expr_use_visitor.rs.html#453-463) to this since empty slice contains no sub patterns. Fixes rust-lang#93242 ```rust PatKind::Slice(_, ref slice, _) => { if slice.is_none(){ need_to_be_read = true; } } // instead of PatKind::Or(_) | PatKind::Box(_) | PatKind::Slice(..) | PatKind::Ref(..) | PatKind::Wild => {} ```
compiler-errors
added a commit
to compiler-errors/rust
that referenced
this issue
Oct 26, 2022
Fake capture closures if typeck results are empty This ICE happens because `closure_min_captures` is empty, the reason it's empty is with the 2021 edition `enable_precise_capture` is set to true, which makes it so that we can't fake capture any information because that result of the `unwrap` is none hence the ICE. Other solution is editing [maybe_read_scrutinee](https://doc.rust-lang.org/nightly/nightly-rustc/src/rustc_typeck/expr_use_visitor.rs.html#453-463) to this since empty slice contains no sub patterns. Fixes rust-lang#93242 ```rust PatKind::Slice(_, ref slice, _) => { if slice.is_none(){ need_to_be_read = true; } } // instead of PatKind::Or(_) | PatKind::Box(_) | PatKind::Slice(..) | PatKind::Ref(..) | PatKind::Wild => {} ```
Dylan-DPC
added a commit
to Dylan-DPC/rust
that referenced
this issue
Oct 28, 2022
Fake capture closures if typeck results are empty This ICE happens because `closure_min_captures` is empty, the reason it's empty is with the 2021 edition `enable_precise_capture` is set to true, which makes it so that we can't fake capture any information because that result of the `unwrap` is none hence the ICE. Other solution is editing [maybe_read_scrutinee](https://doc.rust-lang.org/nightly/nightly-rustc/src/rustc_typeck/expr_use_visitor.rs.html#453-463) to this since empty slice contains no sub patterns. Fixes rust-lang#93242 ```rust PatKind::Slice(_, ref slice, _) => { if slice.is_none(){ need_to_be_read = true; } } // instead of PatKind::Or(_) | PatKind::Box(_) | PatKind::Slice(..) | PatKind::Ref(..) | PatKind::Wild => {} ```
This was referenced May 27, 2023
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Triage: Both snippets (the original and minimized one) are fixed on the latest nightly, @rustbot labels: +E-needs-test |
rustbot
added
the
E-needs-test
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I don't think this needs a new test, this is covered by the PR from @clubby789 I think? (#111831) |
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Yeah, this looks like the same issue (slice pattern with no sub-patterns not capturing the place to read length when it should), and a rough equivalent to the code above is tested in the PR. |
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Thanks for letting me know that! Then we can now close the issue directly :) |
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Code
playground (nightly)
Meta
rustc --version --verbose:Error output
compiler/rustc_mir_build/src/build/matches/mod.rs:1825
Backtrace
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