Stuart Cook
17c25e4483
fix: Do not ICE when missing match arm with ill-formed subty is met Fixes rust-lang/rust#148192 The ICE comes from the following line, calling `normalize_erasing_regions` to a projection type whose trait bound is not met: https://github.com/rust-lang/rust/blob/2fcbda6c1a70606bdb09857e01d01fc6229da712/compiler/rustc_pattern_analysis/src/rustc.rs#L185-L194 The above function is called while trying to lint missing match arms, or scrutinize ctors of missing(not necessary error) match arms. So, the following code can trigger ICEs. ```rust trait WhereTrait { type Type; } fn foo(e: Enum) { match e { Enum::Map(_) => (), // ICE, while trying to lint missing arms } if let Enum::Map(_) = e {} // ICE, while trying to scrutinize missing ctors (even worse) } enum Enum { Map(()), Map2(<() as WhereTrait>::Type), } ``` This ICE won't be triggered with the following code, as this is filtered out before `check_match` as the existence of ill-formed type inside the variant marks the body as tainted by error in `hir_typeck`, but for the above code, the `hir_typeck` complains nothing because everything it sees is locally correct. ```rust fn foo(e: Enum) { match e { Enum::Map2(_) => (), // No ICE } } ``` I've considered visiting and wf checking for the match scrutinee before entering `check_match`, but that might regress the perf and I think just emitting delayed bug would enough as the normalization failure would be originated by other errors like ill-formdness.
This is the main source code repository for Rust. It contains the compiler, standard library, and documentation.
Why Rust?
-
Performance: Fast and memory-efficient, suitable for critical services, embedded devices, and easily integrated with other languages.
-
Reliability: Our rich type system and ownership model ensure memory and thread safety, reducing bugs at compile-time.
-
Productivity: Comprehensive documentation, a compiler committed to providing great diagnostics, and advanced tooling including package manager and build tool (Cargo), auto-formatter (rustfmt), linter (Clippy) and editor support (rust-analyzer).
Quick Start
Read "Installation" from The Book.
Installing from Source
If you really want to install from source (though this is not recommended), see INSTALL.md.
Getting Help
See https://www.rust-lang.org/community for a list of chat platforms and forums.
Contributing
See CONTRIBUTING.md.
License
Rust is primarily distributed under the terms of both the MIT license and the Apache License (Version 2.0), with portions covered by various BSD-like licenses.
See LICENSE-APACHE, LICENSE-MIT, and COPYRIGHT for details.
Trademark
The Rust Foundation owns and protects the Rust and Cargo trademarks and logos (the "Rust Trademarks").
If you want to use these names or brands, please read the Rust language trademark policy.
Third-party logos may be subject to third-party copyrights and trademarks. See Licenses for details.