ICE: local variable without a name #63026
Labels
A-NLL
Area: Non Lexical Lifetimes (NLL)
C-bug
Category: This is a bug.
I-ICE
Issue: The compiler panicked, giving an Internal Compilation Error (ICE) ❄️
regression-from-stable-to-beta
Performance or correctness regression from stable to beta.
T-compiler
Relevant to the compiler team, which will review and decide on the PR/issue.
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jonas-schievink
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A-NLL
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Dumped HIR: Error on it: The error once fixed should be closer to This is caused because of this: rust/src/librustc_mir/borrow_check/error_reporting.rs Lines 332 to 343 in 795d96d It seems to me like its reasonable to remove the |
Centril
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Jul 28, 2019
Avoid ICE when referencing desugared local binding in borrow error To avoid leaking the names of local bindings from expressions like for loops, rust-lang#60984 explicitly ignored them, but an assertion that `LocalKind::Var` *must* have a name would trigger an ICE. Before this change, the binding generated by desugaring the for loop would leak into the diagnostic (rust-lang#63027): ``` error[E0515]: cannot return value referencing local variable `__next` --> return-local-binding-from-desugaring.rs:LL:CC | LL | for ref x in xs { | ----- `__next` is borrowed here ... LL | result | ^^^^^^ returns a value referencing data owned by the current function ``` Ideally `LocalKind` would carry more information to more accurately explain the problem, but for now, in order to avoid the ICE (fix rust-lang#63026), we accept `LocalKind::Var` without a name and produce the following output: ``` error[E0515]: cannot return value referencing local binding --> $DIR/return-local-binding-from-desugaring.rs:30:5 | LL | for ref x in xs { | -- local binding introduced here ... LL | result | ^^^^^^ returns a value referencing data owned by the current function ```
Centril
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to Centril/rust
that referenced
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Jul 28, 2019
Avoid ICE when referencing desugared local binding in borrow error To avoid leaking the names of local bindings from expressions like for loops, rust-lang#60984 explicitly ignored them, but an assertion that `LocalKind::Var` *must* have a name would trigger an ICE. Before this change, the binding generated by desugaring the for loop would leak into the diagnostic (rust-lang#63027): ``` error[E0515]: cannot return value referencing local variable `__next` --> return-local-binding-from-desugaring.rs:LL:CC | LL | for ref x in xs { | ----- `__next` is borrowed here ... LL | result | ^^^^^^ returns a value referencing data owned by the current function ``` Ideally `LocalKind` would carry more information to more accurately explain the problem, but for now, in order to avoid the ICE (fix rust-lang#63026), we accept `LocalKind::Var` without a name and produce the following output: ``` error[E0515]: cannot return value referencing local binding --> $DIR/return-local-binding-from-desugaring.rs:30:5 | LL | for ref x in xs { | -- local binding introduced here ... LL | result | ^^^^^^ returns a value referencing data owned by the current function ```
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The following code causes an internal compiler error on 1.37.0-beta.6 and 1.38.0-nightly. On stable it's a simple error, though the message could be improved (#63027).
(Playground)
Output of
rustup run nightly rustc --crate-type lib lib.rs:rustup run beta rustc --version --verbose:rustup run nightly rustc --version --verbose:The text was updated successfully, but these errors were encountered: