NLL fails to suggest "try removing &mut here"
#54720
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r=me but the incremental tests are unhappy. Looks like the test just needs to be updated though. You probably just need to change #[cfg(not(cfail1))]
#[rustc_clean(label="Hir", cfg="cfail2")]
#[rustc_clean(label="Hir", cfg="cfail3")]
trait TraitChangeModeSelfOwnToMut: Sized {
#[rustc_clean(label="Hir", cfg="cfail2")]
#[rustc_clean(label="Hir", cfg="cfail3")]
#[rustc_dirty(label="HirBody", cfg="cfail2")]
#[rustc_clean(label="HirBody", cfg="cfail3")]
fn method(mut self) {}
}to #[cfg(not(cfail1))]
#[rustc_clean(label="Hir", cfg="cfail2")]
#[rustc_clean(label="Hir", cfg="cfail3")]
trait TraitChangeModeSelfOwnToMut: Sized {
#[rustc_dirty(label="Hir", cfg="cfail2")] // changed!
#[rustc_clean(label="Hir", cfg="cfail3")]
#[rustc_dirty(label="HirBody", cfg="cfail2")]
#[rustc_clean(label="HirBody", cfg="cfail3")]
fn method(mut self) {}
}In particular, in the old system, the |
This commit adds an `ImplicitSelfKind` to the HIR and the MIR that keeps track of whether a implicit self argument is immutable by-value, mutable by-value, immutable reference or mutable reference so that the addition of the `mut` keyword can be suggested for the immutable by-value case.
This commit improves mutability error suggestions by suggesting the removal of `&mut` where a mutable borrow is being taken of a `&mut self` or a `self: &mut Self`.
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I believe that if we use local_decl.source_info.span here it would point at &mut self instead of (&mut self), which would let you make it a machine applicable suggestion instead of a label. Changing this will likely require you to change the above condition, but marginally so.
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I might be misunderstanding but, wouldn't local_decl.source_info.span point to the argument not the use of it as span does?
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I believe you're right, I misread the code. It'd be nice to get the actual span to get the behavior I wanted, but it might be too hard to do in this case. Don't let it be a blocker.
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@bors r+ |
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📌 Commit 2be3069 has been approved by |
NLL fails to suggest "try removing `&mut` here" Fixes #51191. This PR adds ``try removing `&mut` here`` suggestions to functions where a mutable borrow is being taken of a `&mut self` or a `self: &mut Self`. This PR also enables the suggestion for adding a `mut` pattern to by-value implicit self arguments without `mut` patterns already. r? @nikomatsakis
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☀️ Test successful - status-appveyor, status-travis |
| /// (but not a `self: Xxx` one). | ||
| pub has_implicit_self: bool, | ||
| /// Does the function have an implicit self? | ||
| pub implicit_self: ImplicitSelfKind, |
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This is a bit sad, I was hoping this could stay out of the HIR permanently.
| ImplicitSelf(ImplicitSelfKind), | ||
| /// Reference used in a guard expression to ensure immutability. | ||
| RefForGuard, | ||
| } |
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I guess the ideal of lowering away pattern-matching completely is too naive in the face of diagnostics 😭
| /// Represents a `fn x(self);`. | ||
| Imm, | ||
| /// Represents a `fn x(mut self);`. | ||
| Mut, |
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Can't these two be distinguished by binding_mode?
| /// Represents a `fn x(&self);`. | ||
| ImmRef, | ||
| /// Represents a `fn x(&mut self);`. | ||
| MutRef, |
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Can't these two be distinguished by type? (maybe even distinguish &self from self by type?)
Suggest removing `&mut` from a `&mut borrow` Modify the code added in rust-lang#54720. Closes rust-lang#75871
Fixes #51191.
This PR adds
try removing `&mut` heresuggestions to functions where a mutable borrow is being taken of a&mut selfor aself: &mut Self. This PR also enables the suggestion for adding amutpattern to by-value implicit self arguments withoutmutpatterns already.r? @nikomatsakis