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Account for trait/impl difference when suggesting changing argument from ref to mut ref

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Do not ICE when encountering a lifetime error involving an argument with
an immutable reference of a method that differs from the trait definition.

Fix #123414.
This commit is contained in:
Esteban Küber
2024-04-05 23:27:58 +00:00
parent 76cf07d5df
commit 731c0e59a4
7 changed files with 158 additions and 43 deletions
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89
compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs
View File

@@ -21,7 +21,7 @@ use rustc_trait_selection::traits::error_reporting::suggestions::TypeErrCtxtExt;
use crate::diagnostics::BorrowedContentSource;
use crate::util::FindAssignments;
use crate::MirBorrowckCtxt;
use crate::{session_diagnostics, MirBorrowckCtxt};
#[derive(Copy, Clone, Debug, Eq, PartialEq)]
pub(crate) enum AccessKind {
@@ -234,7 +234,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
Some(mir::BorrowKind::Mut { kind: mir::MutBorrowKind::Default }),
|_kind, var_span| {
let place = self.describe_any_place(access_place.as_ref());
crate::session_diagnostics::CaptureVarCause::MutableBorrowUsePlaceClosure {
session_diagnostics::CaptureVarCause::MutableBorrowUsePlaceClosure {
place,
var_span,
}
@@ -667,19 +667,26 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
/// User cannot make signature of a trait mutable without changing the
/// trait. So we find if this error belongs to a trait and if so we move
/// suggestion to the trait or disable it if it is out of scope of this crate
fn is_error_in_trait(&self, local: Local) -> (bool, Option<Span>) {
///
/// The returned values are:
/// - is the current item an assoc `fn` of an impl that corresponds to a trait def? if so, we
/// have to suggest changing both the impl `fn` arg and the trait `fn` arg
/// - is the trait from the local crate? If not, we can't suggest changing signatures
/// - `Span` of the argument in the trait definition
fn is_error_in_trait(&self, local: Local) -> (bool, bool, Option<Span>) {
if self.body.local_kind(local) != LocalKind::Arg {
return (false, None);
return (false, false, None);
}
let my_def = self.body.source.def_id();
let my_hir = self.infcx.tcx.local_def_id_to_hir_id(my_def.as_local().unwrap());
let Some(td) =
self.infcx.tcx.impl_of_method(my_def).and_then(|x| self.infcx.tcx.trait_id_of_impl(x))
else {
return (false, None);
return (false, false, None);
};
(
true,
td.is_local(),
td.as_local().and_then(|tld| match self.infcx.tcx.hir_node_by_def_id(tld) {
Node::Item(hir::Item { kind: hir::ItemKind::Trait(_, _, _, _, items), .. }) => {
let mut f_in_trait_opt = None;
@@ -695,19 +702,16 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
break;
}
f_in_trait_opt.and_then(|f_in_trait| {
match self.infcx.tcx.hir_node(f_in_trait) {
Node::TraitItem(hir::TraitItem {
kind:
hir::TraitItemKind::Fn(
hir::FnSig { decl: hir::FnDecl { inputs, .. }, .. },
_,
),
..
}) => {
let hir::Ty { span, .. } = *inputs.get(local.index() - 1)?;
Some(span)
}
_ => None,
if let Node::TraitItem(ti) = self.infcx.tcx.hir_node(f_in_trait)
&& let hir::TraitItemKind::Fn(sig, _) = ti.kind
&& let Some(ty) = sig.decl.inputs.get(local.index() - 1)
&& let hir::TyKind::Ref(_, mut_ty) = ty.kind
&& let hir::Mutability::Not = mut_ty.mutbl
&& sig.decl.implicit_self.has_implicit_self()
{
Some(ty.span)
} else {
None
}
})
}
@@ -1061,20 +1065,24 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
let (pointer_sigil, pointer_desc) =
if local_decl.ty.is_ref() { ("&", "reference") } else { ("*const", "pointer") };
let (is_trait_sig, local_trait) = self.is_error_in_trait(local);
if is_trait_sig && local_trait.is_none() {
let (is_trait_sig, is_local, local_trait) = self.is_error_in_trait(local);
if is_trait_sig && !is_local {
// Do not suggest to change the signature when the trait comes from another crate.
err.span_label(
local_decl.source_info.span,
format!("this is an immutable {pointer_desc}"),
);
return;
}
let decl_span = match local_trait {
Some(span) => span,
None => local_decl.source_info.span,
};
let decl_span = local_decl.source_info.span;
let label = match *local_decl.local_info() {
LocalInfo::User(mir::BindingForm::ImplicitSelf(_)) => {
let suggestion = suggest_ampmut_self(self.infcx.tcx, decl_span);
Some((true, decl_span, suggestion))
let additional =
local_trait.map(|span| (span, suggest_ampmut_self(self.infcx.tcx, span)));
Some((true, decl_span, suggestion, additional))
}
LocalInfo::User(mir::BindingForm::Var(mir::VarBindingForm {
@@ -1113,7 +1121,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
// don't create labels for compiler-generated spans
Some(_) => None,
None => {
let label = if name != kw::SelfLower {
let (has_sugg, decl_span, sugg) = if name != kw::SelfLower {
suggest_ampmut(
self.infcx.tcx,
local_decl.ty,
@@ -1140,7 +1148,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
),
}
};
Some(label)
Some((has_sugg, decl_span, sugg, None))
}
}
}
@@ -1151,22 +1159,33 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
})) => {
let pattern_span: Span = local_decl.source_info.span;
suggest_ref_mut(self.infcx.tcx, pattern_span)
.map(|span| (true, span, "mut ".to_owned()))
.map(|span| (true, span, "mut ".to_owned(), None))
}
_ => unreachable!(),
};
match label {
Some((true, err_help_span, suggested_code)) => {
err.span_suggestion_verbose(
err_help_span,
format!("consider changing this to be a mutable {pointer_desc}"),
suggested_code,
Some((true, err_help_span, suggested_code, additional)) => {
let mut sugg = vec![(err_help_span, suggested_code)];
if let Some(s) = additional {
sugg.push(s);
}
err.multipart_suggestion_verbose(
format!(
"consider changing this to be a mutable {pointer_desc}{}",
if is_trait_sig {
" in the `impl` method and the `trait` definition"
} else {
""
}
),
sugg,
Applicability::MachineApplicable,
);
}
Some((false, err_label_span, message)) => {
Some((false, err_label_span, message, _)) => {
let def_id = self.body.source.def_id();
let hir_id = if let Some(local_def_id) = def_id.as_local()
&& let Some(body_id) = self.infcx.tcx.hir().maybe_body_owned_by(local_def_id)