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Add support for method calls

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This commit is contained in:
Esteban Küber
2025-08-07 21:09:42 +00:00
parent 1aa5668d20
commit 2484e189bf
3 changed files with 725 additions and 55 deletions
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74
compiler/rustc_borrowck/src/diagnostics/move_errors.rs
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@@ -9,6 +9,7 @@ use rustc_middle::bug;
use rustc_middle::mir::*;
use rustc_middle::ty::{self, Ty, TyCtxt};
use rustc_mir_dataflow::move_paths::{LookupResult, MovePathIndex};
use rustc_span::def_id::DefId;
use rustc_span::{BytePos, DUMMY_SP, ExpnKind, MacroKind, Span};
use rustc_trait_selection::error_reporting::traits::FindExprBySpan;
use rustc_trait_selection::infer::InferCtxtExt;
@@ -507,38 +508,6 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
);
let closure_span = tcx.def_span(def_id);
let mut clause_span = DUMMY_SP;
let typck_result = self.infcx.tcx.typeck(self.mir_def_id());
if let Some(closure_def_id) = def_id.as_local()
&& let hir::Node::Expr(expr) = tcx.hir_node_by_def_id(closure_def_id)
&& let hir::Node::Expr(parent) = tcx.parent_hir_node(expr.hir_id)
&& let hir::ExprKind::Call(callee, _) = parent.kind
&& let Some(ty) = typck_result.node_type_opt(callee.hir_id)
&& let ty::FnDef(fn_def_id, args) = ty.kind()
&& let predicates = tcx.predicates_of(fn_def_id).instantiate(tcx, args)
&& let Some((_, span)) =
predicates.predicates.iter().zip(predicates.spans.iter()).find(
|(pred, _)| match pred.as_trait_clause() {
Some(clause)
if let ty::Closure(clause_closure_def_id, _) =
clause.self_ty().skip_binder().kind()
&& clause_closure_def_id == def_id
&& (tcx.lang_items().fn_mut_trait()
== Some(clause.def_id())
|| tcx.lang_items().fn_trait()
== Some(clause.def_id())) =>
{
// Found `<TyOfCapturingClosure as FnMut>`
true
}
_ => false,
},
)
{
// We point at the `Fn()` or `FnMut()` bound that coerced the closure, which
// could be changed to `FnOnce()` to avoid the move error.
clause_span = *span;
}
self.cannot_move_out_of(span, &place_description)
.with_span_label(upvar_span, "captured outer variable")
@@ -547,7 +516,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
format!("captured by this `{closure_kind}` closure"),
)
.with_span_help(
clause_span,
self.get_closure_bound_clause_span(*def_id),
"`Fn` and `FnMut` closures require captured values to be able to be \
consumed multiple times, but an `FnOnce` consume them only once",
)
@@ -599,6 +568,45 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
err
}
fn get_closure_bound_clause_span(&self, def_id: DefId) -> Span {
let tcx = self.infcx.tcx;
let typeck_result = tcx.typeck(self.mir_def_id());
let Some(closure_def_id) = def_id.as_local() else { return DUMMY_SP };
let hir::Node::Expr(expr) = tcx.hir_node_by_def_id(closure_def_id) else { return DUMMY_SP };
let hir::Node::Expr(parent) = tcx.parent_hir_node(expr.hir_id) else { return DUMMY_SP };
let predicates = match parent.kind {
hir::ExprKind::Call(callee, _) => {
let Some(ty) = typeck_result.node_type_opt(callee.hir_id) else { return DUMMY_SP };
let ty::FnDef(fn_def_id, args) = ty.kind() else { return DUMMY_SP };
tcx.predicates_of(fn_def_id).instantiate(tcx, args)
}
hir::ExprKind::MethodCall(..) => {
let Some((_, method)) = typeck_result.type_dependent_def(parent.hir_id) else {
return DUMMY_SP;
};
let args = typeck_result.node_args(parent.hir_id);
tcx.predicates_of(method).instantiate(tcx, args)
}
_ => return DUMMY_SP,
};
for (pred, span) in predicates.predicates.iter().zip(predicates.spans.iter()) {
tracing::info!(?pred);
tracing::info!(?span);
if let Some(clause) = pred.as_trait_clause()
&& let ty::Closure(clause_closure_def_id, _) = clause.self_ty().skip_binder().kind()
&& *clause_closure_def_id == def_id
&& (tcx.lang_items().fn_mut_trait() == Some(clause.def_id())
|| tcx.lang_items().fn_trait() == Some(clause.def_id()))
{
// Found `<TyOfCapturingClosure as FnMut>`
// We point at the `Fn()` or `FnMut()` bound that coerced the closure, which
// could be changed to `FnOnce()` to avoid the move error.
return *span;
}
}
DUMMY_SP
}
fn add_move_hints(&self, error: GroupedMoveError<'tcx>, err: &mut Diag<'_>, span: Span) {
match error {
GroupedMoveError::MovesFromPlace { mut binds_to, move_from, .. } => {