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Fix #95079 by adding help and suggestion for missing move in nested closure

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This commit is contained in:
Yan Chen 2022-07-22 09:53:39 -07:00
parent 4916e2b9e6
commit 15713e1717
7 changed files with 104 additions and 0 deletions
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37
compiler/rustc_borrowck/src/diagnostics/region_errors.rs
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@ -546,6 +546,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
executing...",
);
diag.note("...therefore, they cannot allow references to captured variables to escape");
self.suggest_move_on_borrowing_closure(&mut diag);
diag
}
@ -716,6 +717,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
self.add_static_impl_trait_suggestion(&mut diag, *fr, fr_name, *outlived_fr);
self.suggest_adding_lifetime_params(&mut diag, *fr, *outlived_fr);
self.suggest_move_on_borrowing_closure(&mut diag);
diag
}
@ -901,4 +903,39 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
suggest_adding_lifetime_params(self.infcx.tcx, sub, ty_sup, ty_sub, diag);
}
fn suggest_move_on_borrowing_closure(&self, diag: &mut Diagnostic) {
let map = self.infcx.tcx.hir();
let body_id = map.body_owned_by(self.mir_def_id());
let expr = &map.body(body_id).value;
let mut closure_span = None::<rustc_span::Span>;
match expr.kind {
hir::ExprKind::MethodCall(.., args, _) => {
// only the first closre parameter of the method. args[0] is MethodCall PathSegment
for i in 1..args.len() {
if let hir::ExprKind::Closure(..) = args[i].kind {
closure_span = Some(args[i].span.shrink_to_lo());
break;
}
}
}
hir::ExprKind::Block(blk, _) => {
if let Some(ref expr) = blk.expr {
// only when the block is a closure
if let hir::ExprKind::Closure(..) = expr.kind {
closure_span = Some(expr.span.shrink_to_lo());
}
}
}
_ => {}
}
if let Some(closure_span) = closure_span {
diag.span_suggestion_verbose(
closure_span,
format!("consider adding 'move' keyword before the nested closure"),
"move ",
Applicability::MaybeIncorrect,
);
}
}
}