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Rollup merge of #110823 - compiler-errors:tweak-await-span, r=b-naber

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Tweak await span to not contain dot

Fixes a discrepancy between method calls and await expressions where the latter are desugared to have a span that *contains* the dot (i.e. `.await`) but method call identifiers don't contain the dot. This leads to weird suggestions suggestions in borrowck -- see linked issue.

Fixes #110761

This mostly touches a bunch of tests to tighten their `await` span.
This commit is contained in:
Matthias Krüger 2023-05-01 01:09:47 +02:00 • committed by GitHub
commit 1b262b8b56
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113 changed files with 594 additions and 807 deletions
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97
compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
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@ -1583,55 +1583,68 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
}
fn suggest_remove_await(&self, obligation: &PredicateObligation<'tcx>, err: &mut Diagnostic) {
let span = obligation.cause.span;
let hir = self.tcx.hir();
if let ObligationCauseCode::AwaitableExpr(Some(hir_id)) = obligation.cause.code().peel_derives()
&& let hir::Node::Expr(expr) = hir.get(*hir_id)
{
// FIXME: use `obligation.predicate.kind()...trait_ref.self_ty()` to see if we have `()`
// and if not maybe suggest doing something else? If we kept the expression around we
// could also check if it is an fn call (very likely) and suggest changing *that*, if
// it is from the local crate.
if let ObligationCauseCode::AwaitableExpr(hir_id) = obligation.cause.code().peel_derives() {
let hir = self.tcx.hir();
if let Some(hir::Node::Expr(expr)) = hir_id.and_then(|hir_id| hir.find(hir_id)) {
// FIXME: use `obligation.predicate.kind()...trait_ref.self_ty()` to see if we have `()`
// and if not maybe suggest doing something else? If we kept the expression around we
// could also check if it is an fn call (very likely) and suggest changing *that*, if
// it is from the local crate.
// use nth(1) to skip one layer of desugaring from `IntoIter::into_iter`
if let Some((_, hir::Node::Expr(await_expr))) = hir.parent_iter(*hir_id).nth(1)
&& let Some(expr_span) = expr.span.find_ancestor_inside(await_expr.span)
{
let removal_span = self.tcx
.sess
.source_map()
.span_extend_while(expr_span, char::is_whitespace)
.unwrap_or(expr_span)
.shrink_to_hi()
.to(await_expr.span.shrink_to_hi());
err.span_suggestion(
span,
removal_span,
"remove the `.await`",
"",
Applicability::MachineApplicable,
);
// FIXME: account for associated `async fn`s.
if let hir::Expr { span, kind: hir::ExprKind::Call(base, _), .. } = expr {
if let ty::PredicateKind::Clause(ty::Clause::Trait(pred)) =
obligation.predicate.kind().skip_binder()
{
err.span_label(*span, &format!("this call returns `{}`", pred.self_ty()));
}
if let Some(typeck_results) = &self.typeck_results
&& let ty = typeck_results.expr_ty_adjusted(base)
&& let ty::FnDef(def_id, _substs) = ty.kind()
&& let Some(hir::Node::Item(hir::Item { ident, span, vis_span, .. })) =
hir.get_if_local(*def_id)
{
let msg = format!(
"alternatively, consider making `fn {}` asynchronous",
ident
);
if vis_span.is_empty() {
err.span_suggestion_verbose(
span.shrink_to_lo(),
&msg,
"async ",
Applicability::MaybeIncorrect,
);
} else {
err.span_suggestion_verbose(
vis_span.shrink_to_hi(),
&msg,
" async",
Applicability::MaybeIncorrect,
);
}
}
} else {
err.span_label(obligation.cause.span, "remove the `.await`");
}
// FIXME: account for associated `async fn`s.
if let hir::Expr { span, kind: hir::ExprKind::Call(base, _), .. } = expr {
if let ty::PredicateKind::Clause(ty::Clause::Trait(pred)) =
obligation.predicate.kind().skip_binder()
{
err.span_label(*span, &format!("this call returns `{}`", pred.self_ty()));
}
if let Some(typeck_results) = &self.typeck_results
&& let ty = typeck_results.expr_ty_adjusted(base)
&& let ty::FnDef(def_id, _substs) = ty.kind()
&& let Some(hir::Node::Item(hir::Item { ident, span, vis_span, .. })) =
hir.get_if_local(*def_id)
{
let msg = format!(
"alternatively, consider making `fn {}` asynchronous",
ident
);
if vis_span.is_empty() {
err.span_suggestion_verbose(
span.shrink_to_lo(),
&msg,
"async ",
Applicability::MaybeIncorrect,
);
} else {
err.span_suggestion_verbose(
vis_span.shrink_to_hi(),
&msg,
" async",
Applicability::MaybeIncorrect,
);
}
}
}
}
}