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Fix wrong suggestion for returning async closure

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This commit is contained in:
yukang
2026-01-13 20:41:41 +08:00
parent 6f109d8a2d
commit ae05a49f33
7 changed files with 161 additions and 30 deletions
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compiler/rustc_trait_selection/src/error_reporting/traits/suggestions.rs
+70 -22
View File
@@ -1034,17 +1034,25 @@ pub(super) fn suggest_fn_call(
&& let ty::Tuple(inputs) = *sig.tupled_inputs_ty.kind()
&& inputs.is_empty()
&& self.tcx.is_lang_item(trait_pred.def_id(), LangItem::Future)
&& let ObligationCauseCode::FunctionArg { arg_hir_id, .. } = obligation.cause.code()
&& let hir::Node::Expr(hir::Expr { kind: hir::ExprKind::Closure(..), .. }) =
self.tcx.hir_node(*arg_hir_id)
&& let Some(hir::Node::Expr(hir::Expr {
kind:
hir::ExprKind::Closure(hir::Closure {
kind: hir::ClosureKind::CoroutineClosure(CoroutineDesugaring::Async),
fn_arg_span: Some(arg_span),
..
}),
..
kind: hir::ExprKind::Closure(closure), ..
})) = self.tcx.hir_get_if_local(def_id)
&& obligation.cause.span.contains(*arg_span)
&& let hir::ClosureKind::CoroutineClosure(CoroutineDesugaring::Async) = closure.kind
&& let Some(arg_span) = closure.fn_arg_span
&& obligation.cause.span.contains(arg_span)
{
let mut body = self.tcx.hir_body(closure.body).value;
let peeled = body.peel_blocks().peel_drop_temps();
if let hir::ExprKind::Closure(inner) = peeled.kind {
body = self.tcx.hir_body(inner.body).value;
}
if !matches!(body.peel_blocks().peel_drop_temps().kind, hir::ExprKind::Block(..)) {
return false;
}
let sm = self.tcx.sess.source_map();
let removal_span = if let Ok(snippet) =
sm.span_to_snippet(arg_span.with_hi(arg_span.hi() + rustc_span::BytePos(1)))
@@ -1053,7 +1061,7 @@ pub(super) fn suggest_fn_call(
// There's a space after `||`, include it in the removal
arg_span.with_hi(arg_span.hi() + rustc_span::BytePos(1))
} else {
*arg_span
arg_span
};
err.span_suggestion_verbose(
removal_span,
@@ -1093,23 +1101,63 @@ pub(super) fn suggest_fn_call(
.collect::<Vec<_>>()
.join(", ");
if matches!(obligation.cause.code(), ObligationCauseCode::FunctionArg { .. })
if let ObligationCauseCode::FunctionArg { arg_hir_id, .. } = obligation.cause.code()
&& obligation.cause.span.can_be_used_for_suggestions()
{
let (span, sugg) = if let Some(snippet) =
self.tcx.sess.source_map().span_to_snippet(obligation.cause.span).ok()
&& snippet.starts_with("|")
{
(obligation.cause.span, format!("({snippet})({args})"))
} else {
(obligation.cause.span.shrink_to_hi(), format!("({args})"))
let span = obligation.cause.span;
let arg_expr = match self.tcx.hir_node(*arg_hir_id) {
hir::Node::Expr(expr) => Some(expr),
_ => None,
};
// When the obligation error has been ensured to have been caused by
// an argument, the `obligation.cause.span` points at the expression
// of the argument, so we can provide a suggestion. Otherwise, we give
// a more general note.
err.span_suggestion_verbose(span, msg, sugg, Applicability::HasPlaceholders);
let is_closure_expr =
arg_expr.is_some_and(|expr| matches!(expr.kind, hir::ExprKind::Closure(..)));
// If the user wrote `|| {}()`, suggesting to call the closure would produce `(|| {}())()`,
// which doesn't help and is often outright wrong.
if args.is_empty()
&& let Some(expr) = arg_expr
&& let hir::ExprKind::Closure(closure) = expr.kind
{
let mut body = self.tcx.hir_body(closure.body).value;
// Async closures desugar to a closure returning a coroutine
if let hir::ClosureKind::CoroutineClosure(hir::CoroutineDesugaring::Async) =
closure.kind
{
let peeled = body.peel_blocks().peel_drop_temps();
if let hir::ExprKind::Closure(inner) = peeled.kind {
body = self.tcx.hir_body(inner.body).value;
}
}
let peeled_body = body.peel_blocks().peel_drop_temps();
if let hir::ExprKind::Call(callee, call_args) = peeled_body.kind
&& call_args.is_empty()
&& let hir::ExprKind::Block(..) = callee.peel_blocks().peel_drop_temps().kind
{
return false;
}
}
if is_closure_expr {
err.multipart_suggestions(
msg,
vec![vec![
(span.shrink_to_lo(), "(".to_string()),
(span.shrink_to_hi(), format!(")({args})")),
]],
Applicability::HasPlaceholders,
);
} else {
err.span_suggestion_verbose(
span.shrink_to_hi(),
msg,
format!("({args})"),
Applicability::HasPlaceholders,
);
}
} else if let DefIdOrName::DefId(def_id) = def_id_or_name {
let name = match self.tcx.hir_get_if_local(def_id) {
Some(hir::Node::Expr(hir::Expr {
tests/ui/async-await/async-closures/suggest-async-block-issue-140265.stderr
+5 -2
View File
@@ -66,8 +66,11 @@ LL | fn takes_future(_fut: impl Future<Output = ()>) {}
| ^^^^^^^^^^^^^^^^^^^ required by this bound in `takes_future`
help: use parentheses to call this closure
|
LL | }(/* i32 */));
| +++++++++++
LL ~ takes_future((async |x: i32| {
LL |
LL | println!("{x}");
LL ~ })(/* i32 */));
|
error: aborting due to 3 previous errors
tests/ui/const-generics/adt_const_params/const_param_ty_bad.stderr
+2 -3
View File
@@ -32,9 +32,8 @@ LL | fn check(_: impl std::marker::ConstParamTy_) {}
| ^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `check`
help: use parentheses to call this closure
|
LL - check(|| {});
LL + check((|| {})());
|
LL | check((|| {})());
| + +++
error[E0277]: `fn()` can't be used as a const parameter type
--> $DIR/const_param_ty_bad.rs:9:11
tests/ui/suggestions/suggest-create-closure-issue-150701.fixed
+15
View File
@@ -0,0 +1,15 @@
// Regression test for #150701
//@ run-rustfix
//@ edition: 2024
use std::future::Future;
fn f(_c: impl Future<Output = ()>) {}
fn main() {
f((async || {})()); //~ ERROR: expected function, found `()`
//~^ ERROR: is not a future
f(async {});
//~^ ERROR: is not a future
}
tests/ui/suggestions/suggest-create-closure-issue-150701.rs
+15
View File
@@ -0,0 +1,15 @@
// Regression test for #150701
//@ run-rustfix
//@ edition: 2024
use std::future::Future;
fn f(_c: impl Future<Output = ()>) {}
fn main() {
f(async || {}()); //~ ERROR: expected function, found `()`
//~^ ERROR: is not a future
f(async || {});
//~^ ERROR: is not a future
}
tests/ui/suggestions/suggest-create-closure-issue-150701.stderr
+52
View File
@@ -0,0 +1,52 @@
error[E0618]: expected function, found `()`
--> $DIR/suggest-create-closure-issue-150701.rs:11:16
|
LL | f(async || {}());
| ^^--
| |
| call expression requires function
|
help: if you meant to create this closure and immediately call it, surround the closure with parentheses
|
LL | f((async || {})());
| + +
error[E0277]: `{async closure@$DIR/suggest-create-closure-issue-150701.rs:11:7: 11:15}` is not a future
--> $DIR/suggest-create-closure-issue-150701.rs:11:7
|
LL | f(async || {}());
| - ^^^^^^^^^^^^^ `{async closure@$DIR/suggest-create-closure-issue-150701.rs:11:7: 11:15}` is not a future
| |
| required by a bound introduced by this call
|
= help: the trait `Future` is not implemented for `{async closure@$DIR/suggest-create-closure-issue-150701.rs:11:7: 11:15}`
note: required by a bound in `f`
--> $DIR/suggest-create-closure-issue-150701.rs:8:15
|
LL | fn f(_c: impl Future<Output = ()>) {}
| ^^^^^^^^^^^^^^^^^^^ required by this bound in `f`
error[E0277]: `{async closure@$DIR/suggest-create-closure-issue-150701.rs:13:7: 13:15}` is not a future
--> $DIR/suggest-create-closure-issue-150701.rs:13:7
|
LL | f(async || {});
| - ^^^^^^^^^^^ `{async closure@$DIR/suggest-create-closure-issue-150701.rs:13:7: 13:15}` is not a future
| |
| required by a bound introduced by this call
|
= help: the trait `Future` is not implemented for `{async closure@$DIR/suggest-create-closure-issue-150701.rs:13:7: 13:15}`
note: required by a bound in `f`
--> $DIR/suggest-create-closure-issue-150701.rs:8:15
|
LL | fn f(_c: impl Future<Output = ()>) {}
| ^^^^^^^^^^^^^^^^^^^ required by this bound in `f`
help: use `async {}` instead of `async || {}` to introduce an async block
|
LL - f(async || {});
LL + f(async {});
|
error: aborting due to 3 previous errors
Some errors have detailed explanations: E0277, E0618.
For more information about an error, try `rustc --explain E0277`.
tests/ui/suggestions/use-parentheses-to-call-closure-issue-145404.stderr
+2 -3
View File
@@ -14,9 +14,8 @@ LL | fn call(&self, _: impl Display) {}
| ^^^^^^^ required by this bound in `S::call`
help: use parentheses to call this closure
|
LL - S.call(|| "hello");
LL + S.call((|| "hello")());
|
LL | S.call((|| "hello")());
| + +++
error: aborting due to 1 previous error