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Fix closure arg extraction in extract_callable_info, generalize it to async closures #132489

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merged 2 commits into from
Nov 21, 2024
Merged

Fix closure arg extraction in extract_callable_info, generalize it to async closures #132489

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78bbc64
Fix closure arg extraction in extract_callable_info
compiler-errors Nov 2, 2024
cbacb6d
Use extract_callable_info, generalize it to async closure
compiler-errors Nov 2, 2024
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55 changes: 8 additions & 47 deletions compiler/rustc_hir_typeck/src/method/suggest.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -31,6 +31,7 @@ use rustc_span::symbol::{Ident, kw, sym};
use rustc_span::{
DUMMY_SP, ErrorGuaranteed, ExpnKind, FileName, MacroKind, Span, Symbol, edit_distance,
};
use rustc_trait_selection::error_reporting::traits::DefIdOrName;
use rustc_trait_selection::error_reporting::traits::on_unimplemented::OnUnimplementedNote;
use rustc_trait_selection::infer::InferCtxtExt;
use rustc_trait_selection::traits::query::evaluate_obligation::InferCtxtExt as _;
Expand All @@ -45,50 +46,6 @@ use crate::errors::{self, CandidateTraitNote, NoAssociatedItem};
use crate::{Expectation, FnCtxt};

impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
fn is_fn_ty(&self, ty: Ty<'tcx>, span: Span) -> bool {
let tcx = self.tcx;
match ty.kind() {
// Not all of these (e.g., unsafe fns) implement `FnOnce`,
// so we look for these beforehand.
// FIXME(async_closures): These don't impl `FnOnce` by default.
ty::Closure(..) | ty::FnDef(..) | ty::FnPtr(..) => true,
// If it's not a simple function, look for things which implement `FnOnce`.
_ => {
let Some(fn_once) = tcx.lang_items().fn_once_trait() else {
return false;
};

// This conditional prevents us from asking to call errors and unresolved types.
// It might seem that we can use `predicate_must_hold_modulo_regions`,
// but since a Dummy binder is used to fill in the FnOnce trait's arguments,
// type resolution always gives a "maybe" here.
if self.autoderef(span, ty).silence_errors().any(|(ty, _)| {
info!("check deref {:?} error", ty);
matches!(ty.kind(), ty::Error(_) | ty::Infer(_))
}) {
return false;
}

self.autoderef(span, ty).silence_errors().any(|(ty, _)| {
info!("check deref {:?} impl FnOnce", ty);
self.probe(|_| {
let trait_ref =
ty::TraitRef::new(tcx, fn_once, [ty, self.next_ty_var(span)]);
let poly_trait_ref = ty::Binder::dummy(trait_ref);
let obligation = Obligation::misc(
tcx,
span,
self.body_id,
self.param_env,
poly_trait_ref,
);
self.predicate_may_hold(&obligation)
})
})
}
}
}

fn is_slice_ty(&self, ty: Ty<'tcx>, span: Span) -> bool {
self.autoderef(span, ty)
.silence_errors()
Expand Down Expand Up @@ -2365,12 +2322,16 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
let is_accessible = field.vis.is_accessible_from(scope, tcx);

if is_accessible {
if self.is_fn_ty(field_ty, span) {
if let Some((what, _, _)) = self.extract_callable_info(field_ty) {
let what = match what {
DefIdOrName::DefId(def_id) => self.tcx.def_descr(def_id),
DefIdOrName::Name(what) => what,
};
let expr_span = expr.span.to(item_name.span);
err.multipart_suggestion(
format!(
"to call the function stored in `{item_name}`, \
surround the field access with parentheses",
"to call the {what} stored in `{item_name}`, \
surround the field access with parentheses",
),
vec![
(expr_span.shrink_to_lo(), '('.to_string()),
Expand Down
177 changes: 97 additions & 80 deletions compiler/rustc_trait_selection/src/error_reporting/traits/suggestions.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -1075,93 +1075,110 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
) -> Option<(DefIdOrName, Ty<'tcx>, Vec<Ty<'tcx>>)> {
// Autoderef is useful here because sometimes we box callables, etc.
let Some((def_id_or_name, output, inputs)) =
(self.autoderef_steps)(found).into_iter().find_map(|(found, _)| {
match *found.kind() {
ty::FnPtr(sig_tys, _) => Some((
DefIdOrName::Name("function pointer"),
sig_tys.output(),
sig_tys.inputs(),
)),
ty::FnDef(def_id, _) => {
let fn_sig = found.fn_sig(self.tcx);
Some((DefIdOrName::DefId(def_id), fn_sig.output(), fn_sig.inputs()))
}
ty::Closure(def_id, args) => {
let fn_sig = args.as_closure().sig();
Some((
DefIdOrName::DefId(def_id),
fn_sig.output(),
fn_sig.inputs().map_bound(|inputs| &inputs[1..]),
))
}
ty::Alias(ty::Opaque, ty::AliasTy { def_id, args, .. }) => {
self.tcx
.item_super_predicates(def_id)
.instantiate(self.tcx, args)
.iter()
.find_map(|pred| {
if let ty::ClauseKind::Projection(proj) = pred.kind().skip_binder()
&& self.tcx.is_lang_item(proj.projection_term.def_id,LangItem::FnOnceOutput)
// args tuple will always be args[1]
&& let ty::Tuple(args) = proj.projection_term.args.type_at(1).kind()
{
Some((
DefIdOrName::DefId(def_id),
pred.kind().rebind(proj.term.expect_type()),
pred.kind().rebind(args.as_slice()),
))
} else {
None
}
})
}
ty::Dynamic(data, _, ty::Dyn) => {
data.iter().find_map(|pred| {
if let ty::ExistentialPredicate::Projection(proj) = pred.skip_binder()
(self.autoderef_steps)(found).into_iter().find_map(|(found, _)| match *found.kind() {
ty::FnPtr(sig_tys, _) => Some((
DefIdOrName::Name("function pointer"),
sig_tys.output(),
sig_tys.inputs(),
)),
ty::FnDef(def_id, _) => {
let fn_sig = found.fn_sig(self.tcx);
Some((DefIdOrName::DefId(def_id), fn_sig.output(), fn_sig.inputs()))
}
ty::Closure(def_id, args) => {
let fn_sig = args.as_closure().sig();
Some((
DefIdOrName::DefId(def_id),
fn_sig.output(),
fn_sig.inputs().map_bound(|inputs| inputs[0].tuple_fields().as_slice()),
))
}
ty::CoroutineClosure(def_id, args) => {
let sig_parts = args.as_coroutine_closure().coroutine_closure_sig();
Some((
DefIdOrName::DefId(def_id),
sig_parts.map_bound(|sig| {
sig.to_coroutine(
self.tcx,
args.as_coroutine_closure().parent_args(),
// Just use infer vars here, since we don't really care
// what these types are, just that we're returning a coroutine.
self.next_ty_var(DUMMY_SP),
self.tcx.coroutine_for_closure(def_id),
self.next_ty_var(DUMMY_SP),
)
}),
sig_parts.map_bound(|sig| sig.tupled_inputs_ty.tuple_fields().as_slice()),
))
}
ty::Alias(ty::Opaque, ty::AliasTy { def_id, args, .. }) => self
.tcx
.item_super_predicates(def_id)
.instantiate(self.tcx, args)
.iter()
.find_map(|pred| {
if let ty::ClauseKind::Projection(proj) = pred.kind().skip_binder()
&& self
.tcx
.is_lang_item(proj.projection_term.def_id, LangItem::FnOnceOutput)
// args tuple will always be args[1]
&& let ty::Tuple(args) = proj.projection_term.args.type_at(1).kind()
{
Some((
DefIdOrName::DefId(def_id),
pred.kind().rebind(proj.term.expect_type()),
pred.kind().rebind(args.as_slice()),
))
} else {
None
}
}),
ty::Dynamic(data, _, ty::Dyn) => data.iter().find_map(|pred| {
if let ty::ExistentialPredicate::Projection(proj) = pred.skip_binder()
&& self.tcx.is_lang_item(proj.def_id, LangItem::FnOnceOutput)
// for existential projection, args are shifted over by 1
&& let ty::Tuple(args) = proj.args.type_at(0).kind()
{
Some((
DefIdOrName::Name("trait object"),
pred.rebind(proj.term.expect_type()),
pred.rebind(args.as_slice()),
))
} else {
None
}
})
{
Some((
DefIdOrName::Name("trait object"),
pred.rebind(proj.term.expect_type()),
pred.rebind(args.as_slice()),
))
} else {
None
}
ty::Param(param) => {
let generics = self.tcx.generics_of(body_id);
let name = if generics.count() > param.index as usize
&& let def = generics.param_at(param.index as usize, self.tcx)
&& matches!(def.kind, ty::GenericParamDefKind::Type { .. })
&& def.name == param.name
}),
ty::Param(param) => {
let generics = self.tcx.generics_of(body_id);
let name = if generics.count() > param.index as usize
&& let def = generics.param_at(param.index as usize, self.tcx)
&& matches!(def.kind, ty::GenericParamDefKind::Type { .. })
&& def.name == param.name
{
DefIdOrName::DefId(def.def_id)
} else {
DefIdOrName::Name("type parameter")
};
param_env.caller_bounds().iter().find_map(|pred| {
if let ty::ClauseKind::Projection(proj) = pred.kind().skip_binder()
&& self
.tcx
.is_lang_item(proj.projection_term.def_id, LangItem::FnOnceOutput)
&& proj.projection_term.self_ty() == found
// args tuple will always be args[1]
&& let ty::Tuple(args) = proj.projection_term.args.type_at(1).kind()
{
DefIdOrName::DefId(def.def_id)
Some((
name,
pred.kind().rebind(proj.term.expect_type()),
pred.kind().rebind(args.as_slice()),
))
} else {
DefIdOrName::Name("type parameter")
};
param_env.caller_bounds().iter().find_map(|pred| {
if let ty::ClauseKind::Projection(proj) = pred.kind().skip_binder()
&& self.tcx.is_lang_item(proj.projection_term.def_id, LangItem::FnOnceOutput)
&& proj.projection_term.self_ty() == found
// args tuple will always be args[1]
&& let ty::Tuple(args) = proj.projection_term.args.type_at(1).kind()
{
Some((
name,
pred.kind().rebind(proj.term.expect_type()),
pred.kind().rebind(args.as_slice()),
))
} else {
None
}
})
}
_ => None,
None
}
})
}
_ => None,
})
else {
return None;
Expand Down
7 changes: 7 additions & 0 deletions tests/ui/closures/correct-args-on-call-suggestion.rs
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Original file line number Diff line number Diff line change
@@ -0,0 +1,7 @@
// Ensure we give the right args when we suggest calling a closure.

fn main() {
let x = |a: i32, b: i32| a + b;
let y: i32 = x;
//~^ ERROR mismatched types
}
20 changes: 20 additions & 0 deletions tests/ui/closures/correct-args-on-call-suggestion.stderr
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Original file line number Diff line number Diff line change
@@ -0,0 +1,20 @@
error[E0308]: mismatched types
--> $DIR/correct-args-on-call-suggestion.rs:5:18
|
LL | let x = |a: i32, b: i32| a + b;
| ---------------- the found closure
LL | let y: i32 = x;
| --- ^ expected `i32`, found closure
| |
| expected due to this
|
= note: expected type `i32`
found closure `{closure@$DIR/correct-args-on-call-suggestion.rs:4:13: 4:29}`
help: use parentheses to call this closure
|
LL | let y: i32 = x(/* i32 */, /* i32 */);
| ++++++++++++++++++++++

error: aborting due to 1 previous error

For more information about this error, try `rustc --explain E0308`.
2 changes: 1 addition & 1 deletion tests/ui/confuse-field-and-method/issue-18343.stderr
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Expand Up @@ -7,7 +7,7 @@ LL | struct Obj<F> where F: FnMut() -> u32 {
LL | o.closure();
| ^^^^^^^ field, not a method
|
help: to call the function stored in `closure`, surround the field access with parentheses
help: to call the closure stored in `closure`, surround the field access with parentheses
|
LL | (o.closure)();
| + +
Expand Down
14 changes: 7 additions & 7 deletions tests/ui/confuse-field-and-method/issue-2392.stderr
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Expand Up @@ -7,7 +7,7 @@ LL | struct Obj<F> where F: FnOnce() -> u32 {
LL | o_closure.closure();
| ^^^^^^^ field, not a method
|
help: to call the function stored in `closure`, surround the field access with parentheses
help: to call the closure stored in `closure`, surround the field access with parentheses
|
LL | (o_closure.closure)();
| + +
Expand Down Expand Up @@ -46,7 +46,7 @@ LL | struct BoxedObj {
LL | boxed_fn.boxed_closure();
| ^^^^^^^^^^^^^ field, not a method
|
help: to call the function stored in `boxed_closure`, surround the field access with parentheses
help: to call the trait object stored in `boxed_closure`, surround the field access with parentheses
|
LL | (boxed_fn.boxed_closure)();
| + +
Expand All @@ -60,7 +60,7 @@ LL | struct BoxedObj {
LL | boxed_closure.boxed_closure();
| ^^^^^^^^^^^^^ field, not a method
|
help: to call the function stored in `boxed_closure`, surround the field access with parentheses
help: to call the trait object stored in `boxed_closure`, surround the field access with parentheses
|
LL | (boxed_closure.boxed_closure)();
| + +
Expand Down Expand Up @@ -99,7 +99,7 @@ LL | struct Obj<F> where F: FnOnce() -> u32 {
LL | check_expression().closure();
| ^^^^^^^ field, not a method
|
help: to call the function stored in `closure`, surround the field access with parentheses
help: to call the trait object stored in `closure`, surround the field access with parentheses
|
LL | (check_expression().closure)();
| + +
Expand All @@ -113,7 +113,7 @@ LL | struct FuncContainer {
LL | (*self.container).f1(1);
| ^^ field, not a method
|
help: to call the function stored in `f1`, surround the field access with parentheses
help: to call the function pointer stored in `f1`, surround the field access with parentheses
|
LL | ((*self.container).f1)(1);
| + +
Expand All @@ -127,7 +127,7 @@ LL | struct FuncContainer {
LL | (*self.container).f2(1);
| ^^ field, not a method
|
help: to call the function stored in `f2`, surround the field access with parentheses
help: to call the function pointer stored in `f2`, surround the field access with parentheses
|
LL | ((*self.container).f2)(1);
| + +
Expand All @@ -141,7 +141,7 @@ LL | struct FuncContainer {
LL | (*self.container).f3(1);
| ^^ field, not a method
|
help: to call the function stored in `f3`, surround the field access with parentheses
help: to call the function pointer stored in `f3`, surround the field access with parentheses
|
LL | ((*self.container).f3)(1);
| + +
Expand Down
2 changes: 1 addition & 1 deletion tests/ui/confuse-field-and-method/issue-32128.stderr
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Expand Up @@ -7,7 +7,7 @@ LL | struct Example {
LL | demo.example(1);
| ^^^^^^^ field, not a method
|
help: to call the function stored in `example`, surround the field access with parentheses
help: to call the trait object stored in `example`, surround the field access with parentheses
|
LL | (demo.example)(1);
| + +
Expand Down
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