Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

diagnostics: wrap fn cast suggestions in parens when needed #130911

Merged
Merged
Show file tree
Hide file tree
Changes from all commits
Commits
File filter

Filter by extension

Filter by extension

Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
Original file line number Diff line number Diff line change
Expand Up @@ -33,7 +33,8 @@ use tracing::{debug, instrument};
use super::on_unimplemented::{AppendConstMessage, OnUnimplementedNote};
use super::suggestions::get_explanation_based_on_obligation;
use super::{
ArgKind, CandidateSimilarity, GetSafeTransmuteErrorAndReason, ImplCandidate, UnsatisfiedConst,
ArgKind, CandidateSimilarity, FindExprBySpan, GetSafeTransmuteErrorAndReason, ImplCandidate,
UnsatisfiedConst,
};
use crate::error_reporting::TypeErrCtxt;
use crate::error_reporting::infer::TyCategory;
Expand Down Expand Up @@ -378,14 +379,34 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
if let (ty::FnPtr(..), ty::FnDef(..)) =
(cand.self_ty().kind(), main_trait_ref.self_ty().skip_binder().kind())
{
err.span_suggestion(
span.shrink_to_hi(),
// Wrap method receivers and `&`-references in parens
let suggestion = if self.tcx.sess.source_map().span_look_ahead(span, ".", Some(50)).is_some() {
vec![
Copy link
Member

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

span_look_ahead is not correct sometimes, can we use the expr way to find out there is a method call?

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I originally tried to do that, but couldn't get a expr of the actual method call. When I tried using FindExprBySpan, it returned None.

(span.shrink_to_lo(), format!("(")),
(span.shrink_to_hi(), format!(" as {})", cand.self_ty())),
]
} else if let Some(body) = self.tcx.hir().maybe_body_owned_by(obligation.cause.body_id) {
let mut expr_finder = FindExprBySpan::new(span, self.tcx);
expr_finder.visit_expr(body.value);
if let Some(expr) = expr_finder.result &&
let hir::ExprKind::AddrOf(_, _, expr) = expr.kind {
vec![
(expr.span.shrink_to_lo(), format!("(")),
(expr.span.shrink_to_hi(), format!(" as {})", cand.self_ty())),
]
} else {
vec![(span.shrink_to_hi(), format!(" as {}", cand.self_ty()))]
}
} else {
vec![(span.shrink_to_hi(), format!(" as {}", cand.self_ty()))]
};
err.multipart_suggestion(
format!(
"the trait `{}` is implemented for fn pointer `{}`, try casting using `as`",
cand.print_trait_sugared(),
cand.self_ty(),
),
format!(" as {}", cand.self_ty()),
suggestion,
Applicability::MaybeIncorrect,
);
true
Expand Down
1 change: 0 additions & 1 deletion src/tools/tidy/src/issues.txt
Original file line number Diff line number Diff line change
Expand Up @@ -4076,7 +4076,6 @@ ui/traits/issue-96664.rs
ui/traits/issue-96665.rs
ui/traits/issue-97576.rs
ui/traits/issue-97695-double-trivial-bound.rs
ui/traits/issue-99875.rs
ui/traits/next-solver/coherence/issue-102048.rs
ui/traits/next-solver/issue-118950-root-region.rs
ui/traits/object/issue-33140-traitobject-crate.rs
Expand Down
Original file line number Diff line number Diff line change
@@ -1,13 +1,13 @@
error[E0277]: the trait bound `fn(Argument) -> Return {function}: Trait` is not satisfied
--> $DIR/issue-99875.rs:12:11
--> $DIR/bare-fn-no-impl-fn-ptr-99875.rs:12:11
|
LL | takes(function);
| ----- ^^^^^^^^ the trait `Trait` is not implemented for fn item `fn(Argument) -> Return {function}`
| |
| required by a bound introduced by this call
|
note: required by a bound in `takes`
--> $DIR/issue-99875.rs:9:18
--> $DIR/bare-fn-no-impl-fn-ptr-99875.rs:9:18
|
LL | fn takes(_: impl Trait) {}
| ^^^^^ required by this bound in `takes`
Expand All @@ -16,17 +16,17 @@ help: the trait `Trait` is implemented for fn pointer `fn(Argument) -> Return`,
LL | takes(function as fn(Argument) -> Return);
| +++++++++++++++++++++++++

error[E0277]: the trait bound `{closure@$DIR/issue-99875.rs:14:11: 14:34}: Trait` is not satisfied
--> $DIR/issue-99875.rs:14:11
error[E0277]: the trait bound `{closure@$DIR/bare-fn-no-impl-fn-ptr-99875.rs:14:11: 14:34}: Trait` is not satisfied
--> $DIR/bare-fn-no-impl-fn-ptr-99875.rs:14:11
|
LL | takes(|_: Argument| -> Return { todo!() });
| ----- ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Trait` is not implemented for closure `{closure@$DIR/issue-99875.rs:14:11: 14:34}`
| ----- ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Trait` is not implemented for closure `{closure@$DIR/bare-fn-no-impl-fn-ptr-99875.rs:14:11: 14:34}`
| |
| required by a bound introduced by this call
|
= help: the trait `Trait` is implemented for fn pointer `fn(Argument) -> Return`
note: required by a bound in `takes`
--> $DIR/issue-99875.rs:9:18
--> $DIR/bare-fn-no-impl-fn-ptr-99875.rs:9:18
|
LL | fn takes(_: impl Trait) {}
| ^^^^^ required by this bound in `takes`
Expand Down
15 changes: 15 additions & 0 deletions tests/ui/traits/fn-pointer/suggest-wrap-parens-method.fixed
Original file line number Diff line number Diff line change
@@ -0,0 +1,15 @@
//@ run-rustfix

trait Foo {}

impl Foo for fn() {}

trait Bar {
fn do_stuff(&self) where Self: Foo {}
}
impl<T> Bar for T {}

fn main() {
(main as fn()).do_stuff();
//~^ ERROR the trait bound
}
15 changes: 15 additions & 0 deletions tests/ui/traits/fn-pointer/suggest-wrap-parens-method.rs
Original file line number Diff line number Diff line change
@@ -0,0 +1,15 @@
//@ run-rustfix

trait Foo {}

impl Foo for fn() {}

trait Bar {
fn do_stuff(&self) where Self: Foo {}
}
impl<T> Bar for T {}

fn main() {
main.do_stuff();
//~^ ERROR the trait bound
}
19 changes: 19 additions & 0 deletions tests/ui/traits/fn-pointer/suggest-wrap-parens-method.stderr
Original file line number Diff line number Diff line change
@@ -0,0 +1,19 @@
error[E0277]: the trait bound `fn() {main}: Foo` is not satisfied
--> $DIR/suggest-wrap-parens-method.rs:13:10
|
LL | main.do_stuff();
| ^^^^^^^^ the trait `Foo` is not implemented for fn item `fn() {main}`
|
note: required by a bound in `Bar::do_stuff`
--> $DIR/suggest-wrap-parens-method.rs:8:36
|
LL | fn do_stuff(&self) where Self: Foo {}
| ^^^ required by this bound in `Bar::do_stuff`
help: the trait `Foo` is implemented for fn pointer `fn()`, try casting using `as`
|
LL | (main as fn()).do_stuff();
| + ++++++++

error: aborting due to 1 previous error

For more information about this error, try `rustc --explain E0277`.
10 changes: 10 additions & 0 deletions tests/ui/traits/fn-pointer/suggest-wrap-parens.fixed
Original file line number Diff line number Diff line change
@@ -0,0 +1,10 @@
//@ run-rustfix

trait Foo {}

impl Foo for fn() {}

fn main() {
let _x: &dyn Foo = &(main as fn());
//~^ ERROR the trait bound
}
10 changes: 10 additions & 0 deletions tests/ui/traits/fn-pointer/suggest-wrap-parens.rs
Original file line number Diff line number Diff line change
@@ -0,0 +1,10 @@
//@ run-rustfix

trait Foo {}

impl Foo for fn() {}

fn main() {
let _x: &dyn Foo = &main;
//~^ ERROR the trait bound
}
15 changes: 15 additions & 0 deletions tests/ui/traits/fn-pointer/suggest-wrap-parens.stderr
Original file line number Diff line number Diff line change
@@ -0,0 +1,15 @@
error[E0277]: the trait bound `fn() {main}: Foo` is not satisfied
--> $DIR/suggest-wrap-parens.rs:8:24
|
LL | let _x: &dyn Foo = &main;
| ^^^^^ the trait `Foo` is not implemented for fn item `fn() {main}`
|
= note: required for the cast from `&fn() {main}` to `&dyn Foo`
help: the trait `Foo` is implemented for fn pointer `fn()`, try casting using `as`
|
LL | let _x: &dyn Foo = &(main as fn());
| + ++++++++

error: aborting due to 1 previous error

For more information about this error, try `rustc --explain E0277`.
Loading