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Suggest box/pin/arc ing receiver on method calls
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estebank committed Mar 30, 2021
1 parent 2917eda commit 6f2d8a0
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Showing 17 changed files with 113 additions and 97 deletions.
35 changes: 29 additions & 6 deletions compiler/rustc_typeck/src/check/expr.rs
Expand Up @@ -973,7 +973,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
error: MethodError<'tcx>,
) {
let rcvr = &args[0];
let try_alt_rcvr = |err: &mut DiagnosticBuilder<'_>, new_rcvr_t| {
let try_alt_rcvr = |err: &mut DiagnosticBuilder<'_>, new_rcvr_t, pre: &str, post: &str| {
if let Some(new_rcvr_t) = new_rcvr_t {
if let Ok(pick) = self.lookup_probe(
span,
Expand All @@ -986,11 +986,24 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
// Make sure the method is defined for the *actual* receiver:
// we don't want to treat `Box<Self>` as a receiver if
// it only works because of an autoderef to `&self`
if pick.autoderefs == 0 {
if pick.autoderefs == 0
// We don't want to suggest a container type when the missing method is
// `.clone()`, otherwise we'd suggest `Arc::new(foo).clone()`, which is
// far from what the user really wants.
&& Some(pick.item.container.id()) != self.tcx.lang_items().clone_trait()
{
err.span_label(
pick.item.ident.span,
&format!("the method is available for `{}` here", new_rcvr_t),
);
err.multipart_suggestion(
"consider wrapping the receiver expression with the appropriate type",
vec![
(rcvr.span.shrink_to_lo(), format!("{}({}", pre, post)),
(rcvr.span.shrink_to_hi(), ")".to_string()),
],
Applicability::MaybeIncorrect,
);
}
}
}
Expand All @@ -1008,10 +1021,20 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
// Try alternative arbitrary self types that could fulfill this call.
// FIXME: probe for all types that *could* be arbitrary self-types, not
// just this list.
try_alt_rcvr(&mut err, self.tcx.mk_lang_item(rcvr_t, LangItem::OwnedBox));
try_alt_rcvr(&mut err, self.tcx.mk_lang_item(rcvr_t, LangItem::Pin));
try_alt_rcvr(&mut err, self.tcx.mk_diagnostic_item(rcvr_t, sym::Arc));
try_alt_rcvr(&mut err, self.tcx.mk_diagnostic_item(rcvr_t, sym::Rc));
for (rcvr_t, post) in &[
(rcvr_t, ""),
(self.tcx.mk_mut_ref(&ty::ReErased, rcvr_t), "&mut "),
(self.tcx.mk_imm_ref(&ty::ReErased, rcvr_t), "&"),
] {
for (rcvr_t, pre) in &[
(self.tcx.mk_lang_item(rcvr_t, LangItem::OwnedBox), "Box::new"),
(self.tcx.mk_lang_item(rcvr_t, LangItem::Pin), "Pin::new"),
(self.tcx.mk_diagnostic_item(rcvr_t, sym::Arc), "Arc::new"),
(self.tcx.mk_diagnostic_item(rcvr_t, sym::Rc), "Rc::new"),
] {
try_alt_rcvr(&mut err, *rcvr_t, pre, post);
}
}
}
err.emit();
}
Expand Down
2 changes: 2 additions & 0 deletions compiler/rustc_typeck/src/check/method/mod.rs
Expand Up @@ -45,6 +45,7 @@ pub struct MethodCallee<'tcx> {
pub sig: ty::FnSig<'tcx>,
}

#[derive(Debug)]
pub enum MethodError<'tcx> {
// Did not find an applicable method, but we did find various near-misses that may work.
NoMatch(NoMatchData<'tcx>),
Expand All @@ -66,6 +67,7 @@ pub enum MethodError<'tcx> {

// Contains a list of static methods that may apply, a list of unsatisfied trait predicates which
// could lead to matches if satisfied, and a list of not-in-scope traits which may work.
#[derive(Debug)]
pub struct NoMatchData<'tcx> {
pub static_candidates: Vec<CandidateSource>,
pub unsatisfied_predicates: Vec<(ty::Predicate<'tcx>, Option<ty::Predicate<'tcx>>)>,
Expand Down
47 changes: 47 additions & 0 deletions src/test/ui/async-await/pin-needed-to-poll.rs
@@ -0,0 +1,47 @@
use std::{
future::Future,
pin::Pin,
task::{Context, Poll},
};

struct Sleep;

impl Future for Sleep {
type Output = ();

fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
Poll::Ready(())
}
}

impl Drop for Sleep {
fn drop(&mut self) {}
}

fn sleep() -> Sleep {
Sleep
}


struct MyFuture {
sleep: Sleep,
}

impl MyFuture {
fn new() -> Self {
Self {
sleep: sleep(),
}
}
}

impl Future for MyFuture {
type Output = ();

fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
self.sleep.poll(cx)
//~^ ERROR no method named `poll` found for struct `Sleep` in the current scope
}
}

fn main() {}
25 changes: 25 additions & 0 deletions src/test/ui/async-await/pin-needed-to-poll.stderr
@@ -0,0 +1,25 @@
error[E0599]: no method named `poll` found for struct `Sleep` in the current scope
--> $DIR/pin-needed-to-poll.rs:42:20
|
LL | struct Sleep;
| ------------- method `poll` not found for this
...
LL | self.sleep.poll(cx)
| ^^^^ method not found in `Sleep`
|
::: $SRC_DIR/core/src/future/future.rs:LL:COL
|
LL | fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output>;
| ---- the method is available for `Pin<&mut Sleep>` here
|
= help: items from traits can only be used if the trait is implemented and in scope
= note: the following trait defines an item `poll`, perhaps you need to implement it:
candidate #1: `Future`
help: consider wrapping the receiver expression with the appropriate type
|
LL | Pin::new(&mut self.sleep).poll(cx)
| ^^^^^^^^^^^^^ ^

error: aborting due to previous error

For more information about this error, try `rustc --explain E0599`.
8 changes: 0 additions & 8 deletions src/test/ui/copy-a-resource.stderr
Expand Up @@ -6,14 +6,6 @@ LL | struct Foo {
...
LL | let _y = x.clone();
| ^^^^^ method not found in `Foo`
|
::: $SRC_DIR/core/src/clone.rs:LL:COL
|
LL | fn clone(&self) -> Self;
| -----
| |
| the method is available for `Arc<Foo>` here
| the method is available for `Rc<Foo>` here
|
= help: items from traits can only be used if the trait is implemented and in scope
= note: the following trait defines an item `clone`, perhaps you need to implement it:
Expand Down
8 changes: 0 additions & 8 deletions src/test/ui/derives/derive-assoc-type-not-impl.stderr
Expand Up @@ -12,14 +12,6 @@ LL | struct NotClone;
...
LL | Bar::<NotClone> { x: 1 }.clone();
| ^^^^^ method cannot be called on `Bar<NotClone>` due to unsatisfied trait bounds
|
::: $SRC_DIR/core/src/clone.rs:LL:COL
|
LL | fn clone(&self) -> Self;
| -----
| |
| the method is available for `Arc<Bar<NotClone>>` here
| the method is available for `Rc<Bar<NotClone>>` here
|
= note: the following trait bounds were not satisfied:
`NotClone: Clone`
Expand Down
8 changes: 0 additions & 8 deletions src/test/ui/issues/issue-2823.stderr
Expand Up @@ -6,14 +6,6 @@ LL | struct C {
...
LL | let _d = c.clone();
| ^^^^^ method not found in `C`
|
::: $SRC_DIR/core/src/clone.rs:LL:COL
|
LL | fn clone(&self) -> Self;
| -----
| |
| the method is available for `Arc<C>` here
| the method is available for `Rc<C>` here
|
= help: items from traits can only be used if the trait is implemented and in scope
= note: the following trait defines an item `clone`, perhaps you need to implement it:
Expand Down
8 changes: 0 additions & 8 deletions src/test/ui/issues/issue-69725.stderr
Expand Up @@ -8,14 +8,6 @@ LL | let _ = Struct::<A>::new().clone();
|
LL | pub struct Struct<A>(A);
| ------------------------ doesn't satisfy `Struct<A>: Clone`
|
::: $SRC_DIR/core/src/clone.rs:LL:COL
|
LL | fn clone(&self) -> Self;
| -----
| |
| the method is available for `Arc<Struct<A>>` here
| the method is available for `Rc<Struct<A>>` here
|
= note: the following trait bounds were not satisfied:
`A: Clone`
Expand Down
8 changes: 0 additions & 8 deletions src/test/ui/non-copyable-void.stderr
Expand Up @@ -3,14 +3,6 @@ error[E0599]: no method named `clone` found for enum `c_void` in the current sco
|
LL | let _z = (*y).clone();
| ^^^^^ method not found in `c_void`
|
::: $SRC_DIR/core/src/clone.rs:LL:COL
|
LL | fn clone(&self) -> Self;
| -----
| |
| the method is available for `Arc<c_void>` here
| the method is available for `Rc<c_void>` here

error: aborting due to previous error

Expand Down
8 changes: 0 additions & 8 deletions src/test/ui/noncopyable-class.stderr
Expand Up @@ -6,14 +6,6 @@ LL | struct Foo {
...
LL | let _y = x.clone();
| ^^^^^ method not found in `Foo`
|
::: $SRC_DIR/core/src/clone.rs:LL:COL
|
LL | fn clone(&self) -> Self;
| -----
| |
| the method is available for `Arc<Foo>` here
| the method is available for `Rc<Foo>` here
|
= help: items from traits can only be used if the trait is implemented and in scope
= note: the following trait defines an item `clone`, perhaps you need to implement it:
Expand Down
5 changes: 5 additions & 0 deletions src/test/ui/self/point-at-arbitrary-self-type-method.stderr
Expand Up @@ -9,6 +9,11 @@ LL | fn foo(self: Box<Self>) {}
...
LL | A.foo();
| ^^^ method not found in `A`
|
help: consider wrapping the receiver expression with the appropriate type
|
LL | Box::new(A).foo();
| ^^^^^^^^^ ^

error: aborting due to previous error

Expand Down
Expand Up @@ -10,6 +10,11 @@ LL | struct A;
...
LL | A.foo()
| ^^^ method not found in `A`
|
help: consider wrapping the receiver expression with the appropriate type
|
LL | Box::new(A).foo()
| ^^^^^^^^^ ^

error: aborting due to previous error

Expand Down

This file was deleted.

Expand Up @@ -6,14 +6,6 @@ LL | struct Qux;
...
LL | Qux.clone();
| ^^^^^ method not found in `Qux`
|
::: $SRC_DIR/core/src/clone.rs:LL:COL
|
LL | fn clone(&self) -> Self;
| -----
| |
| the method is available for `Arc<Qux>` here
| the method is available for `Rc<Qux>` here
|
= help: items from traits can only be used if the trait is implemented and in scope
= note: the trait `Clone` defines an item `clone`, but is explicitely unimplemented
Expand Down
8 changes: 0 additions & 8 deletions src/test/ui/union/union-derive-clone.stderr
Expand Up @@ -25,14 +25,6 @@ LL | struct CloneNoCopy;
...
LL | let w = u.clone();
| ^^^^^ method cannot be called on `U5<CloneNoCopy>` due to unsatisfied trait bounds
|
::: $SRC_DIR/core/src/clone.rs:LL:COL
|
LL | fn clone(&self) -> Self;
| -----
| |
| the method is available for `Arc<U5<CloneNoCopy>>` here
| the method is available for `Rc<U5<CloneNoCopy>>` here
|
= note: the following trait bounds were not satisfied:
`CloneNoCopy: Copy`
Expand Down
8 changes: 0 additions & 8 deletions src/test/ui/unique-object-noncopyable.stderr
Expand Up @@ -10,14 +10,6 @@ LL | trait Foo {
LL | let _z = y.clone();
| ^^^^^ method cannot be called on `Box<dyn Foo>` due to unsatisfied trait bounds
|
::: $SRC_DIR/core/src/clone.rs:LL:COL
|
LL | fn clone(&self) -> Self;
| -----
| |
| the method is available for `Arc<Box<dyn Foo>>` here
| the method is available for `Rc<Box<dyn Foo>>` here
|
::: $SRC_DIR/alloc/src/boxed.rs:LL:COL
|
LL | / pub struct Box<
Expand Down
8 changes: 0 additions & 8 deletions src/test/ui/unique-pinned-nocopy.stderr
Expand Up @@ -7,14 +7,6 @@ LL | struct R {
LL | let _j = i.clone();
| ^^^^^ method cannot be called on `Box<R>` due to unsatisfied trait bounds
|
::: $SRC_DIR/core/src/clone.rs:LL:COL
|
LL | fn clone(&self) -> Self;
| -----
| |
| the method is available for `Arc<Box<R>>` here
| the method is available for `Rc<Box<R>>` here
|
::: $SRC_DIR/alloc/src/boxed.rs:LL:COL
|
LL | / pub struct Box<
Expand Down

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