mikros/rust
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

diagnostics: do not spurriously claim something is "not an iterator"

Browse Source 
Fixes a minor regression caused by #94746, where iter::Filter is
spurriously declared "not an iterator."
This commit is contained in:
Michael Howell 2022-03-11 16:58:14 -07:00
parent 335ffbfa54
commit 317f684160
3 changed files with 22 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

20
compiler/rustc_typeck/src/check/method/suggest.rs
View File

@ -574,6 +574,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
// Pick out the list of unimplemented traits on the receiver.
// This is used for custom error messages with the `#[rustc_on_unimplemented]` attribute.
let mut unimplemented_traits = FxHashMap::default();
let mut unimplemented_traits_only = true;
for (predicate, _parent_pred, cause) in &unsatisfied_predicates {
if let (ty::PredicateKind::Trait(p), Some(cause)) =
(predicate.kind().skip_binder(), cause.as_ref())
@ -596,6 +597,21 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
}
}
// Make sure that, if any traits other than the found ones were involved,
// we don't don't report an unimplemented trait.
// We don't want to say that `iter::Cloned` is not an interator, just
// because of some non-Clone item being iterated over.
for (predicate, _parent_pred, _cause) in &unsatisfied_predicates {
match predicate.kind().skip_binder() {
ty::PredicateKind::Trait(p)
if unimplemented_traits.contains_key(&p.trait_ref.def_id) => {}
_ => {
unimplemented_traits_only = false;
break;
}
}
}
let mut collect_type_param_suggestions =
|self_ty: Ty<'tcx>, parent_pred: ty::Predicate<'tcx>, obligation: &str| {
// We don't care about regions here, so it's fine to skip the binder here.
@ -839,7 +855,9 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
.join("\n");
let actual_prefix = actual.prefix_string(self.tcx);
info!("unimplemented_traits.len() == {}", unimplemented_traits.len());
let (primary_message, label) = if unimplemented_traits.len() == 1 {
let (primary_message, label) = if unimplemented_traits.len() == 1
&& unimplemented_traits_only
{
unimplemented_traits
.into_iter()
.next()

2
src/test/ui/mismatched_types/issue-36053-2.rs
View File

@ -5,6 +5,6 @@
use std::iter::once;
fn main() {
once::<&str>("str").fuse().filter(|a: &str| true).count();
//~^ ERROR not an iterator
//~^ ERROR the method
//~| ERROR type mismatch in closure arguments
}

4
src/test/ui/mismatched_types/issue-36053-2.stderr
View File

@ -12,11 +12,11 @@ note: required by a bound in `filter`
LL | P: FnMut(&Self::Item) -> bool,
| ^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `filter`
error[E0599]: `Filter<Fuse<std::iter::Once<&str>>, [closure@$DIR/issue-36053-2.rs:7:39: 7:53]>` is not an iterator
error[E0599]: the method `count` exists for struct `Filter<Fuse<std::iter::Once<&str>>, [closure@$DIR/issue-36053-2.rs:7:39: 7:53]>`, but its trait bounds were not satisfied
--> $DIR/issue-36053-2.rs:7:55
|
LL | once::<&str>("str").fuse().filter(|a: &str| true).count();
| -------------- ^^^^^ `Filter<Fuse<std::iter::Once<&str>>, [closure@$DIR/issue-36053-2.rs:7:39: 7:53]>` is not an iterator
| -------------- ^^^^^ method cannot be called on `Filter<Fuse<std::iter::Once<&str>>, [closure@$DIR/issue-36053-2.rs:7:39: 7:53]>` due to unsatisfied trait bounds
| |
| doesn't satisfy `<_ as FnOnce<(&&str,)>>::Output = bool`
| doesn't satisfy `_: FnMut<(&&str,)>`