Make derive(Trait) suggestion more accurate

Only suggest `derive(PartialEq)` when both LHS and RHS types
are the same, otherwise the suggestion is not useful.
This commit is contained in:
Esteban Küber 2023-12-27 21:14:43 +00:00
parent 1a47f5b448
commit 7f795a5221
4 changed files with 27 additions and 16 deletions

View File

@ -2252,6 +2252,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
&self,
err: &mut Diagnostic,
errors: Vec<FulfillmentError<'tcx>>,
suggest_derive: bool,
) {
let all_local_types_needing_impls =
errors.iter().all(|e| match e.obligation.predicate.kind().skip_binder() {
@ -2322,10 +2323,15 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
.iter()
.map(|e| (e.obligation.predicate, None, Some(e.obligation.cause.clone())))
.collect();
self.suggest_derive(err, &preds);
if suggest_derive {
self.suggest_derive(err, &preds);
} else {
// The predicate comes from a binop where the lhs and rhs have different types.
let _ = self.note_predicate_source_and_get_derives(err, &preds);
}
}
pub fn suggest_derive(
fn note_predicate_source_and_get_derives(
&self,
err: &mut Diagnostic,
unsatisfied_predicates: &[(
@ -2333,7 +2339,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
Option<ty::Predicate<'tcx>>,
Option<ObligationCause<'tcx>>,
)],
) {
) -> Vec<(String, Span, String)> {
let mut derives = Vec::<(String, Span, Symbol)>::new();
let mut traits = Vec::new();
for (pred, _, _) in unsatisfied_predicates {
@ -2419,6 +2425,20 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
);
}
derives_grouped
}
pub fn suggest_derive(
&self,
err: &mut Diagnostic,
unsatisfied_predicates: &[(
ty::Predicate<'tcx>,
Option<ty::Predicate<'tcx>>,
Option<ObligationCause<'tcx>>,
)],
) {
let derives_grouped =
self.note_predicate_source_and_get_derives(err, unsatisfied_predicates);
for (self_name, self_span, traits) in &derives_grouped {
err.span_suggestion_verbose(
self_span.shrink_to_lo(),

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@ -318,7 +318,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
lhs_expr.span,
format!("cannot use `{}=` on type `{}`", op.node.as_str(), lhs_ty),
);
self.note_unmet_impls_on_type(&mut err, errors);
self.note_unmet_impls_on_type(&mut err, errors, false);
(err, None)
}
IsAssign::No => {
@ -375,7 +375,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
err.span_label(lhs_expr.span, lhs_ty.to_string());
err.span_label(rhs_expr.span, rhs_ty.to_string());
}
self.note_unmet_impls_on_type(&mut err, errors);
let suggest_derive = self.can_eq(self.param_env, lhs_ty, rhs_ty);
self.note_unmet_impls_on_type(&mut err, errors, suggest_derive);
(err, output_def_id)
}
};
@ -852,7 +853,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
Str | Never | Char | Tuple(_) | Array(_, _) => {}
Ref(_, lty, _) if *lty.kind() == Str => {}
_ => {
self.note_unmet_impls_on_type(&mut err, errors);
self.note_unmet_impls_on_type(&mut err, errors, true);
}
}
}

View File

@ -270,11 +270,6 @@ note: an implementation of `PartialEq<&&{integer}>` might be missing for `Foo`
|
LL | struct Foo;
| ^^^^^^^^^^ must implement `PartialEq<&&{integer}>`
help: consider annotating `Foo` with `#[derive(PartialEq)]`
|
LL + #[derive(PartialEq)]
LL | struct Foo;
|
error[E0277]: can't compare `&String` with `str`
--> $DIR/binary-op-suggest-deref.rs:69:20

View File

@ -11,11 +11,6 @@ note: an implementation of `PartialEq<fn(()) -> A {A::Value}>` might be missing
|
LL | enum A {
| ^^^^^^ must implement `PartialEq<fn(()) -> A {A::Value}>`
help: consider annotating `A` with `#[derive(PartialEq)]`
|
LL + #[derive(PartialEq)]
LL | enum A {
|
help: use parentheses to construct this tuple variant
|
LL | a == A::Value(/* () */);