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Better error

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This commit is contained in:
jackh726 2021-10-16 11:50:56 -04:00
parent 82148cdc66
commit e391796d47
4 changed files with 81 additions and 45 deletions
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40
compiler/rustc_typeck/src/check/wfcheck.rs
View file

@ -288,7 +288,6 @@ fn check_gat_where_clauses(
associated_items.in_definition_order().filter(|item| matches!(item.kind, ty::AssocKind::Fn))
{
let id = hir::HirId::make_owner(item.def_id.expect_local());
let span = DUMMY_SP;
let param_env = tcx.param_env(item.def_id.expect_local());
let sig = tcx.fn_sig(item.def_id);
@ -308,7 +307,7 @@ fn check_gat_where_clauses(
for (ty, ty_idx) in &visitor.types {
tcx.infer_ctxt().enter(|infcx| {
let mut outlives_environment = OutlivesEnvironment::new(param_env);
outlives_environment.add_implied_bounds(&infcx, wf_tys.clone(), id, span);
outlives_environment.add_implied_bounds(&infcx, wf_tys.clone(), id, DUMMY_SP);
outlives_environment.save_implied_bounds(id);
let region_bound_pairs =
outlives_environment.region_bound_pairs_map().get(&id).unwrap();
@ -349,7 +348,6 @@ fn check_gat_where_clauses(
name: ty_param.name,
}));
let region_param = generics.param_at(*region_idx, tcx);
// Then create a clause that is required on the GAT
let region_param =
tcx.mk_region(ty::RegionKind::ReEarlyBound(ty::EarlyBoundRegion {
def_id: region_param.def_id,
@ -372,13 +370,35 @@ fn check_gat_where_clauses(
debug!(?clauses);
if !clauses.is_empty() {
let written_predicates: ty::GenericPredicates<'_> = tcx.predicates_of(trait_item.def_id);
for clause in clauses {
let found = written_predicates.predicates.iter().find(|p| p.0 == clause).is_some();
debug!(?clause, ?found);
let mut error = tcx
.sess
.struct_span_err(trait_item.generics.span, &format!("Missing bound: {}", clause));
error.emit();
let clauses: Vec<_> = clauses
.drain_filter(|clause| {
written_predicates.predicates.iter().find(|p| &p.0 == clause).is_none()
})
.map(|clause| format!("{}", clause))
.collect();
if !clauses.is_empty() {
let mut err = tcx.sess.struct_span_err(
trait_item.span,
&format!("Missing required bounds on {}", trait_item.ident),
);
let suggestion = format!(
"{} {}",
if !trait_item.generics.where_clause.predicates.is_empty() {
","
} else {
" where"
},
clauses.join(", "),
);
err.span_suggestion(
trait_item.generics.where_clause.tail_span_for_suggestion(),
"add the required where clauses",
suggestion,
Applicability::MachineApplicable,
);
err.emit()
}
}
}

1
compiler/rustc_typeck/src/lib.rs
View file

@ -69,6 +69,7 @@ This API is completely unstable and subject to change.
#![feature(never_type)]
#![feature(slice_partition_dedup)]
#![feature(control_flow_enum)]
#![feature(hash_drain_filter)]
#![recursion_limit = "256"]
#[macro_use]

29
src/test/ui/generic-associated-types/self-outlives-lint.rs
View file

@ -2,9 +2,10 @@
// check-fail
// We have a `&'a self`, so we need a `Self: 'a`
trait Iterable {
type Item<'x>;
//~^ Missing bound
//~^ Missing required bounds
fn iter<'a>(&'a self) -> Self::Item<'a>;
}
@ -17,9 +18,10 @@ impl<T> Iterable for T {
}
*/
// We have a `&'a T`, so we need a `T: 'x`
trait Deserializer<T> {
type Out<'x>;
//~^ Missing bound
//~^ Missing required bounds
fn deserialize<'a>(&self, input: &'a T) -> Self::Out<'a>;
}
@ -30,19 +32,21 @@ impl<T> Deserializer<T> for () {
}
*/
// We have a `&'b T` and a `'b: 'a`, so it is implied that `T: 'a`. Therefore, we need a `T: 'x`
trait Deserializer2<T> {
type Out<'x>;
//~^ Missing bound
fn deserialize2<'a, 'b: 'a>(&self, input: &'a T, input2: &'b T) -> Self::Out<'a>;
//~^ Missing required bounds
fn deserialize2<'a, 'b: 'a>(&self, input1: &'b T) -> Self::Out<'a>;
}
// We have a `&'a T` and a `&'b U`, so we need a `T: 'x` and a `U: 'y`
trait Deserializer3<T, U> {
type Out<'x, 'y>;
//~^ Missing bound
//~^^ Missing bound
//~^ Missing required bounds
fn deserialize2<'a, 'b>(&self, input: &'a T, input2: &'b U) -> Self::Out<'a, 'b>;
}
// `T` is a param on the function, so it can't be named by the associated type
trait Deserializer4 {
type Out<'x>;
fn deserialize<'a, T>(&self, input: &'a T) -> Self::Out<'a>;
@ -50,36 +54,41 @@ trait Deserializer4 {
struct Wrap<T>(T);
// Even though we might theoretically want `D: 'x`, because we pass `Wrap<T>` and
// we see `&'z Wrap<T>`, we are conservative and only add bounds for direct params
trait Des {
type Out<'x, D>;
fn des<'z, T>(&self, data: &'z Wrap<T>) -> Self::Out<'z, Wrap<T>>;
}
/*
impl Des for () {
type Out<'x, D> = &'x D;
type Out<'x, D> = &'x D; // Not okay
fn des<'a, T>(&self, data: &'a Wrap<T>) -> Self::Out<'a, Wrap<T>> {
data
}
}
*/
// We have `T` and `'z` as GAT substs. Because of `&'z Wrap<T>`, there is an
// implied bound that `T: 'z`, so we require `D: 'x`
trait Des2 {
type Out<'x, D>;
//~^ Missing bound
//~^ Missing required bounds
fn des<'z, T>(&self, data: &'z Wrap<T>) -> Self::Out<'z, T>;
}
/*
impl Des2 for () {
type Out<'x, D> = &'x D;
fn des<'a, T>(&self, data: &'a Wrap<T>) -> Self::Out<'a, T> {
data
&data.0
}
}
*/
// We see `&'z T`, so we require `D: 'x`
trait Des3 {
type Out<'x, D>;
//~^ Missing bound
//~^ Missing required bounds
fn des<'z, T>(&self, data: &'z T) -> Self::Out<'z, T>;
}
/*

56
src/test/ui/generic-associated-types/self-outlives-lint.stderr
View file

@ -1,44 +1,50 @@
error: Missing bound: Self: 'x
--> $DIR/self-outlives-lint.rs:6:14
error: Missing required bounds on Item
--> $DIR/self-outlives-lint.rs:7:5
|
LL | type Item<'x>;
| ^^^^
| ^^^^^^^^^^^^^-
| |
| help: add the required where clauses: `where Self: 'x`
error: Missing bound: T: 'x
--> $DIR/self-outlives-lint.rs:21:13
error: Missing required bounds on Out
--> $DIR/self-outlives-lint.rs:23:5
|
LL | type Out<'x>;
| ^^^^
| ^^^^^^^^^^^^-
| |
| help: add the required where clauses: `where T: 'x`
error: Missing bound: T: 'x
--> $DIR/self-outlives-lint.rs:34:13
error: Missing required bounds on Out
--> $DIR/self-outlives-lint.rs:37:5
|
LL | type Out<'x>;
| ^^^^
| ^^^^^^^^^^^^-
| |
| help: add the required where clauses: `where T: 'x`
error: Missing bound: U: 'y
--> $DIR/self-outlives-lint.rs:40:13
error: Missing required bounds on Out
--> $DIR/self-outlives-lint.rs:44:5
|
LL | type Out<'x, 'y>;
| ^^^^^^^^
| ^^^^^^^^^^^^^^^^-
| |
| help: add the required where clauses: `where U: 'y, T: 'x`
error: Missing bound: T: 'x
--> $DIR/self-outlives-lint.rs:40:13
|
LL | type Out<'x, 'y>;
| ^^^^^^^^
error: Missing bound: D: 'x
--> $DIR/self-outlives-lint.rs:67:13
error: Missing required bounds on Out
--> $DIR/self-outlives-lint.rs:75:5
|
LL | type Out<'x, D>;
| ^^^^^^^
| ^^^^^^^^^^^^^^^-
| |
| help: add the required where clauses: `where D: 'x`
error: Missing bound: D: 'x
--> $DIR/self-outlives-lint.rs:81:13
error: Missing required bounds on Out
--> $DIR/self-outlives-lint.rs:90:5
|
LL | type Out<'x, D>;
| ^^^^^^^
| ^^^^^^^^^^^^^^^-
| |
| help: add the required where clauses: `where D: 'x`
error: aborting due to 7 previous errors
error: aborting due to 6 previous errors