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Add more context to diagnostic

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This commit is contained in:
Esteban Küber 2020-06-28 18:07:26 -07:00
parent 4e08bab87d
commit 6bac3dbfc2
2 changed files with 96 additions and 18 deletions
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78
src/librustc_infer/infer/error_reporting/nice_region_error/static_impl_trait.rs
View file

@ -8,8 +8,10 @@ use rustc_errors::{struct_span_err, Applicability, DiagnosticBuilder, ErrorRepor
use rustc_hir::def_id::{DefId, LOCAL_CRATE};
use rustc_hir::intravisit::{walk_ty, ErasedMap, NestedVisitorMap, Visitor};
use rustc_hir::{self as hir, GenericBound, Item, ItemKind, Lifetime, LifetimeName, Node, TyKind};
use rustc_middle::ty::{self, AssocItemContainer, RegionKind, Ty, TypeFoldable, TypeVisitor};
use rustc_span::Span;
use rustc_middle::ty::{
self, AssocItem, AssocItemContainer, RegionKind, Ty, TypeFoldable, TypeVisitor,
};
use rustc_span::{MultiSpan, Span};
impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
/// Print the error message for lifetime errors when the return type is a static impl Trait.
@ -51,7 +53,7 @@ impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
cause.span,
"...is captured and required to live as long as `'static` here",
);
if self.find_impl_on_dyn_trait(&mut err, param.param_ty, &assoc.container) {
if self.find_impl_on_dyn_trait(&mut err, param.param_ty, assoc) {
err.emit();
return Some(ErrorReported);
} else {
@ -131,7 +133,7 @@ impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
if let SubregionOrigin::Subtype(box TypeTrace { cause, .. }) = &sup_origin {
if let ObligationCauseCode::UnifyReceiver(assoc) = &cause.code {
self.find_impl_on_dyn_trait(&mut err, param.param_ty, &assoc.container);
self.find_impl_on_dyn_trait(&mut err, param.param_ty, assoc);
}
}
@ -263,7 +265,7 @@ impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
&self,
err: &mut DiagnosticBuilder<'_>,
ty: Ty<'_>,
container: &AssocItemContainer,
assoc: &AssocItem,
) -> bool {
let tcx = self.tcx();
let mut suggested = false;
@ -272,7 +274,7 @@ impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
let mut v = TraitObjectVisitor(vec![]);
v.visit_ty(ty);
let container_id = match container {
let container_id = match assoc.container {
// When the obligation comes from an `impl Foo for dyn Bar {}`, we
// have the `DefId` of the `trait` itself, not the relevant `impl`
// block. Because of this, we have to look at all the `trait`s
@ -284,16 +286,35 @@ impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
// have the `DefId` of the relevant `Item`, so we use it directly.
AssocItemContainer::ImplContainer(def_id) => {
if let Some(Node::Item(Item { kind: ItemKind::Impl { self_ty, .. }, .. })) =
tcx.hir().get_if_local(*def_id)
tcx.hir().get_if_local(def_id)
{
for found_did in &v.0 {
let mut hir_v = HirTraitObjectVisitor(vec![], *found_did);
hir_v.visit_ty(self_ty);
if let [span] = &hir_v.0[..] {
let mut multi_span: MultiSpan = vec![*span].into();
multi_span.push_span_label(
*span,
"this trait object has an implicit `'static` lifetime requirement"
.to_string(),
);
multi_span.push_span_label(
assoc.ident.span,
"the `'static` requirement is introduced when calling this method"
.to_string(),
);
err.span_note(
multi_span,
&format!(
"when using method `{}` on `{}`, an implicit `'static` \
requirement is introduced",
assoc.ident,
tcx.def_path_str(*found_did),
),
);
err.span_suggestion_verbose(
span.shrink_to_hi(),
"this `impl` introduces an implicit `'static` requirement, \
consider changing it",
"consider relaxing the implicit `'static` requirement",
" + '_".to_string(),
Applicability::MaybeIncorrect,
);
@ -316,24 +337,53 @@ impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
let impl_did = tcx.hir().local_def_id(*impl_node);
match tcx.hir().get_if_local(impl_did.to_def_id()) {
Some(Node::Item(Item {
kind: ItemKind::Impl { self_ty, of_trait: Some(of_trait), .. },
kind: ItemKind::Impl { self_ty, of_trait: Some(of_trait), items, .. },
..
})) if of_trait.trait_def_id() == Some(*container_id) => Some(self_ty),
})) if of_trait.trait_def_id() == Some(container_id) => Some((
self_ty,
// Get the ident of the method, in order to use its `Span`.
items
.iter()
.filter(|item| item.ident == assoc.ident)
.map(|item| item.ident)
.next()
.unwrap_or(assoc.ident),
)),
_ => None,
}
});
// Given all the `impl`s of the relevant `trait`, look for those that are implemented for
// the trait object in the `fn` parameter type.
for self_ty in impl_self_tys {
for (self_ty, method) in impl_self_tys {
for found_did in &v.0 {
let mut hir_v = HirTraitObjectVisitor(vec![], *found_did);
hir_v.visit_ty(self_ty);
if let [span] = &hir_v.0[..] {
let mut multi_span: MultiSpan = vec![*span].into();
multi_span.push_span_label(
*span,
"this trait object has an implicit `'static` lifetime requirement"
.to_string(),
);
multi_span.push_span_label(
method.span,
"the `'static` requirement is introduced when calling this method"
.to_string(),
);
err.span_note(
multi_span,
&format!(
"when using method `{}` of trait `{}` on `{}`, an implicit `'static` \
requirement is introduced",
method,
tcx.def_path_str(container_id),
tcx.def_path_str(*found_did),
),
);
err.span_suggestion_verbose(
span.shrink_to_hi(),
"this `impl` introduces an implicit `'static` requirement, \
consider changing it",
"consider relaxing the implicit `'static` requirement",
" + '_".to_string(),
Applicability::MaybeIncorrect,
);

36
src/test/ui/suggestions/impl-on-dyn-trait-with-implicit-static-bound.stderr
View file

@ -6,7 +6,14 @@ LL | fn use_it<'a>(val: &'a dyn ObjectTrait) -> impl OtherTrait<'a> + 'a {
LL | val.use_self()
| ^^^^^^^^ ...is captured and required to live as long as `'static` here
|
help: this `impl` introduces an implicit `'static` requirement, consider changing it
note: when using method `use_self` of trait `foo::MyTrait` on `foo::ObjectTrait`, an implicit `'static` requirement is introduced
--> $DIR/impl-on-dyn-trait-with-implicit-static-bound.rs:14:26
|
LL | impl MyTrait for dyn ObjectTrait {
| ^^^^^^^^^^^ this trait object has an implicit `'static` lifetime requirement
LL | fn use_self(&self) -> &() { panic!() }
| -------- the `'static` requirement is introduced when calling this method
help: consider relaxing the implicit `'static` requirement
|
LL | impl MyTrait for dyn ObjectTrait + '_ {
| ^^^^
@ -19,7 +26,14 @@ LL | fn use_it<'a>(val: &'a dyn ObjectTrait) -> impl OtherTrait<'a> + 'a {
LL | val.use_self()
| ^^^^^^^^ ...is captured and required to live as long as `'static` here
|
help: this `impl` introduces an implicit `'static` requirement, consider changing it
note: when using method `use_self` on `bat::ObjectTrait`, an implicit `'static` requirement is introduced
--> $DIR/impl-on-dyn-trait-with-implicit-static-bound.rs:64:14
|
LL | impl dyn ObjectTrait {
| ^^^^^^^^^^^ this trait object has an implicit `'static` lifetime requirement
LL | fn use_self(&self) -> &() { panic!() }
| -------- the `'static` requirement is introduced when calling this method
help: consider relaxing the implicit `'static` requirement
|
LL | impl dyn ObjectTrait + '_ {
| ^^^^
@ -32,7 +46,14 @@ LL | fn use_it<'a>(val: &'a dyn ObjectTrait) -> &'a () {
LL | val.use_self()
| ^^^^^^^^ ...is captured and required to live as long as `'static` here
|
help: this `impl` introduces an implicit `'static` requirement, consider changing it
note: when using method `use_self` of trait `bar::MyTrait` on `bar::ObjectTrait`, an implicit `'static` requirement is introduced
--> $DIR/impl-on-dyn-trait-with-implicit-static-bound.rs:31:26
|
LL | impl MyTrait for dyn ObjectTrait {
| ^^^^^^^^^^^ this trait object has an implicit `'static` lifetime requirement
LL | fn use_self(&self) -> &() { panic!() }
| -------- the `'static` requirement is introduced when calling this method
help: consider relaxing the implicit `'static` requirement
|
LL | impl MyTrait for dyn ObjectTrait + '_ {
| ^^^^
@ -45,7 +66,14 @@ LL | fn use_it<'a>(val: &'a Box<dyn ObjectTrait + 'a>) -> &'a () {
LL | val.use_self()
| ^^^^^^^^ ...is captured and required to live as long as `'static` here
|
help: this `impl` introduces an implicit `'static` requirement, consider changing it
note: when using method `use_self` of trait `baz::MyTrait` on `baz::ObjectTrait`, an implicit `'static` requirement is introduced
--> $DIR/impl-on-dyn-trait-with-implicit-static-bound.rs:48:30
|
LL | impl MyTrait for Box<dyn ObjectTrait> {
| ^^^^^^^^^^^ this trait object has an implicit `'static` lifetime requirement
LL | fn use_self(&self) -> &() { panic!() }
| -------- the `'static` requirement is introduced when calling this method
help: consider relaxing the implicit `'static` requirement
|
LL | impl MyTrait for Box<dyn ObjectTrait + '_> {
| ^^^^