From 29a41f0d86b82c2731cc2ab8c8a26272e773e4c3 Mon Sep 17 00:00:00 2001
From: csmoe <csmoe@msn.com>
Date: Mon, 11 May 2020 14:24:57 +0800
Subject: [PATCH 1/5] add ui test for issue-69276
---
src/librustc_typeck/check/mod.rs | 6 +++++-
src/test/ui/async-await/issue-69276.rs | 12 ++++++++++++
src/test/ui/async-await/issue-69276.stderr | 8 ++++++++
3 files changed, 25 insertions(+), 1 deletion(-)
create mode 100644 src/test/ui/async-await/issue-69276.rs
create mode 100644 src/test/ui/async-await/issue-69276.stderr
diff --git a/src/librustc_typeck/check/mod.rs b/src/librustc_typeck/check/mod.rs
index 956e09ec52b4a..57fdb03250e7a 100644
--- a/src/librustc_typeck/check/mod.rs
+++ b/src/librustc_typeck/check/mod.rs
@@ -1659,6 +1659,7 @@ fn check_opaque_for_inheriting_lifetimes(tcx: TyCtxt<'tcx>, def_id: LocalDefId,
let prohibit_opaque = match item.kind {
ItemKind::OpaqueTy(hir::OpaqueTy {
+ bounds,
origin: hir::OpaqueTyOrigin::AsyncFn | hir::OpaqueTyOrigin::FnReturn,
..
}) => {
@@ -1671,6 +1672,9 @@ fn check_opaque_for_inheriting_lifetimes(tcx: TyCtxt<'tcx>, def_id: LocalDefId,
};
debug!("check_opaque_for_inheriting_lifetimes: visitor={:?}", visitor);
+ for bound in bounds {
+ debug!("check_opaque_for_inheriting_lifetimes: {:?}", bound.trait_ref());
+ }
tcx.predicates_of(def_id)
.predicates
.iter()
@@ -1695,7 +1699,7 @@ fn check_opaque_for_inheriting_lifetimes(tcx: TyCtxt<'tcx>, def_id: LocalDefId,
"`{}` return type cannot contain a projection or `Self` that references lifetimes from \
a parent scope",
if is_async { "async fn" } else { "impl Trait" },
- ),
+ )
);
}
}
diff --git a/src/test/ui/async-await/issue-69276.rs b/src/test/ui/async-await/issue-69276.rs
new file mode 100644
index 0000000000000..224b76e2d903f
--- /dev/null
+++ b/src/test/ui/async-await/issue-69276.rs
@@ -0,0 +1,12 @@
+// edition:2018
+
+struct S<'a>(&'a i32);
+
+impl<'a> S<'a> {
+ async fn new(i: &'a i32) -> Self {
+ //~^ ERROR `async fn` return type cannot contain a projection or `Self` that references lifetimes from a parent scope
+ S(&22)
+ }
+}
+
+fn main() {}
diff --git a/src/test/ui/async-await/issue-69276.stderr b/src/test/ui/async-await/issue-69276.stderr
new file mode 100644
index 0000000000000..1ebfdfa8b54c5
--- /dev/null
+++ b/src/test/ui/async-await/issue-69276.stderr
@@ -0,0 +1,8 @@
+error: `async fn` return type cannot contain a projection or `Self` that references lifetimes from a parent scope
+ --> $DIR/issue-69276.rs:6:33
+ |
+LL | async fn new(i: &'a i32) -> Self {
+ | ^^^^
+
+error: aborting due to previous error
+
From 008d90a66a30bc8ff498f8ad47dea315c1853a75 Mon Sep 17 00:00:00 2001
From: csmoe <csmoe@msn.com>
Date: Sat, 16 May 2020 16:01:59 +0800
Subject: [PATCH 2/5] create error code E0754
---
src/librustc_error_codes/error_codes.rs | 1 +
src/librustc_error_codes/error_codes/E0754.md | 29 +++++++++++++++++++
2 files changed, 30 insertions(+)
create mode 100644 src/librustc_error_codes/error_codes/E0754.md
diff --git a/src/librustc_error_codes/error_codes.rs b/src/librustc_error_codes/error_codes.rs
index e01412bc21cfd..52d40fd0f2fa1 100644
--- a/src/librustc_error_codes/error_codes.rs
+++ b/src/librustc_error_codes/error_codes.rs
@@ -435,6 +435,7 @@ E0750: include_str!("./error_codes/E0750.md"),
E0751: include_str!("./error_codes/E0751.md"),
E0752: include_str!("./error_codes/E0752.md"),
E0753: include_str!("./error_codes/E0753.md"),
+E0754: include_str!("./error_codes/E0754.md"),
;
// E0006, // merged with E0005
// E0008, // cannot bind by-move into a pattern guard
diff --git a/src/librustc_error_codes/error_codes/E0754.md b/src/librustc_error_codes/error_codes/E0754.md
new file mode 100644
index 0000000000000..e7cea98201003
--- /dev/null
+++ b/src/librustc_error_codes/error_codes/E0754.md
@@ -0,0 +1,29 @@
+`async fn`/`impl trait` return type cannot contain a projection or `Self` that references lifetimes from a parent scope.
+
+Erroneous code example:
+
+```compile_fail,E0754,edition2018
+struct S<'a>(&'a i32);
+
+impl<'a> S<'a> {
+ async fn new(i: &'a i32) -> Self {
+ S(&22)
+ }
+}
+```
+
+To fix this error we need to spell out `Self` to `S<'a>`:
+
+```edition2018
+struct S<'a>(&'a i32);
+
+impl<'a> S<'a> {
+ async fn new(i: &'a i32) -> S<'a> {
+ S(&22)
+ }
+}
+```
+
+This will be allowed at some point in the future, but the implementation is not yet complete. See the [issue-61949] for this limitation.
+
+[issue-61949]: https://github.com/rust-lang/rust/issues/61949
From 633e4aafe65cd424cf6c8076869df1b49a4e0ec4 Mon Sep 17 00:00:00 2001
From: csmoe <csmoe@msn.com>
Date: Sat, 16 May 2020 16:08:56 +0800
Subject: [PATCH 3/5] suggest on Self return type
---
src/librustc_typeck/check/mod.rs | 67 +++++++++++++++++---------
src/test/ui/async-await/issue-69276.rs | 12 -----
2 files changed, 43 insertions(+), 36 deletions(-)
delete mode 100644 src/test/ui/async-await/issue-69276.rs
diff --git a/src/librustc_typeck/check/mod.rs b/src/librustc_typeck/check/mod.rs
index 57fdb03250e7a..0906c25baef09 100644
--- a/src/librustc_typeck/check/mod.rs
+++ b/src/librustc_typeck/check/mod.rs
@@ -1639,51 +1639,56 @@ fn check_opaque_for_inheriting_lifetimes(tcx: TyCtxt<'tcx>, def_id: LocalDefId,
struct ProhibitOpaqueVisitor<'tcx> {
opaque_identity_ty: Ty<'tcx>,
generics: &'tcx ty::Generics,
+ ty: Option<Ty<'tcx>>,
};
impl<'tcx> ty::fold::TypeVisitor<'tcx> for ProhibitOpaqueVisitor<'tcx> {
fn visit_ty(&mut self, t: Ty<'tcx>) -> bool {
debug!("check_opaque_for_inheriting_lifetimes: (visit_ty) t={:?}", t);
+ self.ty = Some(t);
if t == self.opaque_identity_ty { false } else { t.super_visit_with(self) }
}
fn visit_region(&mut self, r: ty::Region<'tcx>) -> bool {
debug!("check_opaque_for_inheriting_lifetimes: (visit_region) r={:?}", r);
if let RegionKind::ReEarlyBound(ty::EarlyBoundRegion { index, .. }) = r {
- return *index < self.generics.parent_count as u32;
+ let found_lifetime = *index < self.generics.parent_count as u32;
+ if !found_lifetime {
+ self.ty = None;
+ }
+ return found_lifetime;
}
r.super_visit_with(self)
}
}
+ let mut visitor = ProhibitOpaqueVisitor {
+ opaque_identity_ty: tcx.mk_opaque(
+ def_id.to_def_id(),
+ InternalSubsts::identity_for_item(tcx, def_id.to_def_id()),
+ ),
+ generics: tcx.generics_of(def_id),
+ ty: None,
+ };
+ debug!("check_opaque_for_inheriting_lifetimes: visitor={:?}", visitor);
+
let prohibit_opaque = match item.kind {
ItemKind::OpaqueTy(hir::OpaqueTy {
- bounds,
origin: hir::OpaqueTyOrigin::AsyncFn | hir::OpaqueTyOrigin::FnReturn,
..
- }) => {
- let mut visitor = ProhibitOpaqueVisitor {
- opaque_identity_ty: tcx.mk_opaque(
- def_id.to_def_id(),
- InternalSubsts::identity_for_item(tcx, def_id.to_def_id()),
- ),
- generics: tcx.generics_of(def_id),
- };
- debug!("check_opaque_for_inheriting_lifetimes: visitor={:?}", visitor);
-
- for bound in bounds {
- debug!("check_opaque_for_inheriting_lifetimes: {:?}", bound.trait_ref());
- }
- tcx.predicates_of(def_id)
- .predicates
- .iter()
- .any(|(predicate, _)| predicate.visit_with(&mut visitor))
- }
+ }) => tcx
+ .predicates_of(def_id)
+ .predicates
+ .iter()
+ .any(|(predicate, _)| predicate.visit_with(&mut visitor)),
_ => false,
};
+ debug!(
+ "check_opaque_for_inheriting_lifetimes: prohibit_opaque={:?}, visitor={:?}",
+ prohibit_opaque, visitor
+ );
- debug!("check_opaque_for_inheriting_lifetimes: prohibit_opaque={:?}", prohibit_opaque);
if prohibit_opaque {
let is_async = match item.kind {
ItemKind::OpaqueTy(hir::OpaqueTy { origin, .. }) => match origin {
@@ -1693,14 +1698,28 @@ fn check_opaque_for_inheriting_lifetimes(tcx: TyCtxt<'tcx>, def_id: LocalDefId,
_ => unreachable!(),
};
- tcx.sess.span_err(
+ let mut err = struct_span_err!(
+ tcx.sess,
span,
- &format!(
+ E0754,
"`{}` return type cannot contain a projection or `Self` that references lifetimes from \
a parent scope",
if is_async { "async fn" } else { "impl Trait" },
- )
);
+
+ if let Ok(snippet) = tcx.sess.source_map().span_to_snippet(span) {
+ if snippet == "Self" {
+ if let Some(ty) = visitor.ty {
+ err.span_suggestion(
+ span,
+ "consider spelling out the type instead",
+ format!("{:?}", ty),
+ Applicability::MaybeIncorrect,
+ );
+ }
+ }
+ }
+ err.emit();
}
}
diff --git a/src/test/ui/async-await/issue-69276.rs b/src/test/ui/async-await/issue-69276.rs
deleted file mode 100644
index 224b76e2d903f..0000000000000
--- a/src/test/ui/async-await/issue-69276.rs
+++ /dev/null
@@ -1,12 +0,0 @@
-// edition:2018
-
-struct S<'a>(&'a i32);
-
-impl<'a> S<'a> {
- async fn new(i: &'a i32) -> Self {
- //~^ ERROR `async fn` return type cannot contain a projection or `Self` that references lifetimes from a parent scope
- S(&22)
- }
-}
-
-fn main() {}
From 8841ede3648b5f12284dae850ec065374fd3af46 Mon Sep 17 00:00:00 2001
From: csmoe <csmoe@msn.com>
Date: Sat, 16 May 2020 17:10:08 +0800
Subject: [PATCH 4/5] bless suggestion on spell out
---
src/librustc_error_codes/error_codes.rs | 2 +-
.../error_codes/{E0754.md => E0755.md} | 7 +++++--
src/librustc_typeck/check/mod.rs | 2 +-
.../ui/async-await/issue-61949-self-return-type.stderr | 5 +++--
src/test/ui/async-await/issue-69276.stderr | 8 --------
src/test/ui/impl-trait/bound-normalization-fail.stderr | 5 +++--
6 files changed, 13 insertions(+), 16 deletions(-)
rename src/librustc_error_codes/error_codes/{E0754.md => E0755.md} (70%)
delete mode 100644 src/test/ui/async-await/issue-69276.stderr
diff --git a/src/librustc_error_codes/error_codes.rs b/src/librustc_error_codes/error_codes.rs
index 52d40fd0f2fa1..6467561e509fa 100644
--- a/src/librustc_error_codes/error_codes.rs
+++ b/src/librustc_error_codes/error_codes.rs
@@ -435,7 +435,7 @@ E0750: include_str!("./error_codes/E0750.md"),
E0751: include_str!("./error_codes/E0751.md"),
E0752: include_str!("./error_codes/E0752.md"),
E0753: include_str!("./error_codes/E0753.md"),
-E0754: include_str!("./error_codes/E0754.md"),
+E0755: include_str!("./error_codes/E0755.md"),
;
// E0006, // merged with E0005
// E0008, // cannot bind by-move into a pattern guard
diff --git a/src/librustc_error_codes/error_codes/E0754.md b/src/librustc_error_codes/error_codes/E0755.md
similarity index 70%
rename from src/librustc_error_codes/error_codes/E0754.md
rename to src/librustc_error_codes/error_codes/E0755.md
index e7cea98201003..b6eb2e34ccfc5 100644
--- a/src/librustc_error_codes/error_codes/E0754.md
+++ b/src/librustc_error_codes/error_codes/E0755.md
@@ -1,4 +1,5 @@
-`async fn`/`impl trait` return type cannot contain a projection or `Self` that references lifetimes from a parent scope.
+`async fn`/`impl trait` return type cannot contain a projection
+or `Self` that references lifetimes from a parent scope.
Erroneous code example:
@@ -24,6 +25,8 @@ impl<'a> S<'a> {
}
```
-This will be allowed at some point in the future, but the implementation is not yet complete. See the [issue-61949] for this limitation.
+This will be allowed at some point in the future,
+but the implementation is not yet complete.
+See the [issue-61949] for this limitation.
[issue-61949]: https://github.com/rust-lang/rust/issues/61949
diff --git a/src/librustc_typeck/check/mod.rs b/src/librustc_typeck/check/mod.rs
index 0906c25baef09..bd8f628957dc1 100644
--- a/src/librustc_typeck/check/mod.rs
+++ b/src/librustc_typeck/check/mod.rs
@@ -1701,7 +1701,7 @@ fn check_opaque_for_inheriting_lifetimes(tcx: TyCtxt<'tcx>, def_id: LocalDefId,
let mut err = struct_span_err!(
tcx.sess,
span,
- E0754,
+ E0755,
"`{}` return type cannot contain a projection or `Self` that references lifetimes from \
a parent scope",
if is_async { "async fn" } else { "impl Trait" },
diff --git a/src/test/ui/async-await/issue-61949-self-return-type.stderr b/src/test/ui/async-await/issue-61949-self-return-type.stderr
index 12fb77d8dd637..fe05754c83ff8 100644
--- a/src/test/ui/async-await/issue-61949-self-return-type.stderr
+++ b/src/test/ui/async-await/issue-61949-self-return-type.stderr
@@ -1,8 +1,9 @@
-error: `async fn` return type cannot contain a projection or `Self` that references lifetimes from a parent scope
+error[E0755]: `async fn` return type cannot contain a projection or `Self` that references lifetimes from a parent scope
--> $DIR/issue-61949-self-return-type.rs:11:40
|
LL | pub async fn new(_bar: &'a i32) -> Self {
- | ^^^^
+ | ^^^^ help: consider spelling out the type instead: `Foo<'a>`
error: aborting due to previous error
+For more information about this error, try `rustc --explain E0754`.
diff --git a/src/test/ui/async-await/issue-69276.stderr b/src/test/ui/async-await/issue-69276.stderr
deleted file mode 100644
index 1ebfdfa8b54c5..0000000000000
--- a/src/test/ui/async-await/issue-69276.stderr
+++ /dev/null
@@ -1,8 +0,0 @@
-error: `async fn` return type cannot contain a projection or `Self` that references lifetimes from a parent scope
- --> $DIR/issue-69276.rs:6:33
- |
-LL | async fn new(i: &'a i32) -> Self {
- | ^^^^
-
-error: aborting due to previous error
-
diff --git a/src/test/ui/impl-trait/bound-normalization-fail.stderr b/src/test/ui/impl-trait/bound-normalization-fail.stderr
index f5092044627f6..04b398f5b5283 100644
--- a/src/test/ui/impl-trait/bound-normalization-fail.stderr
+++ b/src/test/ui/impl-trait/bound-normalization-fail.stderr
@@ -20,7 +20,7 @@ help: consider constraining the associated type `<T as impl_trait::Trait>::Assoc
LL | fn foo_fail<T: Trait<Assoc = ()>>() -> impl FooLike<Output=T::Assoc> {
| ^^^^^^^^^^^^
-error: `impl Trait` return type cannot contain a projection or `Self` that references lifetimes from a parent scope
+error[E0755]: `impl Trait` return type cannot contain a projection or `Self` that references lifetimes from a parent scope
--> $DIR/bound-normalization-fail.rs:43:41
|
LL | fn foo2_fail<'a, T: Trait<'a>>() -> impl FooLike<Output=T::Assoc> {
@@ -42,4 +42,5 @@ LL | fn foo2_fail<'a, T: Trait<'a, Assoc = ()>>() -> impl FooLike<Output=T::
error: aborting due to 3 previous errors; 1 warning emitted
-For more information about this error, try `rustc --explain E0271`.
+Some errors have detailed explanations: E0271, E0755.
+For more information about an error, try `rustc --explain E0271`.
From 9be635306cdf06dde62e2c1ebaadcdc33f44f45c Mon Sep 17 00:00:00 2001
From: csmoe <csmoe@msn.com>
Date: Fri, 22 May 2020 12:14:53 +0800
Subject: [PATCH 5/5] resolve error code e0760
---
src/librustc_error_codes/error_codes.rs | 2 +-
src/librustc_error_codes/error_codes/{E0755.md => E0760.md} | 2 +-
src/librustc_typeck/check/mod.rs | 2 +-
src/test/ui/async-await/issue-61949-self-return-type.stderr | 4 ++--
src/test/ui/impl-trait/bound-normalization-fail.stderr | 4 ++--
5 files changed, 7 insertions(+), 7 deletions(-)
rename src/librustc_error_codes/error_codes/{E0755.md => E0760.md} (94%)
diff --git a/src/librustc_error_codes/error_codes.rs b/src/librustc_error_codes/error_codes.rs
index c0b16c22e4d98..97f0c16b4cfb2 100644
--- a/src/librustc_error_codes/error_codes.rs
+++ b/src/librustc_error_codes/error_codes.rs
@@ -437,7 +437,7 @@ E0751: include_str!("./error_codes/E0751.md"),
E0752: include_str!("./error_codes/E0752.md"),
E0753: include_str!("./error_codes/E0753.md"),
E0754: include_str!("./error_codes/E0754.md"),
-E0755: include_str!("./error_codes/E0755.md"),
+E0760: include_str!("./error_codes/E0760.md"),
;
// E0006, // merged with E0005
// E0008, // cannot bind by-move into a pattern guard
diff --git a/src/librustc_error_codes/error_codes/E0755.md b/src/librustc_error_codes/error_codes/E0760.md
similarity index 94%
rename from src/librustc_error_codes/error_codes/E0755.md
rename to src/librustc_error_codes/error_codes/E0760.md
index 0c289146176d9..e1dcfefebcd76 100644
--- a/src/librustc_error_codes/error_codes/E0755.md
+++ b/src/librustc_error_codes/error_codes/E0760.md
@@ -3,7 +3,7 @@ or `Self` that references lifetimes from a parent scope.
Erroneous code example:
-```compile_fail,E0755,edition2018
+```compile_fail,E0760,edition2018
struct S<'a>(&'a i32);
impl<'a> S<'a> {
diff --git a/src/librustc_typeck/check/mod.rs b/src/librustc_typeck/check/mod.rs
index 200263728d934..4646e703496bb 100644
--- a/src/librustc_typeck/check/mod.rs
+++ b/src/librustc_typeck/check/mod.rs
@@ -1690,7 +1690,7 @@ fn check_opaque_for_inheriting_lifetimes(tcx: TyCtxt<'tcx>, def_id: LocalDefId,
let mut err = struct_span_err!(
tcx.sess,
span,
- E0755,
+ E0760,
"`{}` return type cannot contain a projection or `Self` that references lifetimes from \
a parent scope",
if is_async { "async fn" } else { "impl Trait" },
diff --git a/src/test/ui/async-await/issue-61949-self-return-type.stderr b/src/test/ui/async-await/issue-61949-self-return-type.stderr
index f57e097c1254d..4eeef871c5bfc 100644
--- a/src/test/ui/async-await/issue-61949-self-return-type.stderr
+++ b/src/test/ui/async-await/issue-61949-self-return-type.stderr
@@ -1,4 +1,4 @@
-error[E0755]: `async fn` return type cannot contain a projection or `Self` that references lifetimes from a parent scope
+error[E0760]: `async fn` return type cannot contain a projection or `Self` that references lifetimes from a parent scope
--> $DIR/issue-61949-self-return-type.rs:11:40
|
LL | pub async fn new(_bar: &'a i32) -> Self {
@@ -6,4 +6,4 @@ LL | pub async fn new(_bar: &'a i32) -> Self {
error: aborting due to previous error
-For more information about this error, try `rustc --explain E0755`.
+For more information about this error, try `rustc --explain E0760`.
diff --git a/src/test/ui/impl-trait/bound-normalization-fail.stderr b/src/test/ui/impl-trait/bound-normalization-fail.stderr
index c78d4c4a8fd12..03aba10cc79b4 100644
--- a/src/test/ui/impl-trait/bound-normalization-fail.stderr
+++ b/src/test/ui/impl-trait/bound-normalization-fail.stderr
@@ -21,7 +21,7 @@ help: consider constraining the associated type `<T as impl_trait::Trait>::Assoc
LL | fn foo_fail<T: Trait<Assoc = ()>>() -> impl FooLike<Output=T::Assoc> {
| ^^^^^^^^^^^^
-error[E0755]: `impl Trait` return type cannot contain a projection or `Self` that references lifetimes from a parent scope
+error[E0760]: `impl Trait` return type cannot contain a projection or `Self` that references lifetimes from a parent scope
--> $DIR/bound-normalization-fail.rs:43:41
|
LL | fn foo2_fail<'a, T: Trait<'a>>() -> impl FooLike<Output=T::Assoc> {
@@ -43,5 +43,5 @@ LL | fn foo2_fail<'a, T: Trait<'a, Assoc = ()>>() -> impl FooLike<Output=T::
error: aborting due to 3 previous errors; 1 warning emitted
-Some errors have detailed explanations: E0271, E0755.
+Some errors have detailed explanations: E0271, E0760.
For more information about an error, try `rustc --explain E0271`.