From a5888a22dab2f8ddd5f9b819795769d4d34ddb4b Mon Sep 17 00:00:00 2001
From: Niko Matsakis <niko@alum.mit.edu>
Date: Thu, 30 Jun 2022 16:44:41 -0400
Subject: [PATCH 1/2] don't prove WC when projecting from param-env
If the param-env tells you that, forall 'a, `T::Item<'a> = u32`,
we can believe it.
---
.../src/traits/project.rs | 2 +-
.../rustc_typeck/src/check/compare_method.rs | 3 +
.../feature-gate-generic_associated_types.rs | 14 ++--
...ature-gate-generic_associated_types.stderr | 44 +++++------
.../bugs/issue-87755.rs | 9 +--
.../bugs/issue-87755.stderr | 9 ---
.../collectivity-regression.rs | 6 +-
.../collectivity-regression.stderr | 14 ----
.../extended/lending_iterator.rs | 7 +-
.../extended/lending_iterator_2.rs | 7 +-
.../generic-associated-types-where.rs | 16 ++--
.../generic-associated-types-where.stderr | 19 +----
.../generic-associated-types/impl_bounds.rs | 24 ++++--
.../impl_bounds.stderr | 77 ++++++++-----------
.../generic-associated-types/issue-90014.rs | 6 +-
.../issue-90014.stderr | 18 -----
.../generic-associated-types/issue-91883.rs | 6 +-
.../issue-91883.stderr | 26 -------
.../generic-associated-types/issue-92033.rs | 3 +-
.../issue-92033.stderr | 20 -----
.../trait-objects.base.stderr | 6 +-
.../trait-objects.extended.stderr | 17 ----
.../generic-associated-types/trait-objects.rs | 8 +-
.../unsatified-item-lifetime-bound.rs | 1 -
.../unsatified-item-lifetime-bound.stderr | 23 ++----
25 files changed, 125 insertions(+), 260 deletions(-)
delete mode 100644 src/test/ui/generic-associated-types/bugs/issue-87755.stderr
delete mode 100644 src/test/ui/generic-associated-types/collectivity-regression.stderr
delete mode 100644 src/test/ui/generic-associated-types/issue-90014.stderr
delete mode 100644 src/test/ui/generic-associated-types/issue-91883.stderr
delete mode 100644 src/test/ui/generic-associated-types/issue-92033.stderr
delete mode 100644 src/test/ui/generic-associated-types/trait-objects.extended.stderr
diff --git a/compiler/rustc_trait_selection/src/traits/project.rs b/compiler/rustc_trait_selection/src/traits/project.rs
index aba4f144d4bcc..3d723558fb3c4 100644
--- a/compiler/rustc_trait_selection/src/traits/project.rs
+++ b/compiler/rustc_trait_selection/src/traits/project.rs
@@ -1951,7 +1951,7 @@ fn confirm_param_env_candidate<'cx, 'tcx>(
match infcx.at(cause, param_env).eq(cache_projection, obligation_projection) {
Ok(InferOk { value: _, obligations }) => {
nested_obligations.extend(obligations);
- assoc_ty_own_obligations(selcx, obligation, &mut nested_obligations);
+ // NDM assoc_ty_own_obligations(selcx, obligation, &mut nested_obligations);
// FIXME(associated_const_equality): Handle consts here as well? Maybe this progress type should just take
// a term instead.
Progress { term: cache_entry.term, obligations: nested_obligations }
diff --git a/compiler/rustc_typeck/src/check/compare_method.rs b/compiler/rustc_typeck/src/check/compare_method.rs
index 95c82a7d2c3d8..4942e314c5f17 100644
--- a/compiler/rustc_typeck/src/check/compare_method.rs
+++ b/compiler/rustc_typeck/src/check/compare_method.rs
@@ -222,8 +222,11 @@ fn compare_predicate_entailment<'tcx>(
let impl_m_own_bounds = impl_m_predicates.instantiate_own(tcx, impl_to_placeholder_substs);
for (predicate, span) in iter::zip(impl_m_own_bounds.predicates, impl_m_own_bounds.spans) {
let normalize_cause = traits::ObligationCause::misc(span, impl_m_hir_id);
+ debug!("predicate before normalization: {:?}", predicate);
let traits::Normalized { value: predicate, obligations } =
traits::normalize(&mut selcx, param_env, normalize_cause, predicate);
+ debug!("predicate after normalization: {:?}", predicate);
+ debug!("normalization obligations: {:#?}", obligations);
inh.register_predicates(obligations);
let cause = ObligationCause::new(
diff --git a/src/test/ui/feature-gates/feature-gate-generic_associated_types.rs b/src/test/ui/feature-gates/feature-gate-generic_associated_types.rs
index c5c1345148891..2038285d35f4f 100644
--- a/src/test/ui/feature-gates/feature-gate-generic_associated_types.rs
+++ b/src/test/ui/feature-gates/feature-gate-generic_associated_types.rs
@@ -3,8 +3,11 @@ use std::ops::Deref;
trait PointerFamily<U> {
type Pointer<T>: Deref<Target = T>;
//~^ ERROR generic associated types are unstable
- type Pointer2<T>: Deref<Target = T> where T: Clone, U: Clone;
- //~^ ERROR generic associated types are unstable
+ type Pointer2<T>: Deref<Target = T>
+ where
+ T: Clone,
+ U: Clone;
+ //~^^^^ ERROR generic associated types are unstable
//~| ERROR where clauses on associated types are unstable
}
@@ -15,12 +18,13 @@ impl PointerFamily<u32> for Foo {
//~^ ERROR generic associated types are unstable
type Pointer2<U32> = Box<U32>;
//~^ ERROR generic associated types are unstable
- //~| ERROR the trait bound `U32: Clone` is not satisfied
}
trait Bar {
- type Assoc where Self: Sized;
- //~^ ERROR where clauses on associated types are unstable
+ type Assoc
+ where
+ Self: Sized;
+ //~^^^ ERROR where clauses on associated types are unstable
}
impl Bar for Foo {
diff --git a/src/test/ui/feature-gates/feature-gate-generic_associated_types.stderr b/src/test/ui/feature-gates/feature-gate-generic_associated_types.stderr
index 12a40ff0a12f5..89c6ce4072c37 100644
--- a/src/test/ui/feature-gates/feature-gate-generic_associated_types.stderr
+++ b/src/test/ui/feature-gates/feature-gate-generic_associated_types.stderr
@@ -10,8 +10,11 @@ LL | type Pointer<T>: Deref<Target = T>;
error[E0658]: generic associated types are unstable
--> $DIR/feature-gate-generic_associated_types.rs:6:5
|
-LL | type Pointer2<T>: Deref<Target = T> where T: Clone, U: Clone;
- | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL | / type Pointer2<T>: Deref<Target = T>
+LL | | where
+LL | | T: Clone,
+LL | | U: Clone;
+ | |_________________^
|
= note: see issue #44265 <https://github.com/rust-lang/rust/issues/44265> for more information
= help: add `#![feature(generic_associated_types)]` to the crate attributes to enable
@@ -19,14 +22,17 @@ LL | type Pointer2<T>: Deref<Target = T> where T: Clone, U: Clone;
error[E0658]: where clauses on associated types are unstable
--> $DIR/feature-gate-generic_associated_types.rs:6:5
|
-LL | type Pointer2<T>: Deref<Target = T> where T: Clone, U: Clone;
- | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL | / type Pointer2<T>: Deref<Target = T>
+LL | | where
+LL | | T: Clone,
+LL | | U: Clone;
+ | |_________________^
|
= note: see issue #44265 <https://github.com/rust-lang/rust/issues/44265> for more information
= help: add `#![feature(generic_associated_types)]` to the crate attributes to enable
error[E0658]: generic associated types are unstable
- --> $DIR/feature-gate-generic_associated_types.rs:14:5
+ --> $DIR/feature-gate-generic_associated_types.rs:17:5
|
LL | type Pointer<Usize> = Box<Usize>;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -35,7 +41,7 @@ LL | type Pointer<Usize> = Box<Usize>;
= help: add `#![feature(generic_associated_types)]` to the crate attributes to enable
error[E0658]: generic associated types are unstable
- --> $DIR/feature-gate-generic_associated_types.rs:16:5
+ --> $DIR/feature-gate-generic_associated_types.rs:19:5
|
LL | type Pointer2<U32> = Box<U32>;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -44,16 +50,18 @@ LL | type Pointer2<U32> = Box<U32>;
= help: add `#![feature(generic_associated_types)]` to the crate attributes to enable
error[E0658]: where clauses on associated types are unstable
- --> $DIR/feature-gate-generic_associated_types.rs:22:5
+ --> $DIR/feature-gate-generic_associated_types.rs:24:5
|
-LL | type Assoc where Self: Sized;
- | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL | / type Assoc
+LL | | where
+LL | | Self: Sized;
+ | |____________________^
|
= note: see issue #44265 <https://github.com/rust-lang/rust/issues/44265> for more information
= help: add `#![feature(generic_associated_types)]` to the crate attributes to enable
error[E0658]: where clauses on associated types are unstable
- --> $DIR/feature-gate-generic_associated_types.rs:27:5
+ --> $DIR/feature-gate-generic_associated_types.rs:31:5
|
LL | type Assoc = Foo where Self: Sized;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -61,18 +69,6 @@ LL | type Assoc = Foo where Self: Sized;
= note: see issue #44265 <https://github.com/rust-lang/rust/issues/44265> for more information
= help: add `#![feature(generic_associated_types)]` to the crate attributes to enable
-error[E0277]: the trait bound `U32: Clone` is not satisfied
- --> $DIR/feature-gate-generic_associated_types.rs:16:26
- |
-LL | type Pointer2<U32> = Box<U32>;
- | ^^^^^^^^ the trait `Clone` is not implemented for `U32`
- |
-help: consider restricting type parameter `U32`
- |
-LL | type Pointer2<U32: std::clone::Clone> = Box<U32>;
- | +++++++++++++++++++
-
-error: aborting due to 8 previous errors
+error: aborting due to 7 previous errors
-Some errors have detailed explanations: E0277, E0658.
-For more information about an error, try `rustc --explain E0277`.
+For more information about this error, try `rustc --explain E0658`.
diff --git a/src/test/ui/generic-associated-types/bugs/issue-87755.rs b/src/test/ui/generic-associated-types/bugs/issue-87755.rs
index efa487d624fd9..c0c8081164ca3 100644
--- a/src/test/ui/generic-associated-types/bugs/issue-87755.rs
+++ b/src/test/ui/generic-associated-types/bugs/issue-87755.rs
@@ -1,14 +1,13 @@
-// check-fail
-// known-bug: #87755
-
-// This should pass.
+// check-pass
#![feature(generic_associated_types)]
use std::fmt::Debug;
trait Foo {
- type Ass where Self::Ass: Debug;
+ type Ass
+ where
+ Self::Ass: Debug;
}
#[derive(Debug)]
diff --git a/src/test/ui/generic-associated-types/bugs/issue-87755.stderr b/src/test/ui/generic-associated-types/bugs/issue-87755.stderr
deleted file mode 100644
index 5d1aff0117c13..0000000000000
--- a/src/test/ui/generic-associated-types/bugs/issue-87755.stderr
+++ /dev/null
@@ -1,9 +0,0 @@
-error[E0275]: overflow evaluating the requirement `<Bar as Foo>::Ass == _`
- --> $DIR/issue-87755.rs:18:16
- |
-LL | type Ass = Bar;
- | ^^^
-
-error: aborting due to previous error
-
-For more information about this error, try `rustc --explain E0275`.
diff --git a/src/test/ui/generic-associated-types/collectivity-regression.rs b/src/test/ui/generic-associated-types/collectivity-regression.rs
index fb73684390737..04bd17ded4a93 100644
--- a/src/test/ui/generic-associated-types/collectivity-regression.rs
+++ b/src/test/ui/generic-associated-types/collectivity-regression.rs
@@ -1,4 +1,6 @@
// Regression test from https://github.com/rust-lang/rust/pull/98109
+//
+// check-pass
#![feature(generic_associated_types)]
@@ -13,10 +15,6 @@ where
for<'a> T: Get<Value<'a> = ()>,
{
|| {
- //~^ `T` does not live long enough
- //
- // FIXME(#98437). This regressed at some point and
- // probably should work.
let _x = x;
};
}
diff --git a/src/test/ui/generic-associated-types/collectivity-regression.stderr b/src/test/ui/generic-associated-types/collectivity-regression.stderr
deleted file mode 100644
index a858dd7fddcd2..0000000000000
--- a/src/test/ui/generic-associated-types/collectivity-regression.stderr
+++ /dev/null
@@ -1,14 +0,0 @@
-error: `T` does not live long enough
- --> $DIR/collectivity-regression.rs:15:5
- |
-LL | / || {
-LL | |
-LL | | //
-LL | | // FIXME(#98437). This regressed at some point and
-LL | | // probably should work.
-LL | | let _x = x;
-LL | | };
- | |_____^
-
-error: aborting due to previous error
-
diff --git a/src/test/ui/generic-associated-types/extended/lending_iterator.rs b/src/test/ui/generic-associated-types/extended/lending_iterator.rs
index ede164766361e..e80443fada35d 100644
--- a/src/test/ui/generic-associated-types/extended/lending_iterator.rs
+++ b/src/test/ui/generic-associated-types/extended/lending_iterator.rs
@@ -1,10 +1,6 @@
-// revisions: base extended
-//[base] check-fail
-//[extended] check-pass
+// check-pass
#![feature(generic_associated_types)]
-#![cfg_attr(extended, feature(generic_associated_types_extended))]
-#![cfg_attr(extended, allow(incomplete_features))]
pub trait FromLendingIterator<A>: Sized {
fn from_iter<T: for<'x> LendingIterator<Item<'x> = A>>(iter: T) -> Self;
@@ -12,7 +8,6 @@ pub trait FromLendingIterator<A>: Sized {
impl<A> FromLendingIterator<A> for Vec<A> {
fn from_iter<I: for<'x> LendingIterator<Item<'x> = A>>(mut iter: I) -> Self {
- //[base]~^ impl has stricter
let mut v = vec![];
while let Some(item) = iter.next() {
v.push(item);
diff --git a/src/test/ui/generic-associated-types/extended/lending_iterator_2.rs b/src/test/ui/generic-associated-types/extended/lending_iterator_2.rs
index 3c4a2184db90c..7eb012074e09f 100644
--- a/src/test/ui/generic-associated-types/extended/lending_iterator_2.rs
+++ b/src/test/ui/generic-associated-types/extended/lending_iterator_2.rs
@@ -1,10 +1,6 @@
-// revisions: base extended
-//[base] check-fail
-//[extended] check-pass
+// check-pass
#![feature(generic_associated_types)]
-#![cfg_attr(extended, feature(generic_associated_types_extended))]
-#![cfg_attr(extended, allow(incomplete_features))]
pub trait FromLendingIterator<A>: Sized {
fn from_iter<T: for<'x> LendingIterator<Item<'x> = A>>(iter: T) -> Self;
@@ -12,7 +8,6 @@ pub trait FromLendingIterator<A>: Sized {
impl<A> FromLendingIterator<A> for Vec<A> {
fn from_iter<I: for<'x> LendingIterator<Item<'x> = A>>(mut iter: I) -> Self {
- //[base]~^ impl has stricter
let mut v = vec![];
while let Some(item) = iter.next() {
v.push(item);
diff --git a/src/test/ui/generic-associated-types/generic-associated-types-where.rs b/src/test/ui/generic-associated-types/generic-associated-types-where.rs
index 2ecbc8c591259..0b0f6f56e41ce 100644
--- a/src/test/ui/generic-associated-types/generic-associated-types-where.rs
+++ b/src/test/ui/generic-associated-types/generic-associated-types-where.rs
@@ -1,15 +1,18 @@
#![feature(generic_associated_types)]
-
// Checking the interaction with this other feature
#![feature(associated_type_defaults)]
-use std::fmt::{Display, Debug};
+use std::fmt::{Debug, Display};
trait Foo {
- type Assoc where Self: Sized;
- type Assoc2<T> where T: Display;
+ type Assoc
+ where
+ Self: Sized;
+ type Assoc2<T>
+ where
+ T: Display;
type Assoc3<T>;
- type WithDefault<'a, T: Debug + 'a>: ?Sized = dyn Iterator<Item=T>;
+ type WithDefault<'a, T: Debug + 'a>: ?Sized = dyn Iterator<Item = T>;
type NoGenerics;
}
@@ -18,10 +21,9 @@ struct Bar;
impl Foo for Bar {
type Assoc = usize;
type Assoc2<T> = Vec<T>;
- //~^ ERROR `T` doesn't implement `std::fmt::Display`
type Assoc3<T> = Vec<T> where T: Iterator;
//~^ ERROR impl has stricter requirements than trait
- type WithDefault<'a, T: Debug + 'a> = &'a dyn Iterator<Item=T>;
+ type WithDefault<'a, T: Debug + 'a> = &'a dyn Iterator<Item = T>;
type NoGenerics = ::std::cell::Cell<i32>;
}
diff --git a/src/test/ui/generic-associated-types/generic-associated-types-where.stderr b/src/test/ui/generic-associated-types/generic-associated-types-where.stderr
index 68594bba48632..83aefe8686ce1 100644
--- a/src/test/ui/generic-associated-types/generic-associated-types-where.stderr
+++ b/src/test/ui/generic-associated-types/generic-associated-types-where.stderr
@@ -1,17 +1,5 @@
-error[E0277]: `T` doesn't implement `std::fmt::Display`
- --> $DIR/generic-associated-types-where.rs:20:22
- |
-LL | type Assoc2<T> = Vec<T>;
- | ^^^^^^ `T` cannot be formatted with the default formatter
- |
- = note: in format strings you may be able to use `{:?}` (or {:#?} for pretty-print) instead
-help: consider restricting type parameter `T`
- |
-LL | type Assoc2<T: std::fmt::Display> = Vec<T>;
- | +++++++++++++++++++
-
error[E0276]: impl has stricter requirements than trait
- --> $DIR/generic-associated-types-where.rs:22:5
+ --> $DIR/generic-associated-types-where.rs:24:5
|
LL | type Assoc3<T>;
| --------------- definition of `Assoc3` from trait
@@ -19,7 +7,6 @@ LL | type Assoc3<T>;
LL | type Assoc3<T> = Vec<T> where T: Iterator;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ impl has extra requirement `T: Iterator`
-error: aborting due to 2 previous errors
+error: aborting due to previous error
-Some errors have detailed explanations: E0276, E0277.
-For more information about an error, try `rustc --explain E0276`.
+For more information about this error, try `rustc --explain E0276`.
diff --git a/src/test/ui/generic-associated-types/impl_bounds.rs b/src/test/ui/generic-associated-types/impl_bounds.rs
index bb5992c88f08f..3331484af2406 100644
--- a/src/test/ui/generic-associated-types/impl_bounds.rs
+++ b/src/test/ui/generic-associated-types/impl_bounds.rs
@@ -2,10 +2,18 @@
#![feature(associated_type_defaults)]
trait Foo {
- type A<'a> where Self: 'a;
- type B<'a, 'b> where 'a: 'b;
- type C where Self: Clone;
- fn d() where Self: Clone;
+ type A<'a>
+ where
+ Self: 'a;
+ type B<'a, 'b>
+ where
+ 'a: 'b;
+ type C
+ where
+ Self: Clone;
+ fn d()
+ where
+ Self: Clone;
}
#[derive(Copy, Clone)]
@@ -16,11 +24,13 @@ impl<T> Foo for Fooy<T> {
//~^ ERROR `impl` associated type
type B<'a, 'b> = (&'a(), &'b ()) where 'b: 'a;
//~^ ERROR `impl` associated type
- //~| ERROR lifetime bound not satisfied
type C = String where Self: Copy;
//~^ ERROR the trait bound `T: Copy` is not satisfied
- fn d() where Self: Copy {}
- //~^ ERROR the trait bound `T: Copy` is not satisfied
+ fn d()
+ where
+ Self: Copy, //~ ERROR the trait bound `T: Copy` is not satisfied
+ {
+ }
}
fn main() {}
diff --git a/src/test/ui/generic-associated-types/impl_bounds.stderr b/src/test/ui/generic-associated-types/impl_bounds.stderr
index 3d90471e398e6..bca92f1ba6640 100644
--- a/src/test/ui/generic-associated-types/impl_bounds.stderr
+++ b/src/test/ui/generic-associated-types/impl_bounds.stderr
@@ -1,60 +1,46 @@
error: `impl` associated type signature for `A` doesn't match `trait` associated type signature
- --> $DIR/impl_bounds.rs:15:5
+ --> $DIR/impl_bounds.rs:23:5
|
-LL | type A<'a> where Self: 'a;
- | -------------------------- expected
+LL | / type A<'a>
+LL | | where
+LL | | Self: 'a;
+ | |_________________- expected
...
-LL | type A<'a> = (&'a ()) where Self: 'static;
- | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ found
+LL | type A<'a> = (&'a ()) where Self: 'static;
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ found
error: `impl` associated type signature for `B` doesn't match `trait` associated type signature
- --> $DIR/impl_bounds.rs:17:5
+ --> $DIR/impl_bounds.rs:25:5
|
-LL | type B<'a, 'b> where 'a: 'b;
- | ---------------------------- expected
+LL | / type B<'a, 'b>
+LL | | where
+LL | | 'a: 'b;
+ | |_______________- expected
...
-LL | type B<'a, 'b> = (&'a(), &'b ()) where 'b: 'a;
- | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ found
-
-error[E0478]: lifetime bound not satisfied
- --> $DIR/impl_bounds.rs:17:22
- |
-LL | type B<'a, 'b> where 'a: 'b;
- | ---------------------------- definition of `B` from trait
-...
-LL | type B<'a, 'b> = (&'a(), &'b ()) where 'b: 'a;
- | ^^^^^^^^^^^^^^^ - help: try copying this clause from the trait: `, 'a: 'b`
- |
-note: lifetime parameter instantiated with the lifetime `'a` as defined here
- --> $DIR/impl_bounds.rs:17:12
- |
-LL | type B<'a, 'b> = (&'a(), &'b ()) where 'b: 'a;
- | ^^
-note: but lifetime parameter must outlive the lifetime `'b` as defined here
- --> $DIR/impl_bounds.rs:17:16
- |
-LL | type B<'a, 'b> = (&'a(), &'b ()) where 'b: 'a;
- | ^^
+LL | type B<'a, 'b> = (&'a(), &'b ()) where 'b: 'a;
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ found
error[E0277]: the trait bound `T: Copy` is not satisfied
- --> $DIR/impl_bounds.rs:20:5
+ --> $DIR/impl_bounds.rs:27:5
|
LL | type C = String where Self: Copy;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Copy` is not implemented for `T`
|
note: required because of the requirements on the impl of `Copy` for `Fooy<T>`
- --> $DIR/impl_bounds.rs:11:10
+ --> $DIR/impl_bounds.rs:19:10
|
LL | #[derive(Copy, Clone)]
| ^^^^
note: the requirement `Fooy<T>: Copy` appears on the associated impl type `C` but not on the corresponding associated trait type
- --> $DIR/impl_bounds.rs:7:5
+ --> $DIR/impl_bounds.rs:11:5
|
-LL | trait Foo {
- | --- in this trait
+LL | trait Foo {
+ | --- in this trait
...
-LL | type C where Self: Clone;
- | ^^^^^^^^^^^^^^^^^^^^^^^^^ this trait associated type doesn't have the requirement `Fooy<T>: Copy`
+LL | / type C
+LL | | where
+LL | | Self: Clone;
+ | |____________________^ this trait associated type doesn't have the requirement `Fooy<T>: Copy`
= note: this error originates in the derive macro `Copy` (in Nightly builds, run with -Z macro-backtrace for more info)
help: consider restricting type parameter `T`
|
@@ -62,23 +48,23 @@ LL | impl<T: std::marker::Copy> Foo for Fooy<T> {
| +++++++++++++++++++
error[E0277]: the trait bound `T: Copy` is not satisfied
- --> $DIR/impl_bounds.rs:22:24
+ --> $DIR/impl_bounds.rs:31:15
|
-LL | fn d() where Self: Copy {}
- | ^^^^ the trait `Copy` is not implemented for `T`
+LL | Self: Copy,
+ | ^^^^ the trait `Copy` is not implemented for `T`
|
note: required because of the requirements on the impl of `Copy` for `Fooy<T>`
- --> $DIR/impl_bounds.rs:11:10
+ --> $DIR/impl_bounds.rs:19:10
|
LL | #[derive(Copy, Clone)]
| ^^^^
note: the requirement `Fooy<T>: Copy` appears on the impl method `d` but not on the corresponding trait method
- --> $DIR/impl_bounds.rs:8:8
+ --> $DIR/impl_bounds.rs:14:8
|
LL | trait Foo {
| --- in this trait
...
-LL | fn d() where Self: Clone;
+LL | fn d()
| ^ this trait method doesn't have the requirement `Fooy<T>: Copy`
= note: this error originates in the derive macro `Copy` (in Nightly builds, run with -Z macro-backtrace for more info)
help: consider restricting type parameter `T`
@@ -86,7 +72,6 @@ help: consider restricting type parameter `T`
LL | impl<T: std::marker::Copy> Foo for Fooy<T> {
| +++++++++++++++++++
-error: aborting due to 5 previous errors
+error: aborting due to 4 previous errors
-Some errors have detailed explanations: E0277, E0478.
-For more information about an error, try `rustc --explain E0277`.
+For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/generic-associated-types/issue-90014.rs b/src/test/ui/generic-associated-types/issue-90014.rs
index f110b069383d3..3835950d75988 100644
--- a/src/test/ui/generic-associated-types/issue-90014.rs
+++ b/src/test/ui/generic-associated-types/issue-90014.rs
@@ -1,4 +1,5 @@
// edition:2018
+// check-pass
#![feature(generic_associated_types)]
#![feature(type_alias_impl_trait)]
@@ -6,13 +7,14 @@
use std::future::Future;
trait MakeFut {
- type Fut<'a> where Self: 'a;
+ type Fut<'a>
+ where
+ Self: 'a;
fn make_fut<'a>(&'a self) -> Self::Fut<'a>;
}
impl MakeFut for &'_ mut () {
type Fut<'a> = impl Future<Output = ()>;
- //~^ ERROR: the type `&mut ()` does not fulfill the required lifetime
fn make_fut<'a>(&'a self) -> Self::Fut<'a> {
async { () }
diff --git a/src/test/ui/generic-associated-types/issue-90014.stderr b/src/test/ui/generic-associated-types/issue-90014.stderr
deleted file mode 100644
index 51fe3360c7eb2..0000000000000
--- a/src/test/ui/generic-associated-types/issue-90014.stderr
+++ /dev/null
@@ -1,18 +0,0 @@
-error[E0477]: the type `&mut ()` does not fulfill the required lifetime
- --> $DIR/issue-90014.rs:14:20
- |
-LL | type Fut<'a> where Self: 'a;
- | ---------------------------- definition of `Fut` from trait
-...
-LL | type Fut<'a> = impl Future<Output = ()>;
- | ^^^^^^^^^^^^^^^^^^^^^^^^- help: try copying this clause from the trait: `where Self: 'a`
- |
-note: type must outlive the lifetime `'a` as defined here
- --> $DIR/issue-90014.rs:14:14
- |
-LL | type Fut<'a> = impl Future<Output = ()>;
- | ^^
-
-error: aborting due to previous error
-
-For more information about this error, try `rustc --explain E0477`.
diff --git a/src/test/ui/generic-associated-types/issue-91883.rs b/src/test/ui/generic-associated-types/issue-91883.rs
index 3d4585a44df80..31d08f16867c1 100644
--- a/src/test/ui/generic-associated-types/issue-91883.rs
+++ b/src/test/ui/generic-associated-types/issue-91883.rs
@@ -1,3 +1,7 @@
+// Regression test.
+//
+// check-pass
+
#![feature(generic_associated_types)]
use std::fmt::Debug;
@@ -29,7 +33,7 @@ pub trait Transaction<'db>: Send + Sync + Debug + Sized {
impl<'tx> Cursor<'tx> for CursorImpl<'tx> {}
impl<'db> Transaction<'db> for TransactionImpl<'db> {
- type Cursor<'tx> = CursorImpl<'tx>; //~ ERROR lifetime bound not satisfied
+ type Cursor<'tx> = CursorImpl<'tx>;
fn cursor<'tx>(&'tx self) -> Result<Self::Cursor<'tx>, ()>
where
diff --git a/src/test/ui/generic-associated-types/issue-91883.stderr b/src/test/ui/generic-associated-types/issue-91883.stderr
deleted file mode 100644
index ed700876e02dd..0000000000000
--- a/src/test/ui/generic-associated-types/issue-91883.stderr
+++ /dev/null
@@ -1,26 +0,0 @@
-error[E0478]: lifetime bound not satisfied
- --> $DIR/issue-91883.rs:32:24
- |
-LL | / type Cursor<'tx>: Cursor<'tx>
-LL | | where
-LL | | 'db: 'tx,
-LL | | Self: 'tx;
- | |__________________- definition of `Cursor` from trait
-...
-LL | type Cursor<'tx> = CursorImpl<'tx>;
- | ^^^^^^^^^^^^^^^- help: try copying these clauses from the trait: `where 'db: 'tx, Self: 'tx`
- |
-note: lifetime parameter instantiated with the lifetime `'db` as defined here
- --> $DIR/issue-91883.rs:31:6
- |
-LL | impl<'db> Transaction<'db> for TransactionImpl<'db> {
- | ^^^
-note: but lifetime parameter must outlive the lifetime `'tx` as defined here
- --> $DIR/issue-91883.rs:32:17
- |
-LL | type Cursor<'tx> = CursorImpl<'tx>;
- | ^^^
-
-error: aborting due to previous error
-
-For more information about this error, try `rustc --explain E0478`.
diff --git a/src/test/ui/generic-associated-types/issue-92033.rs b/src/test/ui/generic-associated-types/issue-92033.rs
index 1d5f7d5c0099e..7770222b603f6 100644
--- a/src/test/ui/generic-associated-types/issue-92033.rs
+++ b/src/test/ui/generic-associated-types/issue-92033.rs
@@ -1,3 +1,5 @@
+// check-pass
+
#![feature(generic_associated_types)]
struct Texture;
@@ -20,7 +22,6 @@ trait Swapchain {
impl<'s> Surface for &'s Texture {
type TextureIter<'a> = std::option::IntoIter<&'a Texture>;
- //~^ ERROR the type
fn get_texture(&self) -> Self::TextureIter<'_> {
let option: Option<&Texture> = Some(self);
diff --git a/src/test/ui/generic-associated-types/issue-92033.stderr b/src/test/ui/generic-associated-types/issue-92033.stderr
deleted file mode 100644
index 5b90199b8091f..0000000000000
--- a/src/test/ui/generic-associated-types/issue-92033.stderr
+++ /dev/null
@@ -1,20 +0,0 @@
-error[E0477]: the type `&'s Texture` does not fulfill the required lifetime
- --> $DIR/issue-92033.rs:22:28
- |
-LL | / type TextureIter<'a>: Iterator<Item = &'a Texture>
-LL | | where
-LL | | Self: 'a;
- | |_________________- definition of `TextureIter` from trait
-...
-LL | type TextureIter<'a> = std::option::IntoIter<&'a Texture>;
- | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^- help: try copying this clause from the trait: `where Self: 'a`
- |
-note: type must outlive the lifetime `'a` as defined here
- --> $DIR/issue-92033.rs:22:22
- |
-LL | type TextureIter<'a> = std::option::IntoIter<&'a Texture>;
- | ^^
-
-error: aborting due to previous error
-
-For more information about this error, try `rustc --explain E0477`.
diff --git a/src/test/ui/generic-associated-types/trait-objects.base.stderr b/src/test/ui/generic-associated-types/trait-objects.base.stderr
index 1df76a21bf9b4..066a535868981 100644
--- a/src/test/ui/generic-associated-types/trait-objects.base.stderr
+++ b/src/test/ui/generic-associated-types/trait-objects.base.stderr
@@ -1,15 +1,15 @@
error[E0038]: the trait `StreamingIterator` cannot be made into an object
- --> $DIR/trait-objects.rs:14:21
+ --> $DIR/trait-objects.rs:17:21
|
LL | fn min_size(x: &mut dyn for<'a> StreamingIterator<Item<'a> = &'a i32>) -> usize {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `StreamingIterator` cannot be made into an object
|
note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
- --> $DIR/trait-objects.rs:8:10
+ --> $DIR/trait-objects.rs:9:10
|
LL | trait StreamingIterator {
| ----------------- this trait cannot be made into an object...
-LL | type Item<'a> where Self: 'a;
+LL | type Item<'a>
| ^^^^ ...because it contains the generic associated type `Item`
= help: consider moving `Item` to another trait
diff --git a/src/test/ui/generic-associated-types/trait-objects.extended.stderr b/src/test/ui/generic-associated-types/trait-objects.extended.stderr
deleted file mode 100644
index 52d48d57859f4..0000000000000
--- a/src/test/ui/generic-associated-types/trait-objects.extended.stderr
+++ /dev/null
@@ -1,17 +0,0 @@
-error[E0521]: borrowed data escapes outside of function
- --> $DIR/trait-objects.rs:16:5
- |
-LL | fn min_size(x: &mut dyn for<'a> StreamingIterator<Item<'a> = &'a i32>) -> usize {
- | - - let's call the lifetime of this reference `'1`
- | |
- | `x` is a reference that is only valid in the function body
-LL |
-LL | x.size_hint().0
- | ^^^^^^^^^^^^^
- | |
- | `x` escapes the function body here
- | argument requires that `'1` must outlive `'static`
-
-error: aborting due to previous error
-
-For more information about this error, try `rustc --explain E0521`.
diff --git a/src/test/ui/generic-associated-types/trait-objects.rs b/src/test/ui/generic-associated-types/trait-objects.rs
index c1da1e0a326d4..1772e0992bd10 100644
--- a/src/test/ui/generic-associated-types/trait-objects.rs
+++ b/src/test/ui/generic-associated-types/trait-objects.rs
@@ -1,20 +1,22 @@
// revisions: base extended
+//[extended] check-pass
#![feature(generic_associated_types)]
#![cfg_attr(extended, feature(generic_associated_types_extended))]
#![cfg_attr(extended, allow(incomplete_features))]
trait StreamingIterator {
- type Item<'a> where Self: 'a;
+ type Item<'a>
+ where
+ Self: 'a;
fn size_hint(&self) -> (usize, Option<usize>);
// Uncommenting makes `StreamingIterator` not object safe
-// fn next(&mut self) -> Self::Item<'_>;
+ // fn next(&mut self) -> Self::Item<'_>;
}
fn min_size(x: &mut dyn for<'a> StreamingIterator<Item<'a> = &'a i32>) -> usize {
//[base]~^ the trait `StreamingIterator` cannot be made into an object
x.size_hint().0
- //[extended]~^ borrowed data escapes
}
fn main() {}
diff --git a/src/test/ui/generic-associated-types/unsatified-item-lifetime-bound.rs b/src/test/ui/generic-associated-types/unsatified-item-lifetime-bound.rs
index 8b40dac574a43..bd84f7ccaf6ca 100644
--- a/src/test/ui/generic-associated-types/unsatified-item-lifetime-bound.rs
+++ b/src/test/ui/generic-associated-types/unsatified-item-lifetime-bound.rs
@@ -11,7 +11,6 @@ impl X for () {
struct B<'a, T: for<'r> X<Y<'r> = &'r ()>> {
f: <T as X>::Y<'a>,
- //~^ ERROR lifetime bound not satisfied
}
struct C<'a, T: X> {
diff --git a/src/test/ui/generic-associated-types/unsatified-item-lifetime-bound.stderr b/src/test/ui/generic-associated-types/unsatified-item-lifetime-bound.stderr
index ae52010cc50a2..9e5fc221b9846 100644
--- a/src/test/ui/generic-associated-types/unsatified-item-lifetime-bound.stderr
+++ b/src/test/ui/generic-associated-types/unsatified-item-lifetime-bound.stderr
@@ -7,44 +7,31 @@ LL | type Y<'a: 'static>;
= help: you can use the `'static` lifetime directly, in place of `'a`
error[E0478]: lifetime bound not satisfied
- --> $DIR/unsatified-item-lifetime-bound.rs:13:8
+ --> $DIR/unsatified-item-lifetime-bound.rs:17:8
|
LL | f: <T as X>::Y<'a>,
| ^^^^^^^^^^^^^^^
|
note: lifetime parameter instantiated with the lifetime `'a` as defined here
- --> $DIR/unsatified-item-lifetime-bound.rs:12:10
- |
-LL | struct B<'a, T: for<'r> X<Y<'r> = &'r ()>> {
- | ^^
- = note: but lifetime parameter must outlive the static lifetime
-
-error[E0478]: lifetime bound not satisfied
- --> $DIR/unsatified-item-lifetime-bound.rs:18:8
- |
-LL | f: <T as X>::Y<'a>,
- | ^^^^^^^^^^^^^^^
- |
-note: lifetime parameter instantiated with the lifetime `'a` as defined here
- --> $DIR/unsatified-item-lifetime-bound.rs:17:10
+ --> $DIR/unsatified-item-lifetime-bound.rs:16:10
|
LL | struct C<'a, T: X> {
| ^^
= note: but lifetime parameter must outlive the static lifetime
error[E0478]: lifetime bound not satisfied
- --> $DIR/unsatified-item-lifetime-bound.rs:23:8
+ --> $DIR/unsatified-item-lifetime-bound.rs:22:8
|
LL | f: <() as X>::Y<'a>,
| ^^^^^^^^^^^^^^^^
|
note: lifetime parameter instantiated with the lifetime `'a` as defined here
- --> $DIR/unsatified-item-lifetime-bound.rs:22:10
+ --> $DIR/unsatified-item-lifetime-bound.rs:21:10
|
LL | struct D<'a> {
| ^^
= note: but lifetime parameter must outlive the static lifetime
-error: aborting due to 3 previous errors; 1 warning emitted
+error: aborting due to 2 previous errors; 1 warning emitted
For more information about this error, try `rustc --explain E0478`.
From 20ebe8c48883d0c1f455e20d38da51ccc03f34e6 Mon Sep 17 00:00:00 2001
From: Niko Matsakis <niko@alum.mit.edu>
Date: Thu, 30 Jun 2022 16:49:49 -0400
Subject: [PATCH 2/2] add soundness, backwards-incompat test cases
`call-forall` shows the expected behavior: the where-clause proves
too much, so we can't prove it.
`backwards-incompat` shows the problem with that: we can construct
types that we ought not to be able to construct.
---
.../call-back-compat.rs | 33 ++++++++++++++
.../generic-associated-types/call-forall.rs | 43 +++++++++++++++++++
.../call-forall.stderr | 11 +++++
3 files changed, 87 insertions(+)
create mode 100644 src/test/ui/generic-associated-types/call-back-compat.rs
create mode 100644 src/test/ui/generic-associated-types/call-forall.rs
create mode 100644 src/test/ui/generic-associated-types/call-forall.stderr
diff --git a/src/test/ui/generic-associated-types/call-back-compat.rs b/src/test/ui/generic-associated-types/call-back-compat.rs
new file mode 100644
index 0000000000000..6705780396c99
--- /dev/null
+++ b/src/test/ui/generic-associated-types/call-back-compat.rs
@@ -0,0 +1,33 @@
+// known-bug
+// check-pass
+
+#![feature(generic_associated_types)]
+
+trait LendingIterator {
+ type Item<'a>
+ where
+ Self: 'a;
+}
+
+impl<'slice> LendingIterator for &'slice [u32] {
+ type Item<'a> = &'a [u32]
+ where
+ Self: 'a;
+}
+
+impl<'slice> LendingIterator for [u32] {
+ type Item<'a> = &'a [u32]
+ where
+ Self: 'a;
+}
+
+fn broke<T: ?Sized>() -> Option<&'static [u32]>
+where
+ for<'a> T: LendingIterator<Item<'a> = &'a [u32]>,
+{
+ None::<<T as LendingIterator>::Item<'static>>
+ // FIXME: Should not compile, but does, because we are trusting the where-clauses
+ // and don't have implied bounds.
+}
+
+fn main() {}
diff --git a/src/test/ui/generic-associated-types/call-forall.rs b/src/test/ui/generic-associated-types/call-forall.rs
new file mode 100644
index 0000000000000..e33abac1c8ad5
--- /dev/null
+++ b/src/test/ui/generic-associated-types/call-forall.rs
@@ -0,0 +1,43 @@
+#![feature(generic_associated_types)]
+
+trait LendingIterator {
+ type Item<'a>
+ where
+ Self: 'a;
+}
+
+impl<'slice> LendingIterator for &'slice [u32] {
+ type Item<'a> = &'a [u32]
+ where
+ Self: 'a;
+}
+
+impl<'slice> LendingIterator for [u32] {
+ type Item<'a> = &'a [u32]
+ where
+ Self: 'a;
+}
+
+fn call_me<T: ?Sized>()
+where
+ for<'a> T: LendingIterator<Item<'a> = &'a [u32]>,
+{
+ if false {
+ call_me::<T>();
+ }
+}
+
+fn ok_i_will1<'test>() {
+ // Gets an error because we cannot prove that, for all 'a, `&'test [u32]: 'a`.
+ //
+ // This is a bug -- what should happen is that there is an implied bound
+ // so that `for<'a>` really means "for all `'a` that make sense", in which case
+ // this ought to be provable.
+ call_me::<&'test [u32]>; //~ ERROR lifetime may not live long enough
+}
+
+fn ok_i_will2() {
+ // OK because, for all 'a, `[u32]: 'a`.
+ call_me::<[u32]>;
+}
+fn main() {}
diff --git a/src/test/ui/generic-associated-types/call-forall.stderr b/src/test/ui/generic-associated-types/call-forall.stderr
new file mode 100644
index 0000000000000..b4ace1bdd503b
--- /dev/null
+++ b/src/test/ui/generic-associated-types/call-forall.stderr
@@ -0,0 +1,11 @@
+error: lifetime may not live long enough
+ --> $DIR/call-forall.rs:36:5
+ |
+LL | fn ok_i_will1<'test>() {
+ | ----- lifetime `'test` defined here
+...
+LL | call_me::<&'test [u32]>;
+ | ^^^^^^^^^^^^^^^^^^^^^^^ requires that `'test` must outlive `'static`
+
+error: aborting due to previous error
+