From 5035049c798bf3f01409291577cbf87c574ff91d Mon Sep 17 00:00:00 2001
From: Michael Goulet <michael@errs.io>
Date: Wed, 3 Aug 2022 03:11:44 +0000
Subject: [PATCH 1/2] Emit warning when bound is trivially false
---
compiler/rustc_typeck/src/check/wfcheck.rs | 85 ++++++++++++++-----
.../bound-lifetime-in-binding-only.ok.stderr | 24 +++++-
.../bound-lifetime-in-binding-only.rs | 2 +
src/test/ui/associated-types/issue-59324.rs | 2 +-
src/test/ui/associated-types/issue-69398.rs | 1 +
.../ui/associated-types/issue-69398.stderr | 12 +++
.../ui/consts/issue-67696-const-prop-ice.rs | 3 +
.../consts/issue-67696-const-prop-ice.stderr | 20 +++++
.../feature-gate-trivial_bounds.rs | 1 +
.../feature-gate-trivial_bounds.stderr | 12 ++-
.../normalize-under-binder/issue-89118.rs | 2 +
.../normalize-under-binder/issue-89118.stderr | 31 +++++--
src/test/ui/issues/issue-36839.rs | 1 +
src/test/ui/issues/issue-36839.stderr | 12 +++
src/test/ui/issues/issue-39970.rs | 1 +
src/test/ui/issues/issue-39970.stderr | 15 +++-
src/test/ui/issues/issue-42796.rs | 1 +
src/test/ui/issues/issue-42796.stderr | 14 ++-
src/test/ui/issues/issue-50714-1.rs | 3 +-
src/test/ui/issues/issue-50714.rs | 7 +-
src/test/ui/issues/issue-50714.stderr | 8 +-
src/test/ui/mir/issue-91745.rs | 1 +
src/test/ui/mir/issue-91745.stderr | 12 +++
src/test/ui/trait-bounds/issue-94680.rs | 1 +
src/test/ui/trait-bounds/issue-94680.stderr | 15 ++++
src/test/ui/trait-bounds/issue-94999.rs | 1 +
src/test/ui/trait-bounds/issue-94999.stderr | 15 ++++
27 files changed, 261 insertions(+), 41 deletions(-)
create mode 100644 src/test/ui/associated-types/issue-69398.stderr
create mode 100644 src/test/ui/consts/issue-67696-const-prop-ice.stderr
create mode 100644 src/test/ui/issues/issue-36839.stderr
create mode 100644 src/test/ui/mir/issue-91745.stderr
create mode 100644 src/test/ui/trait-bounds/issue-94680.stderr
create mode 100644 src/test/ui/trait-bounds/issue-94999.stderr
diff --git a/compiler/rustc_typeck/src/check/wfcheck.rs b/compiler/rustc_typeck/src/check/wfcheck.rs
index 95f327112253a..d6903a890c301 100644
--- a/compiler/rustc_typeck/src/check/wfcheck.rs
+++ b/compiler/rustc_typeck/src/check/wfcheck.rs
@@ -10,7 +10,7 @@ use rustc_hir::ItemKind;
use rustc_infer::infer::outlives::env::{OutlivesEnvironment, RegionBoundPairs};
use rustc_infer::infer::outlives::obligations::TypeOutlives;
use rustc_infer::infer::{self, InferCtxt, TyCtxtInferExt};
-use rustc_infer::traits::Normalized;
+use rustc_infer::traits::{Normalized, TraitEngine, TraitEngineExt as _};
use rustc_middle::ty::query::Providers;
use rustc_middle::ty::subst::{GenericArgKind, InternalSubsts, Subst};
use rustc_middle::ty::trait_def::TraitSpecializationKind;
@@ -27,7 +27,8 @@ use rustc_trait_selection::traits::query::evaluate_obligation::InferCtxtExt as _
use rustc_trait_selection::traits::query::normalize::AtExt;
use rustc_trait_selection::traits::query::NoSolution;
use rustc_trait_selection::traits::{
- self, ObligationCause, ObligationCauseCode, ObligationCtxt, WellFormedLoc,
+ self, FulfillmentContext, ObligationCause, ObligationCauseCode, ObligationCtxt,
+ SelectionContext, WellFormedLoc,
};
use std::cell::LazyCell;
@@ -1817,7 +1818,7 @@ impl<'tcx> WfCheckingCtxt<'_, 'tcx> {
/// Feature gates RFC 2056 -- trivial bounds, checking for global bounds that
/// aren't true.
fn check_false_global_bounds(&mut self) {
- let tcx = self.ocx.infcx.tcx;
+ let tcx = self.infcx.tcx;
let mut span = self.span;
let empty_env = ty::ParamEnv::empty();
@@ -1833,33 +1834,71 @@ impl<'tcx> WfCheckingCtxt<'_, 'tcx> {
if let ty::PredicateKind::WellFormed(..) = obligation.predicate.kind().skip_binder() {
continue;
}
- let pred = obligation.predicate;
- // Match the existing behavior.
- if pred.is_global() && !pred.has_late_bound_regions() {
- let pred = self.normalize(span, None, pred);
- let hir_node = tcx.hir().find(self.body_id);
- // only use the span of the predicate clause (#90869)
+ let pred = obligation.predicate;
- if let Some(hir::Generics { predicates, .. }) =
- hir_node.and_then(|node| node.generics())
- {
- let obligation_span = obligation.cause.span();
-
- span = predicates
- .iter()
- // There seems to be no better way to find out which predicate we are in
- .find(|pred| pred.span().contains(obligation_span))
- .map(|pred| pred.span())
- .unwrap_or(obligation_span);
- }
+ // only use the span of the predicate clause (#90869)
+ let hir_node = tcx.hir().find(self.body_id);
+ if let Some(hir::Generics { predicates, .. }) =
+ hir_node.and_then(|node| node.generics())
+ {
+ let obligation_span = obligation.cause.span();
+ span = predicates
+ .iter()
+ // There seems to be no better way to find out which predicate we are in
+ .find(|pred| pred.span().contains(obligation_span))
+ .map(|pred| pred.span())
+ .unwrap_or(obligation_span);
+ }
+ // Match the existing behavior.
+ if pred.is_global() && !pred.has_late_bound_regions() {
+ let normalized_pred = self.normalize(span, None, pred);
let obligation = traits::Obligation::new(
traits::ObligationCause::new(span, self.body_id, traits::TrivialBound),
empty_env,
- pred,
+ normalized_pred,
);
- self.ocx.register_obligation(obligation);
+ self.register_obligation(obligation);
+ } else {
+ self.infcx.probe(|_| {
+ // Manually normalize because `wfcx.normalize` may report errors
+ let Normalized { value: normalized_pred, obligations } = traits::normalize(
+ &mut SelectionContext::new(self.infcx),
+ self.param_env,
+ ObligationCause::dummy(),
+ pred,
+ );
+ if normalized_pred.is_global() {
+ let mut fulfill_cx = FulfillmentContext::new_in_snapshot();
+ fulfill_cx.register_predicate_obligations(self.infcx, obligations);
+ fulfill_cx.register_predicate_obligation(
+ self.infcx,
+ traits::Obligation::new(
+ traits::ObligationCause::new(
+ span,
+ self.body_id,
+ traits::TrivialBound,
+ ),
+ empty_env,
+ normalized_pred,
+ ),
+ );
+ if !fulfill_cx.select_all_or_error(self.infcx).is_empty() {
+ self.tcx()
+ .sess
+ .struct_span_warn(
+ span,
+ format!("the where-clause bound `{pred}` is trivially false"),
+ )
+ .span_label(
+ self.span,
+ "this cannot be referenced without causing an error",
+ )
+ .emit();
+ }
+ }
+ });
}
}
}
diff --git a/src/test/ui/associated-types/bound-lifetime-in-binding-only.ok.stderr b/src/test/ui/associated-types/bound-lifetime-in-binding-only.ok.stderr
index b709fae5a8e56..3e4d9cfed9234 100644
--- a/src/test/ui/associated-types/bound-lifetime-in-binding-only.ok.stderr
+++ b/src/test/ui/associated-types/bound-lifetime-in-binding-only.ok.stderr
@@ -1,8 +1,28 @@
+warning: the where-clause bound `for<'a> <Parameterized<'a> as Foo>::Item == &'a i32` is trivially false
+ --> $DIR/bound-lifetime-in-binding-only.rs:67:19
+ |
+LL | fn ok3<T>() where for<'a> Parameterized<'a>: Foo<Item=&'a i32> {
+ | _- ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL | |
+LL | |
+LL | | }
+ | |_- this cannot be referenced without causing an error
+
+warning: the where-clause bound `for<'a> Parameterized<'a>: Foo` is trivially false
+ --> $DIR/bound-lifetime-in-binding-only.rs:67:19
+ |
+LL | fn ok3<T>() where for<'a> Parameterized<'a>: Foo<Item=&'a i32> {
+ | _- ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL | |
+LL | |
+LL | | }
+ | |_- this cannot be referenced without causing an error
+
error: fatal error triggered by #[rustc_error]
- --> $DIR/bound-lifetime-in-binding-only.rs:71:1
+ --> $DIR/bound-lifetime-in-binding-only.rs:73:1
|
LL | fn main() { }
| ^^^^^^^^^
-error: aborting due to previous error
+error: aborting due to previous error; 2 warnings emitted
diff --git a/src/test/ui/associated-types/bound-lifetime-in-binding-only.rs b/src/test/ui/associated-types/bound-lifetime-in-binding-only.rs
index e714457ef7b38..e3e2daf29e073 100644
--- a/src/test/ui/associated-types/bound-lifetime-in-binding-only.rs
+++ b/src/test/ui/associated-types/bound-lifetime-in-binding-only.rs
@@ -65,6 +65,8 @@ fn ok2<T: for<'a,'b> Fn<(&'b Parameterized<'a>,), Output=&'a i32>>() {
#[cfg(ok)]
fn ok3<T>() where for<'a> Parameterized<'a>: Foo<Item=&'a i32> {
+ //[ok]~^ WARNING the where-clause bound
+ //[ok]~| WARNING the where-clause bound
}
#[rustc_error]
diff --git a/src/test/ui/associated-types/issue-59324.rs b/src/test/ui/associated-types/issue-59324.rs
index 162f9e00edd81..87345e54d4536 100644
--- a/src/test/ui/associated-types/issue-59324.rs
+++ b/src/test/ui/associated-types/issue-59324.rs
@@ -12,7 +12,7 @@ pub trait ThriftService<Bug: NotFoo>:
//~^ ERROR the trait bound `Bug: Foo` is not satisfied
//~| ERROR the trait bound `Bug: Foo` is not satisfied
Service<AssocType = <Bug as Foo>::OnlyFoo>
-{
+ {
fn get_service(
//~^ ERROR the trait bound `Bug: Foo` is not satisfied
&self,
diff --git a/src/test/ui/associated-types/issue-69398.rs b/src/test/ui/associated-types/issue-69398.rs
index ca3d66b1c8eb7..01654461afea2 100644
--- a/src/test/ui/associated-types/issue-69398.rs
+++ b/src/test/ui/associated-types/issue-69398.rs
@@ -12,6 +12,7 @@ pub trait Broken {
impl<T> Broken for T {
type Assoc = ();
fn broken(&self) where Self::Assoc: Foo {
+ //~^ WARNING the where-clause bound
let _x: <Self::Assoc as Foo>::Bar;
}
}
diff --git a/src/test/ui/associated-types/issue-69398.stderr b/src/test/ui/associated-types/issue-69398.stderr
new file mode 100644
index 0000000000000..048b1f55e080e
--- /dev/null
+++ b/src/test/ui/associated-types/issue-69398.stderr
@@ -0,0 +1,12 @@
+warning: the where-clause bound `<T as Broken>::Assoc: Foo` is trivially false
+ --> $DIR/issue-69398.rs:14:28
+ |
+LL | fn broken(&self) where Self::Assoc: Foo {
+ | _____- ^^^^^^^^^^^^^^^^
+LL | |
+LL | | let _x: <Self::Assoc as Foo>::Bar;
+LL | | }
+ | |_____- this cannot be referenced without causing an error
+
+warning: 1 warning emitted
+
diff --git a/src/test/ui/consts/issue-67696-const-prop-ice.rs b/src/test/ui/consts/issue-67696-const-prop-ice.rs
index ad52608b3f46d..c04a9fd7a54ae 100644
--- a/src/test/ui/consts/issue-67696-const-prop-ice.rs
+++ b/src/test/ui/consts/issue-67696-const-prop-ice.rs
@@ -11,6 +11,9 @@ trait A {
impl A for [fn(&())] {
fn foo(&self) -> Self where Self: Copy { *(&[] as &[_]) }
+ //~^ WARNING the where-clause bound
+ //~| WARNING the where-clause bound
+ //~| WARNING the where-clause bound
}
impl A for i32 {
diff --git a/src/test/ui/consts/issue-67696-const-prop-ice.stderr b/src/test/ui/consts/issue-67696-const-prop-ice.stderr
new file mode 100644
index 0000000000000..85e2d20389df0
--- /dev/null
+++ b/src/test/ui/consts/issue-67696-const-prop-ice.stderr
@@ -0,0 +1,20 @@
+warning: the where-clause bound `[for<'r> fn(&'r ())]: Copy` is trivially false
+ --> $DIR/issue-67696-const-prop-ice.rs:13:33
+ |
+LL | fn foo(&self) -> Self where Self: Copy { *(&[] as &[_]) }
+ | ----------------------------^^^^^^^^^^------------------- this cannot be referenced without causing an error
+
+warning: the where-clause bound `[for<'r> fn(&'r ())]: Clone` is trivially false
+ --> $DIR/issue-67696-const-prop-ice.rs:13:33
+ |
+LL | fn foo(&self) -> Self where Self: Copy { *(&[] as &[_]) }
+ | ----------------------------^^^^^^^^^^------------------- this cannot be referenced without causing an error
+
+warning: the where-clause bound `[for<'r> fn(&'r ())]: Sized` is trivially false
+ --> $DIR/issue-67696-const-prop-ice.rs:13:33
+ |
+LL | fn foo(&self) -> Self where Self: Copy { *(&[] as &[_]) }
+ | ----------------------------^^^^^^^^^^------------------- this cannot be referenced without causing an error
+
+warning: 3 warnings emitted
+
diff --git a/src/test/ui/feature-gates/feature-gate-trivial_bounds.rs b/src/test/ui/feature-gates/feature-gate-trivial_bounds.rs
index 3dbaf5dea250e..2045c87a30249 100644
--- a/src/test/ui/feature-gates/feature-gate-trivial_bounds.rs
+++ b/src/test/ui/feature-gates/feature-gate-trivial_bounds.rs
@@ -63,6 +63,7 @@ fn return_str() -> str where str: Sized { //~ ERROR
// This is currently accepted because the function pointer isn't
// considered global.
fn global_hr(x: fn(&())) where fn(&()): Foo { // OK
+ //~^ WARNING the where-clause bound
x.test();
}
diff --git a/src/test/ui/feature-gates/feature-gate-trivial_bounds.stderr b/src/test/ui/feature-gates/feature-gate-trivial_bounds.stderr
index 1b87ebd9f20ce..56db31e7ab64b 100644
--- a/src/test/ui/feature-gates/feature-gate-trivial_bounds.stderr
+++ b/src/test/ui/feature-gates/feature-gate-trivial_bounds.stderr
@@ -113,6 +113,16 @@ LL | fn return_str() -> str where str: Sized {
= help: see issue #48214
= help: add `#![feature(trivial_bounds)]` to the crate attributes to enable
-error: aborting due to 11 previous errors
+warning: the where-clause bound `for<'r> fn(&'r ()): Foo` is trivially false
+ --> $DIR/feature-gate-trivial_bounds.rs:65:32
+ |
+LL | fn global_hr(x: fn(&())) where fn(&()): Foo { // OK
+ | _- ^^^^^^^^^^^^
+LL | |
+LL | | x.test();
+LL | | }
+ | |_- this cannot be referenced without causing an error
+
+error: aborting due to 11 previous errors; 1 warning emitted
For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/higher-rank-trait-bounds/normalize-under-binder/issue-89118.rs b/src/test/ui/higher-rank-trait-bounds/normalize-under-binder/issue-89118.rs
index fffb54f86ca03..6b3a02215d95d 100644
--- a/src/test/ui/higher-rank-trait-bounds/normalize-under-binder/issue-89118.rs
+++ b/src/test/ui/higher-rank-trait-bounds/normalize-under-binder/issue-89118.rs
@@ -7,6 +7,7 @@ impl<B: BufferMut, C> BufferUdpStateContext<B> for C {}
trait StackContext
where
Ctx<()>: for<'a> BufferUdpStateContext<&'a ()>,
+ //~^ WARNING the where-clause bound
{
type Dispatcher;
}
@@ -26,6 +27,7 @@ where
struct EthernetWorker<C>(C)
where
Ctx<()>: for<'a> BufferUdpStateContext<&'a ()>;
+ //~^ WARNING the where-clause bound
impl<C> EthernetWorker<C> {}
//~^ ERROR: is not satisfied [E0277]
diff --git a/src/test/ui/higher-rank-trait-bounds/normalize-under-binder/issue-89118.stderr b/src/test/ui/higher-rank-trait-bounds/normalize-under-binder/issue-89118.stderr
index a6858154dfb29..b1fa127c26a1d 100644
--- a/src/test/ui/higher-rank-trait-bounds/normalize-under-binder/issue-89118.stderr
+++ b/src/test/ui/higher-rank-trait-bounds/normalize-under-binder/issue-89118.stderr
@@ -1,5 +1,18 @@
+warning: the where-clause bound `for<'a> Ctx<()>: BufferUdpStateContext<&'a ()>` is trivially false
+ --> $DIR/issue-89118.rs:9:5
+ |
+LL | / trait StackContext
+LL | | where
+LL | | Ctx<()>: for<'a> BufferUdpStateContext<&'a ()>,
+ | | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL | |
+LL | | {
+LL | | type Dispatcher;
+LL | | }
+ | |_- this cannot be referenced without causing an error
+
error[E0277]: the trait bound `for<'a> &'a (): BufferMut` is not satisfied
- --> $DIR/issue-89118.rs:19:8
+ --> $DIR/issue-89118.rs:20:8
|
LL | C: StackContext,
| ^^^^^^^^^^^^ the trait `for<'a> BufferMut` is not implemented for `&'a ()`
@@ -18,8 +31,16 @@ LL | where
LL | Ctx<()>: for<'a> BufferUdpStateContext<&'a ()>,
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `StackContext`
+warning: the where-clause bound `for<'a> Ctx<()>: BufferUdpStateContext<&'a ()>` is trivially false
+ --> $DIR/issue-89118.rs:29:5
+ |
+LL | / struct EthernetWorker<C>(C)
+LL | | where
+LL | | Ctx<()>: for<'a> BufferUdpStateContext<&'a ()>;
+ | |_____^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^- this cannot be referenced without causing an error
+
error[E0277]: the trait bound `for<'a> &'a (): BufferMut` is not satisfied
- --> $DIR/issue-89118.rs:29:9
+ --> $DIR/issue-89118.rs:31:9
|
LL | impl<C> EthernetWorker<C> {}
| ^^^^^^^^^^^^^^^^^ the trait `for<'a> BufferMut` is not implemented for `&'a ()`
@@ -30,7 +51,7 @@ note: required because of the requirements on the impl of `for<'a> BufferUdpStat
LL | impl<B: BufferMut, C> BufferUdpStateContext<B> for C {}
| ^^^^^^^^^^^^^^^^^^^^^^^^ ^
note: required by a bound in `EthernetWorker`
- --> $DIR/issue-89118.rs:28:14
+ --> $DIR/issue-89118.rs:29:14
|
LL | struct EthernetWorker<C>(C)
| -------------- required by a bound in this
@@ -39,7 +60,7 @@ LL | Ctx<()>: for<'a> BufferUdpStateContext<&'a ()>;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `EthernetWorker`
error[E0277]: the trait bound `for<'a> &'a (): BufferMut` is not satisfied
- --> $DIR/issue-89118.rs:22:20
+ --> $DIR/issue-89118.rs:23:20
|
LL | type Handler = Ctx<C::Dispatcher>;
| ^^^^^^^^^^^^^^^^^^ the trait `for<'a> BufferMut` is not implemented for `&'a ()`
@@ -58,6 +79,6 @@ LL | where
LL | Ctx<()>: for<'a> BufferUdpStateContext<&'a ()>,
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `StackContext`
-error: aborting due to 3 previous errors
+error: aborting due to 3 previous errors; 2 warnings emitted
For more information about this error, try `rustc --explain E0277`.
diff --git a/src/test/ui/issues/issue-36839.rs b/src/test/ui/issues/issue-36839.rs
index ca3d66b1c8eb7..01654461afea2 100644
--- a/src/test/ui/issues/issue-36839.rs
+++ b/src/test/ui/issues/issue-36839.rs
@@ -12,6 +12,7 @@ pub trait Broken {
impl<T> Broken for T {
type Assoc = ();
fn broken(&self) where Self::Assoc: Foo {
+ //~^ WARNING the where-clause bound
let _x: <Self::Assoc as Foo>::Bar;
}
}
diff --git a/src/test/ui/issues/issue-36839.stderr b/src/test/ui/issues/issue-36839.stderr
new file mode 100644
index 0000000000000..eefa57e8dcc99
--- /dev/null
+++ b/src/test/ui/issues/issue-36839.stderr
@@ -0,0 +1,12 @@
+warning: the where-clause bound `<T as Broken>::Assoc: Foo` is trivially false
+ --> $DIR/issue-36839.rs:14:28
+ |
+LL | fn broken(&self) where Self::Assoc: Foo {
+ | _____- ^^^^^^^^^^^^^^^^
+LL | |
+LL | | let _x: <Self::Assoc as Foo>::Bar;
+LL | | }
+ | |_____- this cannot be referenced without causing an error
+
+warning: 1 warning emitted
+
diff --git a/src/test/ui/issues/issue-39970.rs b/src/test/ui/issues/issue-39970.rs
index f51e3b522e1c5..b3205eeac78c9 100644
--- a/src/test/ui/issues/issue-39970.rs
+++ b/src/test/ui/issues/issue-39970.rs
@@ -13,6 +13,7 @@ impl<'a> Array<'a> for () {
impl Visit for () where
//(): for<'a> Array<'a, Element=&'a ()>, // No ICE
(): for<'a> Array<'a, Element=()>, // ICE
+ //~^ WARNING the where-clause bound
{}
fn main() {
diff --git a/src/test/ui/issues/issue-39970.stderr b/src/test/ui/issues/issue-39970.stderr
index 1f64a90bc1cf9..506300714f318 100644
--- a/src/test/ui/issues/issue-39970.stderr
+++ b/src/test/ui/issues/issue-39970.stderr
@@ -1,5 +1,16 @@
+warning: the where-clause bound `for<'a> <() as Array<'a>>::Element == ()` is trivially false
+ --> $DIR/issue-39970.rs:15:5
+ |
+LL | / impl Visit for () where
+LL | | //(): for<'a> Array<'a, Element=&'a ()>, // No ICE
+LL | | (): for<'a> Array<'a, Element=()>, // ICE
+ | | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL | |
+LL | | {}
+ | |__- this cannot be referenced without causing an error
+
error[E0271]: type mismatch resolving `for<'a> <() as Array<'a>>::Element == ()`
- --> $DIR/issue-39970.rs:19:5
+ --> $DIR/issue-39970.rs:20:5
|
LL | <() as Visit>::visit();
| ^^^^^^^^^^^^^^^^^^^^ type mismatch resolving `for<'a> <() as Array<'a>>::Element == ()`
@@ -15,6 +26,6 @@ note: required because of the requirements on the impl of `Visit` for `()`
LL | impl Visit for () where
| ^^^^^ ^^
-error: aborting due to previous error
+error: aborting due to previous error; 1 warning emitted
For more information about this error, try `rustc --explain E0271`.
diff --git a/src/test/ui/issues/issue-42796.rs b/src/test/ui/issues/issue-42796.rs
index 5e83a1cd67785..d9b723876e5ef 100644
--- a/src/test/ui/issues/issue-42796.rs
+++ b/src/test/ui/issues/issue-42796.rs
@@ -7,6 +7,7 @@ impl<T, Smoke> Mirror<Smoke> for T {
}
pub fn poison<S>(victim: String) where <String as Mirror<S>>::Image: Copy {
+ //~^ WARNING the where-clause bound
loop { drop(victim); }
}
diff --git a/src/test/ui/issues/issue-42796.stderr b/src/test/ui/issues/issue-42796.stderr
index f3e0e7b20a178..3f641929ef3cd 100644
--- a/src/test/ui/issues/issue-42796.stderr
+++ b/src/test/ui/issues/issue-42796.stderr
@@ -1,5 +1,15 @@
+warning: the where-clause bound `<String as Mirror<S>>::Image: Copy` is trivially false
+ --> $DIR/issue-42796.rs:9:40
+ |
+LL | pub fn poison<S>(victim: String) where <String as Mirror<S>>::Image: Copy {
+ | _- ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL | |
+LL | | loop { drop(victim); }
+LL | | }
+ | |_- this cannot be referenced without causing an error
+
error[E0382]: borrow of moved value: `s`
- --> $DIR/issue-42796.rs:18:20
+ --> $DIR/issue-42796.rs:19:20
|
LL | let s = "Hello!".to_owned();
| - move occurs because `s` has type `String`, which does not implement the `Copy` trait
@@ -11,6 +21,6 @@ LL | println!("{}", s);
|
= note: this error originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info)
-error: aborting due to previous error
+error: aborting due to previous error; 1 warning emitted
For more information about this error, try `rustc --explain E0382`.
diff --git a/src/test/ui/issues/issue-50714-1.rs b/src/test/ui/issues/issue-50714-1.rs
index a25940ce1cbef..0b1c9f46f248b 100644
--- a/src/test/ui/issues/issue-50714-1.rs
+++ b/src/test/ui/issues/issue-50714-1.rs
@@ -6,6 +6,7 @@
extern crate std;
#[start]
-fn start(_: isize, _: *const *const u8) -> isize where fn(&()): Eq { //~ ERROR [E0647]
+fn start(_: isize, _: *const *const u8) -> isize where fn(&()): Eq {
+ //~^ ERROR start function is not allowed to have a `where` clause
0
}
diff --git a/src/test/ui/issues/issue-50714.rs b/src/test/ui/issues/issue-50714.rs
index c571a470cee1c..32da3748fed9c 100644
--- a/src/test/ui/issues/issue-50714.rs
+++ b/src/test/ui/issues/issue-50714.rs
@@ -1,3 +1,8 @@
// Regression test for issue 50714, make sure that this isn't a linker error.
-fn main() where fn(&()): Eq {} //~ ERROR [E0646]
+fn main()
+where
+//~^ ERROR `main` function is not allowed to have a `where` clause
+ fn(&()): Eq,
+{
+}
diff --git a/src/test/ui/issues/issue-50714.stderr b/src/test/ui/issues/issue-50714.stderr
index a11aceb6211c5..d02cb51523a8f 100644
--- a/src/test/ui/issues/issue-50714.stderr
+++ b/src/test/ui/issues/issue-50714.stderr
@@ -1,8 +1,10 @@
error[E0646]: `main` function is not allowed to have a `where` clause
- --> $DIR/issue-50714.rs:3:11
+ --> $DIR/issue-50714.rs:4:1
|
-LL | fn main() where fn(&()): Eq {}
- | ^^^^^^^^^^^^^^^^^ `main` cannot have a `where` clause
+LL | / where
+LL | |
+LL | | fn(&()): Eq,
+ | |________________^ `main` cannot have a `where` clause
error: aborting due to previous error
diff --git a/src/test/ui/mir/issue-91745.rs b/src/test/ui/mir/issue-91745.rs
index ca3d66b1c8eb7..01654461afea2 100644
--- a/src/test/ui/mir/issue-91745.rs
+++ b/src/test/ui/mir/issue-91745.rs
@@ -12,6 +12,7 @@ pub trait Broken {
impl<T> Broken for T {
type Assoc = ();
fn broken(&self) where Self::Assoc: Foo {
+ //~^ WARNING the where-clause bound
let _x: <Self::Assoc as Foo>::Bar;
}
}
diff --git a/src/test/ui/mir/issue-91745.stderr b/src/test/ui/mir/issue-91745.stderr
new file mode 100644
index 0000000000000..bcb191bac9a1f
--- /dev/null
+++ b/src/test/ui/mir/issue-91745.stderr
@@ -0,0 +1,12 @@
+warning: the where-clause bound `<T as Broken>::Assoc: Foo` is trivially false
+ --> $DIR/issue-91745.rs:14:28
+ |
+LL | fn broken(&self) where Self::Assoc: Foo {
+ | _____- ^^^^^^^^^^^^^^^^
+LL | |
+LL | | let _x: <Self::Assoc as Foo>::Bar;
+LL | | }
+ | |_____- this cannot be referenced without causing an error
+
+warning: 1 warning emitted
+
diff --git a/src/test/ui/trait-bounds/issue-94680.rs b/src/test/ui/trait-bounds/issue-94680.rs
index 58e892079e65f..fc8463bcf9214 100644
--- a/src/test/ui/trait-bounds/issue-94680.rs
+++ b/src/test/ui/trait-bounds/issue-94680.rs
@@ -7,6 +7,7 @@ fn main() {
pub fn cloneit(it: &'_ mut T) -> (&'_ mut T, &'_ mut T)
where
for<'any> &'any mut T: Clone,
+ //~^ WARNING the where-clause bound
{
(it.clone(), it)
}
diff --git a/src/test/ui/trait-bounds/issue-94680.stderr b/src/test/ui/trait-bounds/issue-94680.stderr
new file mode 100644
index 0000000000000..ca0be2a70f82a
--- /dev/null
+++ b/src/test/ui/trait-bounds/issue-94680.stderr
@@ -0,0 +1,15 @@
+warning: the where-clause bound `for<'any> &'any mut (): Clone` is trivially false
+ --> $DIR/issue-94680.rs:9:13
+ |
+LL | / pub fn cloneit(it: &'_ mut T) -> (&'_ mut T, &'_ mut T)
+LL | | where
+LL | | for<'any> &'any mut T: Clone,
+ | | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL | |
+LL | | {
+LL | | (it.clone(), it)
+LL | | }
+ | |_________- this cannot be referenced without causing an error
+
+warning: 1 warning emitted
+
diff --git a/src/test/ui/trait-bounds/issue-94999.rs b/src/test/ui/trait-bounds/issue-94999.rs
index e131902346f1b..b2116874072b4 100644
--- a/src/test/ui/trait-bounds/issue-94999.rs
+++ b/src/test/ui/trait-bounds/issue-94999.rs
@@ -24,6 +24,7 @@ impl Holds for X {
impl<Q> Clone for X
where
<S as Identity<Q>>::T: Clone,
+ //~^ WARNING the where-clause bound
X: Holds<Q = Q>,
{
fn clone(&self) -> Self {
diff --git a/src/test/ui/trait-bounds/issue-94999.stderr b/src/test/ui/trait-bounds/issue-94999.stderr
new file mode 100644
index 0000000000000..04dbea8284b53
--- /dev/null
+++ b/src/test/ui/trait-bounds/issue-94999.stderr
@@ -0,0 +1,15 @@
+warning: the where-clause bound `<S as Identity<Q>>::T: Clone` is trivially false
+ --> $DIR/issue-94999.rs:26:5
+ |
+LL | / impl<Q> Clone for X
+LL | | where
+LL | | <S as Identity<Q>>::T: Clone,
+ | | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL | |
+... |
+LL | | }
+LL | | }
+ | |_- this cannot be referenced without causing an error
+
+warning: 1 warning emitted
+
From d7fbaea9d7899ce2ae18dd0c9ba465e6d5e1fa6a Mon Sep 17 00:00:00 2001
From: Michael Goulet <michael@errs.io>
Date: Wed, 3 Aug 2022 06:22:45 +0000
Subject: [PATCH 2/2] Adjust diagnostic
---
compiler/rustc_typeck/src/check/wfcheck.rs | 21 ++++++++++++-------
.../bound-lifetime-in-binding-only.ok.stderr | 12 +++++++----
.../ui/associated-types/issue-69398.stderr | 6 ++++--
.../consts/issue-67696-const-prop-ice.stderr | 18 ++++++++++------
.../feature-gate-trivial_bounds.stderr | 6 ++++--
.../normalize-under-binder/issue-89118.stderr | 12 +++++++----
src/test/ui/issues/issue-36839.stderr | 6 ++++--
src/test/ui/issues/issue-39970.stderr | 6 ++++--
src/test/ui/issues/issue-42796.stderr | 6 ++++--
src/test/ui/mir/issue-91745.stderr | 6 ++++--
src/test/ui/trait-bounds/issue-94680.stderr | 6 ++++--
src/test/ui/trait-bounds/issue-94999.stderr | 6 ++++--
12 files changed, 73 insertions(+), 38 deletions(-)
diff --git a/compiler/rustc_typeck/src/check/wfcheck.rs b/compiler/rustc_typeck/src/check/wfcheck.rs
index d6903a890c301..d2dcd07a24009 100644
--- a/compiler/rustc_typeck/src/check/wfcheck.rs
+++ b/compiler/rustc_typeck/src/check/wfcheck.rs
@@ -1885,17 +1885,22 @@ impl<'tcx> WfCheckingCtxt<'_, 'tcx> {
),
);
if !fulfill_cx.select_all_or_error(self.infcx).is_empty() {
- self.tcx()
+ let mut diag = self.tcx()
.sess
.struct_span_warn(
span,
- format!("the where-clause bound `{pred}` is trivially false"),
- )
- .span_label(
- self.span,
- "this cannot be referenced without causing an error",
- )
- .emit();
+ format!("the where-clause bound `{pred}` is impossible to satisfy"),
+ );
+ diag.span_label(
+ self.span,
+ "this item cannot be referenced without causing an error",
+ );
+ if self.infcx.tcx.sess.opts.unstable_features.is_nightly_build() {
+ diag.help(
+ "add `#![feature(trivial_bounds)]` to the crate attributes to allow it",
+ );
+ }
+ diag.emit();
}
}
});
diff --git a/src/test/ui/associated-types/bound-lifetime-in-binding-only.ok.stderr b/src/test/ui/associated-types/bound-lifetime-in-binding-only.ok.stderr
index 3e4d9cfed9234..06036ee3ac25d 100644
--- a/src/test/ui/associated-types/bound-lifetime-in-binding-only.ok.stderr
+++ b/src/test/ui/associated-types/bound-lifetime-in-binding-only.ok.stderr
@@ -1,4 +1,4 @@
-warning: the where-clause bound `for<'a> <Parameterized<'a> as Foo>::Item == &'a i32` is trivially false
+warning: the where-clause bound `for<'a> <Parameterized<'a> as Foo>::Item == &'a i32` is impossible to satisfy
--> $DIR/bound-lifetime-in-binding-only.rs:67:19
|
LL | fn ok3<T>() where for<'a> Parameterized<'a>: Foo<Item=&'a i32> {
@@ -6,9 +6,11 @@ LL | fn ok3<T>() where for<'a> Parameterized<'a>: Foo<Item=&'a i32> {
LL | |
LL | |
LL | | }
- | |_- this cannot be referenced without causing an error
+ | |_- this item cannot be referenced without causing an error
+ |
+ = help: add `#![feature(trivial_bounds)]` to the crate attributes to allow it
-warning: the where-clause bound `for<'a> Parameterized<'a>: Foo` is trivially false
+warning: the where-clause bound `for<'a> Parameterized<'a>: Foo` is impossible to satisfy
--> $DIR/bound-lifetime-in-binding-only.rs:67:19
|
LL | fn ok3<T>() where for<'a> Parameterized<'a>: Foo<Item=&'a i32> {
@@ -16,7 +18,9 @@ LL | fn ok3<T>() where for<'a> Parameterized<'a>: Foo<Item=&'a i32> {
LL | |
LL | |
LL | | }
- | |_- this cannot be referenced without causing an error
+ | |_- this item cannot be referenced without causing an error
+ |
+ = help: add `#![feature(trivial_bounds)]` to the crate attributes to allow it
error: fatal error triggered by #[rustc_error]
--> $DIR/bound-lifetime-in-binding-only.rs:73:1
diff --git a/src/test/ui/associated-types/issue-69398.stderr b/src/test/ui/associated-types/issue-69398.stderr
index 048b1f55e080e..8bc51ea5eec12 100644
--- a/src/test/ui/associated-types/issue-69398.stderr
+++ b/src/test/ui/associated-types/issue-69398.stderr
@@ -1,4 +1,4 @@
-warning: the where-clause bound `<T as Broken>::Assoc: Foo` is trivially false
+warning: the where-clause bound `<T as Broken>::Assoc: Foo` is impossible to satisfy
--> $DIR/issue-69398.rs:14:28
|
LL | fn broken(&self) where Self::Assoc: Foo {
@@ -6,7 +6,9 @@ LL | fn broken(&self) where Self::Assoc: Foo {
LL | |
LL | | let _x: <Self::Assoc as Foo>::Bar;
LL | | }
- | |_____- this cannot be referenced without causing an error
+ | |_____- this item cannot be referenced without causing an error
+ |
+ = help: add `#![feature(trivial_bounds)]` to the crate attributes to allow it
warning: 1 warning emitted
diff --git a/src/test/ui/consts/issue-67696-const-prop-ice.stderr b/src/test/ui/consts/issue-67696-const-prop-ice.stderr
index 85e2d20389df0..2cbd1bcde740a 100644
--- a/src/test/ui/consts/issue-67696-const-prop-ice.stderr
+++ b/src/test/ui/consts/issue-67696-const-prop-ice.stderr
@@ -1,20 +1,26 @@
-warning: the where-clause bound `[for<'r> fn(&'r ())]: Copy` is trivially false
+warning: the where-clause bound `[for<'r> fn(&'r ())]: Copy` is impossible to satisfy
--> $DIR/issue-67696-const-prop-ice.rs:13:33
|
LL | fn foo(&self) -> Self where Self: Copy { *(&[] as &[_]) }
- | ----------------------------^^^^^^^^^^------------------- this cannot be referenced without causing an error
+ | ----------------------------^^^^^^^^^^------------------- this item cannot be referenced without causing an error
+ |
+ = help: add `#![feature(trivial_bounds)]` to the crate attributes to allow it
-warning: the where-clause bound `[for<'r> fn(&'r ())]: Clone` is trivially false
+warning: the where-clause bound `[for<'r> fn(&'r ())]: Clone` is impossible to satisfy
--> $DIR/issue-67696-const-prop-ice.rs:13:33
|
LL | fn foo(&self) -> Self where Self: Copy { *(&[] as &[_]) }
- | ----------------------------^^^^^^^^^^------------------- this cannot be referenced without causing an error
+ | ----------------------------^^^^^^^^^^------------------- this item cannot be referenced without causing an error
+ |
+ = help: add `#![feature(trivial_bounds)]` to the crate attributes to allow it
-warning: the where-clause bound `[for<'r> fn(&'r ())]: Sized` is trivially false
+warning: the where-clause bound `[for<'r> fn(&'r ())]: Sized` is impossible to satisfy
--> $DIR/issue-67696-const-prop-ice.rs:13:33
|
LL | fn foo(&self) -> Self where Self: Copy { *(&[] as &[_]) }
- | ----------------------------^^^^^^^^^^------------------- this cannot be referenced without causing an error
+ | ----------------------------^^^^^^^^^^------------------- this item cannot be referenced without causing an error
+ |
+ = help: add `#![feature(trivial_bounds)]` to the crate attributes to allow it
warning: 3 warnings emitted
diff --git a/src/test/ui/feature-gates/feature-gate-trivial_bounds.stderr b/src/test/ui/feature-gates/feature-gate-trivial_bounds.stderr
index 56db31e7ab64b..4914b05260ef1 100644
--- a/src/test/ui/feature-gates/feature-gate-trivial_bounds.stderr
+++ b/src/test/ui/feature-gates/feature-gate-trivial_bounds.stderr
@@ -113,7 +113,7 @@ LL | fn return_str() -> str where str: Sized {
= help: see issue #48214
= help: add `#![feature(trivial_bounds)]` to the crate attributes to enable
-warning: the where-clause bound `for<'r> fn(&'r ()): Foo` is trivially false
+warning: the where-clause bound `for<'r> fn(&'r ()): Foo` is impossible to satisfy
--> $DIR/feature-gate-trivial_bounds.rs:65:32
|
LL | fn global_hr(x: fn(&())) where fn(&()): Foo { // OK
@@ -121,7 +121,9 @@ LL | fn global_hr(x: fn(&())) where fn(&()): Foo { // OK
LL | |
LL | | x.test();
LL | | }
- | |_- this cannot be referenced without causing an error
+ | |_- this item cannot be referenced without causing an error
+ |
+ = help: add `#![feature(trivial_bounds)]` to the crate attributes to allow it
error: aborting due to 11 previous errors; 1 warning emitted
diff --git a/src/test/ui/higher-rank-trait-bounds/normalize-under-binder/issue-89118.stderr b/src/test/ui/higher-rank-trait-bounds/normalize-under-binder/issue-89118.stderr
index b1fa127c26a1d..c609a20fcb37a 100644
--- a/src/test/ui/higher-rank-trait-bounds/normalize-under-binder/issue-89118.stderr
+++ b/src/test/ui/higher-rank-trait-bounds/normalize-under-binder/issue-89118.stderr
@@ -1,4 +1,4 @@
-warning: the where-clause bound `for<'a> Ctx<()>: BufferUdpStateContext<&'a ()>` is trivially false
+warning: the where-clause bound `for<'a> Ctx<()>: BufferUdpStateContext<&'a ()>` is impossible to satisfy
--> $DIR/issue-89118.rs:9:5
|
LL | / trait StackContext
@@ -9,7 +9,9 @@ LL | |
LL | | {
LL | | type Dispatcher;
LL | | }
- | |_- this cannot be referenced without causing an error
+ | |_- this item cannot be referenced without causing an error
+ |
+ = help: add `#![feature(trivial_bounds)]` to the crate attributes to allow it
error[E0277]: the trait bound `for<'a> &'a (): BufferMut` is not satisfied
--> $DIR/issue-89118.rs:20:8
@@ -31,13 +33,15 @@ LL | where
LL | Ctx<()>: for<'a> BufferUdpStateContext<&'a ()>,
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `StackContext`
-warning: the where-clause bound `for<'a> Ctx<()>: BufferUdpStateContext<&'a ()>` is trivially false
+warning: the where-clause bound `for<'a> Ctx<()>: BufferUdpStateContext<&'a ()>` is impossible to satisfy
--> $DIR/issue-89118.rs:29:5
|
LL | / struct EthernetWorker<C>(C)
LL | | where
LL | | Ctx<()>: for<'a> BufferUdpStateContext<&'a ()>;
- | |_____^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^- this cannot be referenced without causing an error
+ | |_____^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^- this item cannot be referenced without causing an error
+ |
+ = help: add `#![feature(trivial_bounds)]` to the crate attributes to allow it
error[E0277]: the trait bound `for<'a> &'a (): BufferMut` is not satisfied
--> $DIR/issue-89118.rs:31:9
diff --git a/src/test/ui/issues/issue-36839.stderr b/src/test/ui/issues/issue-36839.stderr
index eefa57e8dcc99..8dd876a690e90 100644
--- a/src/test/ui/issues/issue-36839.stderr
+++ b/src/test/ui/issues/issue-36839.stderr
@@ -1,4 +1,4 @@
-warning: the where-clause bound `<T as Broken>::Assoc: Foo` is trivially false
+warning: the where-clause bound `<T as Broken>::Assoc: Foo` is impossible to satisfy
--> $DIR/issue-36839.rs:14:28
|
LL | fn broken(&self) where Self::Assoc: Foo {
@@ -6,7 +6,9 @@ LL | fn broken(&self) where Self::Assoc: Foo {
LL | |
LL | | let _x: <Self::Assoc as Foo>::Bar;
LL | | }
- | |_____- this cannot be referenced without causing an error
+ | |_____- this item cannot be referenced without causing an error
+ |
+ = help: add `#![feature(trivial_bounds)]` to the crate attributes to allow it
warning: 1 warning emitted
diff --git a/src/test/ui/issues/issue-39970.stderr b/src/test/ui/issues/issue-39970.stderr
index 506300714f318..514a1b1df86aa 100644
--- a/src/test/ui/issues/issue-39970.stderr
+++ b/src/test/ui/issues/issue-39970.stderr
@@ -1,4 +1,4 @@
-warning: the where-clause bound `for<'a> <() as Array<'a>>::Element == ()` is trivially false
+warning: the where-clause bound `for<'a> <() as Array<'a>>::Element == ()` is impossible to satisfy
--> $DIR/issue-39970.rs:15:5
|
LL | / impl Visit for () where
@@ -7,7 +7,9 @@ LL | | (): for<'a> Array<'a, Element=()>, // ICE
| | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
LL | |
LL | | {}
- | |__- this cannot be referenced without causing an error
+ | |__- this item cannot be referenced without causing an error
+ |
+ = help: add `#![feature(trivial_bounds)]` to the crate attributes to allow it
error[E0271]: type mismatch resolving `for<'a> <() as Array<'a>>::Element == ()`
--> $DIR/issue-39970.rs:20:5
diff --git a/src/test/ui/issues/issue-42796.stderr b/src/test/ui/issues/issue-42796.stderr
index 3f641929ef3cd..2e3ea6bf929ad 100644
--- a/src/test/ui/issues/issue-42796.stderr
+++ b/src/test/ui/issues/issue-42796.stderr
@@ -1,4 +1,4 @@
-warning: the where-clause bound `<String as Mirror<S>>::Image: Copy` is trivially false
+warning: the where-clause bound `<String as Mirror<S>>::Image: Copy` is impossible to satisfy
--> $DIR/issue-42796.rs:9:40
|
LL | pub fn poison<S>(victim: String) where <String as Mirror<S>>::Image: Copy {
@@ -6,7 +6,9 @@ LL | pub fn poison<S>(victim: String) where <String as Mirror<S>>::Image: Copy
LL | |
LL | | loop { drop(victim); }
LL | | }
- | |_- this cannot be referenced without causing an error
+ | |_- this item cannot be referenced without causing an error
+ |
+ = help: add `#![feature(trivial_bounds)]` to the crate attributes to allow it
error[E0382]: borrow of moved value: `s`
--> $DIR/issue-42796.rs:19:20
diff --git a/src/test/ui/mir/issue-91745.stderr b/src/test/ui/mir/issue-91745.stderr
index bcb191bac9a1f..ae38f01dc3c80 100644
--- a/src/test/ui/mir/issue-91745.stderr
+++ b/src/test/ui/mir/issue-91745.stderr
@@ -1,4 +1,4 @@
-warning: the where-clause bound `<T as Broken>::Assoc: Foo` is trivially false
+warning: the where-clause bound `<T as Broken>::Assoc: Foo` is impossible to satisfy
--> $DIR/issue-91745.rs:14:28
|
LL | fn broken(&self) where Self::Assoc: Foo {
@@ -6,7 +6,9 @@ LL | fn broken(&self) where Self::Assoc: Foo {
LL | |
LL | | let _x: <Self::Assoc as Foo>::Bar;
LL | | }
- | |_____- this cannot be referenced without causing an error
+ | |_____- this item cannot be referenced without causing an error
+ |
+ = help: add `#![feature(trivial_bounds)]` to the crate attributes to allow it
warning: 1 warning emitted
diff --git a/src/test/ui/trait-bounds/issue-94680.stderr b/src/test/ui/trait-bounds/issue-94680.stderr
index ca0be2a70f82a..73e14dd9dce7a 100644
--- a/src/test/ui/trait-bounds/issue-94680.stderr
+++ b/src/test/ui/trait-bounds/issue-94680.stderr
@@ -1,4 +1,4 @@
-warning: the where-clause bound `for<'any> &'any mut (): Clone` is trivially false
+warning: the where-clause bound `for<'any> &'any mut (): Clone` is impossible to satisfy
--> $DIR/issue-94680.rs:9:13
|
LL | / pub fn cloneit(it: &'_ mut T) -> (&'_ mut T, &'_ mut T)
@@ -9,7 +9,9 @@ LL | |
LL | | {
LL | | (it.clone(), it)
LL | | }
- | |_________- this cannot be referenced without causing an error
+ | |_________- this item cannot be referenced without causing an error
+ |
+ = help: add `#![feature(trivial_bounds)]` to the crate attributes to allow it
warning: 1 warning emitted
diff --git a/src/test/ui/trait-bounds/issue-94999.stderr b/src/test/ui/trait-bounds/issue-94999.stderr
index 04dbea8284b53..91863e754b44a 100644
--- a/src/test/ui/trait-bounds/issue-94999.stderr
+++ b/src/test/ui/trait-bounds/issue-94999.stderr
@@ -1,4 +1,4 @@
-warning: the where-clause bound `<S as Identity<Q>>::T: Clone` is trivially false
+warning: the where-clause bound `<S as Identity<Q>>::T: Clone` is impossible to satisfy
--> $DIR/issue-94999.rs:26:5
|
LL | / impl<Q> Clone for X
@@ -9,7 +9,9 @@ LL | |
... |
LL | | }
LL | | }
- | |_- this cannot be referenced without causing an error
+ | |_- this item cannot be referenced without causing an error
+ |
+ = help: add `#![feature(trivial_bounds)]` to the crate attributes to allow it
warning: 1 warning emitted