diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/type_err_ctxt_ext.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/type_err_ctxt_ext.rs index 6b6438a7887..cdf162ca2eb 100644 --- a/compiler/rustc_trait_selection/src/traits/error_reporting/type_err_ctxt_ext.rs +++ b/compiler/rustc_trait_selection/src/traits/error_reporting/type_err_ctxt_ext.rs @@ -412,8 +412,8 @@ fn report_selection_error( let bound_predicate = obligation.predicate.kind(); match bound_predicate.skip_binder() { ty::PredicateKind::Clause(ty::ClauseKind::Trait(trait_predicate)) => { - let trait_predicate = bound_predicate.rebind(trait_predicate); - let trait_predicate = self.resolve_vars_if_possible(trait_predicate); + let leaf_trait_predicate = + self.resolve_vars_if_possible(bound_predicate.rebind(trait_predicate)); // Let's use the root obligation as the main message, when we care about the // most general case ("X doesn't implement Pattern<'_>") over the case that @@ -424,7 +424,7 @@ fn report_selection_error( let (main_trait_predicate, o) = if let ty::PredicateKind::Clause( ty::ClauseKind::Trait(root_pred) ) = root_obligation.predicate.kind().skip_binder() - && !trait_predicate.self_ty().skip_binder().has_escaping_bound_vars() + && !leaf_trait_predicate.self_ty().skip_binder().has_escaping_bound_vars() && !root_pred.self_ty().has_escaping_bound_vars() // The type of the leaf predicate is (roughly) the same as the type // from the root predicate, as a proxy for "we care about the root" @@ -434,20 +434,20 @@ fn report_selection_error( // `T: Trait` && `&&T: OtherTrait`, we want `OtherTrait` self.can_eq( obligation.param_env, - trait_predicate.self_ty().skip_binder(), + leaf_trait_predicate.self_ty().skip_binder(), root_pred.self_ty().peel_refs(), ) // `&str: Iterator` && `&str: IntoIterator`, we want `IntoIterator` || self.can_eq( obligation.param_env, - trait_predicate.self_ty().skip_binder(), + leaf_trait_predicate.self_ty().skip_binder(), root_pred.self_ty(), ) ) // The leaf trait and the root trait are different, so as to avoid // talking about `&mut T: Trait` and instead remain talking about // `T: Trait` instead - && trait_predicate.def_id() != root_pred.def_id() + && leaf_trait_predicate.def_id() != root_pred.def_id() // The root trait is not `Unsize`, as to avoid talking about it in // `tests/ui/coercion/coerce-issue-49593-box-never.rs`. && Some(root_pred.def_id()) != self.tcx.lang_items().unsize_trait() @@ -459,13 +459,14 @@ fn report_selection_error( root_obligation, ) } else { - (trait_predicate, &obligation) + (leaf_trait_predicate, &obligation) }; - let trait_ref = main_trait_predicate.to_poly_trait_ref(); + let main_trait_ref = main_trait_predicate.to_poly_trait_ref(); + let leaf_trait_ref = leaf_trait_predicate.to_poly_trait_ref(); if let Some(guar) = self.emit_specialized_closure_kind_error( &obligation, - trait_ref, + leaf_trait_ref, ) { return guar; } @@ -473,7 +474,7 @@ fn report_selection_error( // FIXME(effects) let predicate_is_const = false; - if let Err(guar) = trait_predicate.error_reported() + if let Err(guar) = leaf_trait_predicate.error_reported() { return guar; } @@ -507,16 +508,17 @@ fn report_selection_error( notes, parent_label, append_const_msg, - } = self.on_unimplemented_note(trait_ref, o, &mut long_ty_file); + } = self.on_unimplemented_note(main_trait_ref, o, &mut long_ty_file); + let have_alt_message = message.is_some() || label.is_some(); - let is_try_conversion = self.is_try_conversion(span, trait_ref.def_id()); + let is_try_conversion = self.is_try_conversion(span, main_trait_ref.def_id()); let is_unsize = - Some(trait_ref.def_id()) == self.tcx.lang_items().unsize_trait(); + Some(leaf_trait_ref.def_id()) == self.tcx.lang_items().unsize_trait(); let (message, notes, append_const_msg) = if is_try_conversion { ( Some(format!( "`?` couldn't convert the error to `{}`", - trait_ref.skip_binder().self_ty(), + main_trait_ref.skip_binder().self_ty(), )), vec![ "the question mark operation (`?`) implicitly performs a \ @@ -537,13 +539,13 @@ fn report_selection_error( post_message, ); - let (err_msg, safe_transmute_explanation) = if Some(trait_ref.def_id()) + let (err_msg, safe_transmute_explanation) = if Some(main_trait_ref.def_id()) == self.tcx.lang_items().transmute_trait() { // Recompute the safe transmute reason and use that for the error reporting match self.get_safe_transmute_error_and_reason( obligation.clone(), - trait_ref, + main_trait_ref, span, ) { GetSafeTransmuteErrorAndReason::Silent => { @@ -571,7 +573,7 @@ fn report_selection_error( } let mut suggested = false; if is_try_conversion { - suggested = self.try_conversion_context(&obligation, trait_ref.skip_binder(), &mut err); + suggested = self.try_conversion_context(&obligation, main_trait_ref.skip_binder(), &mut err); } if is_try_conversion && let Some(ret_span) = self.return_type_span(&obligation) { @@ -579,19 +581,19 @@ fn report_selection_error( ret_span, format!( "expected `{}` because of this", - trait_ref.skip_binder().self_ty() + main_trait_ref.skip_binder().self_ty() ), ); } - if Some(trait_ref.def_id()) == tcx.lang_items().tuple_trait() { + if Some(leaf_trait_ref.def_id()) == tcx.lang_items().tuple_trait() { self.add_tuple_trait_message( obligation.cause.code().peel_derives(), &mut err, ); } - if Some(trait_ref.def_id()) == tcx.lang_items().drop_trait() + if Some(leaf_trait_ref.def_id()) == tcx.lang_items().drop_trait() && predicate_is_const { err.note("`~const Drop` was renamed to `~const Destruct`"); @@ -601,15 +603,15 @@ fn report_selection_error( let explanation = get_explanation_based_on_obligation( self.tcx, &obligation, - trait_ref, - &trait_predicate, + leaf_trait_ref, + &leaf_trait_predicate, pre_message, ); self.check_for_binding_assigned_block_without_tail_expression( &obligation, &mut err, - trait_predicate, + leaf_trait_predicate, ); self.suggest_add_result_as_return_type(&obligation, &mut err, @@ -618,7 +620,7 @@ fn report_selection_error( if self.suggest_add_reference_to_arg( &obligation, &mut err, - trait_predicate, + leaf_trait_predicate, have_alt_message, ) { self.note_obligation_cause(&mut err, &obligation); @@ -630,7 +632,7 @@ fn report_selection_error( // If it has a custom `#[rustc_on_unimplemented]` // error message, let's display it as the label! err.span_label(span, s); - if !matches!(trait_ref.skip_binder().self_ty().kind(), ty::Param(_)) { + if !matches!(leaf_trait_ref.skip_binder().self_ty().kind(), ty::Param(_)) { // When the self type is a type param We don't need to "the trait // `std::marker::Sized` is not implemented for `T`" as we will point // at the type param with a label to suggest constraining it. @@ -645,7 +647,7 @@ fn report_selection_error( if let ObligationCauseCode::Coercion { source, target } = *obligation.cause.code().peel_derives() { - if Some(trait_ref.def_id()) == self.tcx.lang_items().sized_trait() { + if Some(leaf_trait_ref.def_id()) == self.tcx.lang_items().sized_trait() { self.suggest_borrowing_for_object_cast( &mut err, root_obligation, @@ -657,7 +659,7 @@ fn report_selection_error( let UnsatisfiedConst(unsatisfied_const) = self .maybe_add_note_for_unsatisfied_const( - &trait_predicate, + &leaf_trait_predicate, &mut err, span, ); @@ -674,15 +676,15 @@ fn report_selection_error( err.span_label(tcx.def_span(body), s); } - self.suggest_floating_point_literal(&obligation, &mut err, &trait_ref); - self.suggest_dereferencing_index(&obligation, &mut err, trait_predicate); - suggested |= self.suggest_dereferences(&obligation, &mut err, trait_predicate); - suggested |= self.suggest_fn_call(&obligation, &mut err, trait_predicate); - let impl_candidates = self.find_similar_impl_candidates(trait_predicate); + self.suggest_floating_point_literal(&obligation, &mut err, &leaf_trait_ref); + self.suggest_dereferencing_index(&obligation, &mut err, leaf_trait_predicate); + suggested |= self.suggest_dereferences(&obligation, &mut err, leaf_trait_predicate); + suggested |= self.suggest_fn_call(&obligation, &mut err, leaf_trait_predicate); + let impl_candidates = self.find_similar_impl_candidates(leaf_trait_predicate); suggested = if let &[cand] = &impl_candidates[..] { let cand = cand.trait_ref; if let (ty::FnPtr(_), ty::FnDef(..)) = - (cand.self_ty().kind(), trait_ref.self_ty().skip_binder().kind()) + (cand.self_ty().kind(), main_trait_ref.self_ty().skip_binder().kind()) { err.span_suggestion( span.shrink_to_hi(), @@ -702,31 +704,31 @@ fn report_selection_error( false } || suggested; suggested |= - self.suggest_remove_reference(&obligation, &mut err, trait_predicate); + self.suggest_remove_reference(&obligation, &mut err, leaf_trait_predicate); suggested |= self.suggest_semicolon_removal( &obligation, &mut err, span, - trait_predicate, + leaf_trait_predicate, ); - self.note_version_mismatch(&mut err, &trait_ref); + self.note_version_mismatch(&mut err, &leaf_trait_ref); self.suggest_remove_await(&obligation, &mut err); - self.suggest_derive(&obligation, &mut err, trait_predicate); + self.suggest_derive(&obligation, &mut err, leaf_trait_predicate); - if Some(trait_ref.def_id()) == tcx.lang_items().try_trait() { + if Some(leaf_trait_ref.def_id()) == tcx.lang_items().try_trait() { self.suggest_await_before_try( &mut err, &obligation, - trait_predicate, + leaf_trait_predicate, span, ); } - if self.suggest_add_clone_to_arg(&obligation, &mut err, trait_predicate) { + if self.suggest_add_clone_to_arg(&obligation, &mut err, leaf_trait_predicate) { return err.emit(); } - if self.suggest_impl_trait(&mut err, &obligation, trait_predicate) { + if self.suggest_impl_trait(&mut err, &obligation, leaf_trait_predicate) { return err.emit(); } @@ -741,9 +743,9 @@ fn report_selection_error( ); } - let is_fn_trait = tcx.is_fn_trait(trait_ref.def_id()); + let is_fn_trait = tcx.is_fn_trait(leaf_trait_ref.def_id()); let is_target_feature_fn = if let ty::FnDef(def_id, _) = - *trait_ref.skip_binder().self_ty().kind() + *leaf_trait_ref.skip_binder().self_ty().kind() { !self.tcx.codegen_fn_attrs(def_id).target_features.is_empty() } else { @@ -757,8 +759,8 @@ fn report_selection_error( self.try_to_add_help_message( &obligation, - trait_ref, - &trait_predicate, + leaf_trait_ref, + &leaf_trait_predicate, &mut err, span, is_fn_trait, @@ -769,17 +771,17 @@ fn report_selection_error( // Changing mutability doesn't make a difference to whether we have // an `Unsize` impl (Fixes ICE in #71036) if !is_unsize { - self.suggest_change_mut(&obligation, &mut err, trait_predicate); + self.suggest_change_mut(&obligation, &mut err, leaf_trait_predicate); } // If this error is due to `!: Trait` not implemented but `(): Trait` is // implemented, and fallback has occurred, then it could be due to a // variable that used to fallback to `()` now falling back to `!`. Issue a // note informing about the change in behaviour. - if trait_predicate.skip_binder().self_ty().is_never() + if leaf_trait_predicate.skip_binder().self_ty().is_never() && self.fallback_has_occurred { - let predicate = trait_predicate.map_bound(|trait_pred| { + let predicate = leaf_trait_predicate.map_bound(|trait_pred| { trait_pred.with_self_ty(self.tcx, tcx.types.unit) }); let unit_obligation = obligation.with(tcx, predicate); @@ -794,8 +796,8 @@ fn report_selection_error( } } - self.explain_hrtb_projection(&mut err, trait_predicate, obligation.param_env, &obligation.cause); - self.suggest_desugaring_async_fn_in_trait(&mut err, trait_ref); + self.explain_hrtb_projection(&mut err, leaf_trait_predicate, obligation.param_env, &obligation.cause); + self.suggest_desugaring_async_fn_in_trait(&mut err, main_trait_ref); // Return early if the trait is Debug or Display and the invocation // originates within a standard library macro, because the output @@ -813,15 +815,13 @@ fn report_selection_error( if in_std_macro && matches!( - self.tcx.get_diagnostic_name(trait_ref.def_id()), + self.tcx.get_diagnostic_name(leaf_trait_ref.def_id()), Some(sym::Debug | sym::Display) ) { return err.emit(); } - - err } diff --git a/tests/ui/auto-traits/typeck-default-trait-impl-precedence.stderr b/tests/ui/auto-traits/typeck-default-trait-impl-precedence.stderr index 47bb1a059be..4773ac4ccf7 100644 --- a/tests/ui/auto-traits/typeck-default-trait-impl-precedence.stderr +++ b/tests/ui/auto-traits/typeck-default-trait-impl-precedence.stderr @@ -2,7 +2,7 @@ error[E0277]: the trait bound `&'static u32: Defaulted` is not satisfied --> $DIR/typeck-default-trait-impl-precedence.rs:19:20 | LL | is_defaulted::<&'static u32>(); - | ^^^^^^^^^^^^ the trait `Signed` is not implemented for `&'static u32`, which is required by `&'static u32: Defaulted` + | ^^^^^^^^^^^^ the trait `Signed` is not implemented for `u32`, which is required by `&'static u32: Defaulted` | note: required for `&'static u32` to implement `Defaulted` --> $DIR/typeck-default-trait-impl-precedence.rs:10:19 diff --git a/tests/ui/generic-associated-types/assume-gat-normalization-for-nested-goals.next.stderr b/tests/ui/generic-associated-types/assume-gat-normalization-for-nested-goals.next.stderr index 2c372b6c3a7..9b5d84b5b09 100644 --- a/tests/ui/generic-associated-types/assume-gat-normalization-for-nested-goals.next.stderr +++ b/tests/ui/generic-associated-types/assume-gat-normalization-for-nested-goals.next.stderr @@ -2,7 +2,7 @@ error[E0277]: the trait bound `i32: Baz` is not satisfied --> $DIR/assume-gat-normalization-for-nested-goals.rs:9:30 | LL | type Bar: Baz = i32; - | ^^^ the trait `Eq` is not implemented for `i32`, which is required by `i32: Baz` + | ^^^ the trait `Eq` is not implemented for `::Bar<()>`, which is required by `i32: Baz` | note: required for `i32` to implement `Baz` --> $DIR/assume-gat-normalization-for-nested-goals.rs:16:23 diff --git a/tests/ui/kindck/kindck-send-object.stderr b/tests/ui/kindck/kindck-send-object.stderr index 9f1ff4f3644..7d0c711abc4 100644 --- a/tests/ui/kindck/kindck-send-object.stderr +++ b/tests/ui/kindck/kindck-send-object.stderr @@ -4,7 +4,7 @@ error[E0277]: `&'static (dyn Dummy + 'static)` cannot be sent between threads sa LL | assert_send::<&'static (dyn Dummy + 'static)>(); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `&'static (dyn Dummy + 'static)` cannot be sent between threads safely | - = help: the trait `Sync` is not implemented for `&'static (dyn Dummy + 'static)`, which is required by `&'static (dyn Dummy + 'static): Send` + = help: the trait `Sync` is not implemented for `(dyn Dummy + 'static)`, which is required by `&'static (dyn Dummy + 'static): Send` = note: required for `&'static (dyn Dummy + 'static)` to implement `Send` note: required by a bound in `assert_send` --> $DIR/kindck-send-object.rs:5:18 diff --git a/tests/ui/kindck/kindck-send-object1.stderr b/tests/ui/kindck/kindck-send-object1.stderr index f2aa814676f..7f39dab2086 100644 --- a/tests/ui/kindck/kindck-send-object1.stderr +++ b/tests/ui/kindck/kindck-send-object1.stderr @@ -4,7 +4,7 @@ error[E0277]: `&'a (dyn Dummy + 'a)` cannot be sent between threads safely LL | assert_send::<&'a dyn Dummy>(); | ^^^^^^^^^^^^^ `&'a (dyn Dummy + 'a)` cannot be sent between threads safely | - = help: the trait `Sync` is not implemented for `&'a (dyn Dummy + 'a)`, which is required by `&'a (dyn Dummy + 'a): Send` + = help: the trait `Sync` is not implemented for `(dyn Dummy + 'a)`, which is required by `&'a (dyn Dummy + 'a): Send` = note: required for `&'a (dyn Dummy + 'a)` to implement `Send` note: required by a bound in `assert_send` --> $DIR/kindck-send-object1.rs:5:18 diff --git a/tests/ui/kindck/kindck-send-object2.stderr b/tests/ui/kindck/kindck-send-object2.stderr index cd4d74360f8..a481a132cce 100644 --- a/tests/ui/kindck/kindck-send-object2.stderr +++ b/tests/ui/kindck/kindck-send-object2.stderr @@ -4,7 +4,7 @@ error[E0277]: `&'static (dyn Dummy + 'static)` cannot be sent between threads sa LL | assert_send::<&'static dyn Dummy>(); | ^^^^^^^^^^^^^^^^^^ `&'static (dyn Dummy + 'static)` cannot be sent between threads safely | - = help: the trait `Sync` is not implemented for `&'static (dyn Dummy + 'static)`, which is required by `&'static (dyn Dummy + 'static): Send` + = help: the trait `Sync` is not implemented for `(dyn Dummy + 'static)`, which is required by `&'static (dyn Dummy + 'static): Send` = note: required for `&'static (dyn Dummy + 'static)` to implement `Send` note: required by a bound in `assert_send` --> $DIR/kindck-send-object2.rs:3:18 diff --git a/tests/ui/suggestions/suggest-remove-refs-5.stderr b/tests/ui/suggestions/suggest-remove-refs-5.stderr index 3b6994b45d1..b132c56473e 100644 --- a/tests/ui/suggestions/suggest-remove-refs-5.stderr +++ b/tests/ui/suggestions/suggest-remove-refs-5.stderr @@ -4,7 +4,7 @@ error[E0277]: `&mut &mut &mut &mut Vec` is not an iterator LL | for _ in &mut &mut v {} | ^^^^^^^^^^^ `&mut &mut &mut &mut Vec` is not an iterator | - = help: the trait `Iterator` is not implemented for `&mut &mut &mut &mut Vec`, which is required by `&mut &mut &mut &mut Vec: IntoIterator` + = help: the trait `Iterator` is not implemented for `Vec`, which is required by `&mut &mut &mut &mut Vec: IntoIterator` = note: required for `&mut Vec` to implement `Iterator` = note: 3 redundant requirements hidden = note: required for `&mut &mut &mut &mut Vec` to implement `Iterator` @@ -21,7 +21,7 @@ error[E0277]: `&mut &mut &mut [u8; 1]` is not an iterator LL | for _ in &mut v {} | ^^^^^^ `&mut &mut &mut [u8; 1]` is not an iterator | - = help: the trait `Iterator` is not implemented for `&mut &mut &mut [u8; 1]`, which is required by `&mut &mut &mut [u8; 1]: IntoIterator` + = help: the trait `Iterator` is not implemented for `[u8; 1]`, which is required by `&mut &mut &mut [u8; 1]: IntoIterator` = note: required for `&mut [u8; 1]` to implement `Iterator` = note: 2 redundant requirements hidden = note: required for `&mut &mut &mut [u8; 1]` to implement `Iterator` diff --git a/tests/ui/traits/next-solver/auto-with-drop_tracking_mir.fail.stderr b/tests/ui/traits/next-solver/auto-with-drop_tracking_mir.fail.stderr index 562d7ccf9fe..e0b23bd8110 100644 --- a/tests/ui/traits/next-solver/auto-with-drop_tracking_mir.fail.stderr +++ b/tests/ui/traits/next-solver/auto-with-drop_tracking_mir.fail.stderr @@ -4,7 +4,7 @@ error: future cannot be sent between threads safely LL | is_send(foo()); | ^^^^^ future returned by `foo` is not `Send` | - = help: the trait `Sync` is not implemented for `impl Future`, which is required by `impl Future: Send` + = help: the trait `Sync` is not implemented for `NotSync`, which is required by `impl Future: Send` note: future is not `Send` as this value is used across an await --> $DIR/auto-with-drop_tracking_mir.rs:16:11 | diff --git a/tests/ui/traits/next-solver/diagnostics/point-at-failing-nested.stderr b/tests/ui/traits/next-solver/diagnostics/point-at-failing-nested.stderr index 6bf4e3cb534..9a18a58debd 100644 --- a/tests/ui/traits/next-solver/diagnostics/point-at-failing-nested.stderr +++ b/tests/ui/traits/next-solver/diagnostics/point-at-failing-nested.stderr @@ -4,6 +4,11 @@ error[E0277]: the trait bound `(): Foo` is not satisfied LL | needs_foo::<()>(); | ^^ the trait `Bar` is not implemented for `()`, which is required by `(): Foo` | +help: this trait has no implementations, consider adding one + --> $DIR/point-at-failing-nested.rs:4:1 + | +LL | trait Bar {} + | ^^^^^^^^^ note: required for `()` to implement `Foo` --> $DIR/point-at-failing-nested.rs:9:12 | diff --git a/tests/ui/traits/next-solver/diagnostics/where-clause-doesnt-apply.stderr b/tests/ui/traits/next-solver/diagnostics/where-clause-doesnt-apply.stderr index 77a0cc49754..ab1d4a56c02 100644 --- a/tests/ui/traits/next-solver/diagnostics/where-clause-doesnt-apply.stderr +++ b/tests/ui/traits/next-solver/diagnostics/where-clause-doesnt-apply.stderr @@ -6,6 +6,11 @@ LL | needs_foo(()); | | | required by a bound introduced by this call | +help: this trait has no implementations, consider adding one + --> $DIR/where-clause-doesnt-apply.rs:2:1 + | +LL | trait Bar {} + | ^^^^^^^^^ note: required for `()` to implement `Foo` --> $DIR/where-clause-doesnt-apply.rs:4:9 | diff --git a/tests/ui/traits/suggest-dereferences/root-obligation.stderr b/tests/ui/traits/suggest-dereferences/root-obligation.stderr index 14b2ecbb9f2..bbfbb98fba7 100644 --- a/tests/ui/traits/suggest-dereferences/root-obligation.stderr +++ b/tests/ui/traits/suggest-dereferences/root-obligation.stderr @@ -2,7 +2,7 @@ error[E0277]: the trait bound `&char: Pattern<'_>` is not satisfied --> $DIR/root-obligation.rs:6:38 | LL | .filter(|c| "aeiou".contains(c)) - | -------- ^ the trait `Fn(char)` is not implemented for `&char`, which is required by `&char: Pattern<'_>` + | -------- ^ the trait `Fn(char)` is not implemented for `char`, which is required by `&char: Pattern<'_>` | | | required by a bound introduced by this call | diff --git a/tests/ui/transmutability/references/unsafecell.stderr b/tests/ui/transmutability/references/unsafecell.stderr index 651eb8ceb26..8bb32359355 100644 --- a/tests/ui/transmutability/references/unsafecell.stderr +++ b/tests/ui/transmutability/references/unsafecell.stderr @@ -2,7 +2,7 @@ error[E0277]: `&u8` cannot be safely transmuted into `&UnsafeCell` --> $DIR/unsafecell.rs:27:50 | LL | assert::is_maybe_transmutable::<&'static u8, &'static UnsafeCell>(); - | ^^^^^^^^^^^^^^^^^^^^^^^ the trait `Freeze` is not implemented for `&'static UnsafeCell` + | ^^^^^^^^^^^^^^^^^^^^^^^ the trait `Freeze` is not implemented for `UnsafeCell` | note: required by a bound in `is_maybe_transmutable` --> $DIR/unsafecell.rs:12:14 @@ -17,7 +17,7 @@ error[E0277]: `&UnsafeCell` cannot be safely transmuted into `&UnsafeCell $DIR/unsafecell.rs:29:62 | LL | assert::is_maybe_transmutable::<&'static UnsafeCell, &'static UnsafeCell>(); - | ^^^^^^^^^^^^^^^^^^^^^^^ the trait `Freeze` is not implemented for `&'static UnsafeCell` + | ^^^^^^^^^^^^^^^^^^^^^^^ the trait `Freeze` is not implemented for `UnsafeCell` | note: required by a bound in `is_maybe_transmutable` --> $DIR/unsafecell.rs:12:14