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Auto merge of #124219 - gurry:122989-ice-unexpected-anon-const, r=compiler-errors
Do not ICE on `AnonConst`s in `diagnostic_hir_wf_check` Fixes #122989 Below is the snippet from #122989 that ICEs: ```rust trait Traitor<const N: N<2> = 1, const N: N<2> = N> { fn N(&N) -> N<2> { M } } trait N<const N: Traitor<2> = 12> {} ``` The `AnonConst` that triggers the ICE is the `2` in the param `const N: N<2> = 1`. The currently existing code in `diagnostic_hir_wf_check` deals only with `AnonConst`s that are default values of some param, but the `2` is not a default value. It is just an `AnonConst` HIR node inside a `TraitRef` HIR node corresponding to `N<2>`. Therefore the existing code cannot handle it and this PR ensures that it does.
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Diff for: ‎compiler/rustc_hir_analysis/src/hir_wf_check.rs

+8-6
Original file line numberDiff line numberDiff line change
@@ -163,15 +163,17 @@ fn diagnostic_hir_wf_check<'tcx>(
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kind: hir::GenericParamKind::Type { default: Some(ty), .. },
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..
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}) => vec![*ty],
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hir::Node::AnonConst(_)
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if let Some(const_param_id) =
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tcx.hir().opt_const_param_default_param_def_id(hir_id)
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hir::Node::AnonConst(_) => {
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if let Some(const_param_id) = tcx.hir().opt_const_param_default_param_def_id(hir_id)
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&& let hir::Node::GenericParam(hir::GenericParam {
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kind: hir::GenericParamKind::Const { ty, .. },
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..
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}) = tcx.hir_node_by_def_id(const_param_id) =>
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{
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vec![*ty]
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}) = tcx.hir_node_by_def_id(const_param_id)
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{
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vec![*ty]
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} else {
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vec![]
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}
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}
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ref node => bug!("Unexpected node {:?}", node),
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},

Diff for: ‎tests/crashes/122989.rs

-8
This file was deleted.

Diff for: ‎tests/ui/wf/ice-hir-wf-check-anon-const-issue-122989.rs

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@@ -0,0 +1,21 @@
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// Regression test for ICE #122989
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trait Foo<const N: Bar<2>> {
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//~^ WARN trait objects without an explicit `dyn` are deprecated
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//~| WARN this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
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//~| ERROR cycle detected when computing type of `Foo::N`
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//~| ERROR cycle detected when computing type of `Foo::N`
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//~| ERROR the trait `Foo` cannot be made into an object
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//~| ERROR the trait `Foo` cannot be made into an object
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//~| ERROR the trait `Foo` cannot be made into an object
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//~| ERROR `(dyn Bar<2> + 'static)` is forbidden as the type of a const generic parameter
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fn func() {
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}
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}
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trait Bar<const M: Foo<2>> {}
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//~^ WARN trait objects without an explicit `dyn` are deprecated
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//~| WARN this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
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//~| ERROR the trait `Foo` cannot be made into an object
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//~| ERROR `(dyn Foo<2> + 'static)` is forbidden as the type of a const generic parameter
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fn main() {}

Diff for: ‎tests/ui/wf/ice-hir-wf-check-anon-const-issue-122989.stderr

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warning: trait objects without an explicit `dyn` are deprecated
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--> $DIR/ice-hir-wf-check-anon-const-issue-122989.rs:2:20
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|
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LL | trait Foo<const N: Bar<2>> {
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| ^^^^^^
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|
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= warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
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= note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
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= note: `#[warn(bare_trait_objects)]` on by default
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help: if this is an object-safe trait, use `dyn`
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|
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LL | trait Foo<const N: dyn Bar<2>> {
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| +++
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warning: trait objects without an explicit `dyn` are deprecated
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--> $DIR/ice-hir-wf-check-anon-const-issue-122989.rs:15:20
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|
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LL | trait Bar<const M: Foo<2>> {}
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| ^^^^^^
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|
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= warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
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= note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
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help: if this is an object-safe trait, use `dyn`
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|
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LL | trait Bar<const M: dyn Foo<2>> {}
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| +++
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error[E0391]: cycle detected when computing type of `Foo::N`
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--> $DIR/ice-hir-wf-check-anon-const-issue-122989.rs:2:11
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|
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LL | trait Foo<const N: Bar<2>> {
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| ^^^^^^^^^^^^^^^
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|
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note: ...which requires computing type of `Bar::M`...
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--> $DIR/ice-hir-wf-check-anon-const-issue-122989.rs:15:11
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|
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LL | trait Bar<const M: Foo<2>> {}
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| ^^^^^^^^^^^^^^^
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= note: ...which again requires computing type of `Foo::N`, completing the cycle
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note: cycle used when computing explicit predicates of trait `Foo`
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--> $DIR/ice-hir-wf-check-anon-const-issue-122989.rs:2:1
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|
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LL | trait Foo<const N: Bar<2>> {
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^
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= note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information
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error[E0391]: cycle detected when computing type of `Foo::N`
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--> $DIR/ice-hir-wf-check-anon-const-issue-122989.rs:2:11
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|
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LL | trait Foo<const N: Bar<2>> {
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| ^^^^^^^^^^^^^^^
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|
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note: ...which requires computing type of `Bar::M`...
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--> $DIR/ice-hir-wf-check-anon-const-issue-122989.rs:15:11
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|
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LL | trait Bar<const M: Foo<2>> {}
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| ^^^^^^^^^^^^^^^
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= note: ...which again requires computing type of `Foo::N`, completing the cycle
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note: cycle used when computing explicit predicates of trait `Foo`
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--> $DIR/ice-hir-wf-check-anon-const-issue-122989.rs:2:1
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|
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LL | trait Foo<const N: Bar<2>> {
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^
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= note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information
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= note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
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error[E0038]: the trait `Foo` cannot be made into an object
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--> $DIR/ice-hir-wf-check-anon-const-issue-122989.rs:2:24
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|
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LL | trait Foo<const N: Bar<2>> {
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| ^ `Foo` cannot be made into an object
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|
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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>
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--> $DIR/ice-hir-wf-check-anon-const-issue-122989.rs:11:8
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|
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LL | trait Foo<const N: Bar<2>> {
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| --- this trait cannot be made into an object...
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...
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LL | fn func() {
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| ^^^^ ...because associated function `func` has no `self` parameter
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help: consider turning `func` into a method by giving it a `&self` argument
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|
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LL | fn func(&self) {
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| +++++
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help: alternatively, consider constraining `func` so it does not apply to trait objects
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|
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LL | fn func() where Self: Sized {
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| +++++++++++++++++
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error[E0038]: the trait `Foo` cannot be made into an object
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--> $DIR/ice-hir-wf-check-anon-const-issue-122989.rs:2:11
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|
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LL | trait Foo<const N: Bar<2>> {
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| ^^^^^^^^^^^^^^^ `Foo` cannot be made into an object
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|
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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>
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--> $DIR/ice-hir-wf-check-anon-const-issue-122989.rs:11:8
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|
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LL | trait Foo<const N: Bar<2>> {
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| --- this trait cannot be made into an object...
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...
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LL | fn func() {
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| ^^^^ ...because associated function `func` has no `self` parameter
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help: consider turning `func` into a method by giving it a `&self` argument
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|
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LL | fn func(&self) {
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| +++++
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help: alternatively, consider constraining `func` so it does not apply to trait objects
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|
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LL | fn func() where Self: Sized {
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| +++++++++++++++++
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error: `(dyn Bar<2> + 'static)` is forbidden as the type of a const generic parameter
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--> $DIR/ice-hir-wf-check-anon-const-issue-122989.rs:2:20
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|
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LL | trait Foo<const N: Bar<2>> {
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| ^^^^^^
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|
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= note: the only supported types are integers, `bool` and `char`
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error[E0038]: the trait `Foo` cannot be made into an object
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--> $DIR/ice-hir-wf-check-anon-const-issue-122989.rs:15:11
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|
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LL | trait Bar<const M: Foo<2>> {}
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| ^^^^^^^^^^^^^^^ `Foo` cannot be made into an object
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|
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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>
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--> $DIR/ice-hir-wf-check-anon-const-issue-122989.rs:11:8
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|
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LL | trait Foo<const N: Bar<2>> {
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| --- this trait cannot be made into an object...
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...
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LL | fn func() {
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| ^^^^ ...because associated function `func` has no `self` parameter
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help: consider turning `func` into a method by giving it a `&self` argument
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|
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LL | fn func(&self) {
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| +++++
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help: alternatively, consider constraining `func` so it does not apply to trait objects
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|
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LL | fn func() where Self: Sized {
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| +++++++++++++++++
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error: `(dyn Foo<2> + 'static)` is forbidden as the type of a const generic parameter
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--> $DIR/ice-hir-wf-check-anon-const-issue-122989.rs:15:20
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|
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LL | trait Bar<const M: Foo<2>> {}
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| ^^^^^^
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|
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= note: the only supported types are integers, `bool` and `char`
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error[E0038]: the trait `Foo` cannot be made into an object
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--> $DIR/ice-hir-wf-check-anon-const-issue-122989.rs:2:11
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|
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LL | trait Foo<const N: Bar<2>> {
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| ^^^^^^^^^^^^^^^ `Foo` cannot be made into an object
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|
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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>
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--> $DIR/ice-hir-wf-check-anon-const-issue-122989.rs:11:8
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|
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LL | trait Foo<const N: Bar<2>> {
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| --- this trait cannot be made into an object...
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...
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LL | fn func() {
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| ^^^^ ...because associated function `func` has no `self` parameter
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= note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
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help: consider turning `func` into a method by giving it a `&self` argument
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|
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LL | fn func(&self) {
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| +++++
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help: alternatively, consider constraining `func` so it does not apply to trait objects
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|
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LL | fn func() where Self: Sized {
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| +++++++++++++++++
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error: aborting due to 8 previous errors; 2 warnings emitted
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Some errors have detailed explanations: E0038, E0391.
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For more information about an error, try `rustc --explain E0038`.

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