diff --git a/compiler/rustc_error_codes/src/error_codes/E0723.md b/compiler/rustc_error_codes/src/error_codes/E0723.md index 95d47ab21cb..bc224421915 100644 --- a/compiler/rustc_error_codes/src/error_codes/E0723.md +++ b/compiler/rustc_error_codes/src/error_codes/E0723.md @@ -3,12 +3,8 @@ An unstable feature in `const` contexts was used. Erroneous code example: ```compile_fail,E0723 -trait T {} - -impl T for () {} - -const fn foo() -> impl T { // error: `impl Trait` in const fn is unstable - () +const fn foo(_: T) { // error! + // ... } ``` @@ -18,11 +14,7 @@ feature flag: ``` #![feature(const_fn)] -trait T {} - -impl T for () {} - -const fn foo() -> impl T { - () +const fn foo(_: T) { // ok! + // ... } ``` diff --git a/compiler/rustc_feature/src/active.rs b/compiler/rustc_feature/src/active.rs index cd018ae1204..1982d098542 100644 --- a/compiler/rustc_feature/src/active.rs +++ b/compiler/rustc_feature/src/active.rs @@ -596,6 +596,9 @@ declare_features! ( /// Allows rustc to inject a default alloc_error_handler (active, default_alloc_error_handler, "1.48.0", Some(66741), None), + /// Allows argument and return position `impl Trait` in a `const fn`. + (active, const_impl_trait, "1.48.0", Some(77463), None), + // ------------------------------------------------------------------------- // feature-group-end: actual feature gates // ------------------------------------------------------------------------- diff --git a/compiler/rustc_mir/src/transform/check_consts/ops.rs b/compiler/rustc_mir/src/transform/check_consts/ops.rs index 9a1b77e994d..63b20c7c027 100644 --- a/compiler/rustc_mir/src/transform/check_consts/ops.rs +++ b/compiler/rustc_mir/src/transform/check_consts/ops.rs @@ -558,12 +558,17 @@ pub mod ty { #[derive(Debug)] pub struct ImplTrait; impl NonConstOp for ImplTrait { - fn status_in_item(&self, ccx: &ConstCx<'_, '_>) -> Status { - mcf_status_in_item(ccx) + fn status_in_item(&self, _: &ConstCx<'_, '_>) -> Status { + Status::Unstable(sym::const_impl_trait) } fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> DiagnosticBuilder<'tcx> { - mcf_build_error(ccx, span, "`impl Trait` in const fn is unstable") + feature_err( + &ccx.tcx.sess.parse_sess, + sym::const_impl_trait, + span, + &format!("`impl Trait` is not allowed in {}s", ccx.const_kind()), + ) } } diff --git a/compiler/rustc_span/src/symbol.rs b/compiler/rustc_span/src/symbol.rs index 6309b00f5f5..a2184c00a28 100644 --- a/compiler/rustc_span/src/symbol.rs +++ b/compiler/rustc_span/src/symbol.rs @@ -359,6 +359,7 @@ symbols! { const_fn_union, const_generics, const_if_match, + const_impl_trait, const_in_array_repeat_expressions, const_indexing, const_let, diff --git a/library/core/src/lib.rs b/library/core/src/lib.rs index 49cec162762..3aa68aa1d8d 100644 --- a/library/core/src/lib.rs +++ b/library/core/src/lib.rs @@ -83,6 +83,7 @@ #![feature(const_fn)] #![feature(const_fn_union)] #![feature(const_assume)] +#![cfg_attr(not(bootstrap), feature(const_impl_trait))] #![cfg_attr(not(bootstrap), feature(const_fn_floating_point_arithmetic))] #![cfg_attr(not(bootstrap), feature(const_fn_fn_ptr_basics))] #![feature(const_generics)] diff --git a/src/test/ui/consts/min_const_fn/min_const_fn_impl_trait.rs b/src/test/ui/consts/min_const_fn/min_const_fn_impl_trait.rs index 9cc9b69ac0b..e062c9f0aa3 100644 --- a/src/test/ui/consts/min_const_fn/min_const_fn_impl_trait.rs +++ b/src/test/ui/consts/min_const_fn/min_const_fn_impl_trait.rs @@ -1,9 +1,10 @@ +// gate-test-const_impl_trait + struct AlanTuring(T); -const fn no_rpit2() -> AlanTuring { - //~^ ERROR `impl Trait` in const fn is unstable +const fn no_rpit2() -> AlanTuring { //~ `impl Trait` AlanTuring(0) } -const fn no_rpit() -> impl std::fmt::Debug {} //~ ERROR `impl Trait` in const fn is unstable +const fn no_rpit() -> impl std::fmt::Debug {} //~ `impl Trait` fn main() {} diff --git a/src/test/ui/consts/min_const_fn/min_const_fn_impl_trait.stderr b/src/test/ui/consts/min_const_fn/min_const_fn_impl_trait.stderr index a62a340332d..01c797cd96b 100644 --- a/src/test/ui/consts/min_const_fn/min_const_fn_impl_trait.stderr +++ b/src/test/ui/consts/min_const_fn/min_const_fn_impl_trait.stderr @@ -1,21 +1,21 @@ -error[E0723]: `impl Trait` in const fn is unstable - --> $DIR/min_const_fn_impl_trait.rs:2:24 +error[E0658]: `impl Trait` is not allowed in constant functions + --> $DIR/min_const_fn_impl_trait.rs:4:24 | LL | const fn no_rpit2() -> AlanTuring { | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | - = note: see issue #57563 for more information - = help: add `#![feature(const_fn)]` to the crate attributes to enable + = note: see issue #77463 for more information + = help: add `#![feature(const_impl_trait)]` to the crate attributes to enable -error[E0723]: `impl Trait` in const fn is unstable - --> $DIR/min_const_fn_impl_trait.rs:7:23 +error[E0658]: `impl Trait` is not allowed in constant functions + --> $DIR/min_const_fn_impl_trait.rs:8:23 | LL | const fn no_rpit() -> impl std::fmt::Debug {} | ^^^^^^^^^^^^^^^^^^^^ | - = note: see issue #57563 for more information - = help: add `#![feature(const_fn)]` to the crate attributes to enable + = note: see issue #77463 for more information + = help: add `#![feature(const_impl_trait)]` to the crate attributes to enable error: aborting due to 2 previous errors -For more information about this error, try `rustc --explain E0723`. +For more information about this error, try `rustc --explain E0658`. diff --git a/src/test/ui/type-alias-impl-trait/issue-53096.rs b/src/test/ui/type-alias-impl-trait/issue-53096.rs index bdf426bbd37..6e1973bd18a 100644 --- a/src/test/ui/type-alias-impl-trait/issue-53096.rs +++ b/src/test/ui/type-alias-impl-trait/issue-53096.rs @@ -1,5 +1,5 @@ // check-pass -#![feature(const_fn, const_fn_fn_ptr_basics)] +#![feature(const_impl_trait, const_fn_fn_ptr_basics)] #![feature(type_alias_impl_trait)] type Foo = impl Fn() -> usize; diff --git a/src/test/ui/type-alias-impl-trait/issue-53678-generator-and-const-fn.rs b/src/test/ui/type-alias-impl-trait/issue-53678-generator-and-const-fn.rs index e7f93732430..4582d5386f0 100644 --- a/src/test/ui/type-alias-impl-trait/issue-53678-generator-and-const-fn.rs +++ b/src/test/ui/type-alias-impl-trait/issue-53678-generator-and-const-fn.rs @@ -1,6 +1,6 @@ // check-pass -#![feature(const_fn, generators, generator_trait, type_alias_impl_trait)] +#![feature(const_impl_trait, generators, generator_trait, type_alias_impl_trait)] use std::ops::Generator; diff --git a/src/test/ui/type-alias-impl-trait/structural-match-no-leak.rs b/src/test/ui/type-alias-impl-trait/structural-match-no-leak.rs index d50835608fa..58f0f5b2f65 100644 --- a/src/test/ui/type-alias-impl-trait/structural-match-no-leak.rs +++ b/src/test/ui/type-alias-impl-trait/structural-match-no-leak.rs @@ -1,4 +1,4 @@ -#![feature(const_fn, type_alias_impl_trait)] +#![feature(const_impl_trait, type_alias_impl_trait)] type Bar = impl Send; diff --git a/src/test/ui/type-alias-impl-trait/structural-match.rs b/src/test/ui/type-alias-impl-trait/structural-match.rs index a3ff4ad1d47..74ffa608426 100644 --- a/src/test/ui/type-alias-impl-trait/structural-match.rs +++ b/src/test/ui/type-alias-impl-trait/structural-match.rs @@ -1,4 +1,4 @@ -#![feature(const_fn, type_alias_impl_trait)] +#![feature(const_impl_trait, type_alias_impl_trait)] type Foo = impl Send;