diff --git a/compiler/rustc_ast_lowering/src/lib.rs b/compiler/rustc_ast_lowering/src/lib.rs index aa8ad9784513d..241b47046fe41 100644 --- a/compiler/rustc_ast_lowering/src/lib.rs +++ b/compiler/rustc_ast_lowering/src/lib.rs @@ -1571,8 +1571,10 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { Vec::new() } hir::OpaqueTyOrigin::FnReturn(..) => { - if let FnDeclKind::Impl | FnDeclKind::Trait = - fn_kind.expect("expected RPITs to be lowered with a FnKind") + if matches!( + fn_kind.expect("expected RPITs to be lowered with a FnKind"), + FnDeclKind::Impl | FnDeclKind::Trait + ) || self.tcx.features().lifetime_capture_rules_2024 { // return-position impl trait in trait was decided to capture all // in-scope lifetimes, which we collect for all opaques during resolution. diff --git a/compiler/rustc_feature/src/unstable.rs b/compiler/rustc_feature/src/unstable.rs index 1d4fa9c75d9d1..2d70e112ed03e 100644 --- a/compiler/rustc_feature/src/unstable.rs +++ b/compiler/rustc_feature/src/unstable.rs @@ -195,6 +195,8 @@ declare_features! ( (internal, intrinsics, "1.0.0", None, None), /// Allows using `#[lang = ".."]` attribute for linking items to special compiler logic. (internal, lang_items, "1.0.0", None, None), + /// Changes `impl Trait` to capture all lifetimes in scope. + (unstable, lifetime_capture_rules_2024, "CURRENT_RUSTC_VERSION", None, None), /// Allows `#[link(..., cfg(..))]`; perma-unstable per #37406 (unstable, link_cfg, "1.14.0", None, None), /// Allows the `multiple_supertrait_upcastable` lint. diff --git a/compiler/rustc_span/src/symbol.rs b/compiler/rustc_span/src/symbol.rs index d7e822382ef92..121d975409900 100644 --- a/compiler/rustc_span/src/symbol.rs +++ b/compiler/rustc_span/src/symbol.rs @@ -929,6 +929,7 @@ symbols! { lib, libc, lifetime, + lifetime_capture_rules_2024, lifetimes, likely, line, diff --git a/tests/ui/feature-gates/feature-gate-lifetime-capture-rules-2024.rs b/tests/ui/feature-gates/feature-gate-lifetime-capture-rules-2024.rs new file mode 100644 index 0000000000000..c06107e66a76c --- /dev/null +++ b/tests/ui/feature-gates/feature-gate-lifetime-capture-rules-2024.rs @@ -0,0 +1,6 @@ +fn foo(x: &Vec) -> impl Sized { + x + //~^ ERROR hidden type for `impl Sized` captures lifetime that does not appear in bounds +} + +fn main() {} diff --git a/tests/ui/feature-gates/feature-gate-lifetime-capture-rules-2024.stderr b/tests/ui/feature-gates/feature-gate-lifetime-capture-rules-2024.stderr new file mode 100644 index 0000000000000..173e3dc02cc89 --- /dev/null +++ b/tests/ui/feature-gates/feature-gate-lifetime-capture-rules-2024.stderr @@ -0,0 +1,18 @@ +error[E0700]: hidden type for `impl Sized` captures lifetime that does not appear in bounds + --> $DIR/feature-gate-lifetime-capture-rules-2024.rs:2:5 + | +LL | fn foo(x: &Vec) -> impl Sized { + | --------- ---------- opaque type defined here + | | + | hidden type `&Vec` captures the anonymous lifetime defined here +LL | x + | ^ + | +help: to declare that `impl Sized` captures `'_`, you can add an explicit `'_` lifetime bound + | +LL | fn foo(x: &Vec) -> impl Sized + '_ { + | ++++ + +error: aborting due to 1 previous error + +For more information about this error, try `rustc --explain E0700`. diff --git a/tests/ui/impl-trait/variance.new.stderr b/tests/ui/impl-trait/variance.new.stderr new file mode 100644 index 0000000000000..abf4b1ac2104e --- /dev/null +++ b/tests/ui/impl-trait/variance.new.stderr @@ -0,0 +1,26 @@ +error: [*, o] + --> $DIR/variance.rs:12:36 + | +LL | fn not_captured_early<'a: 'a>() -> impl Sized {} + | ^^^^^^^^^^ + +error: [*, o] + --> $DIR/variance.rs:16:32 + | +LL | fn captured_early<'a: 'a>() -> impl Sized + Captures<'a> {} + | ^^^^^^^^^^^^^^^^^^^^^^^^^ + +error: [o] + --> $DIR/variance.rs:18:40 + | +LL | fn not_captured_late<'a>(_: &'a ()) -> impl Sized {} + | ^^^^^^^^^^ + +error: [o] + --> $DIR/variance.rs:22:36 + | +LL | fn captured_late<'a>(_: &'a ()) -> impl Sized + Captures<'a> {} + | ^^^^^^^^^^^^^^^^^^^^^^^^^ + +error: aborting due to 4 previous errors + diff --git a/tests/ui/impl-trait/variance.stderr b/tests/ui/impl-trait/variance.old.stderr similarity index 83% rename from tests/ui/impl-trait/variance.stderr rename to tests/ui/impl-trait/variance.old.stderr index 6447367541097..8b4d6314359e0 100644 --- a/tests/ui/impl-trait/variance.stderr +++ b/tests/ui/impl-trait/variance.old.stderr @@ -1,23 +1,23 @@ error: [*] - --> $DIR/variance.rs:8:36 + --> $DIR/variance.rs:12:36 | LL | fn not_captured_early<'a: 'a>() -> impl Sized {} | ^^^^^^^^^^ error: [*, o] - --> $DIR/variance.rs:10:32 + --> $DIR/variance.rs:16:32 | LL | fn captured_early<'a: 'a>() -> impl Sized + Captures<'a> {} | ^^^^^^^^^^^^^^^^^^^^^^^^^ error: [] - --> $DIR/variance.rs:12:40 + --> $DIR/variance.rs:18:40 | LL | fn not_captured_late<'a>(_: &'a ()) -> impl Sized {} | ^^^^^^^^^^ error: [o] - --> $DIR/variance.rs:14:36 + --> $DIR/variance.rs:22:36 | LL | fn captured_late<'a>(_: &'a ()) -> impl Sized + Captures<'a> {} | ^^^^^^^^^^^^^^^^^^^^^^^^^ diff --git a/tests/ui/impl-trait/variance.rs b/tests/ui/impl-trait/variance.rs index d6212f8f39372..e111d37761f4b 100644 --- a/tests/ui/impl-trait/variance.rs +++ b/tests/ui/impl-trait/variance.rs @@ -1,3 +1,7 @@ +// revisions: old new + +#![cfg_attr(new, feature(lifetime_capture_rules_2024))] + #![feature(rustc_attrs)] #![allow(internal_features)] #![rustc_variance_of_opaques] @@ -5,11 +9,15 @@ trait Captures<'a> {} impl Captures<'_> for T {} -fn not_captured_early<'a: 'a>() -> impl Sized {} //~ [*] +fn not_captured_early<'a: 'a>() -> impl Sized {} +//[old]~^ [*] +//[new]~^^ [*, o] fn captured_early<'a: 'a>() -> impl Sized + Captures<'a> {} //~ [*, o] -fn not_captured_late<'a>(_: &'a ()) -> impl Sized {} //~ [] +fn not_captured_late<'a>(_: &'a ()) -> impl Sized {} +//[old]~^ [] +//[new]~^^ [o] fn captured_late<'a>(_: &'a ()) -> impl Sized + Captures<'a> {} //~ [o]