diff --git a/compiler/rustc_lint/src/levels.rs b/compiler/rustc_lint/src/levels.rs index fbb20ed101055..472835388620c 100644 --- a/compiler/rustc_lint/src/levels.rs +++ b/compiler/rustc_lint/src/levels.rs @@ -969,14 +969,18 @@ where let mut lint = Diag::new(dcx, level, msg!("unknown lint: `{$name}`")) .with_arg("name", lint_id.lint.name_lower()) .with_note(msg!("the `{$name}` lint is unstable")); - rustc_session::diagnostics::add_feature_diagnostics_for_issue( - &mut lint, - sess, - feature, - GateIssue::Language, - lint_from_cli, - None, - ); + // `staged_api` is only intended for the standard library, so don't + // suggest enabling it just to use this lint. + if feature != sym::staged_api { + rustc_session::diagnostics::add_feature_diagnostics_for_issue( + &mut lint, + sess, + feature, + GateIssue::Language, + lint_from_cli, + None, + ); + } lint } } diff --git a/compiler/rustc_lint_defs/src/builtin.rs b/compiler/rustc_lint_defs/src/builtin.rs index 5ee3c5a741bdc..01076781ebb1d 100644 --- a/compiler/rustc_lint_defs/src/builtin.rs +++ b/compiler/rustc_lint_defs/src/builtin.rs @@ -152,6 +152,7 @@ pub mod hardwired { UNUSED_MUT, UNUSED_QUALIFICATIONS, UNUSED_UNSAFE, + UNUSED_UNSTABLE_REEXPORT_ATTRIBUTES, UNUSED_VARIABLES, UNUSED_VISIBILITIES, USELESS_DEPRECATED, @@ -2791,6 +2792,37 @@ declare_lint! { "detects deprecation attributes with no effect", } +declare_lint! { + /// The `unused_unstable_reexport_attributes` lint detects `#[unstable]` attributes + /// on re-exports where the attribute does not make the re-exported path unstable. + /// + /// ### Example + /// + /// ```rust,compile_fail + /// #![feature(staged_api)] + /// #![stable(feature = "test", since = "1.0.0")] + /// + /// #[stable(feature = "test", since = "1.0.0")] + /// pub struct S; + /// + /// #[unstable(feature = "reexport", issue = "none")] + /// pub use crate::S as T; + /// + /// fn main() {} + /// ``` + /// + /// {{produces}} + /// + /// ### Explanation + /// + /// Stability attributes on re-exports do not currently change the + /// stability of an otherwise stable re-exported item. + pub UNUSED_UNSTABLE_REEXPORT_ATTRIBUTES, + Deny, + "detects ineffective `#[unstable]` attributes on re-exports", + @feature_gate = staged_api; +} + declare_lint! { /// The `ineffective_unstable_trait_impl` lint detects `#[unstable]` attributes which are not used. /// diff --git a/compiler/rustc_passes/src/diagnostics.rs b/compiler/rustc_passes/src/diagnostics.rs index 16a2cc4007318..d79e947c657e5 100644 --- a/compiler/rustc_passes/src/diagnostics.rs +++ b/compiler/rustc_passes/src/diagnostics.rs @@ -964,6 +964,10 @@ pub(crate) struct UnnecessaryPartialStableFeature { #[note("see issue #55436 for more information")] pub(crate) struct IneffectiveUnstableImpl; +#[derive(Diagnostic)] +#[diag("`#[unstable]` does not make this re-exported path unstable")] +pub(crate) struct UnusedUnstableReexportAttributes; + // FIXME(jdonszelmann): move back to rustc_attr #[derive(Diagnostic)] #[diag( diff --git a/compiler/rustc_passes/src/stability.rs b/compiler/rustc_passes/src/stability.rs index 37ec1dc01bd4b..9aeadf9dc859e 100644 --- a/compiler/rustc_passes/src/stability.rs +++ b/compiler/rustc_passes/src/stability.rs @@ -19,8 +19,10 @@ use rustc_hir::{ use rustc_lint_defs as lint; use rustc_lint_defs::builtin::{ DEPRECATED, DUPLICATE_FEATURES, INEFFECTIVE_UNSTABLE_TRAIT_IMPL, STABLE_FEATURES, + UNUSED_UNSTABLE_REEXPORT_ATTRIBUTES, }; use rustc_middle::hir::nested_filter; +use rustc_middle::metadata::Reexport; use rustc_middle::middle::lib_features::{FeatureStability, LibFeatures}; use rustc_middle::middle::privacy::EffectiveVisibilities; use rustc_middle::middle::stability::{AllowUnstable, Deprecated, DeprecationEntry, EvalResult}; @@ -523,7 +525,9 @@ impl<'tcx> Visitor<'tcx> for MissingStabilityAnnotations<'tcx> { /// Cross-references the feature names of unstable APIs with enabled /// features and possibly prints errors. fn check_mod_unstable_api_usage(tcx: TyCtxt<'_>, mod_id: LocalModId) { - tcx.hir_visit_item_likes_in_module(mod_id, &mut Checker { tcx }); + let mut checker = Checker { tcx, mod_id, unstable_reexports: FxIndexMap::default() }; + tcx.hir_visit_item_likes_in_module(mod_id, &mut checker); + checker.emit_unused_unstable_reexport_attributes(); let is_staged_api = tcx.sess.opts.unstable_opts.force_unstable_if_unmarked || tcx.features().staged_api(); @@ -553,8 +557,135 @@ pub(crate) fn provide(providers: &mut Providers) { }; } +struct UnstableReexport { + hir_id: HirId, + span: Span, + has_target: bool, + all_targets_stable: bool, +} + struct Checker<'tcx> { tcx: TyCtxt<'tcx>, + mod_id: LocalModId, + unstable_reexports: FxIndexMap, +} + +impl<'tcx> Checker<'tcx> { + fn unstable_reexport_span(&self, item: &'tcx hir::Item<'tcx>) -> Option { + let attrs = self.tcx.hir_attrs(item.hir_id()); + let (stability, span) = + find_attr!(attrs, Stability { stability, span } => (*stability, *span))?; + + matches!(stability.level, StabilityLevel::Unstable { .. }).then_some(span) + } + + fn classify_reexport_targets( + &self, + targets: impl IntoIterator>, + ) -> (bool, bool) { + let mut has_target = false; + let mut all_targets_stable = true; + + for res in targets { + match res { + Res::Def(_, def_id) => { + has_target = true; + + if self.tcx.lookup_stability(def_id).is_some_and(|stab| !stab.level.is_stable()) + { + all_targets_stable = false; + } + } + + Res::PrimTy(_) => { + has_target = true; + } + + _ => { + all_targets_stable = false; + } + } + } + + (has_target, all_targets_stable) + } + + fn record_unstable_reexport( + &mut self, + item: &'tcx hir::Item<'tcx>, + attr_span: Span, + span: Span, + has_target: bool, + all_targets_stable: bool, + ) { + let entry = self.unstable_reexports.entry(attr_span).or_insert(UnstableReexport { + hir_id: item.hir_id(), + span, + has_target: false, + all_targets_stable: true, + }); + + entry.has_target |= has_target; + entry.all_targets_stable &= all_targets_stable; + } + + fn check_single_unstable_reexport( + &mut self, + item: &'tcx hir::Item<'tcx>, + path: &'tcx UsePath<'tcx>, + ) { + let Some(attr_span) = self.unstable_reexport_span(item) else { + return; + }; + + let (has_target, all_targets_stable) = + self.classify_reexport_targets(path.res.present_items()); + + self.record_unstable_reexport(item, attr_span, path.span, has_target, all_targets_stable); + } + + fn check_glob_unstable_reexport( + &mut self, + item: &'tcx hir::Item<'tcx>, + path: &'tcx UsePath<'tcx>, + ) { + let Some(attr_span) = self.unstable_reexport_span(item) else { + return; + }; + + let glob_def_id = item.owner_id.def_id.to_def_id(); + + let targets = self + .tcx + .module_children_local(self.mod_id.to_local_def_id()) + .iter() + .filter(|child| { + child.reexport_chain.iter().any(|reexport| { + matches!( + *reexport, + Reexport::Glob(def_id) if def_id == glob_def_id + ) + }) + }) + .map(|child| child.res); + + let (has_target, all_targets_stable) = self.classify_reexport_targets(targets); + + self.record_unstable_reexport(item, attr_span, path.span, has_target, all_targets_stable); + } + + fn emit_unused_unstable_reexport_attributes(&self) { + for reexport in self.unstable_reexports.values() { + if reexport.has_target && reexport.all_targets_stable { + self.tcx.emit_node_span_lint( + UNUSED_UNSTABLE_REEXPORT_ATTRIBUTES, + reexport.hir_id, + reexport.span, + diagnostics::UnusedUnstableReexportAttributes, + ); + } + } + } } impl<'tcx> Visitor<'tcx> for Checker<'tcx> { @@ -583,6 +714,20 @@ impl<'tcx> Visitor<'tcx> for Checker<'tcx> { self.tcx.check_stability(def_id, Some(item.hir_id()), item.span, None); } + hir::ItemKind::Use(path, hir::UseKind::Single(_)) + if self.tcx.features().staged_api() + && self.tcx.local_visibility(item.owner_id.def_id).is_public() => + { + self.check_single_unstable_reexport(item, path); + } + + hir::ItemKind::Use(path, hir::UseKind::Glob) + if self.tcx.features().staged_api() + && self.tcx.local_visibility(item.owner_id.def_id).is_public() => + { + self.check_glob_unstable_reexport(item, path); + } + // For implementations of traits, check the stability of each item // individually as it's possible to have a stable trait with unstable // items. diff --git a/library/alloc/src/io/mod.rs b/library/alloc/src/io/mod.rs index 44d780292317f..d7e07aa5d0282 100644 --- a/library/alloc/src/io/mod.rs +++ b/library/alloc/src/io/mod.rs @@ -194,6 +194,8 @@ pub use core::io::SimpleMessage; pub use core::io::const_error; #[unstable(feature = "core_io_borrowed_buf", issue = "117693")] pub use core::io::{BorrowedBuf, BorrowedCursor}; +#[allow(clippy::useless_attribute)] +#[allow(unused_unstable_reexport_attributes)] // FIXME(#161153) #[unstable(feature = "alloc_io", issue = "154046")] pub use core::io::{ Chain, Cursor, Empty, Error, ErrorKind, IoSlice, IoSliceMut, Repeat, Result, Seek, SeekFrom, @@ -209,6 +211,8 @@ use core::io::{ use self::read::{append_to_string, default_read_buf_exact, default_read_exact}; use self::util::{bytes, lines, split, uninlined_slow_read_byte}; +#[allow(clippy::useless_attribute)] +#[allow(unused_unstable_reexport_attributes)] // FIXME(#161153) #[unstable(feature = "alloc_io", issue = "154046")] pub use self::{ buf_read::BufRead, diff --git a/library/core/src/io/mod.rs b/library/core/src/io/mod.rs index a44d271535a9e..df463e4b29f79 100644 --- a/library/core/src/io/mod.rs +++ b/library/core/src/io/mod.rs @@ -20,6 +20,8 @@ pub use self::error::RawOsError; pub use self::error::SimpleMessage; #[unstable(feature = "io_const_error", issue = "133448")] pub use self::error::const_error; +#[allow(clippy::useless_attribute)] +#[allow(unused_unstable_reexport_attributes)] // FIXME(#161153) #[unstable(feature = "core_io", issue = "154046")] pub use self::{ cursor::Cursor, diff --git a/library/core/src/lib.rs b/library/core/src/lib.rs index f026434acbbc1..afdcc3371a4a3 100644 --- a/library/core/src/lib.rs +++ b/library/core/src/lib.rs @@ -227,6 +227,8 @@ pub mod offload; #[unstable(feature = "contracts", issue = "128044")] pub mod contracts; +#[allow(clippy::useless_attribute)] +#[allow(unused_unstable_reexport_attributes)] // FIXME(#161153) #[unstable(feature = "derive_macro_global_path", issue = "154645")] pub use crate::macros::builtin::derive; #[stable(feature = "cfg_select", since = "1.95.0")] diff --git a/library/core/src/ops/mod.rs b/library/core/src/ops/mod.rs index 6fa96c242fa76..3f5ac28db6ff7 100644 --- a/library/core/src/ops/mod.rs +++ b/library/core/src/ops/mod.rs @@ -156,6 +156,8 @@ mod unsize; pub use self::arith::{Add, Div, Mul, Neg, Rem, Sub}; #[stable(feature = "op_assign_traits", since = "1.8.0")] pub use self::arith::{AddAssign, DivAssign, MulAssign, RemAssign, SubAssign}; +#[allow(clippy::useless_attribute)] +#[allow(unused_unstable_reexport_attributes)] // FIXME(#161153) #[unstable(feature = "async_fn_traits", issue = "none")] pub use self::async_function::{AsyncFn, AsyncFnMut, AsyncFnOnce}; #[stable(feature = "rust1", since = "1.0.0")] diff --git a/library/std/src/lib.rs b/library/std/src/lib.rs index 980ec4416f04a..6f52867775a07 100644 --- a/library/std/src/lib.rs +++ b/library/std/src/lib.rs @@ -712,8 +712,12 @@ pub mod arch { pub use std_detect::is_aarch64_feature_detected; #[unstable(feature = "stdarch_arm_feature_detection", issue = "111190")] pub use std_detect::is_arm_feature_detected; + #[allow(clippy::useless_attribute)] + #[allow(unused_unstable_reexport_attributes)] // FIXME(#161153) #[unstable(feature = "is_loongarch_feature_detected", issue = "117425")] pub use std_detect::is_loongarch_feature_detected; + #[allow(clippy::useless_attribute)] + #[allow(unused_unstable_reexport_attributes)] // FIXME(#161153) #[unstable(feature = "is_riscv_feature_detected", issue = "111192")] pub use std_detect::is_riscv_feature_detected; #[stable(feature = "stdarch_s390x_feature_detection", since = "1.93.0")] @@ -750,6 +754,8 @@ pub use core::cfg_select; reason = "`concat_bytes` is not stable enough for use and is subject to change" )] pub use core::concat_bytes; +#[allow(clippy::useless_attribute)] +#[allow(unused_unstable_reexport_attributes)] // FIXME(#161153) #[unstable(feature = "derive_macro_global_path", issue = "154645")] pub use core::derive; #[stable(feature = "matches_macro", since = "1.42.0")] diff --git a/library/std/src/prelude/mod.rs b/library/std/src/prelude/mod.rs index 78eb79ac666a2..e0608d78c2e3c 100644 --- a/library/std/src/prelude/mod.rs +++ b/library/std/src/prelude/mod.rs @@ -181,12 +181,16 @@ pub mod rust_future { #[doc(no_inline)] pub use super::v1::*; + #[allow(clippy::useless_attribute)] + #[allow(unused_unstable_reexport_attributes)] // FIXME(#161153) #[unstable(feature = "prelude_next", issue = "none")] #[doc(no_inline)] pub use core::prelude::rust_future::*; // There are two different panic macros, one in `core` and one in `std`. They are slightly // different. For `std` we explicitly want the one defined in `std`. + #[allow(clippy::useless_attribute)] + #[allow(unused_unstable_reexport_attributes)] // FIXME(#161153) #[unstable(feature = "prelude_next", issue = "none")] pub use super::v1::panic; } diff --git a/tests/ui/feature-gates/feature-gate-unused_unstable_reexport_attributes.rs b/tests/ui/feature-gates/feature-gate-unused_unstable_reexport_attributes.rs new file mode 100644 index 0000000000000..87d3d42b46bc8 --- /dev/null +++ b/tests/ui/feature-gates/feature-gate-unused_unstable_reexport_attributes.rs @@ -0,0 +1,7 @@ +//@ check-pass +//@ normalize-stderr: "(\n)\n$" -> "$1" +// This lint is only available with `staged_api`. +#![allow(unused_unstable_reexport_attributes)] +//~^ WARNING unknown lint: `unused_unstable_reexport_attributes` + +fn main() {} diff --git a/tests/ui/feature-gates/feature-gate-unused_unstable_reexport_attributes.stderr b/tests/ui/feature-gates/feature-gate-unused_unstable_reexport_attributes.stderr new file mode 100644 index 0000000000000..7aff3ca5e9dc2 --- /dev/null +++ b/tests/ui/feature-gates/feature-gate-unused_unstable_reexport_attributes.stderr @@ -0,0 +1,10 @@ +warning: unknown lint: `unused_unstable_reexport_attributes` + --> $DIR/feature-gate-unused_unstable_reexport_attributes.rs:4:10 + | +LL | #![allow(unused_unstable_reexport_attributes)] + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | + = note: the `unused_unstable_reexport_attributes` lint is unstable + = note: `#[warn(unknown_lints)]` on by default + +warning: 1 warning emitted diff --git a/tests/ui/stability-attribute/auxiliary/stable-glob-source.rs b/tests/ui/stability-attribute/auxiliary/stable-glob-source.rs new file mode 100644 index 0000000000000..3d5bc44bc7862 --- /dev/null +++ b/tests/ui/stability-attribute/auxiliary/stable-glob-source.rs @@ -0,0 +1,10 @@ +#![crate_type = "lib"] +#![crate_name = "stable_glob_source"] +#![feature(staged_api)] +#![stable(feature = "stable_glob_source", since = "1.0.0")] + +#[stable(feature = "stable_glob_source", since = "1.0.0")] +pub fn stable_a() {} + +#[stable(feature = "stable_glob_source", since = "1.0.0")] +pub fn stable_b() {} diff --git a/tests/ui/stability-attribute/unused-unstable-reexport-attributes-glob.rs b/tests/ui/stability-attribute/unused-unstable-reexport-attributes-glob.rs new file mode 100644 index 0000000000000..bb875cb0630df --- /dev/null +++ b/tests/ui/stability-attribute/unused-unstable-reexport-attributes-glob.rs @@ -0,0 +1,20 @@ +//@ aux-build:lint-stability.rs +//@ aux-build:stable-glob-source.rs +//@ normalize-stderr: "(\n)\n$" -> "$1" + +#![crate_type = "lib"] +#![feature(staged_api)] +#![stable(feature = "reexport_test", since = "1.0.0")] + +extern crate lint_stability; +extern crate stable_glob_source; + +// Every item introduced by this glob is stable, so the unstable annotation +// cannot make the exported paths unstable. +#[unstable(feature = "stable_glob_reexport", issue = "none")] +pub use stable_glob_source::*; //~ ERROR `#[unstable]` does not make this re-exported path unstable + +// This glob contains unstable items, so #94972 makes the annotation +// relevant when checking the import itself. +#[unstable(feature = "unstable_test_feature", issue = "none")] +pub use lint_stability::*; diff --git a/tests/ui/stability-attribute/unused-unstable-reexport-attributes-glob.stderr b/tests/ui/stability-attribute/unused-unstable-reexport-attributes-glob.stderr new file mode 100644 index 0000000000000..44f007996b3bd --- /dev/null +++ b/tests/ui/stability-attribute/unused-unstable-reexport-attributes-glob.stderr @@ -0,0 +1,9 @@ +error: `#[unstable]` does not make this re-exported path unstable + --> $DIR/unused-unstable-reexport-attributes-glob.rs:15:9 + | +LL | pub use stable_glob_source::*; + | ^^^^^^^^^^^^^^^^^^ + | + = note: `#[deny(unused_unstable_reexport_attributes)]` on by default + +error: aborting due to 1 previous error diff --git a/tests/ui/stability-attribute/unused-unstable-reexport-attributes-grouped.rs b/tests/ui/stability-attribute/unused-unstable-reexport-attributes-grouped.rs new file mode 100644 index 0000000000000..4a9b3b6a8a532 --- /dev/null +++ b/tests/ui/stability-attribute/unused-unstable-reexport-attributes-grouped.rs @@ -0,0 +1,32 @@ +//@ aux-build:lint-stability.rs +//@ normalize-stderr: "(\n)\n$" -> "$1" + +#![crate_type = "lib"] +#![feature(staged_api)] +#![stable(feature = "reexport_test", since = "1.0.0")] + +extern crate lint_stability; + +// Both targets are stable. +// This should produce exactly one error for the shared attribute. +#[unstable(feature = "grouped_stable", issue = "none")] +pub use lint_stability::{ + stable as grouped_stable_a, //~ ERROR `#[unstable]` does not make this re-exported path unstable + stable_text as grouped_stable_b, +}; + +// The annotation is used by #94972 to allow importing the unstable member +// without enabling its feature in this crate. +#[unstable(feature = "grouped_mixed", issue = "none")] +pub use lint_stability::{ + stable as grouped_mixed_stable, + unstable as grouped_mixed_unstable, +}; + +// Both targets are already unstable. This is the #94972-style case and +// should not warn. +#[unstable(feature = "unstable_test_feature", issue = "none")] +pub use lint_stability::{ + unstable as grouped_unstable_a, + unstable_text as grouped_unstable_b, +}; diff --git a/tests/ui/stability-attribute/unused-unstable-reexport-attributes-grouped.stderr b/tests/ui/stability-attribute/unused-unstable-reexport-attributes-grouped.stderr new file mode 100644 index 0000000000000..b3ee0b09b0ae0 --- /dev/null +++ b/tests/ui/stability-attribute/unused-unstable-reexport-attributes-grouped.stderr @@ -0,0 +1,9 @@ +error: `#[unstable]` does not make this re-exported path unstable + --> $DIR/unused-unstable-reexport-attributes-grouped.rs:14:5 + | +LL | stable as grouped_stable_a, + | ^^^^^^ + | + = note: `#[deny(unused_unstable_reexport_attributes)]` on by default + +error: aborting due to 1 previous error diff --git a/tests/ui/stability-attribute/unused-unstable-reexport-attributes.rs b/tests/ui/stability-attribute/unused-unstable-reexport-attributes.rs new file mode 100644 index 0000000000000..1e46da673fd15 --- /dev/null +++ b/tests/ui/stability-attribute/unused-unstable-reexport-attributes.rs @@ -0,0 +1,23 @@ +//@ aux-build:lint-stability.rs +//@ normalize-stderr: "(\n)\n$" -> "$1" + +#![crate_type = "lib"] +#![feature(staged_api)] +#![stable(feature = "reexport_test", since = "1.0.0")] + +extern crate core; +extern crate lint_stability; + +// An unstable annotation cannot currently make a stable item unstable +// through a re-export. +#[unstable(feature = "reexport_test_unstable", issue = "none")] +pub use lint_stability::stable as supposedly_unstable; //~ ERROR `#[unstable]` does not make this re-exported path unstable + +// Primitive re-exports do not have a DefId, but the primitive itself is stable. +#[unstable(feature = "primitive_reexport", issue = "none")] +pub use core::primitive::bool as supposedly_unstable_bool; //~ ERROR `#[unstable]` does not make this re-exported path unstable + +// This is intentional: #94972 allows an unstable upstream item to be +// re-exported without enabling its feature in this crate. +#[unstable(feature = "unstable_test_feature", issue = "none")] +pub use lint_stability::unstable as still_unstable; diff --git a/tests/ui/stability-attribute/unused-unstable-reexport-attributes.stderr b/tests/ui/stability-attribute/unused-unstable-reexport-attributes.stderr new file mode 100644 index 0000000000000..2129efe6a616f --- /dev/null +++ b/tests/ui/stability-attribute/unused-unstable-reexport-attributes.stderr @@ -0,0 +1,15 @@ +error: `#[unstable]` does not make this re-exported path unstable + --> $DIR/unused-unstable-reexport-attributes.rs:14:9 + | +LL | pub use lint_stability::stable as supposedly_unstable; + | ^^^^^^^^^^^^^^^^^^^^^^ + | + = note: `#[deny(unused_unstable_reexport_attributes)]` on by default + +error: `#[unstable]` does not make this re-exported path unstable + --> $DIR/unused-unstable-reexport-attributes.rs:18:9 + | +LL | pub use core::primitive::bool as supposedly_unstable_bool; + | ^^^^^^^^^^^^^^^^^^^^^ + +error: aborting due to 2 previous errors