From 4aaf467e2686750bd74f6011f51deca3bd797ce9 Mon Sep 17 00:00:00 2001 From: Deadbeef Date: Sat, 25 Jan 2025 21:38:15 +0800 Subject: [PATCH 1/2] Implement MIR const trait stability checks --- compiler/rustc_const_eval/messages.ftl | 3 +- .../src/check_consts/check.rs | 168 +++++++++--------- .../rustc_const_eval/src/check_consts/mod.rs | 20 +-- .../rustc_const_eval/src/check_consts/ops.rs | 27 ++- compiler/rustc_const_eval/src/errors.rs | 12 +- .../const-traits/staged-api-user-crate.rs | 1 + .../const-traits/staged-api-user-crate.stderr | 13 +- tests/ui/traits/const-traits/staged-api.rs | 7 +- .../ui/traits/const-traits/staged-api.stderr | 101 ++++++++++- 9 files changed, 232 insertions(+), 120 deletions(-) diff --git a/compiler/rustc_const_eval/messages.ftl b/compiler/rustc_const_eval/messages.ftl index 485c8696342ab..d600d223bffd3 100644 --- a/compiler/rustc_const_eval/messages.ftl +++ b/compiler/rustc_const_eval/messages.ftl @@ -403,7 +403,7 @@ const_eval_uninhabited_enum_variant_read = const_eval_uninhabited_enum_variant_written = writing discriminant of an uninhabited enum variant -const_eval_unmarked_const_fn_exposed = `{$def_path}` cannot be (indirectly) exposed to stable +const_eval_unmarked_const_item_exposed = `{$def_path}` cannot be (indirectly) exposed to stable .help = either mark the callee as `#[rustc_const_stable_indirect]`, or the caller as `#[rustc_const_unstable]` const_eval_unmarked_intrinsic_exposed = intrinsic `{$def_path}` cannot be (indirectly) exposed to stable .help = mark the caller as `#[rustc_const_unstable]`, or mark the intrinsic `#[rustc_intrinsic_const_stable_indirect]` (but this requires team approval) @@ -414,6 +414,7 @@ const_eval_unreachable_unwind = const_eval_unsized_local = unsized locals are not supported const_eval_unstable_const_fn = `{$def_path}` is not yet stable as a const fn +const_eval_unstable_const_trait = `{$def_path}` is not yet stable as a const trait const_eval_unstable_in_stable_exposed = const function that might be (indirectly) exposed to stable cannot use `#[feature({$gate})]` .is_function_call = mark the callee as `#[rustc_const_stable_indirect]` if it does not itself require any unstable features diff --git a/compiler/rustc_const_eval/src/check_consts/check.rs b/compiler/rustc_const_eval/src/check_consts/check.rs index ed34996a7a7d7..b9e7c1ebb44d1 100644 --- a/compiler/rustc_const_eval/src/check_consts/check.rs +++ b/compiler/rustc_const_eval/src/check_consts/check.rs @@ -8,6 +8,7 @@ use std::ops::Deref; use rustc_attr_parsing::{ConstStability, StabilityLevel}; use rustc_errors::{Diag, ErrorGuaranteed}; +use rustc_hir::def::DefKind; use rustc_hir::def_id::DefId; use rustc_hir::{self as hir, LangItem}; use rustc_index::bit_set::DenseBitSet; @@ -29,7 +30,7 @@ use super::ops::{self, NonConstOp, Status}; use super::qualifs::{self, HasMutInterior, NeedsDrop, NeedsNonConstDrop}; use super::resolver::FlowSensitiveAnalysis; use super::{ConstCx, Qualif}; -use crate::check_consts::is_safe_to_expose_on_stable_const_fn; +use crate::check_consts::is_fn_or_trait_safe_to_expose_on_stable; use crate::errors; type QualifResults<'mir, 'tcx, Q> = @@ -470,6 +471,88 @@ impl<'mir, 'tcx> Checker<'mir, 'tcx> { self.tcx.crate_level_attribute_injection_span(self.tcx.local_def_id_to_hir_id(id)) }) } + + /// Check the const stability of the given item (fn or trait). + fn check_callee_stability(&mut self, def_id: DefId) { + match self.tcx.lookup_const_stability(def_id) { + Some(ConstStability { level: StabilityLevel::Stable { .. }, .. }) => { + // All good. + } + None => { + // This doesn't need a separate const-stability check -- const-stability equals + // regular stability, and regular stability is checked separately. + // However, we *do* have to worry about *recursive* const stability. + if self.enforce_recursive_const_stability() + && !is_fn_or_trait_safe_to_expose_on_stable(self.tcx, def_id) + { + self.dcx().emit_err(errors::UnmarkedConstItemExposed { + span: self.span, + def_path: self.tcx.def_path_str(def_id), + }); + } + } + Some(ConstStability { + level: StabilityLevel::Unstable { implied_by: implied_feature, issue, .. }, + feature, + .. + }) => { + // An unstable const fn/trait with a feature gate. + let callee_safe_to_expose_on_stable = + is_fn_or_trait_safe_to_expose_on_stable(self.tcx, def_id); + + // We only honor `span.allows_unstable` aka `#[allow_internal_unstable]` if + // the callee is safe to expose, to avoid bypassing recursive stability. + // This is not ideal since it means the user sees an error, not the macro + // author, but that's also the case if one forgets to set + // `#[allow_internal_unstable]` in the first place. Note that this cannot be + // integrated in the check below since we want to enforce + // `callee_safe_to_expose_on_stable` even if + // `!self.enforce_recursive_const_stability()`. + if (self.span.allows_unstable(feature) + || implied_feature.is_some_and(|f| self.span.allows_unstable(f))) + && callee_safe_to_expose_on_stable + { + return; + } + + // We can't use `check_op` to check whether the feature is enabled because + // the logic is a bit different than elsewhere: local functions don't need + // the feature gate, and there might be an "implied" gate that also suffices + // to allow this. + let feature_enabled = def_id.is_local() + || self.tcx.features().enabled(feature) + || implied_feature.is_some_and(|f| self.tcx.features().enabled(f)) + || { + // When we're compiling the compiler itself we may pull in + // crates from crates.io, but those crates may depend on other + // crates also pulled in from crates.io. We want to ideally be + // able to compile everything without requiring upstream + // modifications, so in the case that this looks like a + // `rustc_private` crate (e.g., a compiler crate) and we also have + // the `-Z force-unstable-if-unmarked` flag present (we're + // compiling a compiler crate), then let this missing feature + // annotation slide. + // This matches what we do in `eval_stability_allow_unstable` for + // regular stability. + feature == sym::rustc_private + && issue == NonZero::new(27812) + && self.tcx.sess.opts.unstable_opts.force_unstable_if_unmarked + }; + // Even if the feature is enabled, we still need check_op to double-check + // this if the callee is not safe to expose on stable. + if !feature_enabled || !callee_safe_to_expose_on_stable { + self.check_op(ops::CallUnstable { + def_id, + feature, + feature_enabled, + safe_to_expose_on_stable: callee_safe_to_expose_on_stable, + suggestion_span: self.crate_inject_span(), + is_function_call: self.tcx.def_kind(def_id) != DefKind::Trait, + }); + } + } + } + } } impl<'tcx> Visitor<'tcx> for Checker<'_, 'tcx> { @@ -716,8 +799,7 @@ impl<'tcx> Visitor<'tcx> for Checker<'_, 'tcx> { span: *fn_span, call_source, }); - // FIXME(const_trait_impl): do a more fine-grained check whether this - // particular trait can be const-stably called. + self.check_callee_stability(trait_did); } else { // Not even a const trait. self.check_op(ops::FnCallNonConst { @@ -793,7 +875,7 @@ impl<'tcx> Visitor<'tcx> for Checker<'_, 'tcx> { // fallback body is safe to expose on stable. let is_const_stable = intrinsic.const_stable || (!intrinsic.must_be_overridden - && is_safe_to_expose_on_stable_const_fn(tcx, callee)); + && is_fn_or_trait_safe_to_expose_on_stable(tcx, callee)); match tcx.lookup_const_stability(callee) { None => { // This doesn't need a separate const-stability check -- const-stability equals @@ -842,83 +924,7 @@ impl<'tcx> Visitor<'tcx> for Checker<'_, 'tcx> { } // Finally, stability for regular function calls -- this is the big one. - match tcx.lookup_const_stability(callee) { - Some(ConstStability { level: StabilityLevel::Stable { .. }, .. }) => { - // All good. - } - None => { - // This doesn't need a separate const-stability check -- const-stability equals - // regular stability, and regular stability is checked separately. - // However, we *do* have to worry about *recursive* const stability. - if self.enforce_recursive_const_stability() - && !is_safe_to_expose_on_stable_const_fn(tcx, callee) - { - self.dcx().emit_err(errors::UnmarkedConstFnExposed { - span: self.span, - def_path: self.tcx.def_path_str(callee), - }); - } - } - Some(ConstStability { - level: StabilityLevel::Unstable { implied_by: implied_feature, issue, .. }, - feature, - .. - }) => { - // An unstable const fn with a feature gate. - let callee_safe_to_expose_on_stable = - is_safe_to_expose_on_stable_const_fn(tcx, callee); - - // We only honor `span.allows_unstable` aka `#[allow_internal_unstable]` if - // the callee is safe to expose, to avoid bypassing recursive stability. - // This is not ideal since it means the user sees an error, not the macro - // author, but that's also the case if one forgets to set - // `#[allow_internal_unstable]` in the first place. Note that this cannot be - // integrated in the check below since we want to enforce - // `callee_safe_to_expose_on_stable` even if - // `!self.enforce_recursive_const_stability()`. - if (self.span.allows_unstable(feature) - || implied_feature.is_some_and(|f| self.span.allows_unstable(f))) - && callee_safe_to_expose_on_stable - { - return; - } - - // We can't use `check_op` to check whether the feature is enabled because - // the logic is a bit different than elsewhere: local functions don't need - // the feature gate, and there might be an "implied" gate that also suffices - // to allow this. - let feature_enabled = callee.is_local() - || tcx.features().enabled(feature) - || implied_feature.is_some_and(|f| tcx.features().enabled(f)) - || { - // When we're compiling the compiler itself we may pull in - // crates from crates.io, but those crates may depend on other - // crates also pulled in from crates.io. We want to ideally be - // able to compile everything without requiring upstream - // modifications, so in the case that this looks like a - // `rustc_private` crate (e.g., a compiler crate) and we also have - // the `-Z force-unstable-if-unmarked` flag present (we're - // compiling a compiler crate), then let this missing feature - // annotation slide. - // This matches what we do in `eval_stability_allow_unstable` for - // regular stability. - feature == sym::rustc_private - && issue == NonZero::new(27812) - && tcx.sess.opts.unstable_opts.force_unstable_if_unmarked - }; - // Even if the feature is enabled, we still need check_op to double-check - // this if the callee is not safe to expose on stable. - if !feature_enabled || !callee_safe_to_expose_on_stable { - self.check_op(ops::FnCallUnstable { - def_id: callee, - feature, - feature_enabled, - safe_to_expose_on_stable: callee_safe_to_expose_on_stable, - suggestion_span: self.crate_inject_span(), - }); - } - } - } + self.check_callee_stability(callee); } // Forbid all `Drop` terminators unless the place being dropped is a local with no diff --git a/compiler/rustc_const_eval/src/check_consts/mod.rs b/compiler/rustc_const_eval/src/check_consts/mod.rs index ab68691f1b97a..bfa0a0319c344 100644 --- a/compiler/rustc_const_eval/src/check_consts/mod.rs +++ b/compiler/rustc_const_eval/src/check_consts/mod.rs @@ -56,7 +56,7 @@ impl<'mir, 'tcx> ConstCx<'mir, 'tcx> { self.const_kind == Some(hir::ConstContext::ConstFn) && (self.tcx.features().staged_api() || self.tcx.sess.opts.unstable_opts.force_unstable_if_unmarked) - && is_safe_to_expose_on_stable_const_fn(self.tcx, self.def_id().to_def_id()) + && is_fn_or_trait_safe_to_expose_on_stable(self.tcx, self.def_id().to_def_id()) } fn is_async(&self) -> bool { @@ -84,28 +84,14 @@ pub fn rustc_allow_const_fn_unstable( attr::rustc_allow_const_fn_unstable(tcx.sess, attrs).any(|name| name == feature_gate) } -/// Returns `true` if the given `const fn` is "safe to expose on stable". -/// -/// Panics if the given `DefId` does not refer to a `const fn`. +/// Returns `true` if the given `def_id` (trait or function) is "safe to expose on stable". /// /// This is relevant within a `staged_api` crate. Unlike with normal features, the use of unstable /// const features *recursively* taints the functions that use them. This is to avoid accidentally /// exposing e.g. the implementation of an unstable const intrinsic on stable. So we partition the /// world into two functions: those that are safe to expose on stable (and hence may not use /// unstable features, not even recursively), and those that are not. -pub fn is_safe_to_expose_on_stable_const_fn(tcx: TyCtxt<'_>, def_id: DefId) -> bool { - // A default body in a `#[const_trait]` is not const-stable because const trait fns currently - // cannot be const-stable. These functions can't be called from anything stable, so we shouldn't - // restrict them to only call const-stable functions. - if tcx.is_const_default_method(def_id) { - // FIXME(const_trait_impl): we have to eventually allow some of these if these things can ever be stable. - // They should probably behave like regular `const fn` for that... - return false; - } - - // Const-stability is only relevant for `const fn`. - assert!(tcx.is_const_fn(def_id)); - +pub fn is_fn_or_trait_safe_to_expose_on_stable(tcx: TyCtxt<'_>, def_id: DefId) -> bool { match tcx.lookup_const_stability(def_id) { None => { // In a `staged_api` crate, we do enforce recursive const stability for all unmarked diff --git a/compiler/rustc_const_eval/src/check_consts/ops.rs b/compiler/rustc_const_eval/src/check_consts/ops.rs index 3c83a7b92cdc6..7756e51c4c5f2 100644 --- a/compiler/rustc_const_eval/src/check_consts/ops.rs +++ b/compiler/rustc_const_eval/src/check_consts/ops.rs @@ -377,11 +377,11 @@ fn build_error_for_const_call<'tcx>( err } -/// A call to an `#[unstable]` const fn or `#[rustc_const_unstable]` function. +/// A call to an `#[unstable]` const fn, `#[rustc_const_unstable]` function or trait. /// -/// Contains the name of the feature that would allow the use of this function. +/// Contains the name of the feature that would allow the use of this function/trait. #[derive(Debug)] -pub(crate) struct FnCallUnstable { +pub(crate) struct CallUnstable { pub def_id: DefId, pub feature: Symbol, /// If this is true, then the feature is enabled, but we need to still check if it is safe to @@ -389,24 +389,33 @@ pub(crate) struct FnCallUnstable { pub feature_enabled: bool, pub safe_to_expose_on_stable: bool, pub suggestion_span: Option, + /// true if `def_id` is the function we are calling, false if `def_id` is an unstable trait. + pub is_function_call: bool, } -impl<'tcx> NonConstOp<'tcx> for FnCallUnstable { +impl<'tcx> NonConstOp<'tcx> for CallUnstable { fn status_in_item(&self, _ccx: &ConstCx<'_, 'tcx>) -> Status { Status::Unstable { gate: self.feature, gate_already_checked: self.feature_enabled, safe_to_expose_on_stable: self.safe_to_expose_on_stable, - is_function_call: true, + is_function_call: self.is_function_call, } } fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> Diag<'tcx> { assert!(!self.feature_enabled); - let mut err = ccx.dcx().create_err(errors::UnstableConstFn { - span, - def_path: ccx.tcx.def_path_str(self.def_id), - }); + let mut err = if self.is_function_call { + ccx.dcx().create_err(errors::UnstableConstFn { + span, + def_path: ccx.tcx.def_path_str(self.def_id), + }) + } else { + ccx.dcx().create_err(errors::UnstableConstTrait { + span, + def_path: ccx.tcx.def_path_str(self.def_id), + }) + }; // FIXME: make this translatable let msg = format!("add `#![feature({})]` to the crate attributes to enable", self.feature); #[allow(rustc::untranslatable_diagnostic)] diff --git a/compiler/rustc_const_eval/src/errors.rs b/compiler/rustc_const_eval/src/errors.rs index 1ee9214c4b2a0..a2635885098e3 100644 --- a/compiler/rustc_const_eval/src/errors.rs +++ b/compiler/rustc_const_eval/src/errors.rs @@ -121,6 +121,14 @@ pub(crate) struct UnstableConstFn { pub def_path: String, } +#[derive(Diagnostic)] +#[diag(const_eval_unstable_const_trait)] +pub(crate) struct UnstableConstTrait { + #[primary_span] + pub span: Span, + pub def_path: String, +} + #[derive(Diagnostic)] #[diag(const_eval_unstable_intrinsic)] pub(crate) struct UnstableIntrinsic { @@ -139,9 +147,9 @@ pub(crate) struct UnstableIntrinsic { } #[derive(Diagnostic)] -#[diag(const_eval_unmarked_const_fn_exposed)] +#[diag(const_eval_unmarked_const_item_exposed)] #[help] -pub(crate) struct UnmarkedConstFnExposed { +pub(crate) struct UnmarkedConstItemExposed { #[primary_span] pub span: Span, pub def_path: String, diff --git a/tests/ui/traits/const-traits/staged-api-user-crate.rs b/tests/ui/traits/const-traits/staged-api-user-crate.rs index 7587042cf276d..4aa75a50355b0 100644 --- a/tests/ui/traits/const-traits/staged-api-user-crate.rs +++ b/tests/ui/traits/const-traits/staged-api-user-crate.rs @@ -11,6 +11,7 @@ fn non_const_context() { const fn stable_const_context() { Unstable::func(); //~^ ERROR cannot call conditionally-const associated function `::func` in constant functions + //~| ERROR `staged_api::MyTrait` is not yet stable as a const trait } fn main() {} diff --git a/tests/ui/traits/const-traits/staged-api-user-crate.stderr b/tests/ui/traits/const-traits/staged-api-user-crate.stderr index 400c76fcaf494..8ac83770cf7a4 100644 --- a/tests/ui/traits/const-traits/staged-api-user-crate.stderr +++ b/tests/ui/traits/const-traits/staged-api-user-crate.stderr @@ -9,6 +9,17 @@ LL | Unstable::func(); = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date -error: aborting due to 1 previous error +error: `staged_api::MyTrait` is not yet stable as a const trait + --> $DIR/staged-api-user-crate.rs:12:5 + | +LL | Unstable::func(); + | ^^^^^^^^^^^^^^^^ + | +help: add `#![feature(unstable)]` to the crate attributes to enable + | +LL + #![feature(unstable)] + | + +error: aborting due to 2 previous errors For more information about this error, try `rustc --explain E0658`. diff --git a/tests/ui/traits/const-traits/staged-api.rs b/tests/ui/traits/const-traits/staged-api.rs index 755a4e456bcf9..406aaab547165 100644 --- a/tests/ui/traits/const-traits/staged-api.rs +++ b/tests/ui/traits/const-traits/staged-api.rs @@ -22,7 +22,7 @@ impl const MyTrait for Foo { fn func() {} } -#[rustc_allow_const_fn_unstable(const_trait_impl)] +#[rustc_allow_const_fn_unstable(const_trait_impl, unstable)] const fn conditionally_const() { T::func(); } @@ -37,10 +37,13 @@ fn non_const_context() { const fn const_context() { Unstable::func(); //~^ ERROR cannot use `#[feature(const_trait_impl)]` + //~| ERROR cannot use `#[feature(unstable)]` Foo::func(); //~^ ERROR cannot use `#[feature(const_trait_impl)]` + //~| ERROR cannot use `#[feature(unstable)]` Unstable2::func(); //~^ ERROR cannot use `#[feature(const_trait_impl)]` + //~| ERROR cannot use `#[feature(unstable)]` conditionally_const::(); //~^ ERROR cannot use `#[feature(const_trait_impl)]` } @@ -59,8 +62,10 @@ pub const fn const_context_not_const_stable() { const fn stable_const_context() { Unstable::func(); //~^ ERROR cannot use `#[feature(const_trait_impl)]` + //~| ERROR cannot use `#[feature(unstable)]` Foo::func(); //~^ ERROR cannot use `#[feature(const_trait_impl)]` + //~| ERROR cannot use `#[feature(unstable)]` const_context_not_const_stable(); //~^ ERROR cannot use `#[feature(local_feature)]` conditionally_const::(); diff --git a/tests/ui/traits/const-traits/staged-api.stderr b/tests/ui/traits/const-traits/staged-api.stderr index acc93f747a8ec..5e206d5793496 100644 --- a/tests/ui/traits/const-traits/staged-api.stderr +++ b/tests/ui/traits/const-traits/staged-api.stderr @@ -15,8 +15,25 @@ LL + #[rustc_allow_const_fn_unstable(const_trait_impl)] LL | const fn const_context() { | +error: const function that might be (indirectly) exposed to stable cannot use `#[feature(unstable)]` + --> $DIR/staged-api.rs:38:5 + | +LL | Unstable::func(); + | ^^^^^^^^^^^^^^^^ + | +help: if the function is not (yet) meant to be exposed to stable, add `#[rustc_const_unstable]` (this is what you probably want to do) + | +LL + #[rustc_const_unstable(feature = "...", issue = "...")] +LL | const fn const_context() { + | +help: otherwise, as a last resort `#[rustc_allow_const_fn_unstable]` can be used to bypass stability checks (this requires team approval) + | +LL + #[rustc_allow_const_fn_unstable(unstable)] +LL | const fn const_context() { + | + error: const function that might be (indirectly) exposed to stable cannot use `#[feature(const_trait_impl)]` - --> $DIR/staged-api.rs:40:5 + --> $DIR/staged-api.rs:41:5 | LL | Foo::func(); | ^^^^^^^^^^^ @@ -32,8 +49,25 @@ LL + #[rustc_allow_const_fn_unstable(const_trait_impl)] LL | const fn const_context() { | +error: const function that might be (indirectly) exposed to stable cannot use `#[feature(unstable)]` + --> $DIR/staged-api.rs:41:5 + | +LL | Foo::func(); + | ^^^^^^^^^^^ + | +help: if the function is not (yet) meant to be exposed to stable, add `#[rustc_const_unstable]` (this is what you probably want to do) + | +LL + #[rustc_const_unstable(feature = "...", issue = "...")] +LL | const fn const_context() { + | +help: otherwise, as a last resort `#[rustc_allow_const_fn_unstable]` can be used to bypass stability checks (this requires team approval) + | +LL + #[rustc_allow_const_fn_unstable(unstable)] +LL | const fn const_context() { + | + error: const function that might be (indirectly) exposed to stable cannot use `#[feature(const_trait_impl)]` - --> $DIR/staged-api.rs:42:5 + --> $DIR/staged-api.rs:44:5 | LL | Unstable2::func(); | ^^^^^^^^^^^^^^^^^ @@ -49,9 +83,26 @@ LL + #[rustc_allow_const_fn_unstable(const_trait_impl)] LL | const fn const_context() { | -error: const function that might be (indirectly) exposed to stable cannot use `#[feature(const_trait_impl)]` +error: const function that might be (indirectly) exposed to stable cannot use `#[feature(unstable)]` --> $DIR/staged-api.rs:44:5 | +LL | Unstable2::func(); + | ^^^^^^^^^^^^^^^^^ + | +help: if the function is not (yet) meant to be exposed to stable, add `#[rustc_const_unstable]` (this is what you probably want to do) + | +LL + #[rustc_const_unstable(feature = "...", issue = "...")] +LL | const fn const_context() { + | +help: otherwise, as a last resort `#[rustc_allow_const_fn_unstable]` can be used to bypass stability checks (this requires team approval) + | +LL + #[rustc_allow_const_fn_unstable(unstable)] +LL | const fn const_context() { + | + +error: const function that might be (indirectly) exposed to stable cannot use `#[feature(const_trait_impl)]` + --> $DIR/staged-api.rs:47:5 + | LL | conditionally_const::(); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | @@ -67,7 +118,7 @@ LL | const fn const_context() { | error: const function that might be (indirectly) exposed to stable cannot use `#[feature(const_trait_impl)]` - --> $DIR/staged-api.rs:60:5 + --> $DIR/staged-api.rs:63:5 | LL | Unstable::func(); | ^^^^^^^^^^^^^^^^ @@ -83,8 +134,25 @@ LL + #[rustc_allow_const_fn_unstable(const_trait_impl)] LL | const fn stable_const_context() { | +error: const function that might be (indirectly) exposed to stable cannot use `#[feature(unstable)]` + --> $DIR/staged-api.rs:63:5 + | +LL | Unstable::func(); + | ^^^^^^^^^^^^^^^^ + | +help: if the function is not (yet) meant to be exposed to stable, add `#[rustc_const_unstable]` (this is what you probably want to do) + | +LL + #[rustc_const_unstable(feature = "...", issue = "...")] +LL | const fn stable_const_context() { + | +help: otherwise, as a last resort `#[rustc_allow_const_fn_unstable]` can be used to bypass stability checks (this requires team approval) + | +LL + #[rustc_allow_const_fn_unstable(unstable)] +LL | const fn stable_const_context() { + | + error: const function that might be (indirectly) exposed to stable cannot use `#[feature(const_trait_impl)]` - --> $DIR/staged-api.rs:62:5 + --> $DIR/staged-api.rs:66:5 | LL | Foo::func(); | ^^^^^^^^^^^ @@ -100,8 +168,25 @@ LL + #[rustc_allow_const_fn_unstable(const_trait_impl)] LL | const fn stable_const_context() { | +error: const function that might be (indirectly) exposed to stable cannot use `#[feature(unstable)]` + --> $DIR/staged-api.rs:66:5 + | +LL | Foo::func(); + | ^^^^^^^^^^^ + | +help: if the function is not (yet) meant to be exposed to stable, add `#[rustc_const_unstable]` (this is what you probably want to do) + | +LL + #[rustc_const_unstable(feature = "...", issue = "...")] +LL | const fn stable_const_context() { + | +help: otherwise, as a last resort `#[rustc_allow_const_fn_unstable]` can be used to bypass stability checks (this requires team approval) + | +LL + #[rustc_allow_const_fn_unstable(unstable)] +LL | const fn stable_const_context() { + | + error: const function that might be (indirectly) exposed to stable cannot use `#[feature(local_feature)]` - --> $DIR/staged-api.rs:64:5 + --> $DIR/staged-api.rs:69:5 | LL | const_context_not_const_stable(); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ @@ -119,7 +204,7 @@ LL | const fn stable_const_context() { | error: const function that might be (indirectly) exposed to stable cannot use `#[feature(const_trait_impl)]` - --> $DIR/staged-api.rs:66:5 + --> $DIR/staged-api.rs:71:5 | LL | conditionally_const::(); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ @@ -135,5 +220,5 @@ LL + #[rustc_allow_const_fn_unstable(const_trait_impl)] LL | const fn stable_const_context() { | -error: aborting due to 8 previous errors +error: aborting due to 13 previous errors From d250657a3c398e80e4d53bd311cafce82512b87a Mon Sep 17 00:00:00 2001 From: Deadbeef Date: Tue, 28 Jan 2025 04:33:39 +0000 Subject: [PATCH 2/2] add test case for implicitly stable const fn --- tests/ui/traits/const-traits/staged-api.rs | 13 +++ .../ui/traits/const-traits/staged-api.stderr | 105 +++++++++++++++++- 2 files changed, 117 insertions(+), 1 deletion(-) diff --git a/tests/ui/traits/const-traits/staged-api.rs b/tests/ui/traits/const-traits/staged-api.rs index 406aaab547165..9a030dafd6bc4 100644 --- a/tests/ui/traits/const-traits/staged-api.rs +++ b/tests/ui/traits/const-traits/staged-api.rs @@ -72,4 +72,17 @@ const fn stable_const_context() { //~^ ERROR cannot use `#[feature(const_trait_impl)]` } +const fn implicitly_stable_const_context() { + Unstable::func(); + //~^ ERROR cannot use `#[feature(const_trait_impl)]` + //~| ERROR cannot use `#[feature(unstable)]` + Foo::func(); + //~^ ERROR cannot use `#[feature(const_trait_impl)]` + //~| ERROR cannot use `#[feature(unstable)]` + const_context_not_const_stable(); + //~^ ERROR cannot use `#[feature(local_feature)]` + conditionally_const::(); + //~^ ERROR cannot use `#[feature(const_trait_impl)]` +} + fn main() {} diff --git a/tests/ui/traits/const-traits/staged-api.stderr b/tests/ui/traits/const-traits/staged-api.stderr index 5e206d5793496..a7a7a1ee7215b 100644 --- a/tests/ui/traits/const-traits/staged-api.stderr +++ b/tests/ui/traits/const-traits/staged-api.stderr @@ -220,5 +220,108 @@ LL + #[rustc_allow_const_fn_unstable(const_trait_impl)] LL | const fn stable_const_context() { | -error: aborting due to 13 previous errors +error: const function that might be (indirectly) exposed to stable cannot use `#[feature(const_trait_impl)]` + --> $DIR/staged-api.rs:76:5 + | +LL | Unstable::func(); + | ^^^^^^^^^^^^^^^^ + | +help: if the function is not (yet) meant to be exposed to stable, add `#[rustc_const_unstable]` (this is what you probably want to do) + | +LL + #[rustc_const_unstable(feature = "...", issue = "...")] +LL | const fn implicitly_stable_const_context() { + | +help: otherwise, as a last resort `#[rustc_allow_const_fn_unstable]` can be used to bypass stability checks (this requires team approval) + | +LL + #[rustc_allow_const_fn_unstable(const_trait_impl)] +LL | const fn implicitly_stable_const_context() { + | + +error: const function that might be (indirectly) exposed to stable cannot use `#[feature(unstable)]` + --> $DIR/staged-api.rs:76:5 + | +LL | Unstable::func(); + | ^^^^^^^^^^^^^^^^ + | +help: if the function is not (yet) meant to be exposed to stable, add `#[rustc_const_unstable]` (this is what you probably want to do) + | +LL + #[rustc_const_unstable(feature = "...", issue = "...")] +LL | const fn implicitly_stable_const_context() { + | +help: otherwise, as a last resort `#[rustc_allow_const_fn_unstable]` can be used to bypass stability checks (this requires team approval) + | +LL + #[rustc_allow_const_fn_unstable(unstable)] +LL | const fn implicitly_stable_const_context() { + | + +error: const function that might be (indirectly) exposed to stable cannot use `#[feature(const_trait_impl)]` + --> $DIR/staged-api.rs:79:5 + | +LL | Foo::func(); + | ^^^^^^^^^^^ + | +help: if the function is not (yet) meant to be exposed to stable, add `#[rustc_const_unstable]` (this is what you probably want to do) + | +LL + #[rustc_const_unstable(feature = "...", issue = "...")] +LL | const fn implicitly_stable_const_context() { + | +help: otherwise, as a last resort `#[rustc_allow_const_fn_unstable]` can be used to bypass stability checks (this requires team approval) + | +LL + #[rustc_allow_const_fn_unstable(const_trait_impl)] +LL | const fn implicitly_stable_const_context() { + | + +error: const function that might be (indirectly) exposed to stable cannot use `#[feature(unstable)]` + --> $DIR/staged-api.rs:79:5 + | +LL | Foo::func(); + | ^^^^^^^^^^^ + | +help: if the function is not (yet) meant to be exposed to stable, add `#[rustc_const_unstable]` (this is what you probably want to do) + | +LL + #[rustc_const_unstable(feature = "...", issue = "...")] +LL | const fn implicitly_stable_const_context() { + | +help: otherwise, as a last resort `#[rustc_allow_const_fn_unstable]` can be used to bypass stability checks (this requires team approval) + | +LL + #[rustc_allow_const_fn_unstable(unstable)] +LL | const fn implicitly_stable_const_context() { + | + +error: const function that might be (indirectly) exposed to stable cannot use `#[feature(local_feature)]` + --> $DIR/staged-api.rs:82:5 + | +LL | const_context_not_const_stable(); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | + = help: mark the callee as `#[rustc_const_stable_indirect]` if it does not itself require any unstable features +help: if the caller is not (yet) meant to be exposed to stable, add `#[rustc_const_unstable]` (this is what you probably want to do) + | +LL + #[rustc_const_unstable(feature = "...", issue = "...")] +LL | const fn implicitly_stable_const_context() { + | +help: otherwise, as a last resort `#[rustc_allow_const_fn_unstable]` can be used to bypass stability checks (this requires team approval) + | +LL + #[rustc_allow_const_fn_unstable(local_feature)] +LL | const fn implicitly_stable_const_context() { + | + +error: const function that might be (indirectly) exposed to stable cannot use `#[feature(const_trait_impl)]` + --> $DIR/staged-api.rs:84:5 + | +LL | conditionally_const::(); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | +help: if the function is not (yet) meant to be exposed to stable, add `#[rustc_const_unstable]` (this is what you probably want to do) + | +LL + #[rustc_const_unstable(feature = "...", issue = "...")] +LL | const fn implicitly_stable_const_context() { + | +help: otherwise, as a last resort `#[rustc_allow_const_fn_unstable]` can be used to bypass stability checks (this requires team approval) + | +LL + #[rustc_allow_const_fn_unstable(const_trait_impl)] +LL | const fn implicitly_stable_const_context() { + | + +error: aborting due to 19 previous errors