From e8ae1dab12bc1388cd5f6545ccc88297b779f511 Mon Sep 17 00:00:00 2001 From: lcnr Date: Thu, 21 Aug 2025 15:45:40 +0200 Subject: [PATCH] next-solver fix const_trait_impl bootstrap --- compiler/rustc_middle/src/ty/context.rs | 7 ++++-- .../src/solve/effect_goals.rs | 18 +++++++------ .../const-traits/constructor-const-fn.rs | 15 +++++++++++ .../const-traits/reservation-impl-ice.rs | 13 ++++++++++ .../const-traits/reservation-impl-ice.stderr | 25 +++++++++++++++++++ 5 files changed, 69 insertions(+), 9 deletions(-) create mode 100644 tests/ui/traits/const-traits/constructor-const-fn.rs create mode 100644 tests/ui/traits/const-traits/reservation-impl-ice.rs create mode 100644 tests/ui/traits/const-traits/reservation-impl-ice.stderr diff --git a/compiler/rustc_middle/src/ty/context.rs b/compiler/rustc_middle/src/ty/context.rs index 49a4733de3b0a..c215e44a9650b 100644 --- a/compiler/rustc_middle/src/ty/context.rs +++ b/compiler/rustc_middle/src/ty/context.rs @@ -33,7 +33,7 @@ use rustc_errors::{ Applicability, Diag, DiagCtxtHandle, ErrorGuaranteed, LintDiagnostic, LintEmitter, MultiSpan, }; use rustc_hir::attrs::AttributeKind; -use rustc_hir::def::{CtorKind, DefKind}; +use rustc_hir::def::{CtorKind, CtorOf, DefKind}; use rustc_hir::def_id::{CrateNum, DefId, LOCAL_CRATE, LocalDefId}; use rustc_hir::definitions::{DefPathData, Definitions, DisambiguatorState}; use rustc_hir::intravisit::VisitorExt; @@ -445,7 +445,10 @@ impl<'tcx> Interner for TyCtxt<'tcx> { } fn fn_is_const(self, def_id: DefId) -> bool { - debug_assert_matches!(self.def_kind(def_id), DefKind::Fn | DefKind::AssocFn); + debug_assert_matches!( + self.def_kind(def_id), + DefKind::Fn | DefKind::AssocFn | DefKind::Ctor(CtorOf::Struct, CtorKind::Fn) + ); self.is_conditionally_const(def_id) } diff --git a/compiler/rustc_next_trait_solver/src/solve/effect_goals.rs b/compiler/rustc_next_trait_solver/src/solve/effect_goals.rs index 9a22bf58c0352..b7ae9994c6273 100644 --- a/compiler/rustc_next_trait_solver/src/solve/effect_goals.rs +++ b/compiler/rustc_next_trait_solver/src/solve/effect_goals.rs @@ -6,7 +6,7 @@ use rustc_type_ir::inherent::*; use rustc_type_ir::lang_items::TraitSolverLangItem; use rustc_type_ir::solve::SizedTraitKind; use rustc_type_ir::solve::inspect::ProbeKind; -use rustc_type_ir::{self as ty, Interner, elaborate}; +use rustc_type_ir::{self as ty, Interner, TypingMode, elaborate}; use tracing::instrument; use super::assembly::{Candidate, structural_traits}; @@ -135,12 +135,16 @@ where } let impl_polarity = cx.impl_polarity(impl_def_id); - match impl_polarity { + let certainty = match impl_polarity { ty::ImplPolarity::Negative => return Err(NoSolution), - ty::ImplPolarity::Reservation => { - unimplemented!("reservation impl for const trait: {:?}", goal) - } - ty::ImplPolarity::Positive => {} + ty::ImplPolarity::Reservation => match ecx.typing_mode() { + TypingMode::Coherence => Certainty::AMBIGUOUS, + TypingMode::Analysis { .. } + | TypingMode::Borrowck { .. } + | TypingMode::PostBorrowckAnalysis { .. } + | TypingMode::PostAnalysis => return Err(NoSolution), + }, + ty::ImplPolarity::Positive => Certainty::Yes, }; if !cx.impl_is_const(impl_def_id) { @@ -171,7 +175,7 @@ where }); ecx.add_goals(GoalSource::ImplWhereBound, const_conditions); - ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) + ecx.evaluate_added_goals_and_make_canonical_response(certainty) }) } diff --git a/tests/ui/traits/const-traits/constructor-const-fn.rs b/tests/ui/traits/const-traits/constructor-const-fn.rs new file mode 100644 index 0000000000000..4a7bf531df234 --- /dev/null +++ b/tests/ui/traits/const-traits/constructor-const-fn.rs @@ -0,0 +1,15 @@ +//@ check-pass +//@ compile-flags: -Znext-solver +#![feature(const_trait_impl)] +const fn impls_fn Foo>(_: &F) {} + +struct Foo(u32); + +const fn foo() { + // This previously triggered an incorrect assert + // when checking whether the constructor of `Foo` + // is const. + impls_fn(&Foo) +} + +fn main() {} diff --git a/tests/ui/traits/const-traits/reservation-impl-ice.rs b/tests/ui/traits/const-traits/reservation-impl-ice.rs new file mode 100644 index 0000000000000..efaea1cc6b2bf --- /dev/null +++ b/tests/ui/traits/const-traits/reservation-impl-ice.rs @@ -0,0 +1,13 @@ +//@ compile-flags: -Znext-solver +#![feature(const_from, never_type, const_trait_impl)] + +const fn impls_from>() {} + +const fn foo() { + // This previously ICE'd when encountering the reservation impl + // from the standard library. + impls_from::<()>(); + //~^ ERROR the trait bound `(): From` is not satisfied +} + +fn main() {} diff --git a/tests/ui/traits/const-traits/reservation-impl-ice.stderr b/tests/ui/traits/const-traits/reservation-impl-ice.stderr new file mode 100644 index 0000000000000..a3fdcbac69e39 --- /dev/null +++ b/tests/ui/traits/const-traits/reservation-impl-ice.stderr @@ -0,0 +1,25 @@ +error[E0277]: the trait bound `(): From` is not satisfied + --> $DIR/reservation-impl-ice.rs:9:18 + | +LL | impls_from::<()>(); + | ^^ the trait `From` is not implemented for `()` + | + = help: the following other types implement trait `From`: + `(T, T)` implements `From<[T; 2]>` + `(T, T, T)` implements `From<[T; 3]>` + `(T, T, T, T)` implements `From<[T; 4]>` + `(T, T, T, T, T)` implements `From<[T; 5]>` + `(T, T, T, T, T, T)` implements `From<[T; 6]>` + `(T, T, T, T, T, T, T)` implements `From<[T; 7]>` + `(T, T, T, T, T, T, T, T)` implements `From<[T; 8]>` + `(T, T, T, T, T, T, T, T, T)` implements `From<[T; 9]>` + and 4 others +note: required by a bound in `impls_from` + --> $DIR/reservation-impl-ice.rs:4:24 + | +LL | const fn impls_from>() {} + | ^^^^^^^^^^^^^^ required by this bound in `impls_from` + +error: aborting due to 1 previous error + +For more information about this error, try `rustc --explain E0277`.