From fafe9e71d5c949c41a5a562e44cc40d72c5f7244 Mon Sep 17 00:00:00 2001 From: Matthew Jasper Date: Fri, 5 May 2023 15:50:17 +0100 Subject: [PATCH] Normalize consistently for specializations --- .../src/traits/specialize/mod.rs | 39 +++++++++++-------- .../specialize-associated-type.rs | 37 ++++++++++++++++++ .../specialize_on_type_error.rs | 33 ++++++++++++++++ .../specialize_on_type_error.stderr | 12 ++++++ 4 files changed, 104 insertions(+), 17 deletions(-) create mode 100644 tests/ui/specialization/min_specialization/specialize-associated-type.rs create mode 100644 tests/ui/specialization/min_specialization/specialize_on_type_error.rs create mode 100644 tests/ui/specialization/min_specialization/specialize_on_type_error.stderr diff --git a/compiler/rustc_trait_selection/src/traits/specialize/mod.rs b/compiler/rustc_trait_selection/src/traits/specialize/mod.rs index 233d35aed38..8bbebadb22a 100644 --- a/compiler/rustc_trait_selection/src/traits/specialize/mod.rs +++ b/compiler/rustc_trait_selection/src/traits/specialize/mod.rs @@ -99,14 +99,13 @@ pub fn translate_substs<'tcx>( return source_substs; } - fulfill_implication(infcx, param_env, source_trait_ref, target_impl).unwrap_or_else( - |()| { + fulfill_implication(infcx, param_env, source_trait_ref, source_impl, target_impl) + .unwrap_or_else(|()| { bug!( "When translating substitutions from {source_impl:?} to {target_impl:?}, \ the expected specialization failed to hold" ) - }, - ) + }) } specialization_graph::Node::Trait(..) => source_trait_ref.substs, }; @@ -153,20 +152,9 @@ pub(super) fn specializes(tcx: TyCtxt<'_>, (impl1_def_id, impl2_def_id): (DefId, // Create an infcx, taking the predicates of impl1 as assumptions: let infcx = tcx.infer_ctxt().build(); - let impl1_trait_ref = - match traits::fully_normalize(&infcx, ObligationCause::dummy(), penv, impl1_trait_ref) { - Ok(impl1_trait_ref) => impl1_trait_ref, - Err(_errors) => { - tcx.sess.delay_span_bug( - tcx.def_span(impl1_def_id), - format!("failed to fully normalize {impl1_trait_ref}"), - ); - impl1_trait_ref - } - }; // Attempt to prove that impl2 applies, given all of the above. - fulfill_implication(&infcx, penv, impl1_trait_ref, impl2_def_id).is_ok() + fulfill_implication(&infcx, penv, impl1_trait_ref, impl1_def_id, impl2_def_id).is_ok() } /// Attempt to fulfill all obligations of `target_impl` after unification with @@ -178,6 +166,7 @@ fn fulfill_implication<'tcx>( infcx: &InferCtxt<'tcx>, param_env: ty::ParamEnv<'tcx>, source_trait_ref: ty::TraitRef<'tcx>, + source_impl: DefId, target_impl: DefId, ) -> Result, ()> { debug!( @@ -185,6 +174,22 @@ fn fulfill_implication<'tcx>( param_env, source_trait_ref, target_impl ); + let source_trait_ref = match traits::fully_normalize( + &infcx, + ObligationCause::dummy(), + param_env, + source_trait_ref, + ) { + Ok(source_trait_ref) => source_trait_ref, + Err(_errors) => { + infcx.tcx.sess.delay_span_bug( + infcx.tcx.def_span(source_impl), + format!("failed to fully normalize {source_trait_ref}"), + ); + source_trait_ref + } + }; + let source_trait = ImplSubject::Trait(source_trait_ref); let selcx = &mut SelectionContext::new(&infcx); @@ -194,7 +199,7 @@ fn fulfill_implication<'tcx>( // do the impls unify? If not, no specialization. let Ok(InferOk { obligations: more_obligations, .. }) = - infcx.at(&ObligationCause::dummy(), param_env, ).eq(DefineOpaqueTypes::No,source_trait, target_trait) + infcx.at(&ObligationCause::dummy(), param_env).eq(DefineOpaqueTypes::No, source_trait, target_trait) else { debug!( "fulfill_implication: {:?} does not unify with {:?}", diff --git a/tests/ui/specialization/min_specialization/specialize-associated-type.rs b/tests/ui/specialization/min_specialization/specialize-associated-type.rs new file mode 100644 index 00000000000..c4960b0c28e --- /dev/null +++ b/tests/ui/specialization/min_specialization/specialize-associated-type.rs @@ -0,0 +1,37 @@ +// Another regression test for #109815. + +// check-pass + +#![feature(min_specialization)] +#![feature(rustc_attrs)] + +#[rustc_specialization_trait] +trait X {} +trait Z { + type Assoc: X; +} +struct A(T); + +impl X for () {} + +impl Z for A { + type Assoc = (); +} + +trait MyFrom { + fn from(other: T) -> Self; +} + +impl MyFrom<()> for T { + default fn from(other: ()) -> T { + panic!(); + } +} + +impl MyFrom< as Z>::Assoc> for T { + fn from(other: ()) -> T { + panic!(); + } +} + +fn main() {} diff --git a/tests/ui/specialization/min_specialization/specialize_on_type_error.rs b/tests/ui/specialization/min_specialization/specialize_on_type_error.rs new file mode 100644 index 00000000000..24e92a0abc3 --- /dev/null +++ b/tests/ui/specialization/min_specialization/specialize_on_type_error.rs @@ -0,0 +1,33 @@ +// A regression test for #109815. + +#![feature(min_specialization)] +#![feature(rustc_attrs)] + +#[rustc_specialization_trait] +trait X {} +trait Y: X {} +trait Z { + type Assoc: Y; +} +struct A(T); + +impl Z for A {} +//~^ ERROR not all trait items implemented + +trait MyFrom { + fn from(other: T) -> Self; +} + +impl MyFrom for T { + default fn from(other: T) -> T { + other + } +} + +impl MyFrom< as Z>::Assoc> for T { + fn from(other: as Z>::Assoc) -> T { + other + } +} + +fn main() {} diff --git a/tests/ui/specialization/min_specialization/specialize_on_type_error.stderr b/tests/ui/specialization/min_specialization/specialize_on_type_error.stderr new file mode 100644 index 00000000000..cc12302bd8c --- /dev/null +++ b/tests/ui/specialization/min_specialization/specialize_on_type_error.stderr @@ -0,0 +1,12 @@ +error[E0046]: not all trait items implemented, missing: `Assoc` + --> $DIR/specialize_on_type_error.rs:14:1 + | +LL | type Assoc: Y; + | ------------- `Assoc` from trait +... +LL | impl Z for A {} + | ^^^^^^^^^^^^^^^^^^^^^ missing `Assoc` in implementation + +error: aborting due to previous error + +For more information about this error, try `rustc --explain E0046`.