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More assertions, tests, and miri coverage

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This commit is contained in:
Michael Goulet 2025-01-11 19:31:28 +00:00
parent 9dc41a048d
commit d98b99af56
13 changed files with 173 additions and 86 deletions
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57
compiler/rustc_trait_selection/src/traits/vtable.rs
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@ -2,8 +2,6 @@ use std::fmt::Debug;
use std::ops::ControlFlow;
use rustc_hir::def_id::DefId;
use rustc_infer::infer::TyCtxtInferExt;
use rustc_infer::traits::ObligationCause;
use rustc_infer::traits::util::PredicateSet;
use rustc_middle::bug;
use rustc_middle::query::Providers;
@ -14,7 +12,7 @@ use rustc_span::DUMMY_SP;
use smallvec::{SmallVec, smallvec};
use tracing::debug;
use crate::traits::{ObligationCtxt, impossible_predicates, is_vtable_safe_method};
use crate::traits::{impossible_predicates, is_vtable_safe_method};
#[derive(Clone, Debug)]
pub enum VtblSegment<'tcx> {
@ -228,6 +226,11 @@ fn vtable_entries<'tcx>(
trait_ref: ty::TraitRef<'tcx>,
) -> &'tcx [VtblEntry<'tcx>] {
debug_assert!(!trait_ref.has_non_region_infer() && !trait_ref.has_non_region_param());
debug_assert_eq!(
tcx.normalize_erasing_regions(ty::TypingEnv::fully_monomorphized(), trait_ref),
trait_ref,
"vtable trait ref should be normalized"
);
debug!("vtable_entries({:?})", trait_ref);
@ -305,6 +308,11 @@ fn vtable_entries<'tcx>(
// for `Supertrait`'s methods in the vtable of `Subtrait`.
pub(crate) fn first_method_vtable_slot<'tcx>(tcx: TyCtxt<'tcx>, key: ty::TraitRef<'tcx>) -> usize {
debug_assert!(!key.has_non_region_infer() && !key.has_non_region_param());
debug_assert_eq!(
tcx.normalize_erasing_regions(ty::TypingEnv::fully_monomorphized(), key),
key,
"vtable trait ref should be normalized"
);
let ty::Dynamic(source, _, _) = *key.self_ty().kind() else {
bug!();
@ -323,11 +331,9 @@ pub(crate) fn first_method_vtable_slot<'tcx>(tcx: TyCtxt<'tcx>, key: ty::TraitRe
vptr_offset += TyCtxt::COMMON_VTABLE_ENTRIES.len();
}
VtblSegment::TraitOwnEntries { trait_ref: vtable_principal, emit_vptr } => {
if trait_refs_are_compatible(
tcx,
ty::ExistentialTraitRef::erase_self_ty(tcx, vtable_principal),
target_principal,
) {
if ty::ExistentialTraitRef::erase_self_ty(tcx, vtable_principal)
== target_principal
{
return ControlFlow::Break(vptr_offset);
}
@ -358,6 +364,12 @@ pub(crate) fn supertrait_vtable_slot<'tcx>(
),
) -> Option<usize> {
debug_assert!(!key.has_non_region_infer() && !key.has_non_region_param());
debug_assert_eq!(
tcx.normalize_erasing_regions(ty::TypingEnv::fully_monomorphized(), key),
key,
"upcasting trait refs should be normalized"
);
let (source, target) = key;
// If the target principal is `None`, we can just return `None`.
@ -384,11 +396,9 @@ pub(crate) fn supertrait_vtable_slot<'tcx>(
VtblSegment::TraitOwnEntries { trait_ref: vtable_principal, emit_vptr } => {
vptr_offset +=
tcx.own_existential_vtable_entries(vtable_principal.def_id).len();
if trait_refs_are_compatible(
tcx,
ty::ExistentialTraitRef::erase_self_ty(tcx, vtable_principal),
target_principal,
) {
if ty::ExistentialTraitRef::erase_self_ty(tcx, vtable_principal)
== target_principal
{
if emit_vptr {
return ControlFlow::Break(Some(vptr_offset));
} else {
@ -408,27 +418,6 @@ pub(crate) fn supertrait_vtable_slot<'tcx>(
prepare_vtable_segments(tcx, source_principal, vtable_segment_callback).unwrap()
}
fn trait_refs_are_compatible<'tcx>(
tcx: TyCtxt<'tcx>,
vtable_principal: ty::ExistentialTraitRef<'tcx>,
target_principal: ty::ExistentialTraitRef<'tcx>,
) -> bool {
if vtable_principal.def_id != target_principal.def_id {
return false;
}
let (infcx, param_env) =
tcx.infer_ctxt().build_with_typing_env(ty::TypingEnv::fully_monomorphized());
let ocx = ObligationCtxt::new(&infcx);
let source_principal = ocx.normalize(&ObligationCause::dummy(), param_env, vtable_principal);
let target_principal = ocx.normalize(&ObligationCause::dummy(), param_env, target_principal);
let Ok(()) = ocx.eq(&ObligationCause::dummy(), param_env, target_principal, source_principal)
else {
return false;
};
ocx.select_all_or_error().is_empty()
}
pub(super) fn provide(providers: &mut Providers) {
*providers = Providers {
own_existential_vtable_entries,