bjoernager/rust
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make relate's const ty assertion use semantic equality

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This commit is contained in:
Boxy 2023-02-11 23:05:11 +00:00
parent 8dabf5da9e
commit a85b0101e6
7 changed files with 237 additions and 22 deletions
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28
compiler/rustc_infer/src/infer/combine.rs
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@ -31,6 +31,7 @@ use super::{InferCtxt, MiscVariable, TypeTrace};
use crate::traits::{Obligation, PredicateObligations};
use rustc_data_structures::sso::SsoHashMap;
use rustc_hir::def_id::DefId;
use rustc_middle::infer::canonical::OriginalQueryValues;
use rustc_middle::infer::unify_key::{ConstVarValue, ConstVariableValue};
use rustc_middle::infer::unify_key::{ConstVariableOrigin, ConstVariableOriginKind};
use rustc_middle::traits::ObligationCause;
@ -152,6 +153,33 @@ impl<'tcx> InferCtxt<'tcx> {
let a = self.shallow_resolve(a);
let b = self.shallow_resolve(b);
// We should never have to relate the `ty` field on `Const` as it is checked elsewhere that consts have the
// correct type for the generic param they are an argument for. However there have been a number of cases
// historically where asserting that the types are equal has found bugs in the compiler so this is valuable
// to check even if it is a bit nasty impl wise :(
//
// This probe is probably not strictly necessary but it seems better to be safe and not accidentally find
// ourselves with a check to find bugs being required for code to compile because it made inference progress.
self.probe(|_| {
if a.ty() == b.ty() {
return;
}
// We don't have access to trait solving machinery in `rustc_infer` so the logic for determining if the
// two const param's types are able to be equal has to go through a canonical query with the actual logic
// in `rustc_trait_selection`.
let canonical = self.canonicalize_query(
(relation.param_env(), a.ty(), b.ty()),
&mut OriginalQueryValues::default(),
);
if let Err(()) = self.tcx.check_const_param_definitely_unequal(canonical) {
self.tcx.sess.delay_span_bug(
DUMMY_SP,
&format!("cannot relate consts of different types (a={:?}, b={:?})", a, b,),
);
}
});
match (a.kind(), b.kind()) {
(
ty::ConstKind::Infer(InferConst::Var(a_vid)),