carbon-language/carbon-lang
1
0
Fork 0
mirror of https://github.com/carbon-language/carbon-lang.git synced 2026-10-06 07:34:45 +01:00
Code Issues Packages Projects Releases 10 Wiki Activity

Switch EvalLookupSingleImplWitness from "concrete" to "final" terminology (#6246)

Browse Source 
A `final impl` can have a symbolic witness, but that witness is still
final. Using "final" here per discussion on
[#generics-and-templates](https://discord.com/channels/655572317891461132/941071822756143115/1428851511672312120).

I'm also changing the variant a little because `concrete_witness` was
only called when `has_concrete_value` was true, so it can be more
careful about its contract. Having a more explicit `None` also
simplifies `has_value`. I think it doesn't change the overall cost much
past that.
This commit is contained in:
Jon Ross-Perkins
2025-10-20 17:25:26 +00:00
committed by GitHub
parent 1df0d4566e
commit b1f734e1cd
4 changed files with 38 additions and 36 deletions
Download Patch File Download Diff File Expand all files Collapse all files
toolchain/check/impl_lookup.cpp
+5 -5
View File
@@ -847,14 +847,14 @@ static auto CollectCandidateImplsForQuery(
auto EvalLookupSingleImplWitness(Context& context, SemIR::LocId loc_id,
SemIR::LookupImplWitness eval_query,
SemIR::InstId self_facet_value_inst_id,
bool poison_concrete_results)
bool poison_final_results)
-> EvalImplLookupResult {
auto query_specific_interface =
context.specific_interfaces().Get(eval_query.query_specific_interface_id);
auto facet_lookup_result = LookupImplWitnessInSelfFacetValue(
context, self_facet_value_inst_id, query_specific_interface);
if (facet_lookup_result.has_concrete_value()) {
if (facet_lookup_result.has_final_value()) {
return facet_lookup_result;
}
@@ -927,19 +927,19 @@ auto EvalLookupSingleImplWitness(Context& context, SemIR::LocId loc_id,
context, loc_id, query_is_concrete, query_self_const_id,
query_specific_interface, candidate.impl_id);
if (result.has_value()) {
// Record the query which found a concrete impl witness. It's illegal to
// Record the query which found a final impl witness. It's illegal to
// write a final impl afterward that would match the same query.
//
// If the impl was effectively final, then we don't need to poison here. A
// change of query result will already be diagnosed at the point where the
// new impl decl was written that changes the result.
if (poison_concrete_results && result.has_concrete_value() &&
if (poison_final_results && result.has_final_value() &&
!IsImplEffectivelyFinal(context,
context.impls().Get(candidate.impl_id))) {
context.poisoned_concrete_impl_lookup_queries().push_back(
{.loc_id = loc_id,
.query = eval_query,
.impl_witness = result.concrete_witness()});
.impl_witness = result.final_witness()});
}
return result;
}