diff options
| -rw-r--r-- | src/hir_typeck/expr_cs.cpp | 57 |
1 files changed, 52 insertions, 5 deletions
diff --git a/src/hir_typeck/expr_cs.cpp b/src/hir_typeck/expr_cs.cpp index 473fb143..bc4fc8a0 100644 --- a/src/hir_typeck/expr_cs.cpp +++ b/src/hir_typeck/expr_cs.cpp @@ -5160,7 +5160,7 @@ namespace { return false; } - static const ::std::vector<::HIR::TypeRef>& merge_lists(const Context& context, const ::std::vector<::HIR::TypeRef>& list_a, const ::std::vector<::HIR::TypeRef>& list_b, ::std::vector<::HIR::TypeRef>& out) + static ::std::vector<::HIR::TypeRef>& merge_lists(const Context& context, ::std::vector<::HIR::TypeRef>& list_a, ::std::vector<::HIR::TypeRef>& list_b, ::std::vector<::HIR::TypeRef>& out) { if( list_a.size() == 0 ) return list_b; @@ -5204,7 +5204,6 @@ namespace { } #endif - // Prefer cases where this type is being created from a known type if( ivar_ent.types_coerce_from.size() == 0 && ivar_ent.types_coerce_to.size() == 0 && ivar_ent.types_unsize_from.size() == 0 && ivar_ent.types_unsize_to.size() == 0 ) @@ -5256,14 +5255,62 @@ namespace { return DedupKeep::Both; }); + // TODO: If there is a type that appears on both sides, pick it? + // HACK: Merge into a single lists ::std::vector< ::HIR::TypeRef> types_from_o; - const auto& types_from = H::merge_lists(context, ivar_ent.types_coerce_from, ivar_ent.types_unsize_from, types_from_o); + auto& types_from = H::merge_lists(context, ivar_ent.types_coerce_from, ivar_ent.types_unsize_from, types_from_o); ::std::vector< ::HIR::TypeRef> types_to_o; - const auto& types_to = H::merge_lists(context, ivar_ent.types_coerce_to, ivar_ent.types_unsize_to, types_to_o); + auto& types_to = H::merge_lists(context, ivar_ent.types_coerce_to , ivar_ent.types_unsize_to , types_to_o ); + // Same type on both sides, pick it. + if( types_from == types_to && types_from.size() == 1 ) { + const auto& new_ty = types_from[0]; + DEBUG("- IVar " << ty_l << " = " << new_ty << " (only)"); + context.equate_types(sp, ty_l, new_ty); + ivar_ent.reset(); + return ; + } - #if 1 + // Eliminate possibilities that don't fit known constraints + if( types_to.size() > 0 && types_from.size() > 0 ) + { + // TODO: Search `types_to` too + for(auto it = types_from.begin(); it != types_from.end(); ) + { + bool remove = false; + const auto& new_ty = context.get_type(*it); + if( !new_ty.m_data.is_Infer() ) + { + for(const auto& bound : context.link_assoc) + { + if( bound.impl_ty != ty_l ) + continue ; + + // TODO: Monomorphise this type replacing mentions of the current ivar with the replacement? + + // Search for any trait impl that could match this, + bool has = context.m_resolve.find_trait_impls(sp, bound.trait, bound.params, new_ty, [&](const auto , auto){return true;}); + if( !has ) { + // If none was found, remove from the possibility list + remove = true; + DEBUG("Remove possibility " << new_ty << " because it failed a bound"); + break ; + } + } + } + + if( remove ) { + it = types_from.erase(it); + } + else { + ++it; + } + } + } + + // Prefer cases where this type is being created from a known type + #if 0 if( types_from.size() == 1 && types_to.size() == 1 ) { const auto& ty_to = types_to[0]; const auto& ty_from = types_from[0]; |