diff options
Diffstat (limited to 'src/hir_typeck')
| -rw-r--r-- | src/hir_typeck/expr_cs.cpp | 72 |
1 files changed, 62 insertions, 10 deletions
diff --git a/src/hir_typeck/expr_cs.cpp b/src/hir_typeck/expr_cs.cpp index 12819251..52af3924 100644 --- a/src/hir_typeck/expr_cs.cpp +++ b/src/hir_typeck/expr_cs.cpp @@ -4986,8 +4986,28 @@ namespace { else { // No equivalence added } - // - Fall through and search for the impl - DEBUG("- Unsize, no ivar equivalence"); + + // TODO: If this was a compiler-inserted bound (from a coercion rule), then do deref checks +#if 0 + { + ::HIR::TypeRef tmp_ty; + const ::HIR::TypeRef* ty_ptr = &src_ty; + while( (ty_ptr = context.m_resolve.autoderef(sp, *ty_ptr, tmp_ty)) ) + { + const auto& cur_ty = context.m_ivars.get_type(*ty_ptr); + if( cur_ty.m_data.is_Infer() ) { + break; + } + auto cmp = dst_ty.compare_with_placeholders(sp, cur_ty, context.m_ivars.callback_resolve_infer()); + if( cmp != ::HIR::Compare::Unequal ) + { + // TODO: This is a deref coercion, so what can actually be done? + TODO(sp, "Handle Unsize with deref - " << src_ty << " -> " << dst_ty); + } + } + } +#endif + DEBUG("- Unsize, no deref or ivar"); } if( v.trait == context.m_crate.get_lang_item_path(sp, "coerce_unsized") ) { @@ -5052,7 +5072,7 @@ namespace { // > This makes `let v: usize = !0;` work without special cases auto cmp2 = v.left_ty.compare_with_placeholders(sp, out_ty, context.m_ivars.callback_resolve_infer()); if( cmp2 == ::HIR::Compare::Unequal ) { - DEBUG("- (fail) known result can't match (" << context.m_ivars.fmt_type(v.left_ty) << " and " << context.m_ivars.fmt_type(out_ty) << ")"); + DEBUG("[check_associated] - (fail) known result can't match (" << context.m_ivars.fmt_type(v.left_ty) << " and " << context.m_ivars.fmt_type(out_ty) << ")"); return false; } // if solid or fuzzy, leave as-is @@ -5071,9 +5091,10 @@ namespace { } else { count += 1; - DEBUG("- (possible) " << impl); + DEBUG("[check_associated] - (possible) " << impl); if( possible_impl_ty == ::HIR::TypeRef() ) { + DEBUG("[check_associated] First - " << impl); possible_impl_ty = impl.get_impl_type(); possible_params = impl.get_trait_params(); best_impl = mv$(impl); @@ -5084,27 +5105,33 @@ namespace { // NOTE: `overlaps_with` (should be) reflective else if( impl.overlaps_with(best_impl) ) { - DEBUG("- overlaps with " << best_impl); + DEBUG("[check_associated] - Overlaps with existing - " << best_impl); + // if not more specific than the existing best, ignore. if( ! impl.more_specific_than(best_impl) ) { - possible_impl_ty = impl.get_impl_type(); - possible_params = impl.get_trait_params(); - best_impl = mv$(impl); + // Ignore + DEBUG("[check_associated] - Less specific than existing"); count -= 1; } + // If the existing best is not more specific than the new one, use the new one else if( ! best_impl.more_specific_than(impl) ) { - // Ignore + DEBUG("[check_associated] - More specific than existing - " << impl); + possible_impl_ty = impl.get_impl_type(); + possible_params = impl.get_trait_params(); + best_impl = mv$(impl); count -= 1; } else { - DEBUG("> Neither is more specific. Error?"); + // Supposedly, `more_specific_than` should be reflexive... + DEBUG("[check_associated] > Neither is more specific. Error?"); } } else { // Disjoint impls. + DEBUG("[check_associated] Disjoint impl -" << impl); } #endif @@ -5680,6 +5707,31 @@ namespace { // TODO: Monomorphise this type replacing mentions of the current ivar with the replacement? +#if 0 // NOTE: The following shouldn't happen + if( bound.trait == context.m_crate.get_lang_item_path(sp, "unsize") /* && bound.is_from_coerce*/ ) + { + bool possible = false; + + ::HIR::TypeRef tmp_ty; + const ::HIR::TypeRef* ty_ptr = &new_ty; + while( (ty_ptr = context.m_resolve.autoderef(sp, *ty_ptr, tmp_ty)) ) + { + const auto& cur_ty = context.get_type(*ty_ptr); + if( cur_ty.m_data.is_Infer() ) { + break; + } + auto cmp = ty_l.compare_with_placeholders(sp, cur_ty, context.m_ivars.callback_resolve_infer()); + if( cmp != ::HIR::Compare::Unequal ) + { + possible = true; + break; + } + } + if( possible ) + continue ; + } +#endif + // 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 ) { |