HIR VTables - Fix handling of ATY name conflicts

src/hir_expand/vtable.cpp

@@ -59,7 +59,7 @@ namespace {
  struct Foo {
  ::HIR::Trait* trait_ptr;
  ::HIR::GenericParams params;
- unsigned int i;
+ bool has_conflict;
  void add_types_from_trait(const HIR::GenericPath& path, const HIR::Trait& tr, const HIR::TraitPath::assoc_list_t& assoc) {
  for(const auto& ty : tr.m_types) {
  bool is_known = false;
@@ -71,20 +71,24 @@ namespace {
  }
  }
  if( !is_known ) {
- DEBUG(ty.first << " #" << i);
+ auto i = params.m_types.size();
+ DEBUG(ty.first << " #" << i << " (from " << path << ")");
  auto rv = trait_ptr->m_type_indexes.insert( ::std::make_pair(ty.first, i) );
  if(rv.second == false) {
- TODO(Span(), "Handle conflicting associated types - '" << ty.first << "'");
+ // NOTE: Some traits have multiple parents with the same ATY name
+ // E.g. `::"rustc_data_structures-0_0_0"::graph::ControlFlowGraph`
+ DEBUG("Conflicting ATY name " << ty.first);
+ rv.first->second = UINT_MAX;
+ this->has_conflict = true;
  }
  else {
  params.m_types.push_back( ::HIR::TypeParamDef { RcString::new_interned(FMT("a#" << ty.first)), {}, ty.second.is_sized } );
  }
- i ++;
  }
  }
  }
  };
- Foo visitor { &tr, {}, static_cast<unsigned int>(tr.m_params.m_types.size()) };
+ Foo visitor { &tr, {}, false };
  for(const auto& tp : tr.m_params.m_types) {
  visitor.params.m_types.push_back( ::HIR::TypeParamDef { tp.m_name, {}, tp.m_is_sized } );
  }
@@ -94,6 +98,7 @@ namespace {
  assert(st.m_trait_ptr);
  visitor.add_types_from_trait(st.m_path, *st.m_trait_ptr, st.m_type_bounds);
  }
+ bool has_conflicting_aty_name = visitor.has_conflict;
  auto args = mv$(visitor.params);
 
  struct VtableConstruct {
@@ -248,7 +253,7 @@ namespace {
  // - Alignment of data
  vtc.fields.push_back(::std::make_pair( "#align", ::HIR::VisEnt<::HIR::TypeRef> { ::HIR::Publicity::new_none(), ::HIR::CoreType::Usize } ));
  // - Add methods
- if( ! vtc.add_ents_from_trait(tr, trait_path) )
+ if( ! vtc.add_ents_from_trait(tr, trait_path) || has_conflicting_aty_name )
  {
  tr.m_value_indexes.clear();
  tr.m_type_indexes.clear();