Add associated_items_for_impl_trait_in_trait query

compiler/rustc_symbol_mangling/src/v0.rs

@@ -791,6 +791,7 @@ impl<'tcx> Printer<'tcx> for &mut SymbolMangler<'tcx> {
             | DefPathData::Use
             | DefPathData::GlobalAsm
             | DefPathData::Impl
+            | DefPathData::ImplTraitAssocTy
             | DefPathData::MacroNs(_)
             | DefPathData::LifetimeNs(_) => {
                 bug!("symbol_names: unexpected DefPathData: {:?}", disambiguated_data.data)