+pub(crate) fn generic_arg_to_chalk<'a, T>(
+ db: &dyn HirDatabase,
+ kind_id: Either<TypeParamId, ConstParamId>,
+ arg: &'a GenericArg,
+ this: &mut T,
+ for_type: impl FnOnce(&mut T, &TypeRef) -> Ty + 'a,
+ for_const: impl FnOnce(&mut T, &ConstScalarOrPath) -> Const + 'a,
+) -> Option<crate::GenericArg> {
+ let kind = match kind_id {
+ Either::Left(_) => ParamKind::Type,
+ Either::Right(id) => {
+ let ty = db.const_param_ty(id);
+ ParamKind::Const(ty)
+ }
+ };
+ Some(match (arg, kind) {
+ (GenericArg::Type(type_ref), ParamKind::Type) => {
+ let ty = for_type(this, type_ref);
+ GenericArgData::Ty(ty).intern(Interner)
+ }
+ (GenericArg::Const(c), ParamKind::Const(_)) => {
+ GenericArgData::Const(for_const(this, c)).intern(Interner)
+ }
+ (GenericArg::Const(_), ParamKind::Type) => {
+ GenericArgData::Ty(TyKind::Error.intern(Interner)).intern(Interner)
+ }
+ (GenericArg::Type(t), ParamKind::Const(ty)) => {
+ // We want to recover simple idents, which parser detects them
+ // as types. Maybe here is not the best place to do it, but
+ // it works.
+ if let TypeRef::Path(p) = t {
+ let p = p.mod_path();
+ if p.kind == PathKind::Plain {
+ if let [n] = p.segments() {
+ let c = ConstScalarOrPath::Path(n.clone());
+ return Some(GenericArgData::Const(for_const(this, &c)).intern(Interner));
+ }
+ }
+ }
+ unknown_const_as_generic(ty)
+ }
+ (GenericArg::Lifetime(_), _) => return None,
+ })
+}
+
+pub(crate) fn const_or_path_to_chalk(
+ db: &dyn HirDatabase,
+ resolver: &Resolver,
+ value: &ConstScalarOrPath,
+ mode: ParamLoweringMode,
+ args: impl FnOnce() -> Generics,
+ debruijn: DebruijnIndex,
+) -> Const {
+ match value {
+ ConstScalarOrPath::Scalar(s) => usize_const(s.as_usize()),
+ ConstScalarOrPath::Path(n) => {
+ let path = ModPath::from_segments(PathKind::Plain, Some(n.clone()));
+ path_to_const(db, resolver, &path, mode, args, debruijn)
+ .unwrap_or_else(|| unknown_const_usize())
+ }
+ }