Avoid unnecessary cloning in Parser::get_ident_from_generic_arg.

This commit is contained in:
Nicholas Nethercote 2022-08-16 12:14:52 +10:00
parent 3e04fed6fa
commit 9619a2e3a3

View File

@ -527,7 +527,7 @@ impl<'a> Parser<'a> {
Ok(ident_gen_args) => ident_gen_args,
Err(()) => return Ok(Some(AngleBracketedArg::Arg(arg))),
};
if binder.is_some() {
if binder {
// FIXME(compiler-errors): this could be improved by suggesting lifting
// this up to the trait, at least before this becomes real syntax.
// e.g. `Trait<for<'a> Assoc = Ty>` -> `for<'a> Trait<Assoc = Ty>`
@ -720,28 +720,24 @@ impl<'a> Parser<'a> {
/// Given a arg inside of generics, we try to destructure it as if it were the LHS in
/// `LHS = ...`, i.e. an associated type binding.
/// This returns (optionally, if they are present) any `for<'a, 'b>` binder args, the
/// This returns a bool indicating if there are any `for<'a, 'b>` binder args, the
/// identifier, and any GAT arguments.
fn get_ident_from_generic_arg(
&self,
gen_arg: &GenericArg,
) -> Result<(Option<Vec<ast::GenericParam>>, Ident, Option<GenericArgs>), ()> {
) -> Result<(bool, Ident, Option<GenericArgs>), ()> {
if let GenericArg::Type(ty) = gen_arg {
if let ast::TyKind::Path(qself, path) = &ty.kind
&& qself.is_none()
&& let [seg] = path.segments.as_slice()
{
return Ok((None, seg.ident, seg.args.as_deref().cloned()));
return Ok((false, seg.ident, seg.args.as_deref().cloned()));
} else if let ast::TyKind::TraitObject(bounds, ast::TraitObjectSyntax::None) = &ty.kind
&& let [ast::GenericBound::Trait(trait_ref, ast::TraitBoundModifier::None)] =
bounds.as_slice()
&& let [seg] = trait_ref.trait_ref.path.segments.as_slice()
{
return Ok((
Some(trait_ref.bound_generic_params.clone()),
seg.ident,
seg.args.as_deref().cloned(),
));
return Ok((true, seg.ident, seg.args.as_deref().cloned()));
}
}
Err(())