Current nightly:
#[stable(feature = "rust1", since = "1.0.0")]
impl ops::Index<ops::Range<usize>> for String {
type Output = str;
#[inline]
fn index(&self, index: ops::Range<usize>) -> &str {
&self[..][index]
}
}
#[stable(feature = "rust1", since = "1.0.0")]
impl ops::Index<ops::RangeTo<usize>> for String {
type Output = str;
#[inline]
fn index(&self, index: ops::RangeTo<usize>) -> &str {
&self[..][index]
}
}
#[stable(feature = "rust1", since = "1.0.0")]
impl ops::Index<ops::RangeFrom<usize>> for String {
type Output = str;
#[inline]
fn index(&self, index: ops::RangeFrom<usize>) -> &str {
&self[..][index]
}
}
#[stable(feature = "rust1", since = "1.0.0")]
impl ops::Index<ops::RangeFull> for String {
type Output = str;
#[inline]
fn index(&self, _index: ops::RangeFull) -> &str {
unsafe { str::from_utf8_unchecked(&self.vec) }
}
}
#[stable(feature = "inclusive_range", since = "1.26.0")]
impl ops::Index<ops::RangeInclusive<usize>> for String {
type Output = str;
#[inline]
fn index(&self, index: ops::RangeInclusive<usize>) -> &str {
Index::index(&**self, index)
}
}
#[stable(feature = "inclusive_range", since = "1.26.0")]
impl ops::Index<ops::RangeToInclusive<usize>> for String {
type Output = str;
#[inline]
fn index(&self, index: ops::RangeToInclusive<usize>) -> &str {
Index::index(&**self, index)
}
}
#[stable(feature = "derefmut_for_string", since = "1.3.0")]
impl ops::IndexMut<ops::Range<usize>> for String {
#[inline]
fn index_mut(&mut self, index: ops::Range<usize>) -> &mut str {
&mut self[..][index]
}
}
#[stable(feature = "derefmut_for_string", since = "1.3.0")]
impl ops::IndexMut<ops::RangeTo<usize>> for String {
#[inline]
fn index_mut(&mut self, index: ops::RangeTo<usize>) -> &mut str {
&mut self[..][index]
}
}
#[stable(feature = "derefmut_for_string", since = "1.3.0")]
impl ops::IndexMut<ops::RangeFrom<usize>> for String {
#[inline]
fn index_mut(&mut self, index: ops::RangeFrom<usize>) -> &mut str {
&mut self[..][index]
}
}
#[stable(feature = "derefmut_for_string", since = "1.3.0")]
impl ops::IndexMut<ops::RangeFull> for String {
#[inline]
fn index_mut(&mut self, _index: ops::RangeFull) -> &mut str {
unsafe { str::from_utf8_unchecked_mut(&mut *self.vec) }
}
}
#[stable(feature = "inclusive_range", since = "1.26.0")]
impl ops::IndexMut<ops::RangeInclusive<usize>> for String {
#[inline]
fn index_mut(&mut self, index: ops::RangeInclusive<usize>) -> &mut str {
IndexMut::index_mut(&mut **self, index)
}
}
#[stable(feature = "inclusive_range", since = "1.26.0")]
impl ops::IndexMut<ops::RangeToInclusive<usize>> for String {
#[inline]
fn index_mut(&mut self, index: ops::RangeToInclusive<usize>) -> &mut str {
IndexMut::index_mut(&mut **self, index)
}
}
Would it not be clearer to implement it as
#[stable(feature = "rust1", since = "1.0.0")]
impl<I> Index<I> for String
where
str: Index<I>,
{
type Output = str;
#[inline]
fn index(&self, index: I) -> &str {
&unsafe { str::from_utf8_unchecked(&self.vec) }[index]
}
}
#[stable(feature = "derefmut_for_string", since = "1.3.0")]
impl<I> ops::IndexMut<I> for String
where
str: IndexMut<I>,
{
#[inline]
fn index_mut(&mut self, index: I) -> &mut str {
&mut unsafe { str::from_utf8_unchecked_mut(&mut *self.vec) }[index]
}
}
? Why isn't it implemented this way? (Type inference issues?)