Feature gate: #![feature(substr_range)]

This is a tracking issue for str::substr_range, slice::subslice_range, and slice::element_offset as described in this ACP.

These methods can be used for error handling and to extend str::lines, str::split, slice::split, and other related methods.

Public API

impl str {
    fn substr_range(&self, substr: &str) -> Option<Range<usize>>;
}

impl<T> [T] {
    fn subslice_range(&self, subslice: &[T]) -> Option<Range<usize>>;
    fn element_offset(&self, element: &T) -> Option<usize>;
}

Steps / History

• ACP
• Implementation: Add elem_offset and related methods #126770
• Rename elem_offset to element_offset #132830
• Final comment period (FCP)¹
• Stabilization PR 1: Stabilize slice::element_offset #150777
• Stabilization PR 2: Stabilize substr_range and related methods #141266

Unresolved Questions

• Switch to the new std::range return types