Description
Location
slice::sort_unstable_by
Summary
I ran into a bug with total sort order again which caused a panic. While looking for what others were doing in that situation I ran into a pull request where someone attempted to work around this with unstable sort (cantino/mcfly#454).
Reading the documentation implies in the first part that the worst that happens is not a sorted slice, whereas in the end it mentions that it can panic:
If the comparison function compare does not implement a total order the resulting order of elements in the slice is unspecified.
later
May panic if compare does not implement a total order.
The documentation on sort_by is clearer in that regard:
If the comparison function compare does not implement a total order, the function may panic; even if the function exits normally, the resulting order of elements in the slice is unspecified. See also the note on panicking below.
This should probably be aligned.