julia

473d0db2 - Specialize findlast for integer AbstractUnitRanges and StepRanges (#54902)

Specialize findlast for integer AbstractUnitRanges and StepRanges (#54902) For monotonic ranges, `findfirst` and `findlast` with `==(val)` as the predicate should be identical, as each value appears only once in the range. Since `findfirst` is specialized for some ranges, we may define `findlast` as well analogously. On v"1.12.0-DEV.770" ```julia julia> @btime findlast(==(1), $(Ref(1:1_000))[]) 1.186 μs (0 allocations: 0 bytes) 1 ``` This PR ```julia julia> @btime findlast(==(1), $(Ref(1:1_000))[]) 3.171 ns (0 allocations: 0 bytes) 1 ``` I've also specialized `findfirst(iszero, r::AbstractRange)` to make this be equivalent to `findfirst(==(0), ::AbstractRange)` for numerical ranges. Similarly, for `isone`. These now take the fast path as well. Thirdly, I've added some `convert` calls to address issues like ```julia julia> r = Int128(1):Int128(1):Int128(4); julia> findfirst(==(Int128(2)), r) |> typeof Int128 julia> keytype(r) Int64 ``` This PR ensures that the return type always corresponds to `keytype`, which is what the docstring promises. This PR also fixes ```julia julia> findfirst(==(0), UnitRange(-0.5, 0.5)) ERROR: InexactError: Int64(0.5) Stacktrace: [1] Int64 @ ./float.jl:994 [inlined] [2] findfirst(p::Base.Fix2{typeof(==), Int64}, r::UnitRange{Float64}) @ Base ./array.jl:2397 [3] top-level scope @ REPL[1]:1 ``` which now returns `nothing`, as expected.