julia

1a904090 - Add `_unsetindex!` methods for `SubArray`s and `CartesianIndex`es (#53383)

Add `_unsetindex!` methods for `SubArray`s and `CartesianIndex`es (#53383) With this, the following (and equivalent calls) work: ```julia julia> copyto!(view(zeros(BigInt, 2), 1:2), Vector{BigInt}(undef,2)) 2-element view(::Vector{BigInt}, 1:2) with eltype BigInt: #undef #undef julia> copyto!(view(zeros(BigInt, 2), 1:2), view(Vector{BigInt}(undef,2), 1:2)) 2-element view(::Vector{BigInt}, 1:2) with eltype BigInt: #undef #undef ``` Close https://github.com/JuliaLang/julia/issues/53098. With this, all the `_unsetindex!` branches in `copyto_unaliased!` work for `Array`-views, and this makes certain indexing operations vectorize and speed-up: ```julia julia> using BenchmarkTools julia> a = view(rand(100,100), 1:100, 1:100); b = view(similar(a), axes(a)...); julia> @btime copyto!($b, $a); 16.427 μs (0 allocations: 0 bytes) # master 2.308 μs (0 allocations: 0 bytes) # PR ``` Improves (but doesn't resolve) https://github.com/JuliaLang/julia/issues/40962 and https://github.com/JuliaLang/julia/issues/53158 ```julia julia> a = rand(40,40); b = rand(40,40); julia> @btime $a[1:end,1:end] .= $b; 5.383 μs (0 allocations: 0 bytes) # v"1.12.0-DEV.16" 3.194 μs (0 allocations: 0 bytes) # PR ``` ƒ Co-authored-by: Jameson Nash <vtjnash@gmail.com>