add method setindex for CartesianIndex (JuliaLang#35280)

base/multidimensional.jl

@@ -7,7 +7,7 @@ module IteratorsMD
                  ndims, IteratorSize, convert, show, iterate, promote_rule, to_indices
 
     import .Base: +, -, *, (:)
-    import .Base: simd_outer_range, simd_inner_length, simd_index
+    import .Base: simd_outer_range, simd_inner_length, simd_index, setindex
     using .Base: IndexLinear, IndexCartesian, AbstractCartesianIndex, fill_to_length, tail,
         ReshapedArray, ReshapedArrayLF, OneTo
     using .Base.Iterators: Reverse, PartitionIterator
@@ -96,6 +96,8 @@ module IteratorsMD
     # access to index tuple
     Tuple(index::CartesianIndex) = index.I
 
+    Base.setindex(x::CartesianIndex,i,j) = CartesianIndex(Base.setindex(Tuple(x),i,j))
+
     # equality
     Base.:(==)(a::CartesianIndex{N}, b::CartesianIndex{N}) where N = a.I == b.I
 

test/cartesian.jl

@@ -5,13 +5,15 @@ ex = Base.Cartesian.exprresolve(:(if 5 > 4; :x; else :y; end))
 @test ex.args[2] == QuoteNode(:x)
 
 @test Base.Cartesian.lreplace!("val_col", Base.Cartesian.LReplace{String}(:col, "col", 1)) == "val_1"
+@test Base.setindex(CartesianIndex(1,5,4),3,2) == CartesianIndex(1, 3, 4)
 
 # test conversions for CartesianIndex
 
 @testset "CartesianIndex Conversions" begin
     @test convert(Int, CartesianIndex(42)) === 42
     @test convert(Float64, CartesianIndex(42)) === 42.0
     @test convert(Tuple, CartesianIndex(42, 1)) === (42, 1)
+
     # can't convert higher-dimensional indices to Int
     @test_throws MethodError convert(Int, CartesianIndex(42, 1))
 end
@@ -64,3 +66,5 @@ end
     @test iterate(I, CartesianIndex(3, typemax(Int)))[1] == CartesianIndex(4,typemax(Int))
     @test iterate(I, CartesianIndex(4, typemax(Int)))    === nothing
 end
+
+