Merge pull request JuliaLang#34770 from JuliaLang/teh/oa92

Convert range type in `reduced_index`

base/reducedim.jl

@@ -4,7 +4,7 @@
 
 # for reductions that expand 0 dims to 1
 reduced_index(i::OneTo) = OneTo(1)
-reduced_index(i::Union{Slice, IdentityUnitRange}) = first(i):first(i)
+reduced_index(i::Union{Slice, IdentityUnitRange}) = oftype(i, first(i):first(i))
 reduced_index(i::AbstractUnitRange) =
  throw(ArgumentError(
 """
@@ -20,7 +20,7 @@ reduced_indices0(a::AbstractArray, region) = reduced_indices0(axes(a), region)
 function reduced_indices(inds::Indices{N}, d::Int) where N
  d < 1 && throw(ArgumentError("dimension must be ≥ 1, got $d"))
  if d == 1
- return (reduced_index(inds[1]), tail(inds)...)
+ return (reduced_index(inds[1]), tail(inds)...)::typeof(inds)
  elseif 1 < d <= N
  return tuple(inds[1:d-1]..., oftype(inds[d], reduced_index(inds[d])), inds[d+1:N]...)::typeof(inds)
  else
@@ -34,7 +34,7 @@ function reduced_indices0(inds::Indices{N}, d::Int) where N
  ind = inds[d]
  rd = isempty(ind) ? ind : reduced_index(inds[d])
  if d == 1
- return (rd, tail(inds)...)
+ return (rd, tail(inds)...)::typeof(inds)
  else
  return tuple(inds[1:d-1]..., oftype(inds[d], rd), inds[d+1:N]...)::typeof(inds)
  end

test/offsetarray.jl

@@ -440,6 +440,14 @@ I = findall(!iszero, z)
 @test std(A_3_3, dims=2) == OffsetArray(reshape([3,3,3], (3,1)), A_3_3.offsets)
 @test sum(OffsetArray(fill(1,3000), -1000)) == 3000
 
+# https://github.com/JuliaArrays/OffsetArrays.jl/issues/92
+A92 = OffsetArray(reshape(1:27, 3, 3, 3), -2, -2, -2)
+B92 = view(A92, :, :, -1:0)
+@test axes(B92) == (-1:1, -1:1, 1:2)
+@test sum(B92, dims=(2,3)) == OffsetArray(reshape([51,57,63], Val(3)), -2, -2, 0)
+B92 = view(A92, :, :, Base.IdentityUnitRange(-1:0))
+@test sum(B92, dims=(2,3)) == OffsetArray(reshape([51,57,63], Val(3)), -2, -2, -2)
+
 @test norm(v) ≈ norm(parent(v))
 @test norm(A) ≈ norm(parent(A))
 @test dot(v, v) ≈ dot(v0, v0)