specialize iterate for Iterators.Reverse (#24)

Author: nsajko

src/ZeroDimensionalArrays.jl

@@ -82,6 +82,14 @@ Base.@nospecializeinfer function Base.iterate((@nospecialize a::ZeroDimensionalA
     nothing
 end
 
+function Base.iterate(r::Iterators.Reverse{<:ZeroDimensionalArray})
+    a = Iterators.reverse(r)
+    iterate(a)
+end
+Base.@nospecializeinfer function Base.iterate((@nospecialize a::Iterators.Reverse{<:ZeroDimensionalArray}), @nospecialize state::Any)
+    nothing
+end
+
 function construct_given_eltype(::Type{Arr}, ::Type{T}, v) where {Arr <: ZeroDimensionalArray, T}
     c = type_to_constructor_function(Arr)
     c(T, v)

test/runtests.jl

@@ -28,12 +28,11 @@ using Aqua: Aqua
             @test @inferred isassigned(Arr(x))
             @test @inferred isassigned(Arr(x), 1)
             @test !(isassigned(Arr(x), 2))
-            @test (@inferred iterate(Arr(x))) isa Tuple{typeof(x), Any}
-            @test x === first(iterate(Arr(x)))
-            @test let a = Arr(x)
-                nothing === @inferred iterate(a, last(iterate(a)))
+            for it ∈ (Arr(x), Iterators.reverse(Arr(x)))
+                @test (@inferred iterate(it)) isa Tuple{typeof(x), Any}
+                @test x === first(iterate(it))
+                @test nothing === @inferred iterate(it, last(iterate(it)))
             end
-            @test nothing === @inferred iterate(Arr(x), nothing)
             @test (@inferred similar(Arr(x))) isa Box{typeof(x)}
             @test (@inferred similar(Arr(x), Float32)) isa Box{Float32}
             @test (@inferred copy(Arr(x))) isa Arr{typeof(x)}