Fix cat

Author: mtfishman

src/blocksparsearrayinterface/broadcast.jl

@@ -53,9 +53,11 @@ function Base.Broadcast.BroadcastStyle(
 end
 
 function Base.similar(bc::Broadcasted{<:Broadcast.BlockSparseArrayStyle}, elt::Type, ax)
+    # Find the first array in the broadcast expression.
     # TODO: Make this more generic, base it off sure this handles GPU arrays properly.
-    m = Mapped(bc)
-    return similar(first(m.args), elt, ax)
+    bc′ = Base.Broadcast.flatten(bc)
+    arg = bc′.args[findfirst(arg -> arg isa AbstractArray, bc′.args)]
+    return similar(arg, elt, ax)
 end
 
 # Catches cases like `dest .= value` or `dest .= value1 .+ value2`.

test/test_basics.jl

@@ -426,7 +426,7 @@ arrayts = (Array, JLArray)
         @test a1' * a2 ≈ Array(a1)' * Array(a2)
         @test dot(a1, a2) ≈ a1' * a2
     end
-    false && @testset "cat" begin
+    @testset "cat" begin
         a1 = dev(BlockSparseArray{elt}(undef, [2, 3], [2, 3]))
         a1[Block(2, 1)] = dev(randn(elt, size(@view(a1[Block(2, 1)]))))
         a2 = dev(BlockSparseArray{elt}(undef, [2, 3], [2, 3]))