better error for unsupported array types

Author: SimonDanisch

src/broadcast.jl

@@ -104,10 +104,15 @@ function Base.foreach(func, over::GPUArray, Bs...)
 end
 
 
-arg_length(x::Array) = error("No array in GPU Broadcast supported. Try converting it to a gpu array")
+function arg_length(x::AbstractArray)
+    if !isbits(x)
+        error("Non isbits Arrays in GPU Broadcast not supported (So arrays that don't contain pointers to memory are, e.g. UnitRanges). Try converting it to a gpu array. Found: $(typeof(x))")
+    end
+    UInt32.(size(x))
+end
 arg_length(x::Tuple) = (UInt32(length(x)),)
 arg_length(x::GPUArray) = UInt32.(size(x))
-arg_length(x) = ()
+arg_length(x) = () # Scalar
 
 abstract type BroadcastDescriptor{Typ} end