Fixes

ext/cuda/data_layouts.jl

@@ -195,9 +195,16 @@ Base.@propagate_inbounds function rcopyto_at!(
     v,
 )
     dest, bc = pair.first, pair.second
-    if v <= size(dest, 4)
+    if 1 ≤ v <= size(dest, 4)
+        dest[I] = isascalar(bc) ? bc[] : bc[I]
+    end
+    return nothing
+end
+Base.@propagate_inbounds function rcopyto_at!(pair::Pair{<:DataF, <:Any}, I, v)
+    dest, bc = pair.first, pair.second
+    if 1 ≤ v <= size(dest, 4)
         bcI = isascalar(bc) ? bc[] : bc[I]
-        dest[I] = bcI
+        dest[] = bcI
     end
     return nothing
 end

src/DataLayouts/broadcast.jl

@@ -611,8 +611,21 @@ function Base.copyto!(
     fmbc::FusedMultiBroadcast{T},
 ) where {N, T <: NTuple{N, Pair{<:AbstractData, <:Any}}}
     dest1 = first(fmbc.pairs).first
+    fmb_inst = FusedMultiBroadcast(
+        map(fmbc.pairs) do pair
+            bc = pair.second
+            bc′ = if isascalar(bc)
+                Base.Broadcast.instantiate(
+                    Base.Broadcast.Broadcasted(bc.style, bc.f, bc.args, ()),
+                )
+            else
+                bc
+            end
+            Pair(pair.first, bc′)
+        end,
+    )
     # check_fused_broadcast_axes(fmbc) # we should already have checked the axes
-    fused_copyto!(fmbc, dest1, ClimaComms.device(dest1))
+    fused_copyto!(fmb_inst, dest1, ClimaComms.device(dest1))
 end
 
 function fused_copyto!(

src/Fields/broadcast.jl

@@ -157,14 +157,7 @@ function Base.copyto!(
     fmb_data = FusedMultiBroadcast(
         map(fmbc.pairs) do pair
             bc = Base.Broadcast.instantiate(todata(pair.second))
-            bc′ = if isascalar(bc)
-                Base.Broadcast.instantiate(
-                    Base.Broadcast.Broadcasted(bc.style, bc.f, bc.args, ()),
-                )
-            else
-                bc
-            end
-            Pair(field_values(pair.first), bc′)
+            Pair(field_values(pair.first), bc)
         end,
     )
     check_mismatched_spaces(fmbc)

test/Fields/field_multi_broadcast_fusion.jl

@@ -1,5 +1,6 @@
 #=
 julia --check-bounds=yes --project=test
+julia -g2 --check-bounds=yes --project=test
 julia --project=test
 using Revise; include(joinpath("test", "Fields", "field_multi_broadcast_fusion.jl"))
 =#
@@ -39,6 +40,8 @@ if !(@isdefined(TU))
     import .TestUtilities as TU
 end
 
+@show ClimaComms.device()
+
 function CenterExtrudedFiniteDifferenceSpaceLineHSpace(
     ::Type{FT};
     zelem = 10,
@@ -338,7 +341,13 @@ end
     FT = Float64
     device = ClimaComms.device()
     ArrayType = device isa ClimaComms.CUDADevice ? CuArray : Array
-    VF_data() = VF{FT}(ArrayType(ones(FT, 3, 2)))
+    colspace = TU.ColumnCenterFiniteDifferenceSpace(
+        FT;
+        zelem = 3,
+        context = ClimaComms.context(device),
+    )
+    VF_data() = Fields.Field(FT, colspace)
+
     X = Fields.FieldVector(; x1 = VF_data(), x2 = VF_data(), x3 = VF_data())
     Y = Fields.FieldVector(; y1 = VF_data(), y2 = VF_data(), y3 = VF_data())
     test_kernel!(; fused!, unfused!, X, Y)