no method matching copyto!(::KnetArray{Float32,4}, ::AutoGrad.Result{KnetArray{Float32,4}})

[denizyuret]

@barisbatuhan says: I have implemented a residual block myself in my project and I am having an issue in the residual block. If I only predict by giving an input (no backward pass), the method works without an issue. However, if training is enabled, then I am getting this error:

LoadError: MethodError: no method matching copyto!(::KnetArray{Float32,4}, ::AutoGrad.Result{KnetArray{Float32,4}})

The code piece I am getting error is given below:
https://drive.google.com/file/d/1jP-QxsWGvIUHo3FKiSmNzt5PChY4Y_Be/view?usp=sharing

Here is the error log:
https://drive.google.com/file/d/1zwGZQTdFTBXoy_acYT2G-o2Bx57Q6qzn/view?usp=sharing

The workaround of using + instead of .+ works, but we should fix .+ as well.