Tricky parametric type dispatch

[mauro3]

No, you cannot do this in general. This is why similar exists for arrays and you should probably use a similar approach. X-ref:

Stripping parameter from parametric types

No, you can’t. The approved solution is wrong – there’s no relation between the ordering of type parameters of a subtype (in this case, SomeArrayType) and its supertype (AbstractArray). Tamas_Papp’s solution is correct. In generic code, this is usually done by calling the similar function. However, we can also generalize that solution to abstract types as follows (by adding in <: so that it can select subtypes): stripN(::Type{<:AbstractArray{T, N}}) where {T, N} = AbstractArray{T, M} where M