Allocations when using getfield with a tuple/vector of symbols

General Usage Performance
,
2

You could use generated function:

@generated function getfield_unrolled(t::T, f::Symbol) where {T}
    names = fieldnames(T)
    exprs = [:($(QuoteNode(name)) == f && return getfield(t, $(QuoteNode(name)))) for (c, name) in enumerate(names)]

    push!(exprs, :(throw(ErrorException("type $T has no field $f"))))
    return quote
        $(exprs...)
    end
end

and get

julia> @btime getfield_unrolled($test, $(tup[1]))
  1.855 ns (0 allocations: 0 bytes)
"A"
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