macro hygiene and type parameters

[SimonDanisch]

macro test()
    quote
        const MyTest{Arg} = Tuple{Arg}
    end
end

@test # gives: syntax: invalid variable expression in "where"

expr = quote
    const MyTest{Arg} = Tuple{Arg}
end

eval(expr) # works

@mbauman figured out, that this might be a hygiene issue:

macro test()
    quote
        const MyTest{$(esc(:Arg))} = Tuple{$(esc(:Arg))}
    end
end
@test # works