@show imε output

I noticed, in Julia 1.0.0, the following:

julia> @show imε;
imε = imɛ

The output produced by the @show macro uses 2 different characters for the epsilon: first, U+03b5 and then the correct U+02b5 (in some fonts the difference between ε and ɛ is very noticeable):

julia> for i in "imε = imɛ"; display(i); end
'i': ASCII/Unicode U+0069 (category Ll: Letter, lowercase)
'm': ASCII/Unicode U+006d (category Ll: Letter, lowercase)
'ε': Unicode U+03b5 (category Ll: Letter, lowercase)
' ': ASCII/Unicode U+0020 (category Zs: Separator, space)
'=': ASCII/Unicode U+003d (category Sm: Symbol, math)
' ': ASCII/Unicode U+0020 (category Zs: Separator, space)
'i': ASCII/Unicode U+0069 (category Ll: Letter, lowercase)
'm': ASCII/Unicode U+006d (category Ll: Letter, lowercase)
'ɛ': Unicode U+025b (category Ll: Letter, lowercase)

Any ideas of why this is so and how to fix it?

Start by reproducing the Julia 1.0.0 example in the issue with @show imε, then inspect DualNumbers.jl's handling of the displayed variable name. Compare the Unicode code points in the input and output; done means @show emits the same epsilon character consistently.