# How to overload +=?

**URL:** <https://discourse.julialang.org/t/how-to-overload/71523>\
**Category:** General Usage\
**Created:** [November 15, 2021, 7:46pm UTC](https://discourse.julialang.org/t/how-to-overload/71523 "2021-11-15T19:46:50Z")\
**Posts on this page:** 1\
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**Author:** ![giordano](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/giordano/32/2166_2.png) [@giordano](https://discourse.julialang.org/u/giordano)\
**Post date:** [November 15, 2021, 8:03pm UTC](https://discourse.julialang.org/t/how-to-overload/71523/7 "2021-11-15T20:03:09Z")

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> [@mzaffalon](#):
>
> ```julia
> julia> Base.:+(a::A, b::A) = A(a.a+b.a)
> 
> ```

Note that this wouldn’t mutate the argument (which one?), in case this is what you were expecting, since you marked the type as mutable.

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