Oh, and maybe this goes against the Go ethos, but Python has a library called Sympy for Computer Algebra, and it's quite nice. It clearly relies on operator overloading.
I'm guessing this won't happen for a long time because operator overloading has a reputation (rightly or wrongly) for being abused. Oh well!
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More philosophical point: Overloading in programming started with mathematical operators, no? The motivation for having it as a language feature is very clear (if you know enough mathematics). What happened?