RFC: Change operator method lookup to be less magical

[rust-highfive]

Issue by nikomatsakis
Wednesday Feb 13, 2013 at 21:40 GMT

For earlier discussion, see rust-lang/rust#4920

This issue was labelled with: A-traits, A-typesystem, B-RFC, I-cleanup, P-backcompat-lang in the Rust repository

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Right now, operator "methods" proceed according to the same logic as any other method. But this leads to surprising results like this: https://gist.github.com/bstrie/4948410

Also, operators are already handled somewhat specially because we auto-ref their arguments. This means that you can write val1-of-my-linear-type == val2-of-my-linear-type and it doesn't move or do anything creepy (to call eq explicitly, in contrast, you'd write val1-of-my-linear-type.eq(&val2-of-my-linear-type)).

I think method lookup for operators should never apply any automatic transformations to the receiver or arguments, other than the current auto-ref behavior (which means that a OP b is kind of implicitly (&a).OP(&b))

@pcwalton I expect you in particular might have an opinion about this.

[nikomatsakis]

This has largely been covered by other RFCs and/or implemented. Closing.