Add limited implementation inheritance via traits

[rust-highfive]

Issue by brson
Thursday Oct 17, 2013 at 18:48 GMT

For earlier discussion, see rust-lang/rust#9912

This issue was labelled with: A-grammar, A-traits, A-typesystem, B-RFC, P-high in the Rust repository

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Not sure if 'implementation inheritance' is the right name for this.

Servo people are complaining a lot about not being able to inherit the memory layout of supertypes, since the DOM is a classic OO hierarchy. Seems like we just have to do it. The basic idea is to let traits specify struct fields.

Needs a complete design, something simple.

[nrc]

dup of #349