> on arithmetic expression and type promotion/conversion rules I agree, those are complicated (not sure about the needlessly). However, one can avoid the bulk

> on arithmetic expression and type promotion/conversion rules I agree, those are complicated (not sure about the needlessly). However, one can avoid the bulk of the issue but not doing unsigned arithmetic. > C++ static polymorphism I am not clear on what's the connection between static polymorphism and ABI compatibility. In general, C++ always view ABI compatibility as a property of the platform/tools and not of the languages. We do have a pretty standard ABI (Itanium 64) where everbody seems to have converge. I am not super familiar with rust trait implementation, but it doesn't looks like the language force any particular implementation details. the current compatibility seems more a consequence of having just one rust compiler/tool chain as opposed to a conscious design decision.