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Joe Savona
1fd4bad525
This is an incremental step to removing `Place.memberPath`. This PR changes how we handle MemberExpressions in rvalue position, converting to a new `PropertyLoad` InstructionValue variant. Example: ``` let x = a.b; x.y = b.c; => Const tmp1 = PropertyLoad a, 'b'; Const x = Place tmp1; Const tmp2 = PropertyLoad b, 'c'; Reassign x.y = tmp2 ``` That we already recently made a chance to ensure that _if_ the lvalue is a member expression, that we convert the RHS to a Place. So although `x.y = b.c` could technically be lowered to a single instruction (with the`b.c` as a PropertyLoad), we force this to a temporary to ensure that we can independently memoize the RHS value. The net result is that the following combinations are possible: * `x = y`, lvalue identifier, rvalue identifier * `x.y = y` lvalue member path, rvalue identifier * `x = y.z` lvalue identifier, rvalue property load As noted above, `x.y = a.b` no longer occurs (and there's an invariant for this in one of the passes). A follow-up PR will add a PropertyStore instruction so that we can remove member paths in lvalue position too.