julia

58399e22 - Extend `PartialStruct` to represent non-contiguously defined fields (#57304)

Extend `PartialStruct` to represent non-contiguously defined fields (#57304) So far, `PartialStruct` has been unable to represent non-contiguously defined fields, where e.g. a struct would have fields 1 and 3 defined but not field 2. This PR extends it so that such information may be represented with `PartialStruct`, extending the applicability of optimizations e.g. introduced in #55297 by @aviatesk or #57222. The semantics of `new` prevent the creation of a struct with non-contiguously defined fields, therefore this change is mostly relevant to model mutable structs whose fields may be previously set or assumed to be defined after creation, or immutable structs whose creation is opaque. Notably, with this change we may now infer information about structs in the following case: ```julia mutable struct A; x; y; z; A() = new(); end function f() mut = A() # some opaque call preventing optimizations # who knows, maybe `identity` will set fields from `mut` in a future world age! invokelatest(identity, mut) isdefined(mut, :z) && isdefined(mut, :x) || return isdefined(mut, :x) & isdefined(mut, :z) # this now infers as `true` isdefined(mut, :y) # this does not end ``` whereas previously, only information gained successively with `isdefined(mut, :x) && isdefined(mut, :y) && isdefined(mut, :z)` could allow inference to model `mut` having its `z` field defined. --------- Co-authored-by: Cédric Belmant <cedric.belmant@juliahub.com> Co-authored-by: Shuhei Kadowaki <aviatesk@gmail.com>