1

Combine `ty::Projection` and `ty::Opaque` into `ty::Alias` by compiler-errors ·...

 1 year ago
source link: https://github.com/rust-lang/rust/pull/104986
Go to the source link to view the article. You can view the picture content, updated content and better typesetting reading experience. If the link is broken, please click the button below to view the snapshot at that time.

Member

@compiler-errors compiler-errors commented Nov 27, 2022 •

edited

Implements rust-lang/types-team#79.

This PR consolidates ty::Projection and ty::Opaque into a single ty::Alias, with an AliasKind and AliasTy type (renamed from ty::ProjectionTy, which is the inner data of ty::Projection) defined as so:

enum AliasKind {
  Projection,
  Opaque,
}

struct AliasTy<'tcx> {
  def_id: DefId,
  substs: SubstsRef<'tcx>,
}

Since we don't have access to TyCtxt in type flags computation, and because repeatedly calling DefKind on the def-id is expensive, these two types are distinguished with ty::AliasKind, conveniently glob-imported into ty::{Projection, Opaque}. For example:

  match ty.kind() {
-   ty::Opaque(..) => 
+   ty::Alias(ty::Opaque, ..) => {}
    _ => {}
  }

This PR also consolidates match arms that treated ty::Opaque and ty::Projection identically.

r? @ghost

xFrednet reacted with hooray emoji

report

Recommend

About Joyk


Aggregate valuable and interesting links.
Joyk means Joy of geeK