Refactor: VariantIdx::from_u32(0) -> FIRST_VARIANT

Since structs are always `VariantIdx(0)`, there's a bunch of files where the only reason they had `VariantIdx` or `vec::Idx` imported at all was to get the first variant.

So this uses a constant for that, and adds some doc-comments to `VariantIdx` while I'm there, since it doesn't have any today.
This commit is contained in:
Scott McMurray 2023-03-25 18:43:03 -07:00
parent 96bd50dd47
commit 0439d13176
25 changed files with 80 additions and 78 deletions

View file

@ -5,7 +5,7 @@ use rustc_middle::mir::*;
use rustc_middle::ty::query::Providers;
use rustc_middle::ty::InternalSubsts;
use rustc_middle::ty::{self, EarlyBinder, GeneratorSubsts, Ty, TyCtxt};
use rustc_target::abi::VariantIdx;
use rustc_target::abi::{VariantIdx, FIRST_VARIANT};
use rustc_index::vec::{Idx, IndexVec};
@ -816,11 +816,8 @@ pub fn build_adt_ctor(tcx: TyCtxt<'_>, ctor_id: DefId) -> Body<'_> {
let source_info = SourceInfo::outermost(span);
let variant_index = if adt_def.is_enum() {
adt_def.variant_index_with_ctor_id(ctor_id)
} else {
VariantIdx::new(0)
};
let variant_index =
if adt_def.is_enum() { adt_def.variant_index_with_ctor_id(ctor_id) } else { FIRST_VARIANT };
// Generate the following MIR:
//