bjoernager/rust
bjoernager/rust
1
Fork 0
Code Activity

Auto merge of #102056 - b-naber:unevaluated, r=lcnr

Browse source 
Introduce mir::Unevaluated

Previously the distinction between unevaluated constants in the type-system and in mir was not explicit and a little confusing. Probably better to introduce its own type for that.

r? `@lcnr`
This commit is contained in:
bors 2022-09-23 13:39:11 +00:00
commit 9a963e3bad
38 changed files with 220 additions and 156 deletions
Download patch file Download diff file Expand all files Collapse all files

18
compiler/rustc_const_eval/src/transform/check_consts/qualifs.rs
View file

@ -5,6 +5,7 @@
use rustc_errors::ErrorGuaranteed;
use rustc_hir::LangItem;
use rustc_infer::infer::TyCtxtInferExt;
use rustc_middle::mir;
use rustc_middle::mir::*;
use rustc_middle::ty::{self, subst::SubstsRef, AdtDef, Ty};
use rustc_span::DUMMY_SP;
@ -350,17 +351,13 @@ where
// FIXME(valtrees): check whether const qualifs should behave the same
// way for type and mir constants.
let uneval = match constant.literal {
ConstantKind::Ty(ct) if matches!(ct.kind(), ty::ConstKind::Unevaluated(_)) => {
let ty::ConstKind::Unevaluated(uv) = ct.kind() else { unreachable!() };
Some(uv.expand())
}
ConstantKind::Ty(_) => None,
ConstantKind::Ty(ct) if matches!(ct.kind(), ty::ConstKind::Param(_)) => None,
ConstantKind::Ty(c) => bug!("expected ConstKind::Param here, found {:?}", c),
ConstantKind::Unevaluated(uv, _) => Some(uv),
ConstantKind::Val(..) => None,
};
if let Some(ty::Unevaluated { def, substs: _, promoted }) = uneval {
if let Some(mir::UnevaluatedConst { def, substs: _, promoted }) = uneval {
// Use qualifs of the type for the promoted. Promoteds in MIR body should be possible
// only for `NeedsNonConstDrop` with precise drop checking. This is the only const
// check performed after the promotion. Verify that with an assertion.
@ -368,11 +365,8 @@ where
// Don't peek inside trait associated constants.
if promoted.is_none() && cx.tcx.trait_of_item(def.did).is_none() {
let qualifs = if let Some((did, param_did)) = def.as_const_arg() {
cx.tcx.at(constant.span).mir_const_qualif_const_arg((did, param_did))
} else {
cx.tcx.at(constant.span).mir_const_qualif(def.did)
};
assert_eq!(def.const_param_did, None, "expected associated const: {def:?}");
let qualifs = cx.tcx.at(constant.span).mir_const_qualif(def.did);
if !Q::in_qualifs(&qualifs) {
return false;

3
compiler/rustc_const_eval/src/transform/promote_consts.rs
View file

@ -13,6 +13,7 @@
//! move analysis runs after promotion on broken MIR.
use rustc_hir as hir;
use rustc_middle::mir;
use rustc_middle::mir::traversal::ReversePostorderIter;
use rustc_middle::mir::visit::{MutVisitor, MutatingUseContext, PlaceContext, Visitor};
use rustc_middle::mir::*;
@ -840,7 +841,7 @@ impl<'a, 'tcx> Promoter<'a, 'tcx> {
promoted.span = span;
promoted.local_decls[RETURN_PLACE] = LocalDecl::new(ty, span);
let substs = tcx.erase_regions(InternalSubsts::identity_for_item(tcx, def.did));
let uneval = ty::Unevaluated { def, substs, promoted: Some(promoted_id) };
let uneval = mir::UnevaluatedConst { def, substs, promoted: Some(promoted_id) };
Operand::Constant(Box::new(Constant {
span,