bjoernager/rust
bjoernager/rust
1
Fork 0
Code Activity

Introduce min_generic_const_args and directly represent paths

Browse source 
Co-authored-by: Boxy UwU <rust@boxyuwu.dev>
Co-authored-by: León Orell Valerian Liehr <me@fmease.dev>
This commit is contained in:
Noah Lev 2024-11-19 05:01:59 +00:00 • committed by Boxy
parent b71fb5edc0
commit 59e339f766
21 changed files with 361 additions and 195 deletions
Download patch file Download diff file Expand all files Collapse all files

104
compiler/rustc_middle/src/ty/consts.rs
View file

@ -1,13 +1,14 @@
use std::borrow::Cow;
use rustc_data_structures::intern::Interned;
use rustc_error_messages::MultiSpan;
use rustc_hir::def::{DefKind, Res};
use rustc_hir::def_id::{DefId, LocalDefId};
use rustc_hir::{self as hir, HirId};
use rustc_hir::def_id::LocalDefId;
use rustc_hir::{self as hir};
use rustc_macros::HashStable;
use rustc_type_ir::{self as ir, TypeFlags, WithCachedTypeInfo};
use tracing::{debug, instrument};
use crate::middle::resolve_bound_vars as rbv;
use crate::mir::interpret::{LitToConstInput, Scalar};
use crate::ty::{self, GenericArgs, Ty, TyCtxt, TypeVisitableExt};
@ -142,7 +143,7 @@ impl<'tcx> Const<'tcx> {
pub fn new_error_with_message<S: Into<MultiSpan>>(
tcx: TyCtxt<'tcx>,
span: S,
msg: &'static str,
msg: impl Into<Cow<'static, str>>,
) -> Const<'tcx> {
let reported = tcx.dcx().span_delayed_bug(span, msg);
Const::new_error(tcx, reported)
@ -183,46 +184,8 @@ impl<'tcx> rustc_type_ir::inherent::Const<TyCtxt<'tcx>> for Const<'tcx> {
}
}
/// In some cases, [`hir::ConstArg`]s that are being used in the type system
/// through const generics need to have their type "fed" to them
/// using the query system.
///
/// Use this enum with [`Const::from_const_arg`] to instruct it with the
/// desired behavior.
#[derive(Debug, Clone, Copy)]
pub enum FeedConstTy {
/// Feed the type.
///
/// The `DefId` belongs to the const param that we are supplying
/// this (anon) const arg to.
Param(DefId),
/// Don't feed the type.
No,
}
impl<'tcx> Const<'tcx> {
/// Convert a [`hir::ConstArg`] to a [`ty::Const`](Self).
#[instrument(skip(tcx), level = "debug")]
pub fn from_const_arg(
tcx: TyCtxt<'tcx>,
const_arg: &'tcx hir::ConstArg<'tcx>,
feed: FeedConstTy,
) -> Self {
if let FeedConstTy::Param(param_def_id) = feed
&& let hir::ConstArgKind::Anon(anon) = &const_arg.kind
{
tcx.feed_anon_const_type(anon.def_id, tcx.type_of(param_def_id));
}
match const_arg.kind {
hir::ConstArgKind::Path(qpath) => {
// FIXME(min_generic_const_args): for now only params are lowered to ConstArgKind::Path
Self::from_param(tcx, qpath, const_arg.hir_id)
}
hir::ConstArgKind::Anon(anon) => Self::from_anon_const(tcx, anon.def_id),
}
}
// FIXME: move this and try_from_lit to hir_ty_lowering like lower_const_arg/from_const_arg
/// Literals and const generic parameters are eagerly converted to a constant, everything else
/// becomes `Unevaluated`.
#[instrument(skip(tcx), level = "debug")]
@ -240,7 +203,7 @@ impl<'tcx> Const<'tcx> {
let ty = tcx.type_of(def).no_bound_vars().expect("const parameter types cannot be generic");
match Self::try_from_lit_or_param(tcx, ty, expr) {
match Self::try_from_lit(tcx, ty, expr) {
Some(v) => v,
None => ty::Const::new_unevaluated(tcx, ty::UnevaluatedConst {
def: def.to_def_id(),
@ -249,40 +212,8 @@ impl<'tcx> Const<'tcx> {
}
}
/// Lower a const param to a [`Const`].
///
/// IMPORTANT: `qpath` must be a const param, otherwise this will panic
fn from_param(tcx: TyCtxt<'tcx>, qpath: hir::QPath<'tcx>, hir_id: HirId) -> Self {
let hir::QPath::Resolved(_, &hir::Path { res: Res::Def(DefKind::ConstParam, def_id), .. }) =
qpath
else {
span_bug!(qpath.span(), "non-param {qpath:?} passed to Const::from_param")
};
match tcx.named_bound_var(hir_id) {
Some(rbv::ResolvedArg::EarlyBound(_)) => {
// Find the name and index of the const parameter by indexing the generics of
// the parent item and construct a `ParamConst`.
let item_def_id = tcx.parent(def_id);
let generics = tcx.generics_of(item_def_id);
let index = generics.param_def_id_to_index[&def_id];
let name = tcx.item_name(def_id);
ty::Const::new_param(tcx, ty::ParamConst::new(index, name))
}
Some(rbv::ResolvedArg::LateBound(debruijn, index, _)) => {
ty::Const::new_bound(tcx, debruijn, ty::BoundVar::from_u32(index))
}
Some(rbv::ResolvedArg::Error(guar)) => ty::Const::new_error(tcx, guar),
arg => bug!("unexpected bound var resolution for {:?}: {arg:?}", hir_id),
}
}
#[instrument(skip(tcx), level = "debug")]
fn try_from_lit_or_param(
tcx: TyCtxt<'tcx>,
ty: Ty<'tcx>,
expr: &'tcx hir::Expr<'tcx>,
) -> Option<Self> {
fn try_from_lit(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>, expr: &'tcx hir::Expr<'tcx>) -> Option<Self> {
// Unwrap a block, so that e.g. `{ P }` is recognised as a parameter. Const arguments
// currently have to be wrapped in curly brackets, so it's necessary to special-case.
let expr = match &expr.kind {
@ -321,7 +252,7 @@ impl<'tcx> Const<'tcx> {
Err(e) => {
tcx.dcx().span_delayed_bug(
expr.span,
format!("Const::from_anon_const: couldn't lit_to_const {e:?}"),
format!("Const::try_from_lit: couldn't lit_to_const {e:?}"),
);
}
}
@ -414,20 +345,3 @@ impl<'tcx> Const<'tcx> {
matches!(self.kind(), ty::ConstKind::Infer(_))
}
}
pub fn const_param_default<'tcx>(
tcx: TyCtxt<'tcx>,
def_id: LocalDefId,
) -> ty::EarlyBinder<'tcx, Const<'tcx>> {
let default_ct = match tcx.hir_node_by_def_id(def_id) {
hir::Node::GenericParam(hir::GenericParam {
kind: hir::GenericParamKind::Const { default: Some(ct), .. },
..
}) => ct,
_ => span_bug!(
tcx.def_span(def_id),
"`const_param_default` expected a generic parameter with a constant"
),
};
ty::EarlyBinder::bind(Const::from_const_arg(tcx, default_ct, FeedConstTy::No))
}

6
compiler/rustc_middle/src/ty/context.rs
View file

@ -30,7 +30,7 @@ use rustc_errors::{
Applicability, Diag, DiagCtxtHandle, ErrorGuaranteed, LintDiagnostic, MultiSpan,
};
use rustc_hir as hir;
use rustc_hir::def::DefKind;
use rustc_hir::def::{CtorKind, DefKind};
use rustc_hir::def_id::{CrateNum, DefId, LOCAL_CRATE, LocalDefId};
use rustc_hir::definitions::Definitions;
use rustc_hir::intravisit::Visitor;
@ -230,7 +230,9 @@ impl<'tcx> Interner for TyCtxt<'tcx> {
DefKind::OpaqueTy => ty::AliasTermKind::OpaqueTy,
DefKind::TyAlias => ty::AliasTermKind::WeakTy,
DefKind::AssocConst => ty::AliasTermKind::ProjectionConst,
DefKind::AnonConst => ty::AliasTermKind::UnevaluatedConst,
DefKind::AnonConst | DefKind::Const | DefKind::Ctor(_, CtorKind::Const) => {
ty::AliasTermKind::UnevaluatedConst
}
kind => bug!("unexpected DefKind in AliasTy: {kind:?}"),
}
}

3
compiler/rustc_middle/src/ty/mod.rs
View file

@ -62,7 +62,7 @@ pub use self::closure::{
place_to_string_for_capture,
};
pub use self::consts::{
Const, ConstInt, ConstKind, Expr, ExprKind, FeedConstTy, ScalarInt, UnevaluatedConst, ValTree,
Const, ConstInt, ConstKind, Expr, ExprKind, ScalarInt, UnevaluatedConst, ValTree,
};
pub use self::context::{
CtxtInterners, CurrentGcx, DeducedParamAttrs, Feed, FreeRegionInfo, GlobalCtxt, Lift, TyCtxt,
@ -2249,7 +2249,6 @@ pub fn provide(providers: &mut Providers) {
incoherent_impls: trait_def::incoherent_impls_provider,
trait_impls_in_crate: trait_def::trait_impls_in_crate_provider,
traits: trait_def::traits_provider,
const_param_default: consts::const_param_default,
vtable_allocation: vtable::vtable_allocation_provider,
..*providers
};