bjoernager/rust
bjoernager/rust
1
Fork 0
Code Activity

Split part of adt_const_params into unsized_const_params

Browse source
This commit is contained in:
Boxy 2024-07-14 13:38:51 +01:00 • committed by Boxy
parent 42cc42b942
commit d0c11bf6e3
140 changed files with 1130 additions and 559 deletions
Download patch file Download diff file Expand all files Collapse all files

56
compiler/rustc_trait_selection/src/traits/misc.rs
View file

@ -4,6 +4,7 @@ use crate::regions::InferCtxtRegionExt;
use crate::traits::{self, FulfillmentError, ObligationCause};
use hir::LangItem;
use rustc_ast::Mutability;
use rustc_data_structures::fx::FxIndexSet;
use rustc_hir as hir;
use rustc_infer::infer::outlives::env::OutlivesEnvironment;
@ -19,7 +20,7 @@ pub enum CopyImplementationError<'tcx> {
}
pub enum ConstParamTyImplementationError<'tcx> {
TypeNotSized,
UnsizedConstParamsFeatureRequired,
InvalidInnerTyOfBuiltinTy(Vec<(Ty<'tcx>, InfringingFieldsReason<'tcx>)>),
InfrigingFields(Vec<(&'tcx ty::FieldDef, Ty<'tcx>, InfringingFieldsReason<'tcx>)>),
NotAnAdtOrBuiltinAllowed,
@ -79,9 +80,9 @@ pub fn type_allowed_to_implement_copy<'tcx>(
Ok(())
}
/// Checks that the fields of the type (an ADT) all implement `ConstParamTy`.
/// Checks that the fields of the type (an ADT) all implement `(Unsized?)ConstParamTy`.
///
/// If fields don't implement `ConstParamTy`, return an error containing a list of
/// If fields don't implement `(Unsized?)ConstParamTy`, return an error containing a list of
/// those violating fields.
///
/// If it's not an ADT, int ty, `bool` or `char`, returns `Err(NotAnAdtOrBuiltinAllowed)`.
@ -89,30 +90,10 @@ pub fn type_allowed_to_implement_const_param_ty<'tcx>(
tcx: TyCtxt<'tcx>,
param_env: ty::ParamEnv<'tcx>,
self_type: Ty<'tcx>,
lang_item: LangItem,
parent_cause: ObligationCause<'tcx>,
) -> Result<(), ConstParamTyImplementationError<'tcx>> {
{
// Check for sizedness before recursing into ADT fields so that if someone tries to write:
// ```rust
// #[derive(ConstParamTy)]
// struct Foo([u8])
// ```
// They are told that const parameter types must be sized, instead of it saying that
// the trait implementation `[u8]: ConstParamTy` is not satisfied.
let infcx = tcx.infer_ctxt().build();
let ocx = traits::ObligationCtxt::new_with_diagnostics(&infcx);
ocx.register_bound(
parent_cause.clone(),
param_env,
self_type,
tcx.require_lang_item(LangItem::Sized, Some(parent_cause.span)),
);
if !ocx.select_all_or_error().is_empty() {
return Err(ConstParamTyImplementationError::TypeNotSized);
}
};
assert!(matches!(lang_item, LangItem::ConstParamTy | LangItem::UnsizedConstParamTy));
let inner_tys: Vec<_> = match *self_type.kind() {
// Trivially okay as these types are all:
@ -121,14 +102,23 @@ pub fn type_allowed_to_implement_const_param_ty<'tcx>(
// - Have structural equality
ty::Uint(_) | ty::Int(_) | ty::Bool | ty::Char => return Ok(()),
ty::Ref(..) => return Err(ConstParamTyImplementationError::NotAnAdtOrBuiltinAllowed),
// Handle types gated under `feature(unsized_const_params)`
// FIXME(unsized_const_params): Make `const N: [u8]` work then forbid references
ty::Slice(inner_ty) | ty::Ref(_, inner_ty, Mutability::Not)
if lang_item == LangItem::UnsizedConstParamTy =>
{
vec![inner_ty]
}
ty::Str if lang_item == LangItem::UnsizedConstParamTy => {
vec![Ty::new_slice(tcx, tcx.types.u8)]
}
ty::Str | ty::Slice(..) | ty::Ref(_, _, Mutability::Not) => {
return Err(ConstParamTyImplementationError::UnsizedConstParamsFeatureRequired);
}
ty::Array(inner_ty, _) => vec![inner_ty],
// Even if we currently require const params to be `Sized` we may aswell handle them correctly
// here anyway.
ty::Slice(inner_ty) | ty::Array(inner_ty, _) => vec![inner_ty],
// `str` morally acts like a newtype around `[u8]`
ty::Str => vec![Ty::new_slice(tcx, tcx.types.u8)],
ty::Tuple(inner_tys) => inner_tys.into_iter().collect(),
ty::Adt(adt, args) if adt.is_enum() || adt.is_struct() => {
@ -139,7 +129,7 @@ pub fn type_allowed_to_implement_const_param_ty<'tcx>(
adt,
args,
parent_cause.clone(),
hir::LangItem::ConstParamTy,
lang_item,
)
.map_err(ConstParamTyImplementationError::InfrigingFields)?;
@ -159,7 +149,7 @@ pub fn type_allowed_to_implement_const_param_ty<'tcx>(
parent_cause.clone(),
param_env,
inner_ty,
tcx.require_lang_item(LangItem::ConstParamTy, Some(parent_cause.span)),
tcx.require_lang_item(lang_item, Some(parent_cause.span)),
);
let errors = ocx.select_all_or_error();