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Auto merge of #113210 - fee1-dead-contrib:effects-mvp, r=oli-obk

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Effects/keyword generics MVP

This adds `feature(effects)`, which adds `const host: bool` to the generics of const functions, const traits and const impls. This will be used to replace the current logic around const traits.

r? `@oli-obk`
This commit is contained in:
bors 2023-07-05 13:42:00 +00:00
commit e4cd161006
15 changed files with 269 additions and 26 deletions
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30
compiler/rustc_hir_analysis/src/collect/generics_of.rs
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@ -9,7 +9,7 @@ use rustc_hir::def_id::LocalDefId;
use rustc_middle::ty::{self, TyCtxt};
use rustc_session::lint;
use rustc_span::symbol::{kw, Symbol};
use rustc_span::Span;
use rustc_span::{sym, Span};
pub(super) fn generics_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::Generics {
use rustc_hir::*;
@ -101,6 +101,7 @@ pub(super) fn generics_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::Generics {
param_def_id_to_index,
has_self: generics.has_self,
has_late_bound_regions: generics.has_late_bound_regions,
host_effect_index: None,
};
} else {
// HACK(eddyb) this provides the correct generics when
@ -226,10 +227,12 @@ pub(super) fn generics_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::Generics {
let has_self = opt_self.is_some();
let mut parent_has_self = false;
let mut own_start = has_self as u32;
let mut host_effect_index = None;
let parent_count = parent_def_id.map_or(0, |def_id| {
let generics = tcx.generics_of(def_id);
assert!(!has_self);
parent_has_self = generics.has_self;
host_effect_index = generics.host_effect_index;
own_start = generics.count() as u32;
generics.parent_count + generics.params.len()
});
@ -251,11 +254,11 @@ pub(super) fn generics_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::Generics {
// Now create the real type and const parameters.
let type_start = own_start - has_self as u32 + params.len() as u32;
let mut i = 0;
let mut i: u32 = 0;
let mut next_index = || {
let prev = i;
i += 1;
prev as u32 + type_start
prev + type_start
};
const TYPE_DEFAULT_NOT_ALLOWED: &'static str = "defaults for type parameters are only allowed in \
@ -295,7 +298,13 @@ pub(super) fn generics_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::Generics {
})
}
GenericParamKind::Const { default, .. } => {
if !matches!(allow_defaults, Defaults::Allowed) && default.is_some() {
let is_host_param = tcx.has_attr(param.def_id, sym::rustc_host);
if !matches!(allow_defaults, Defaults::Allowed)
&& default.is_some()
// `rustc_host` effect params are allowed to have defaults.
&& !is_host_param
{
tcx.sess.span_err(
param.span,
"defaults for const parameters are only allowed in \
@ -303,8 +312,18 @@ pub(super) fn generics_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::Generics {
);
}
let index = next_index();
if is_host_param {
if let Some(idx) = host_effect_index {
bug!("parent also has host effect param? index: {idx}, def: {def_id:?}");
}
host_effect_index = Some(parent_count + index as usize);
}
Some(ty::GenericParamDef {
index: next_index(),
index,
name: param.name.ident().name,
def_id: param.def_id.to_def_id(),
pure_wrt_drop: param.pure_wrt_drop,
@ -356,6 +375,7 @@ pub(super) fn generics_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::Generics {
param_def_id_to_index,
has_self: has_self || parent_has_self,
has_late_bound_regions: has_late_bound_regions(tcx, node),
host_effect_index,
}
}