bjoernager/rust
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lower impl const to bind to host effect param

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This commit is contained in:
Deadbeef 2023-07-25 05:58:53 +00:00
parent 4f7bb9890c
commit 92f4c59e48
24 changed files with 236 additions and 137 deletions
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1
compiler/rustc_ast_lowering/src/asm.rs
View file

@ -207,6 +207,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
&sym.path,
ParamMode::Optional,
&ImplTraitContext::Disallowed(ImplTraitPosition::Path),
None,
);
hir::InlineAsmOperand::SymStatic { path, def_id }
} else {

6
compiler/rustc_ast_lowering/src/expr.rs
View file

@ -100,6 +100,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
ParamMode::Optional,
ParenthesizedGenericArgs::Err,
&ImplTraitContext::Disallowed(ImplTraitPosition::Path),
None,
));
let receiver = self.lower_expr(receiver);
let args =
@ -260,6 +261,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
path,
ParamMode::Optional,
&ImplTraitContext::Disallowed(ImplTraitPosition::Path),
None,
);
hir::ExprKind::Path(qpath)
}
@ -307,6 +309,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
&se.path,
ParamMode::Optional,
&ImplTraitContext::Disallowed(ImplTraitPosition::Path),
None,
)),
self.arena
.alloc_from_iter(se.fields.iter().map(|x| self.lower_expr_field(x))),
@ -1179,6 +1182,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
path,
ParamMode::Optional,
&ImplTraitContext::Disallowed(ImplTraitPosition::Path),
None,
);
// Destructure like a tuple struct.
let tuple_struct_pat = hir::PatKind::TupleStruct(
@ -1198,6 +1202,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
path,
ParamMode::Optional,
&ImplTraitContext::Disallowed(ImplTraitPosition::Path),
None,
);
// Destructure like a unit struct.
let unit_struct_pat = hir::PatKind::Path(qpath);
@ -1222,6 +1227,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
&se.path,
ParamMode::Optional,
&ImplTraitContext::Disallowed(ImplTraitPosition::Path),
None,
);
let fields_omitted = match &se.rest {
StructRest::Base(e) => {

84
compiler/rustc_ast_lowering/src/item.rs
View file

@ -85,6 +85,7 @@ impl<'a, 'hir> ItemLowerer<'a, 'hir> {
allow_try_trait: Some([sym::try_trait_v2, sym::yeet_desugar_details][..].into()),
allow_gen_future: Some([sym::gen_future, sym::closure_track_caller][..].into()),
generics_def_id_map: Default::default(),
host_param_id: None,
};
lctx.with_hir_id_owner(owner, |lctx| f(lctx));
@ -139,8 +140,24 @@ impl<'a, 'hir> ItemLowerer<'a, 'hir> {
// This is used to track which lifetimes have already been defined,
// and which need to be replicated when lowering an async fn.
if let hir::ItemKind::Impl(impl_) = parent_hir.node().expect_item().kind {
lctx.is_in_trait_impl = impl_.of_trait.is_some();
match parent_hir.node().expect_item().kind {
hir::ItemKind::Impl(impl_) => {
lctx.is_in_trait_impl = impl_.of_trait.is_some();
}
hir::ItemKind::Trait(_, _, generics, _, _) if lctx.tcx.features().effects => {
lctx.host_param_id = generics
.params
.iter()
.find(|param| {
parent_hir
.attrs
.get(param.hir_id.local_id)
.iter()
.any(|attr| attr.has_name(sym::rustc_host))
})
.map(|param| param.def_id);
}
_ => {}
}
match ctxt {
@ -384,6 +401,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
self.lower_generics(ast_generics, *constness, id, &itctx, |this| {
let trait_ref = trait_ref.as_ref().map(|trait_ref| {
this.lower_trait_ref(
*constness,
trait_ref,
&ImplTraitContext::Disallowed(ImplTraitPosition::Trait),
)
@ -414,7 +432,6 @@ impl<'hir> LoweringContext<'_, 'hir> {
polarity,
defaultness,
defaultness_span,
constness: self.lower_constness(*constness),
generics,
of_trait: trait_ref,
self_ty: lowered_ty,
@ -1358,6 +1375,29 @@ impl<'hir> LoweringContext<'_, 'hir> {
}
}
// Desugar `~const` bound in generics into an additional `const host: bool` param
// if the effects feature is enabled. This needs to be done before we lower where
// clauses since where clauses need to bind to the DefId of the host param
let host_param_parts = if let Const::Yes(span) = constness && self.tcx.features().effects {
if let Some(param) = generics.params.iter().find(|x| {
x.attrs.iter().any(|x| x.has_name(sym::rustc_host))
}) {
// user has manually specified a `rustc_host` param, in this case, we set
// the param id so that lowering logic can use that. But we don't create
// another host param, so this gives `None`.
self.host_param_id = Some(self.local_def_id(param.id));
None
} else {
let param_node_id = self.next_node_id();
let hir_id = self.next_id();
let def_id = self.create_def(self.local_def_id(parent_node_id), param_node_id, DefPathData::TypeNs(sym::host), span);
self.host_param_id = Some(def_id);
Some((span, hir_id, def_id))
}
} else {
None
};
let mut predicates: SmallVec<[hir::WherePredicate<'hir>; 4]> = SmallVec::new();
predicates.extend(generics.params.iter().filter_map(|param| {
self.lower_generic_bound_predicate(
@ -1405,22 +1445,11 @@ impl<'hir> LoweringContext<'_, 'hir> {
let impl_trait_bounds = std::mem::take(&mut self.impl_trait_bounds);
predicates.extend(impl_trait_bounds.into_iter());
// Desugar `~const` bound in generics into an additional `const host: bool` param
// if the effects feature is enabled.
if let Const::Yes(span) = constness && self.tcx.features().effects
// Do not add host param if it already has it (manually specified)
&& !params.iter().any(|x| {
self.attrs.get(&x.hir_id.local_id).map_or(false, |attrs| {
attrs.iter().any(|x| x.has_name(sym::rustc_host))
})
})
{
let param_node_id = self.next_node_id();
if let Some((span, hir_id, def_id)) = host_param_parts {
let const_node_id = self.next_node_id();
let def_id = self.create_def(self.local_def_id(parent_node_id), param_node_id, DefPathData::TypeNs(sym::host), span);
let anon_const: LocalDefId = self.create_def(def_id, const_node_id, DefPathData::AnonConst, span);
let anon_const: LocalDefId =
self.create_def(def_id, const_node_id, DefPathData::AnonConst, span);
let hir_id = self.next_id();
let const_id = self.next_id();
let const_expr_id = self.next_id();
let bool_id = self.next_id();
@ -1430,14 +1459,15 @@ impl<'hir> LoweringContext<'_, 'hir> {
let attr_id = self.tcx.sess.parse_sess.attr_id_generator.mk_attr_id();
let attrs = self.arena.alloc_from_iter([
Attribute {
kind: AttrKind::Normal(P(NormalAttr::from_ident(Ident::new(sym::rustc_host, span)))),
let attrs = self.arena.alloc_from_iter([Attribute {
kind: AttrKind::Normal(P(NormalAttr::from_ident(Ident::new(
sym::rustc_host,
span,
id: attr_id,
style: AttrStyle::Outer,
},
]);
)))),
span,
id: attr_id,
style: AttrStyle::Outer,
}]);
self.attrs.insert(hir_id.local_id, attrs);
let const_body = self.lower_body(|this| {
@ -1476,7 +1506,11 @@ impl<'hir> LoweringContext<'_, 'hir> {
}),
)),
)),
default: Some(hir::AnonConst { def_id: anon_const, hir_id: const_id, body: const_body }),
default: Some(hir::AnonConst {
def_id: anon_const,
hir_id: const_id,
body: const_body,
}),
},
colon_span: None,
pure_wrt_drop: false,

85
compiler/rustc_ast_lowering/src/lib.rs
View file

@ -142,6 +142,8 @@ struct LoweringContext<'a, 'hir> {
/// defined on the TAIT, so we have type Foo<'a1> = ... and we establish a mapping in this
/// field from the original parameter 'a to the new parameter 'a1.
generics_def_id_map: Vec<FxHashMap<LocalDefId, LocalDefId>>,
host_param_id: Option<LocalDefId>,
}
trait ResolverAstLoweringExt {
@ -1267,6 +1269,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
span: t.span
},
itctx,
ast::Const::No,
);
let bounds = this.arena.alloc_from_iter([bound]);
let lifetime_bound = this.elided_dyn_bound(t.span);
@ -1277,7 +1280,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
}
let id = self.lower_node_id(t.id);
let qpath = self.lower_qpath(t.id, qself, path, param_mode, itctx);
let qpath = self.lower_qpath(t.id, qself, path, param_mode, itctx, None);
self.ty_path(id, t.span, qpath)
}
@ -1361,10 +1364,12 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
this.arena.alloc_from_iter(bounds.iter().filter_map(|bound| match bound {
GenericBound::Trait(
ty,
TraitBoundModifier::None
modifier @ (TraitBoundModifier::None
| TraitBoundModifier::MaybeConst
| TraitBoundModifier::Negative,
) => Some(this.lower_poly_trait_ref(ty, itctx)),
| TraitBoundModifier::Negative),
) => {
Some(this.lower_poly_trait_ref(ty, itctx, modifier.to_constness()))
}
// `~const ?Bound` will cause an error during AST validation
// anyways, so treat it like `?Bound` as compilation proceeds.
GenericBound::Trait(
@ -2189,7 +2194,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
) -> hir::GenericBound<'hir> {
match tpb {
GenericBound::Trait(p, modifier) => hir::GenericBound::Trait(
self.lower_poly_trait_ref(p, itctx),
self.lower_poly_trait_ref(p, itctx, modifier.to_constness()),
self.lower_trait_bound_modifier(*modifier),
),
GenericBound::Outlives(lifetime) => {
@ -2332,8 +2337,20 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
}
}
fn lower_trait_ref(&mut self, p: &TraitRef, itctx: &ImplTraitContext) -> hir::TraitRef<'hir> {
let path = match self.lower_qpath(p.ref_id, &None, &p.path, ParamMode::Explicit, itctx) {
fn lower_trait_ref(
&mut self,
constness: ast::Const,
p: &TraitRef,
itctx: &ImplTraitContext,
) -> hir::TraitRef<'hir> {
let path = match self.lower_qpath(
p.ref_id,
&None,
&p.path,
ParamMode::Explicit,
itctx,
Some(constness),
) {
hir::QPath::Resolved(None, path) => path,
qpath => panic!("lower_trait_ref: unexpected QPath `{qpath:?}`"),
};
@ -2345,10 +2362,11 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
&mut self,
p: &PolyTraitRef,
itctx: &ImplTraitContext,
constness: ast::Const,
) -> hir::PolyTraitRef<'hir> {
let bound_generic_params =
self.lower_lifetime_binder(p.trait_ref.ref_id, &p.bound_generic_params);
let trait_ref = self.lower_trait_ref(&p.trait_ref, itctx);
let trait_ref = self.lower_trait_ref(constness, &p.trait_ref, itctx);
hir::PolyTraitRef { bound_generic_params, trait_ref, span: self.lower_span(p.span) }
}
@ -2702,6 +2720,57 @@ struct GenericArgsCtor<'hir> {
}
impl<'hir> GenericArgsCtor<'hir> {
fn push_constness(&mut self, lcx: &mut LoweringContext<'_, 'hir>, constness: ast::Const) {
if !lcx.tcx.features().effects {
return;
}
// if bound is non-const, don't add host effect param
let ast::Const::Yes(span) = constness else { return };
let span = lcx.lower_span(span);
let id = lcx.next_node_id();
let hir_id = lcx.next_id();
let body = lcx.lower_body(|lcx| {
(
&[],
match constness {
ast::Const::Yes(_) => {
let hir_id = lcx.next_id();
let res =
Res::Def(DefKind::ConstParam, lcx.host_param_id.unwrap().to_def_id());
let expr_kind = hir::ExprKind::Path(hir::QPath::Resolved(
None,
lcx.arena.alloc(hir::Path {
span,
res,
segments: arena_vec![lcx; hir::PathSegment::new(Ident {
name: sym::host,
span,
}, hir_id, res)],
}),
));
lcx.expr(span, expr_kind)
}
ast::Const::No => lcx.expr(
span,
hir::ExprKind::Lit(
lcx.arena.alloc(hir::Lit { span, node: ast::LitKind::Bool(true) }),
),
),
},
)
});
let def_id =
lcx.create_def(lcx.current_hir_id_owner.def_id, id, DefPathData::AnonConst, span);
lcx.children.push((def_id, hir::MaybeOwner::NonOwner(hir_id)));
self.args.push(hir::GenericArg::Const(hir::ConstArg {
value: hir::AnonConst { def_id, hir_id, body },
span,
}))
}
fn is_empty(&self) -> bool {
self.args.is_empty()
&& self.bindings.is_empty()

3
compiler/rustc_ast_lowering/src/pat.rs
View file

@ -38,6 +38,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
path,
ParamMode::Optional,
&ImplTraitContext::Disallowed(ImplTraitPosition::Path),
None,
);
let (pats, ddpos) = self.lower_pat_tuple(pats, "tuple struct");
break hir::PatKind::TupleStruct(qpath, pats, ddpos);
@ -54,6 +55,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
path,
ParamMode::Optional,
&ImplTraitContext::Disallowed(ImplTraitPosition::Path),
None,
);
break hir::PatKind::Path(qpath);
}
@ -64,6 +66,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
path,
ParamMode::Optional,
&ImplTraitContext::Disallowed(ImplTraitPosition::Path),
None,
);
let fs = self.arena.alloc_from_iter(fields.iter().map(|f| {

13
compiler/rustc_ast_lowering/src/path.rs
View file

@ -23,6 +23,8 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
p: &Path,
param_mode: ParamMode,
itctx: &ImplTraitContext,
// constness of the impl/bound if this is a trait path
constness: Option<ast::Const>,
) -> hir::QPath<'hir> {
let qself_position = qself.as_ref().map(|q| q.position);
let qself = qself.as_ref().map(|q| self.lower_ty(&q.ty, itctx));
@ -73,6 +75,8 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
param_mode,
parenthesized_generic_args,
itctx,
// if this is the last segment, add constness to the trait path
if i == proj_start - 1 { constness } else { None },
)
},
)),
@ -119,6 +123,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
param_mode,
ParenthesizedGenericArgs::Err,
itctx,
None,
));
let qpath = hir::QPath::TypeRelative(ty, hir_segment);
@ -159,6 +164,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
param_mode,
ParenthesizedGenericArgs::Err,
&ImplTraitContext::Disallowed(ImplTraitPosition::Path),
None,
)
})),
span: self.lower_span(p.span),
@ -172,8 +178,9 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
param_mode: ParamMode,
parenthesized_generic_args: ParenthesizedGenericArgs,
itctx: &ImplTraitContext,
constness: Option<ast::Const>,
) -> hir::PathSegment<'hir> {
debug!("path_span: {:?}, lower_path_segment(segment: {:?})", path_span, segment,);
debug!("path_span: {:?}, lower_path_segment(segment: {:?})", path_span, segment);
let (mut generic_args, infer_args) = if let Some(generic_args) = segment.args.as_deref() {
match generic_args {
GenericArgs::AngleBracketed(data) => {
@ -231,6 +238,10 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
)
};
if let Some(constness) = constness {
generic_args.push_constness(self, constness);
}
let has_lifetimes =
generic_args.args.iter().any(|arg| matches!(arg, GenericArg::Lifetime(_)));