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always create DefIds when lowering anon-consts

This commit is contained in:
lcnr 2024-11-25 18:42:10 +01:00 committed by Boxy
parent 467e200cd5
commit 94131bd0a8
9 changed files with 61 additions and 185 deletions

View file

@ -12,23 +12,16 @@ use rustc_span::hygiene::LocalExpnId;
use rustc_span::symbol::{Symbol, kw, sym};
use tracing::debug;
use crate::{ImplTraitContext, InvocationParent, PendingAnonConstInfo, Resolver};
use crate::{ImplTraitContext, InvocationParent, Resolver};
pub(crate) fn collect_definitions(
resolver: &mut Resolver<'_, '_>,
fragment: &AstFragment,
expansion: LocalExpnId,
) {
let InvocationParent { parent_def, pending_anon_const_info, impl_trait_context, in_attr } =
let InvocationParent { parent_def, impl_trait_context, in_attr } =
resolver.invocation_parents[&expansion];
let mut visitor = DefCollector {
resolver,
parent_def,
pending_anon_const_info,
expansion,
impl_trait_context,
in_attr,
};
let mut visitor = DefCollector { resolver, parent_def, expansion, impl_trait_context, in_attr };
fragment.visit_with(&mut visitor);
}
@ -36,13 +29,6 @@ pub(crate) fn collect_definitions(
struct DefCollector<'a, 'ra, 'tcx> {
resolver: &'a mut Resolver<'ra, 'tcx>,
parent_def: LocalDefId,
/// If we have an anon const that consists of a macro invocation, e.g. `Foo<{ m!() }>`,
/// we need to wait until we know what the macro expands to before we create the def for
/// the anon const. That's because we lower some anon consts into `hir::ConstArgKind::Path`,
/// which don't have defs.
///
/// See `Self::visit_anon_const()`.
pending_anon_const_info: Option<PendingAnonConstInfo>,
impl_trait_context: ImplTraitContext,
in_attr: bool,
expansion: LocalExpnId,
@ -110,61 +96,13 @@ impl<'a, 'ra, 'tcx> DefCollector<'a, 'ra, 'tcx> {
fn visit_macro_invoc(&mut self, id: NodeId) {
let id = id.placeholder_to_expn_id();
let pending_anon_const_info = self.pending_anon_const_info.take();
let old_parent = self.resolver.invocation_parents.insert(id, InvocationParent {
parent_def: self.parent_def,
pending_anon_const_info,
impl_trait_context: self.impl_trait_context,
in_attr: self.in_attr,
});
assert!(old_parent.is_none(), "parent `LocalDefId` is reset for an invocation");
}
/// Determines whether the const argument `AnonConst` is a simple macro call, optionally
/// surrounded with braces.
///
/// If this const argument *is* a trivial macro call then the id for the macro call is
/// returned along with the information required to build the anon const's def if
/// the macro call expands to a non-trivial expression.
fn is_const_arg_trivial_macro_expansion(
&self,
anon_const: &'a AnonConst,
) -> Option<(PendingAnonConstInfo, NodeId)> {
anon_const.value.optionally_braced_mac_call(false).map(|(block_was_stripped, id)| {
(
PendingAnonConstInfo {
id: anon_const.id,
span: anon_const.value.span,
block_was_stripped,
},
id,
)
})
}
/// Determines whether the expression `const_arg_sub_expr` is a simple macro call, sometimes
/// surrounded with braces if a set of braces has not already been entered. This is required
/// as `{ N }` is treated as equivalent to a bare parameter `N` whereas `{{ N }}` is treated as
/// a real block expression and is lowered to an anonymous constant which is not allowed to use
/// generic parameters.
///
/// If this expression is a trivial macro call then the id for the macro call is
/// returned along with the information required to build the anon const's def if
/// the macro call expands to a non-trivial expression.
fn is_const_arg_sub_expr_trivial_macro_expansion(
&self,
const_arg_sub_expr: &'a Expr,
) -> Option<(PendingAnonConstInfo, NodeId)> {
let pending_anon = self.pending_anon_const_info.unwrap_or_else(||
panic!("Checking expr is trivial macro call without having entered anon const: `{const_arg_sub_expr:?}`"),
);
const_arg_sub_expr.optionally_braced_mac_call(pending_anon.block_was_stripped).map(
|(block_was_stripped, id)| {
(PendingAnonConstInfo { block_was_stripped, ..pending_anon }, id)
},
)
}
}
impl<'a, 'ra, 'tcx> visit::Visitor<'a> for DefCollector<'a, 'ra, 'tcx> {
@ -376,78 +314,34 @@ impl<'a, 'ra, 'tcx> visit::Visitor<'a> for DefCollector<'a, 'ra, 'tcx> {
}
fn visit_anon_const(&mut self, constant: &'a AnonConst) {
// HACK(min_generic_const_args): don't create defs for anon consts if we think they will
// later be turned into ConstArgKind::Path's. because this is before resolve is done, we
// may accidentally identify a construction of a unit struct as a param and not create a
// def. we'll then create a def later in ast lowering in this case. the parent of nested
// items will be messed up, but that's ok because there can't be any if we're just looking
// for bare idents.
if let Some((pending_anon, macro_invoc)) =
self.is_const_arg_trivial_macro_expansion(constant)
{
self.pending_anon_const_info = Some(pending_anon);
return self.visit_macro_invoc(macro_invoc);
} else if constant.value.is_potential_trivial_const_arg(true) {
return visit::walk_anon_const(self, constant);
}
let def = self.create_def(constant.id, kw::Empty, DefKind::AnonConst, constant.value.span);
self.with_parent(def, |this| visit::walk_anon_const(this, constant));
let parent =
self.create_def(constant.id, kw::Empty, DefKind::AnonConst, constant.value.span);
self.with_parent(parent, |this| visit::walk_anon_const(this, constant));
}
fn visit_expr(&mut self, expr: &'a Expr) {
// If we're visiting the expression of a const argument that was a macro call then
// check if it is *still* unknown whether it is a trivial const arg or not. If so
// recurse into the macro call and delay creating the anon const def until expansion.
if self.pending_anon_const_info.is_some()
&& let Some((pending_anon, macro_invoc)) =
self.is_const_arg_sub_expr_trivial_macro_expansion(expr)
{
self.pending_anon_const_info = Some(pending_anon);
return self.visit_macro_invoc(macro_invoc);
}
// See self.pending_anon_const_info for explanation
let parent_def = self
.pending_anon_const_info
.take()
// If we already stripped away a set of braces then do not do it again when determining
// if the macro expanded to a trivial const arg. This arises in cases such as:
// `Foo<{ bar!() }>` where `bar!()` expands to `{ N }`. This should not be considered a
// trivial const argument even though `{ N }` by itself *is*.
.filter(|pending_anon| {
!expr.is_potential_trivial_const_arg(!pending_anon.block_was_stripped)
})
.map(|pending_anon| {
self.create_def(pending_anon.id, kw::Empty, DefKind::AnonConst, pending_anon.span)
})
.unwrap_or(self.parent_def);
self.with_parent(parent_def, |this| {
let parent_def = match expr.kind {
ExprKind::MacCall(..) => return this.visit_macro_invoc(expr.id),
ExprKind::Closure(..) | ExprKind::Gen(..) => {
this.create_def(expr.id, kw::Empty, DefKind::Closure, expr.span)
let parent_def = match expr.kind {
ExprKind::MacCall(..) => return self.visit_macro_invoc(expr.id),
ExprKind::Closure(..) | ExprKind::Gen(..) => {
self.create_def(expr.id, kw::Empty, DefKind::Closure, expr.span)
}
ExprKind::ConstBlock(ref constant) => {
for attr in &expr.attrs {
visit::walk_attribute(self, attr);
}
ExprKind::ConstBlock(ref constant) => {
for attr in &expr.attrs {
visit::walk_attribute(this, attr);
}
let def = this.create_def(
constant.id,
kw::Empty,
DefKind::InlineConst,
constant.value.span,
);
this.with_parent(def, |this| visit::walk_anon_const(this, constant));
return;
}
_ => this.parent_def,
};
let def = self.create_def(
constant.id,
kw::Empty,
DefKind::InlineConst,
constant.value.span,
);
self.with_parent(def, |this| visit::walk_anon_const(this, constant));
return;
}
_ => self.parent_def,
};
this.with_parent(parent_def, |this| visit::walk_expr(this, expr))
})
self.with_parent(parent_def, |this| visit::walk_expr(this, expr))
}
fn visit_ty(&mut self, ty: &'a Ty) {

View file

@ -4521,7 +4521,7 @@ impl<'a, 'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'a, 'ast, 'ra, 'tcx> {
);
self.resolve_anon_const_manual(
constant.value.is_potential_trivial_const_arg(true),
constant.value.is_potential_trivial_const_arg(),
anon_const_kind,
|this| this.resolve_expr(&constant.value, None),
)
@ -4685,7 +4685,7 @@ impl<'a, 'ast, 'ra: 'ast, 'tcx> LateResolutionVisitor<'a, 'ast, 'ra, 'tcx> {
// that is how they will be later lowered to HIR.
if const_args.contains(&idx) {
self.resolve_anon_const_manual(
argument.is_potential_trivial_const_arg(true),
argument.is_potential_trivial_const_arg(),
AnonConstKind::ConstArg(IsRepeatExpr::No),
|this| this.resolve_expr(argument, None),
);

View file

@ -174,7 +174,6 @@ impl<'ra> ParentScope<'ra> {
#[derive(Copy, Debug, Clone)]
struct InvocationParent {
parent_def: LocalDefId,
pending_anon_const_info: Option<PendingAnonConstInfo>,
impl_trait_context: ImplTraitContext,
in_attr: bool,
}
@ -182,23 +181,11 @@ struct InvocationParent {
impl InvocationParent {
const ROOT: Self = Self {
parent_def: CRATE_DEF_ID,
pending_anon_const_info: None,
impl_trait_context: ImplTraitContext::Existential,
in_attr: false,
};
}
#[derive(Copy, Debug, Clone)]
struct PendingAnonConstInfo {
// A const arg is only a "trivial" const arg if it has at *most* one set of braces
// around the argument. We track whether we have stripped an outter brace so that
// if a macro expands to a braced expression *and* the macro was itself inside of
// some braces then we can consider it to be a non-trivial const argument.
block_was_stripped: bool,
id: NodeId,
span: Span,
}
#[derive(Copy, Debug, Clone)]
enum ImplTraitContext {
Existential,