Rollup merge of #125258 - compiler-errors:static-if-no-lt, r=nnethercote
Resolve elided lifetimes in assoc const to static if no other lifetimes are in scope Implements the change to elided lifetime resolution in *associated consts* subject to FCP here: https://github.com/rust-lang/rust/issues/125190#issue-2301532282 Specifically, walk the enclosing lifetime ribs in an associated const, and if we find no other lifetimes, then resolve to `'static`. Also make it work for traits, but don't lint -- just give a hard error in that case.
This commit is contained in:
许杰友 Jieyou Xu (Joe)
GitHub
commit
23b936f981
21 changed files with 385 additions and 209 deletions
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@ -310,9 +310,10 @@ enum LifetimeRibKind {
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/// error on default object bounds (e.g., `Box<dyn Foo>`).
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AnonymousReportError,
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/// Resolves elided lifetimes to `'static`, but gives a warning that this behavior
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/// is a bug and will be reverted soon.
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AnonymousWarn(NodeId),
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/// Resolves elided lifetimes to `'static` if there are no other lifetimes in scope,
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/// otherwise give a warning that the previous behavior of introducing a new early-bound
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/// lifetime is a bug and will be removed (if `emit_lint` is enabled).
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StaticIfNoLifetimeInScope { lint_id: NodeId, emit_lint: bool },
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/// Signal we cannot find which should be the anonymous lifetime.
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ElisionFailure,
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@ -1212,7 +1213,7 @@ impl<'a: 'ast, 'ast, 'tcx> Visitor<'ast> for LateResolutionVisitor<'a, '_, 'ast,
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}
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LifetimeRibKind::AnonymousCreateParameter { .. }
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| LifetimeRibKind::AnonymousReportError
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| LifetimeRibKind::AnonymousWarn(_)
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| LifetimeRibKind::StaticIfNoLifetimeInScope { .. }
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| LifetimeRibKind::Elided(_)
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| LifetimeRibKind::ElisionFailure
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| LifetimeRibKind::ConcreteAnonConst(_)
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@ -1580,7 +1581,7 @@ impl<'a: 'ast, 'b, 'ast, 'tcx> LateResolutionVisitor<'a, 'b, 'ast, 'tcx> {
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// lifetime would be illegal.
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LifetimeRibKind::Item
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| LifetimeRibKind::AnonymousReportError
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| LifetimeRibKind::AnonymousWarn(_)
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| LifetimeRibKind::StaticIfNoLifetimeInScope { .. }
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| LifetimeRibKind::ElisionFailure => Some(LifetimeUseSet::Many),
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// An anonymous lifetime is legal here, and bound to the right
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// place, go ahead.
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@ -1643,7 +1644,7 @@ impl<'a: 'ast, 'b, 'ast, 'tcx> LateResolutionVisitor<'a, 'b, 'ast, 'tcx> {
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| LifetimeRibKind::Generics { .. }
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| LifetimeRibKind::ElisionFailure
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| LifetimeRibKind::AnonymousReportError
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| LifetimeRibKind::AnonymousWarn(_) => {}
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| LifetimeRibKind::StaticIfNoLifetimeInScope { .. } => {}
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}
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}
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@ -1677,16 +1678,36 @@ impl<'a: 'ast, 'b, 'ast, 'tcx> LateResolutionVisitor<'a, 'b, 'ast, 'tcx> {
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self.record_lifetime_res(lifetime.id, res, elision_candidate);
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return;
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}
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LifetimeRibKind::AnonymousWarn(node_id) => {
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self.r.lint_buffer.buffer_lint(
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lint::builtin::ELIDED_LIFETIMES_IN_ASSOCIATED_CONSTANT,
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node_id,
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lifetime.ident.span,
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lint::BuiltinLintDiag::AssociatedConstElidedLifetime {
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elided,
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span: lifetime.ident.span,
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},
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);
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LifetimeRibKind::StaticIfNoLifetimeInScope { lint_id: node_id, emit_lint } => {
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let mut lifetimes_in_scope = vec![];
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for rib in &self.lifetime_ribs[..i] {
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lifetimes_in_scope.extend(rib.bindings.iter().map(|(ident, _)| ident.span));
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// Consider any anonymous lifetimes, too
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if let LifetimeRibKind::AnonymousCreateParameter { binder, .. } = rib.kind
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&& let Some(extra) = self.r.extra_lifetime_params_map.get(&binder)
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{
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lifetimes_in_scope.extend(extra.iter().map(|(ident, _, _)| ident.span));
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}
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}
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if lifetimes_in_scope.is_empty() {
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self.record_lifetime_res(
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lifetime.id,
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LifetimeRes::Static,
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elision_candidate,
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);
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return;
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} else if emit_lint {
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self.r.lint_buffer.buffer_lint(
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lint::builtin::ELIDED_LIFETIMES_IN_ASSOCIATED_CONSTANT,
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node_id,
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lifetime.ident.span,
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lint::BuiltinLintDiag::AssociatedConstElidedLifetime {
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elided,
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span: lifetime.ident.span,
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lifetimes_in_scope: lifetimes_in_scope.into(),
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},
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);
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}
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}
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LifetimeRibKind::AnonymousReportError => {
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if elided {
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@ -1904,7 +1925,7 @@ impl<'a: 'ast, 'b, 'ast, 'tcx> LateResolutionVisitor<'a, 'b, 'ast, 'tcx> {
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// impl Foo for std::cell::Ref<u32> // note lack of '_
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// async fn foo(_: std::cell::Ref<u32>) { ... }
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LifetimeRibKind::AnonymousCreateParameter { report_in_path: true, .. }
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| LifetimeRibKind::AnonymousWarn(_) => {
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| LifetimeRibKind::StaticIfNoLifetimeInScope { .. } => {
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let sess = self.r.tcx.sess;
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let subdiag = rustc_errors::elided_lifetime_in_path_suggestion(
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sess.source_map(),
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@ -2838,19 +2859,27 @@ impl<'a: 'ast, 'b, 'ast, 'tcx> LateResolutionVisitor<'a, 'b, 'ast, 'tcx> {
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kind: LifetimeBinderKind::ConstItem,
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},
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|this| {
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this.visit_generics(generics);
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this.visit_ty(ty);
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this.with_lifetime_rib(
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LifetimeRibKind::StaticIfNoLifetimeInScope {
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lint_id: item.id,
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emit_lint: false,
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},
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|this| {
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this.visit_generics(generics);
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this.visit_ty(ty);
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// Only impose the restrictions of `ConstRibKind` for an
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// actual constant expression in a provided default.
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if let Some(expr) = expr {
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// We allow arbitrary const expressions inside of associated consts,
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// even if they are potentially not const evaluatable.
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//
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// Type parameters can already be used and as associated consts are
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// not used as part of the type system, this is far less surprising.
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this.resolve_const_body(expr, None);
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}
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// Only impose the restrictions of `ConstRibKind` for an
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// actual constant expression in a provided default.
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if let Some(expr) = expr {
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// We allow arbitrary const expressions inside of associated consts,
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// even if they are potentially not const evaluatable.
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//
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// Type parameters can already be used and as associated consts are
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// not used as part of the type system, this is far less surprising.
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this.resolve_const_body(expr, None);
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}
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},
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)
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},
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);
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}
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@ -3030,30 +3059,37 @@ impl<'a: 'ast, 'b, 'ast, 'tcx> LateResolutionVisitor<'a, 'b, 'ast, 'tcx> {
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kind: LifetimeBinderKind::ConstItem,
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},
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|this| {
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this.with_lifetime_rib(LifetimeRibKind::AnonymousWarn(item.id), |this| {
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// If this is a trait impl, ensure the const
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// exists in trait
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this.check_trait_item(
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item.id,
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item.ident,
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&item.kind,
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ValueNS,
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item.span,
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seen_trait_items,
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|i, s, c| ConstNotMemberOfTrait(i, s, c),
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);
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this.with_lifetime_rib(
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LifetimeRibKind::StaticIfNoLifetimeInScope {
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lint_id: item.id,
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// In impls, it's not a hard error yet due to backcompat.
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emit_lint: true,
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},
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|this| {
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// If this is a trait impl, ensure the const
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// exists in trait
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this.check_trait_item(
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item.id,
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item.ident,
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&item.kind,
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ValueNS,
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item.span,
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seen_trait_items,
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|i, s, c| ConstNotMemberOfTrait(i, s, c),
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);
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this.visit_generics(generics);
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this.visit_ty(ty);
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if let Some(expr) = expr {
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// We allow arbitrary const expressions inside of associated consts,
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// even if they are potentially not const evaluatable.
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//
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// Type parameters can already be used and as associated consts are
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// not used as part of the type system, this is far less surprising.
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this.resolve_const_body(expr, None);
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}
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});
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this.visit_generics(generics);
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this.visit_ty(ty);
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if let Some(expr) = expr {
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// We allow arbitrary const expressions inside of associated consts,
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// even if they are potentially not const evaluatable.
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//
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// Type parameters can already be used and as associated consts are
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// not used as part of the type system, this is far less surprising.
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this.resolve_const_body(expr, None);
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}
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},
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);
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},
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);
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}
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