rustdoc: Pretty-print assoc const defaults on-demand

src/librustdoc/clean/mod.rs

@@ -912,7 +912,9 @@ impl Clean<Item> for hir::TraitItem<'_> {
  cx.with_param_env(local_did, |cx| {
  let inner = match self.kind {
  hir::TraitItemKind::Const(ref ty, default) => {
- AssocConstItem(ty.clean(cx), default.map(|e| print_const_expr(cx.tcx, e)))
+ let default =
+ default.map(|e| ConstantKind::Local { def_id: local_did, body: e });
+ AssocConstItem(ty.clean(cx), default)
  }
  hir::TraitItemKind::Fn(ref sig, hir::TraitFn::Provided(body)) => {
  let mut m = clean_function(cx, sig, &self.generics, body);
@@ -959,7 +961,8 @@ impl Clean<Item> for hir::ImplItem<'_> {
  cx.with_param_env(local_did, |cx| {
  let inner = match self.kind {
  hir::ImplItemKind::Const(ref ty, expr) => {
- AssocConstItem(ty.clean(cx), Some(print_const_expr(cx.tcx, expr)))
+ let default = Some(ConstantKind::Local { def_id: local_did, body: expr });
+ AssocConstItem(ty.clean(cx), default)
  }
  hir::ImplItemKind::Fn(ref sig, body) => {
  let mut m = clean_function(cx, sig, &self.generics, body);
@@ -1009,7 +1012,7 @@ impl Clean<Item> for ty::AssocItem {
  ty::AssocKind::Const => {
  let ty = tcx.type_of(self.def_id);
  let default = if self.defaultness.has_value() {
- Some(inline::print_inlined_const(tcx, self.def_id))
+ Some(ConstantKind::Extern { def_id: self.def_id })
  } else {
  None
  };

src/librustdoc/clean/types.rs

@@ -670,7 +670,7 @@ crate enum ItemKind {
  MacroItem(Macro),
  ProcMacroItem(ProcMacro),
  PrimitiveItem(PrimitiveType),
- AssocConstItem(Type, Option<String>),
+ AssocConstItem(Type, Option<ConstantKind>),
  /// An associated item in a trait or trait impl.
  ///
  /// The bounds may be non-empty if there is a `where` clause.
@@ -2153,7 +2153,21 @@ crate enum ConstantKind {
 
 impl Constant {
  crate fn expr(&self, tcx: TyCtxt<'_>) -> String {
- match self.kind {
+ self.kind.expr(tcx)
+ }
+
+ crate fn value(&self, tcx: TyCtxt<'_>) -> Option<String> {
+ self.kind.value(tcx)
+ }
+
+ crate fn is_literal(&self, tcx: TyCtxt<'_>) -> bool {
+ self.kind.is_literal(tcx)
+ }
+}
+
+impl ConstantKind {
+ crate fn expr(&self, tcx: TyCtxt<'_>) -> String {
+ match *self {
  ConstantKind::TyConst { ref expr } => expr.clone(),
  ConstantKind::Extern { def_id } => print_inlined_const(tcx, def_id),
  ConstantKind::Local { body, .. } | ConstantKind::Anonymous { body } => {
@@ -2163,7 +2177,7 @@ impl Constant {
  }
 
  crate fn value(&self, tcx: TyCtxt<'_>) -> Option<String> {
- match self.kind {
+ match *self {
  ConstantKind::TyConst { .. } | ConstantKind::Anonymous { .. } => None,
  ConstantKind::Extern { def_id } | ConstantKind::Local { def_id, .. } => {
  print_evaluated_const(tcx, def_id)
@@ -2172,7 +2186,7 @@ impl Constant {
  }
 
  crate fn is_literal(&self, tcx: TyCtxt<'_>) -> bool {
- match self.kind {
+ match *self {
  ConstantKind::TyConst { .. } => false,
  ConstantKind::Extern { def_id } => def_id.as_local().map_or(false, |def_id| {
  is_literal_expr(tcx, tcx.hir().local_def_id_to_hir_id(def_id))

src/librustdoc/html/render/mod.rs

@@ -762,7 +762,6 @@ fn assoc_const(
  w: &mut Buffer,
  it: &clean::Item,
  ty: &clean::Type,
- _default: Option<&String>,
  link: AssocItemLink<'_>,
  extra: &str,
  cx: &Context<'_>,
@@ -958,15 +957,9 @@ fn render_assoc_item(
  clean::MethodItem(ref m, _) => {
  method(w, item, m.header, &m.generics, &m.decl, link, parent, cx, render_mode)
  }
- clean::AssocConstItem(ref ty, ref default) => assoc_const(
- w,
- item,
- ty,
- default.as_ref(),
- link,
- if parent == ItemType::Trait { " " } else { "" },
- cx,
- ),
+ clean::AssocConstItem(ref ty, _) => {
+ assoc_const(w, item, ty, link, if parent == ItemType::Trait { " " } else { "" }, cx)
+ }
  clean::AssocTypeItem(ref bounds, ref default) => assoc_type(
  w,
  item,
@@ -1467,7 +1460,7 @@ fn render_impl(
  w.write_str("</h4>");
  w.write_str("</div>");
  }
- clean::AssocConstItem(ref ty, ref default) => {
+ clean::AssocConstItem(ref ty, _) => {
  let source_id = format!("{}.{}", item_type, name);
  let id = cx.derive_id(source_id.clone());
  write!(
@@ -1482,7 +1475,6 @@ fn render_impl(
  w,
  item,
  ty,
- default.as_ref(),
  link.anchor(if trait_.is_some() { &source_id } else { &id }),
  "",
  cx,

src/librustdoc/json/conversions.rs

@@ -219,7 +219,9 @@ fn from_clean_item(item: clean::Item, tcx: TyCtxt<'_>) -> ItemEnum {
  MacroItem(m) => ItemEnum::Macro(m.source),
  ProcMacroItem(m) => ItemEnum::ProcMacro(m.into_tcx(tcx)),
  PrimitiveItem(p) => ItemEnum::PrimitiveType(p.as_sym().to_string()),
- AssocConstItem(t, s) => ItemEnum::AssocConst { type_: t.into_tcx(tcx), default: s },
+ AssocConstItem(ty, default) => {
+ ItemEnum::AssocConst { type_: ty.into_tcx(tcx), default: default.map(|c| c.expr(tcx)) }
+ }
  AssocTypeItem(g, t) => ItemEnum::AssocType {
  bounds: g.into_iter().map(|x| x.into_tcx(tcx)).collect(),
  default: t.map(|x| x.into_tcx(tcx)),