rustdoc: rich-text and visibility-aware formatting for constant values

Author: fmease

src/librustdoc/clean/inline.rs

@@ -596,6 +596,8 @@ fn build_module_items(
 }
 
 pub(crate) fn print_inlined_const(tcx: TyCtxt<'_>, did: DefId) -> String {
+    // FIXME: Both branches rely on HIR pretty-printing which
+    //        leaks private and doc(hidden) struct fields.
     if let Some(did) = did.as_local() {
         let hir_id = tcx.hir().local_def_id_to_hir_id(did);
         rustc_hir_pretty::id_to_string(&tcx.hir(), hir_id)

src/librustdoc/clean/types.rs

@@ -37,11 +37,11 @@ use crate::clean::cfg::Cfg;
 use crate::clean::clean_visibility;
 use crate::clean::external_path;
 use crate::clean::inline::{self, print_inlined_const};
-use crate::clean::utils::{is_literal_expr, print_const_expr, print_evaluated_const};
+use crate::clean::utils::is_literal_expr;
 use crate::core::DocContext;
 use crate::formats::cache::Cache;
 use crate::formats::item_type::ItemType;
-use crate::html::render::Context;
+use crate::html::render::{constant::Renderer as ConstantRenderer, Context};
 use crate::passes::collect_intra_doc_links::UrlFragment;
 
 pub(crate) use self::FnRetTy::*;
@@ -2292,8 +2292,8 @@ impl Constant {
         self.kind.expr(tcx)
     }
 
-    pub(crate) fn value(&self, tcx: TyCtxt<'_>) -> Option<String> {
-        self.kind.value(tcx)
+    pub(crate) fn eval_and_render(&self, renderer: &ConstantRenderer<'_, '_>) -> Option<String> {
+        self.kind.eval_and_render(renderer)
     }
 
     pub(crate) fn is_literal(&self, tcx: TyCtxt<'_>) -> bool {
@@ -2307,16 +2307,16 @@ impl ConstantKind {
             ConstantKind::TyConst { ref expr } => expr.clone(),
             ConstantKind::Extern { def_id } => print_inlined_const(tcx, def_id),
             ConstantKind::Local { body, .. } | ConstantKind::Anonymous { body } => {
-                print_const_expr(tcx, body)
+                super::utils::print_const_expr(tcx, body)
             }
         }
     }
 
-    pub(crate) fn value(&self, tcx: TyCtxt<'_>) -> Option<String> {
+    pub(crate) fn eval_and_render(&self, renderer: &ConstantRenderer<'_, '_>) -> Option<String> {
         match *self {
             ConstantKind::TyConst { .. } | ConstantKind::Anonymous { .. } => None,
             ConstantKind::Extern { def_id } | ConstantKind::Local { def_id, .. } => {
-                print_evaluated_const(tcx, def_id)
+                crate::html::render::eval_and_render_const(def_id, renderer)
             }
         }
     }

src/librustdoc/clean/utils.rs

@@ -16,17 +16,12 @@ use rustc_data_structures::thin_vec::ThinVec;
 use rustc_hir as hir;
 use rustc_hir::def::{DefKind, Res};
 use rustc_hir::def_id::{DefId, LOCAL_CRATE};
-use rustc_middle::mir;
-use rustc_middle::mir::interpret::ConstValue;
 use rustc_middle::ty::subst::{GenericArgKind, SubstsRef};
 use rustc_middle::ty::{self, DefIdTree, TyCtxt};
 use rustc_span::symbol::{kw, sym, Symbol};
 use std::fmt::Write as _;
 use std::mem;
 
-#[cfg(test)]
-mod tests;
-
 pub(crate) fn krate(cx: &mut DocContext<'_>) -> Crate {
     let module = crate::visit_ast::RustdocVisitor::new(cx).visit();
 
@@ -238,6 +233,8 @@ pub(crate) fn print_const(cx: &DocContext<'_>, n: ty::Const<'_>) -> String {
             let mut s = if let Some(def) = def.as_local() {
                 print_const_expr(cx.tcx, cx.tcx.hir().body_owned_by(def.did))
             } else {
+                // FIXME: This relies on the HIR pretty-printer which leaks private and
+                //        doc(hidden) struct fields.
                 inline::print_inlined_const(cx.tcx, def.did)
             };
             if let Some(promoted) = promoted {
@@ -261,69 +258,6 @@ pub(crate) fn print_const(cx: &DocContext<'_>, n: ty::Const<'_>) -> String {
     }
 }
 
-pub(crate) fn print_evaluated_const(tcx: TyCtxt<'_>, def_id: DefId) -> Option<String> {
-    tcx.const_eval_poly(def_id).ok().and_then(|val| {
-        let ty = tcx.type_of(def_id);
-        match (val, ty.kind()) {
-            (_, &ty::Ref(..)) => None,
-            (ConstValue::Scalar(_), &ty::Adt(_, _)) => None,
-            (ConstValue::Scalar(_), _) => {
-                let const_ = mir::ConstantKind::from_value(val, ty);
-                Some(print_const_with_custom_print_scalar(tcx, const_))
-            }
-            _ => None,
-        }
-    })
-}
-
-fn format_integer_with_underscore_sep(num: &str) -> String {
-    let num_chars: Vec<_> = num.chars().collect();
-    let mut num_start_index = if num_chars.get(0) == Some(&'-') { 1 } else { 0 };
-    let chunk_size = match num[num_start_index..].as_bytes() {
-        [b'0', b'b' | b'x', ..] => {
-            num_start_index += 2;
-            4
-        }
-        [b'0', b'o', ..] => {
-            num_start_index += 2;
-            let remaining_chars = num_chars.len() - num_start_index;
-            if remaining_chars <= 6 {
-                // don't add underscores to Unix permissions like 0755 or 100755
-                return num.to_string();
-            }
-            3
-        }
-        _ => 3,
-    };
-
-    num_chars[..num_start_index]
-        .iter()
-        .chain(num_chars[num_start_index..].rchunks(chunk_size).rev().intersperse(&['_']).flatten())
-        .collect()
-}
-
-fn print_const_with_custom_print_scalar(tcx: TyCtxt<'_>, ct: mir::ConstantKind<'_>) -> String {
-    // Use a slightly different format for integer types which always shows the actual value.
-    // For all other types, fallback to the original `pretty_print_const`.
-    match (ct, ct.ty().kind()) {
-        (mir::ConstantKind::Val(ConstValue::Scalar(int), _), ty::Uint(ui)) => {
-            format!("{}{}", format_integer_with_underscore_sep(&int.to_string()), ui.name_str())
-        }
-        (mir::ConstantKind::Val(ConstValue::Scalar(int), _), ty::Int(i)) => {
-            let ty = tcx.lift(ct.ty()).unwrap();
-            let size = tcx.layout_of(ty::ParamEnv::empty().and(ty)).unwrap().size;
-            let data = int.assert_bits(size);
-            let sign_extended_data = size.sign_extend(data) as i128;
-            format!(
-                "{}{}",
-                format_integer_with_underscore_sep(&sign_extended_data.to_string()),
-                i.name_str()
-            )
-        }
-        _ => ct.to_string(),
-    }
-}
-
 pub(crate) fn is_literal_expr(tcx: TyCtxt<'_>, hir_id: hir::HirId) -> bool {
     if let hir::Node::Expr(expr) = tcx.hir().get(hir_id) {
         if let hir::ExprKind::Lit(_) = &expr.kind {

src/librustdoc/clean/utils/tests.rs

@@ -379,7 +379,11 @@ pub(crate) fn run_global_ctxt(
         impl_trait_bounds: Default::default(),
         generated_synthetics: Default::default(),
         auto_traits,
-        cache: Cache::new(access_levels, render_options.document_private),
+        cache: Cache::new(
+            access_levels,
+            render_options.document_private,
+            render_options.document_hidden,
+        ),
         inlined: FxHashSet::default(),
         output_format,
         render_options,

src/librustdoc/core.rs

@@ -87,6 +87,10 @@ pub(crate) struct Cache {
     /// This is stored in `Cache` so it doesn't need to be passed through all rustdoc functions.
     pub(crate) document_private: bool,
 
+    /// Whether to document `#[doc(hidden)]` items.
+    /// This is stored in `Cache` so it doesn't need to be passed through all rustdoc functions.
+    pub(crate) document_hidden: bool,
+
     /// Crates marked with [`#[doc(masked)]`][doc_masked].
     ///
     /// [doc_masked]: https://doc.rust-lang.org/nightly/unstable-book/language-features/doc-masked.html
@@ -132,8 +136,12 @@ struct CacheBuilder<'a, 'tcx> {
 }
 
 impl Cache {
-    pub(crate) fn new(access_levels: AccessLevels<DefId>, document_private: bool) -> Self {
-        Cache { access_levels, document_private, ..Cache::default() }
+    pub(crate) fn new(
+        access_levels: AccessLevels<DefId>,
+        document_private: bool,
+        document_hidden: bool,
+    ) -> Self {
+        Cache { access_levels, document_private, document_hidden, ..Cache::default() }
     }
 
     /// Populates the `Cache` with more data. The returned `Crate` will be missing some data that was

src/librustdoc/formats/cache.rs

@@ -654,6 +654,13 @@ pub(crate) fn href_with_root_path(
             // documented on their parent's page
             tcx.parent(did)
         }
+        DefKind::Field => {
+            let parent_id = tcx.parent(did);
+            match tcx.def_kind(parent_id) {
+                DefKind::Variant => tcx.parent(parent_id),
+                _ => parent_id,
+            }
+        }
         _ => did,
     };
     let cache = cx.cache();