Provide doc links at item definitions on source pages

src/librustdoc/html/format.rs

@@ -517,6 +517,7 @@ impl clean::GenericArgs {
 }
 
 // Possible errors when computing href link source for a `DefId`
+#[derive(Debug)]
 pub(crate) enum HrefError {
     /// This item is known to rustdoc, but from a crate that does not have documentation generated.
     ///

src/librustdoc/html/highlight.rs

@@ -728,18 +728,25 @@ fn string<T: Display>(
                     LinkFromSrc::Local(span) => context
                         .href_from_span(*span, true)
                         .map(|s| format!("{}{}", context_info.root_path, s)),
-                    LinkFromSrc::External(def_id) => {
-                        format::href_with_root_path(*def_id, context, Some(context_info.root_path))
-                            .ok()
-                            .map(|(url, _, _)| url)
-                    }
+                    LinkFromSrc::External(span) => context.href_from_span(*span, true).map(|s| {
+                        if s.starts_with("http://") || s.starts_with("https://") {
+                            s
+                        } else {
+                            format!("{}{}", context_info.root_path, s)
+                        }
+                    }),
                     LinkFromSrc::Primitive(prim) => format::href_with_root_path(
                         PrimitiveType::primitive_locations(context.tcx())[prim],
                         context,
                         Some(context_info.root_path),
                     )
                     .ok()
                     .map(|(url, _, _)| url),
+                    LinkFromSrc::Doc(def_id) => {
+                        format::href_with_root_path(*def_id, context, Some(&context_info.root_path))
+                            .ok()
+                            .map(|(doc_link, _, _)| doc_link)
+                    }
                 }
             })
         {

src/librustdoc/html/render/context.rs

@@ -116,7 +116,6 @@ pub(crate) struct SharedContext<'tcx> {
     /// to `Some(...)`, it'll store redirections and then generate a JSON file at the top level of
     /// the crate.
     redirections: Option<RefCell<FxHashMap<String, String>>>,
-
     /// Correspondance map used to link types used in the source code pages to allow to click on
     /// links to jump to the type's definition.
     pub(crate) span_correspondance_map: FxHashMap<rustc_span::Span, LinkFromSrc>,
@@ -336,7 +335,12 @@ impl<'tcx> Context<'tcx> {
                     let e = ExternalCrate { crate_num: cnum };
                     (e.name(self.tcx()), e.src_root(self.tcx()))
                 }
-                ExternalLocation::Unknown => return None,
+                ExternalLocation::Unknown => {
+                    let e = ExternalCrate { crate_num: cnum };
+                    let name = e.name(self.tcx());
+                    root = name.to_string();
+                    (name, e.src_root(self.tcx()))
+                }
             };
 
             sources::clean_path(&src_root, file, false, |component| {

src/librustdoc/html/render/span_map.rs

@@ -1,11 +1,12 @@
+use crate::clean::types::rustc_span;
 use crate::clean::{self, PrimitiveType};
 use crate::html::sources;
 
 use rustc_data_structures::fx::FxHashMap;
 use rustc_hir::def::{DefKind, Res};
-use rustc_hir::def_id::DefId;
+use rustc_hir::def_id::{DefId, LOCAL_CRATE};
 use rustc_hir::intravisit::{self, Visitor};
-use rustc_hir::{ExprKind, HirId, Mod, Node};
+use rustc_hir::{ExprKind, HirId, Item, ItemKind, Mod, Node};
 use rustc_middle::hir::nested_filter;
 use rustc_middle::ty::TyCtxt;
 use rustc_span::Span;
@@ -22,8 +23,9 @@ use std::path::{Path, PathBuf};
 #[derive(Debug)]
 pub(crate) enum LinkFromSrc {
     Local(clean::Span),
-    External(DefId),
+    External(clean::Span),
     Primitive(PrimitiveType),
+    Doc(DefId),
 }
 
 /// This function will do at most two things:
@@ -64,31 +66,52 @@ struct SpanMapVisitor<'tcx> {
 impl<'tcx> SpanMapVisitor<'tcx> {
     /// This function is where we handle `hir::Path` elements and add them into the "span map".
     fn handle_path(&mut self, path: &rustc_hir::Path<'_>, path_span: Option<Span>) {
-        let info = match path.res {
+        match path.res {
             // FIXME: For now, we only handle `DefKind` if it's not `DefKind::TyParam` or
             // `DefKind::Macro`. Would be nice to support them too alongside the other `DefKind`
             // (such as primitive types!).
             Res::Def(kind, def_id) if kind != DefKind::TyParam => {
                 if matches!(kind, DefKind::Macro(_)) {
                     return;
                 }
-                Some(def_id)
+                let span = rustc_span(def_id, self.tcx);
+                let link = if def_id.as_local().is_some() {
+                    LinkFromSrc::Local(span)
+                } else {
+                    LinkFromSrc::External(span)
+                };
+                self.matches.insert(path_span.unwrap_or(path.span), link);
+            }
+            Res::Local(_) => {
+                if let Some(span) = self.tcx.hir().res_span(path.res) {
+                    self.matches.insert(
+                        path_span.unwrap_or(path.span),
+                        LinkFromSrc::Local(clean::Span::new(span)),
+                    );
+                }
             }
-            Res::Local(_) => None,
             Res::PrimTy(p) => {
                 // FIXME: Doesn't handle "path-like" primitives like arrays or tuples.
                 let span = path_span.unwrap_or(path.span);
                 self.matches.insert(span, LinkFromSrc::Primitive(PrimitiveType::from(p)));
-                return;
             }
-            Res::Err => return,
-            _ => return,
-        };
-        if let Some(span) = self.tcx.hir().res_span(path.res) {
-            self.matches
-                .insert(path_span.unwrap_or(path.span), LinkFromSrc::Local(clean::Span::new(span)));
-        } else if let Some(def_id) = info {
-            self.matches.insert(path_span.unwrap_or(path.span), LinkFromSrc::External(def_id));
+            Res::Err => {}
+            _ => {}
+        }
+    }
+
+    /// Used to generate links on items' definition to go to their documentation page.
+    pub(crate) fn extract_info_from_hir_id(&mut self, hir_id: HirId) {
+        if let Some(def_id) = self.tcx.hir().opt_local_def_id(hir_id) {
+            if let Some(span) = self.tcx.def_ident_span(def_id) {
+                let cspan = clean::Span::new(span);
+                let def_id = def_id.to_def_id();
+                // If the span isn't from the current crate, we ignore it.
+                if cspan.is_dummy() || cspan.cnum(self.tcx.sess) != LOCAL_CRATE {
+                    return;
+                }
+                self.matches.insert(span, LinkFromSrc::Doc(def_id));
+            }
         }
     }
 }
@@ -117,6 +140,9 @@ impl<'tcx> Visitor<'tcx> for SpanMapVisitor<'tcx> {
                     LinkFromSrc::Local(clean::Span::new(m.spans.inner_span)),
                 );
             }
+        } else {
+            // If it's a "mod foo {}", we want to look to its documentation page.
+            self.extract_info_from_hir_id(id);
         }
         intravisit::walk_mod(self, m, id);
     }
@@ -134,13 +160,13 @@ impl<'tcx> Visitor<'tcx> for SpanMapVisitor<'tcx> {
                     hir.maybe_body_owned_by(body_id).expect("a body which isn't a body"),
                 );
                 if let Some(def_id) = typeck_results.type_dependent_def_id(expr.hir_id) {
-                    self.matches.insert(
-                        segment.ident.span,
-                        match hir.span_if_local(def_id) {
-                            Some(span) => LinkFromSrc::Local(clean::Span::new(span)),
-                            None => LinkFromSrc::External(def_id),
-                        },
-                    );
+                    let span = rustc_span(def_id, self.tcx);
+                    let link = if def_id.as_local().is_some() {
+                        LinkFromSrc::Local(span)
+                    } else {
+                        LinkFromSrc::External(span)
+                    };
+                    self.matches.insert(segment.ident.span, link);
                 }
             }
         }
@@ -151,4 +177,28 @@ impl<'tcx> Visitor<'tcx> for SpanMapVisitor<'tcx> {
         self.handle_path(path, None);
         intravisit::walk_use(self, path, id);
     }
+
+    fn visit_item(&mut self, item: &'tcx Item<'tcx>) {
+        match item.kind {
+            ItemKind::Static(_, _, _)
+            | ItemKind::Const(_, _)
+            | ItemKind::Fn(_, _, _)
+            | ItemKind::Macro(_, _)
+            | ItemKind::TyAlias(_, _)
+            | ItemKind::Enum(_, _)
+            | ItemKind::Struct(_, _)
+            | ItemKind::Union(_, _)
+            | ItemKind::Trait(_, _, _, _, _)
+            | ItemKind::TraitAlias(_, _) => self.extract_info_from_hir_id(item.hir_id()),
+            ItemKind::Impl(_)
+            | ItemKind::Use(_, _)
+            | ItemKind::ExternCrate(_)
+            | ItemKind::ForeignMod { .. }
+            | ItemKind::GlobalAsm(_)
+            | ItemKind::OpaqueTy(_)
+            // We already have "visit_mod" above so no need to check it here.
+            | ItemKind::Mod(_) => {}
+        }
+        intravisit::walk_item(self, item);
+    }
 }

src/test/rustdoc-gui/source-anchor-scroll.goml

@@ -7,11 +7,11 @@ size: (600, 800)
 // We check that the scroll is at the top first.
 assert-property: ("html", {"scrollTop": "0"})
 
-click: '//a[text() = "barbar"]'
+click: '//a[text() = "barbar" and @href="../../src/link_to_definition/lib.rs.html#4-6"]'
 assert-property: ("html", {"scrollTop": "125"})
-click: '//a[text() = "bar"]'
+click: '//a[text() = "bar" and @href="../../src/link_to_definition/lib.rs.html#27-35"]'
 assert-property: ("html", {"scrollTop": "166"})
-click: '//a[text() = "sub_fn"]'
+click: '//a[text() = "sub_fn" and @href="../../src/link_to_definition/lib.rs.html#1-3"]'
 assert-property: ("html", {"scrollTop": "53"})
 
 // We now check that clicking on lines doesn't change the scroll

src/test/rustdoc/check-source-code-urls-to-def.rs

@@ -28,11 +28,11 @@ impl Foo {
 
 fn babar() {}
 
-// @has - '//a/@href' '/struct.String.html'
+// @has - '//a/@href' '/string.rs.html'
 // @has - '//a/@href' '/primitive.u32.html'
 // @has - '//a/@href' '/primitive.str.html'
 // @count - '//a[@href="../../src/foo/check-source-code-urls-to-def.rs.html#23"]' 5
-// @has - '//a[@href="../../source_code/struct.SourceCode.html"]' 'source_code::SourceCode'
+// @has - '//a[@href="../../src/source_code/source_code.rs.html#1"]' 'source_code::SourceCode'
 pub fn foo(a: u32, b: &str, c: String, d: Foo, e: bar::Bar, f: source_code::SourceCode) {
     let x = 12;
     let y: Foo = Foo;

src/test/rustdoc/jump-to-def-doc-links.rs

@@ -0,0 +1,51 @@
+// compile-flags: -Zunstable-options --generate-link-to-definition
+
+#![crate_name = "foo"]
+
+// @has 'src/foo/jump-to-def-doc-links.rs.html'
+
+// @has - '//a[@href="../../foo/struct.Bar.html"]' 'Bar'
+// @has - '//a[@href="../../foo/struct.Foo.html"]' 'Foo'
+pub struct Bar; pub struct Foo;
+
+// @has - '//a[@href="../../foo/enum.Enum.html"]' 'Enum'
+pub enum Enum {
+    Variant1(String),
+    Variant2(u8),
+}
+
+// @has - '//a[@href="../../foo/struct.Struct.html"]' 'Struct'
+pub struct Struct {
+    pub a: u8,
+    b: Foo,
+}
+
+impl Struct {
+    pub fn foo() {}
+    pub fn foo2(&self) {}
+    fn bar() {}
+    fn bar(&self) {}
+}
+
+// @has - '//a[@href="../../foo/trait.Trait.html"]' 'Trait'
+pub trait Trait {
+    fn foo();
+}
+
+impl Trait for Struct {
+    fn foo() {}
+}
+
+// @has - '//a[@href="../../foo/union.Union.html"]' 'Union'
+pub union Union {
+    pub a: u16,
+    pub f: u32,
+}
+
+// @has - '//a[@href="../../foo/fn.bar.html"]' 'bar'
+pub fn bar(b: Bar) {
+     let x = Foo;
+}
+
+// @has - '//a[@href="../../foo/bar/index.html"]' 'bar'
+pub mod bar {}