Auto merge of #37954 - eddyb:rustdoc-2, r=alexcrichton

rustdoc: link to cross-crate sources directly.

Fixes #37684 by implementing proper support for getting the `Span` of definitions across crates.
In rustdoc this is used to generate direct links to the original source instead of fragile redirects.

This functionality could be expanded further for making error reporting code more uniform and seamless across crates, although at the moment there is no actual source to print, only file/line/column information.

Closes #37870 which is also "fixes" #37684 by throwing away the builtin macro docs from libcore.
After this lands, #37727 could be reverted, although it doesn't matter much either way.

1 files changed, 12 insertions, 10 deletions

diff --git a/src/librustdoc/html/format.rs b/src/librustdoc/html/format.rs
index aed41916f5c..6dc6e80dae0 100644
--- a/src/librustdoc/html/format.rs
+++ b/src/librustdoc/html/format.rs
@@ -18,7 +18,7 @@
 use std::fmt;
 use std::iter::repeat;
 
-use rustc::hir::def_id::{DefId, LOCAL_CRATE};
+use rustc::hir::def_id::DefId;
 use syntax::abi::Abi;
 use rustc::hir;
 
@@ -403,9 +403,9 @@ pub fn href(did: DefId) -> Option<(String, ItemType, Vec<String>)> {
         None => match cache.external_paths.get(&did) {
             Some(&(ref fqp, shortty)) => {
                 (fqp, shortty, match cache.extern_locations[&did.krate] {
-                    (_, render::Remote(ref s)) => s.to_string(),
-                    (_, render::Local) => repeat("../").take(loc.len()).collect(),
-                    (_, render::Unknown) => return None,
+                    (.., render::Remote(ref s)) => s.to_string(),
+                    (.., render::Local) => repeat("../").take(loc.len()).collect(),
+                    (.., render::Unknown) => return None,
                 })
             }
             None => return None,
@@ -479,7 +479,7 @@ fn primitive_link(f: &mut fmt::Formatter,
     let mut needs_termination = false;
     if !f.alternate() {
         match m.primitive_locations.get(&prim) {
-            Some(&LOCAL_CRATE) => {
+            Some(&def_id) if def_id.is_local() => {
                 let len = CURRENT_LOCATION_KEY.with(|s| s.borrow().len());
                 let len = if len == 0 {0} else {len - 1};
                 write!(f, "<a class='primitive' href='{}primitive.{}.html'>",
@@ -487,14 +487,16 @@ fn primitive_link(f: &mut fmt::Formatter,
                        prim.to_url_str())?;
                 needs_termination = true;
             }
-            Some(&cnum) => {
-                let loc = match m.extern_locations[&cnum] {
-                    (ref cname, render::Remote(ref s)) => Some((cname, s.to_string())),
-                    (ref cname, render::Local) => {
+            Some(&def_id) => {
+                let loc = match m.extern_locations[&def_id.krate] {
+                    (ref cname, _, render::Remote(ref s)) => {
+                        Some((cname, s.to_string()))
+                    }
+                    (ref cname, _, render::Local) => {
                         let len = CURRENT_LOCATION_KEY.with(|s| s.borrow().len());
                         Some((cname, repeat("../").take(len).collect::<String>()))
                     }
-                    (_, render::Unknown) => None,
+                    (.., render::Unknown) => None,
                 };
                 if let Some((cname, root)) = loc {
                     write!(f, "<a class='primitive' href='{}{}/primitive.{}.html'>",