From b308a8c036bcc90cf294c84a1d43b80f7223066c Mon Sep 17 00:00:00 2001
From: Seo Sanghyeon <sanxiyn@gmail.com>
Date: Tue, 29 Mar 2016 01:11:08 +0900
Subject: [PATCH] Avoid linking to itself in implementors section of trait page

---
 src/librustdoc/clean/mod.rs   | 11 +++++++++++
 src/librustdoc/html/format.rs | 32 +++++++++++++++++++++++---------
 src/librustdoc/html/render.rs |  5 ++++-
 3 files changed, 38 insertions(+), 10 deletions(-)

diff --git a/src/librustdoc/clean/mod.rs b/src/librustdoc/clean/mod.rs
index b26e56008ac..5020b93d925 100644
--- a/src/librustdoc/clean/mod.rs
+++ b/src/librustdoc/clean/mod.rs
@@ -1505,6 +1505,13 @@ pub fn primitive_type(&self) -> Option<PrimitiveType> {
             _ => None,
         }
     }
+
+    pub fn trait_name(&self) -> Option<String> {
+        match *self {
+            ResolvedPath { ref path, .. } => Some(path.last_name()),
+            _ => None,
+        }
+    }
 }
 
 impl GetDefId for Type {
@@ -1994,6 +2001,10 @@ pub fn singleton(name: String) -> Path {
             }]
         }
     }
+
+    pub fn last_name(&self) -> String {
+        self.segments.last().unwrap().name.clone()
+    }
 }
 
 impl Clean<Path> for hir::Path {
diff --git a/src/librustdoc/html/format.rs b/src/librustdoc/html/format.rs
index e9a883d6d7a..015f5c91a65 100644
--- a/src/librustdoc/html/format.rs
+++ b/src/librustdoc/html/format.rs
@@ -561,19 +561,33 @@ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
     }
 }
 
+fn fmt_impl(i: &clean::Impl, f: &mut fmt::Formatter, link_trait: bool) -> fmt::Result {
+    write!(f, "impl{} ", i.generics)?;
+    if let Some(ref ty) = i.trait_ {
+        write!(f, "{}",
+               if i.polarity == Some(clean::ImplPolarity::Negative) { "!" } else { "" })?;
+        if link_trait {
+            write!(f, "{}", *ty)?;
+        } else {
+            write!(f, "{}", ty.trait_name().unwrap())?;
+        }
+        write!(f, " for ")?;
+    }
+    write!(f, "{}{}", i.for_, WhereClause(&i.generics))?;
+    Ok(())
+}
+
 impl fmt::Display for clean::Impl {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        write!(f, "impl{} ", self.generics)?;
-        if let Some(ref ty) = self.trait_ {
-            write!(f, "{}{} for ",
-                   if self.polarity == Some(clean::ImplPolarity::Negative) { "!" } else { "" },
-                   *ty)?;
-        }
-        write!(f, "{}{}", self.for_, WhereClause(&self.generics))?;
-        Ok(())
+        fmt_impl(self, f, true)
     }
 }
 
+// The difference from above is that trait is not hyperlinked.
+pub fn fmt_impl_for_trait_page(i: &clean::Impl, f: &mut fmt::Formatter) -> fmt::Result {
+    fmt_impl(i, f, false)
+}
+
 impl fmt::Display for clean::Arguments {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         for (i, input) in self.values.iter().enumerate() {
@@ -667,7 +681,7 @@ impl fmt::Display for clean::Import {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match *self {
             clean::SimpleImport(ref name, ref src) => {
-                if *name == src.path.segments.last().unwrap().name {
+                if *name == src.path.last_name() {
                     write!(f, "use {};", *src)
                 } else {
                     write!(f, "use {} as {};", *src, *name)
diff --git a/src/librustdoc/html/render.rs b/src/librustdoc/html/render.rs
index 0f436efd70b..042d9f011e9 100644
--- a/src/librustdoc/html/render.rs
+++ b/src/librustdoc/html/render.rs
@@ -69,6 +69,7 @@
 use html::format::{ConstnessSpace};
 use html::format::{TyParamBounds, WhereClause, href, AbiSpace};
 use html::format::{VisSpace, Method, UnsafetySpace, MutableSpace};
+use html::format::fmt_impl_for_trait_page;
 use html::item_type::ItemType;
 use html::markdown::{self, Markdown};
 use html::{highlight, layout};
@@ -2006,7 +2007,9 @@ fn trait_item(w: &mut fmt::Formatter, cx: &Context, m: &clean::Item, t: &clean::
     match cache.implementors.get(&it.def_id) {
         Some(implementors) => {
             for i in implementors {
-                writeln!(w, "<li><code>{}</code></li>", i.impl_)?;
+                write!(w, "<li><code>")?;
+                fmt_impl_for_trait_page(&i.impl_, w)?;
+                writeln!(w, "</code></li>")?;
             }
         }
         None => {}