rustdoc: rename the type in an impl to match its containing page

src/librustdoc/html/format.rs

@@ -440,28 +440,29 @@ pub fn href(did: DefId) -> Option<(String, ItemType, Vec<String>)> {
 /// Used when rendering a `ResolvedPath` structure. This invokes the `path`
 /// rendering function with the necessary arguments for linking to a local path.
 fn resolved_path(w: &mut fmt::Formatter, did: DefId, path: &clean::Path,
-                 print_all: bool, use_absolute: bool) -> fmt::Result {
+                 print_all: bool, use_absolute: bool, rename: Option<&str>) -> fmt::Result {
     let last = path.segments.last().unwrap();
+    let last_name = rename.unwrap_or(&last.name);
 
     if print_all {
         for seg in &path.segments[..path.segments.len() - 1] {
             write!(w, "{}::", seg.name)?;
         }
     }
     if w.alternate() {
-        write!(w, "{:#}{:#}", HRef::new(did, &last.name), last.args)?;
+        write!(w, "{:#}{:#}", HRef::new(did, last_name), last.args)?;
     } else {
         let path = if use_absolute {
             match href(did) {
                 Some((_, _, fqp)) => {
                     format!("{}::{}",
                             fqp[..fqp.len() - 1].join("::"),
-                            HRef::new(did, fqp.last().unwrap()))
+                            HRef::new(did, rename.or(fqp.last().map(|n| &**n)).unwrap()))
                 }
-                None => HRef::new(did, &last.name).to_string(),
+                None => HRef::new(did, last_name).to_string(),
             }
         } else {
-            HRef::new(did, &last.name).to_string()
+            HRef::new(did, last_name).to_string()
         };
         write!(w, "{}{}", path, last.args)?;
     }
@@ -547,7 +548,14 @@ impl<'a> fmt::Display for HRef<'a> {
     }
 }
 
-fn fmt_type(t: &clean::Type, f: &mut fmt::Formatter, use_absolute: bool) -> fmt::Result {
+/// Writes the given type into the given formatter, optionally printing its full path or using the
+/// given name instead.
+fn fmt_type(
+    t: &clean::Type,
+    f: &mut fmt::Formatter,
+    use_absolute: bool,
+    rename: Option<&str>,
+) -> fmt::Result {
     match *t {
         clean::Generic(ref name) => {
             f.write_str(name)
@@ -557,7 +565,7 @@ fn fmt_type(t: &clean::Type, f: &mut fmt::Formatter, use_absolute: bool) -> fmt:
                 f.write_str("dyn ")?;
             }
             // Paths like T::Output and Self::Output should be rendered with all segments
-            resolved_path(f, did, path, is_generic, use_absolute)?;
+            resolved_path(f, did, path, is_generic, use_absolute, rename)?;
             tybounds(f, typarams)
         }
         clean::Infer => write!(f, "_"),
@@ -657,17 +665,17 @@ fn fmt_type(t: &clean::Type, f: &mut fmt::Formatter, use_absolute: bool) -> fmt:
                 }
                 clean::ResolvedPath { typarams: Some(ref v), .. } if !v.is_empty() => {
                     write!(f, "{}{}{}(", amp, lt, m)?;
-                    fmt_type(&ty, f, use_absolute)?;
+                    fmt_type(&ty, f, use_absolute, rename)?;
                     write!(f, ")")
                 }
                 clean::Generic(..) => {
                     primitive_link(f, PrimitiveType::Reference,
                                    &format!("{}{}{}", amp, lt, m))?;
-                    fmt_type(&ty, f, use_absolute)
+                    fmt_type(&ty, f, use_absolute, rename)
                 }
                 _ => {
                     write!(f, "{}{}{}", amp, lt, m)?;
-                    fmt_type(&ty, f, use_absolute)
+                    fmt_type(&ty, f, use_absolute, rename)
                 }
             }
         }
@@ -736,14 +744,15 @@ fn fmt_type(t: &clean::Type, f: &mut fmt::Formatter, use_absolute: bool) -> fmt:
 
 impl fmt::Display for clean::Type {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        fmt_type(self, f, false)
+        fmt_type(self, f, false, None)
     }
 }
 
 fn fmt_impl(i: &clean::Impl,
             f: &mut fmt::Formatter,
             link_trait: bool,
-            use_absolute: bool) -> fmt::Result {
+            use_absolute: bool,
+            rename: Option<&str>) -> fmt::Result {
     if f.alternate() {
         write!(f, "impl{:#} ", i.generics)?;
     } else {
@@ -771,9 +780,9 @@ fn fmt_impl(i: &clean::Impl,
     }
 
     if let Some(ref ty) = i.blanket_impl {
-        fmt_type(ty, f, use_absolute)?;
+        fmt_type(ty, f, use_absolute, rename)?;
     } else {
-        fmt_type(&i.for_, f, use_absolute)?;
+        fmt_type(&i.for_, f, use_absolute, rename)?;
     }
 
     fmt::Display::fmt(&WhereClause { gens: &i.generics, indent: 0, end_newline: true }, f)?;
@@ -782,15 +791,23 @@ fn fmt_impl(i: &clean::Impl,
 
 impl fmt::Display for clean::Impl {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        fmt_impl(self, f, true, false)
+        fmt_impl(self, f, true, false, None)
     }
 }
 
 // The difference from above is that trait is not hyperlinked.
 pub fn fmt_impl_for_trait_page(i: &clean::Impl,
                                f: &mut fmt::Formatter,
-                               use_absolute: bool) -> fmt::Result {
-    fmt_impl(i, f, false, use_absolute)
+                               use_absolute: bool,
+                               rename: Option<&str>) -> fmt::Result {
+    fmt_impl(i, f, false, use_absolute, rename)
+}
+
+/// Renders an `impl` block signature, but with the `for` type renamed to the given name.
+pub fn fmt_impl_renamed(i: &clean::Impl,
+                        f: &mut fmt::Formatter,
+                        rename: Option<&str>) -> fmt::Result {
+    fmt_impl(i, f, true, false, rename)
 }
 
 impl fmt::Display for clean::Arguments {
@@ -946,7 +963,7 @@ impl<'a> fmt::Display for VisSpace<'a> {
                 {
                     f.write_str("in ")?;
                 }
-                resolved_path(f, did, path, true, false)?;
+                resolved_path(f, did, path, true, false, None)?;
                 f.write_str(") ")
             }
         }
@@ -1004,7 +1021,7 @@ impl fmt::Display for clean::Import {
 impl fmt::Display for clean::ImportSource {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match self.did {
-            Some(did) => resolved_path(f, did, &self.path, true, false),
+            Some(did) => resolved_path(f, did, &self.path, true, false, None),
             _ => {
                 for (i, seg) in self.path.segments.iter().enumerate() {
                     if i > 0 {

src/librustdoc/html/render.rs

@@ -73,7 +73,7 @@ use html::escape::Escape;
 use html::format::{AsyncSpace, ConstnessSpace};
 use html::format::{GenericBounds, WhereClause, href, AbiSpace};
 use html::format::{VisSpace, Method, UnsafetySpace, MutableSpace};
-use html::format::fmt_impl_for_trait_page;
+use html::format::{fmt_impl_for_trait_page, fmt_impl_renamed};
 use html::item_type::ItemType;
 use html::markdown::{self, Markdown, MarkdownHtml, MarkdownSummaryLine, ErrorCodes, IdMap};
 use html::{highlight, layout, static_files};
@@ -2796,7 +2796,7 @@ fn render_implementor(cx: &Context, implementor: &Impl, w: &mut fmt::Formatter,
         _ => false,
     };
     render_impl(w, cx, implementor, AssocItemLink::Anchor(None), RenderMode::Normal,
-                implementor.impl_item.stable_since(), false, Some(use_absolute))?;
+                implementor.impl_item.stable_since(), false, Some(use_absolute), None)?;
     Ok(())
 }
 
@@ -2806,8 +2806,9 @@ fn render_impls(cx: &Context, w: &mut fmt::Formatter,
     for i in traits {
         let did = i.trait_did().unwrap();
         let assoc_link = AssocItemLink::GotoSource(did, &i.inner_impl().provided_trait_methods);
-        render_impl(w, cx, i, assoc_link,
-                    RenderMode::Normal, containing_item.stable_since(), true, None)?;
+        let rename = containing_item.name.deref();
+        render_impl(w, cx, i, assoc_link, RenderMode::Normal,
+                    containing_item.stable_since(), true, None, rename)?;
     }
     Ok(())
 }
@@ -3065,7 +3066,7 @@ fn item_trait(
                 );
                 render_impl(w, cx, &implementor, assoc_link,
                             RenderMode::Normal, implementor.impl_item.stable_since(), false,
-                            None)?;
+                            None, None)?;
             }
         }
 
@@ -3713,9 +3714,10 @@ fn render_assoc_items(w: &mut fmt::Formatter,
                 RenderMode::ForDeref { mut_: deref_mut_ }
             }
         };
+        let rename = containing_item.name.deref();
         for i in &non_trait {
             render_impl(w, cx, i, AssocItemLink::Anchor(None), render_mode,
-                        containing_item.stable_since(), true, None)?;
+                        containing_item.stable_since(), true, None, rename)?;
         }
     }
     if let AssocItemRender::DerefFor { .. } = what {
@@ -3896,7 +3898,8 @@ fn spotlight_decl(decl: &clean::FnDecl) -> Result<String, fmt::Error> {
 
 fn render_impl(w: &mut fmt::Formatter, cx: &Context, i: &Impl, link: AssocItemLink,
                render_mode: RenderMode, outer_version: Option<&str>,
-               show_def_docs: bool, use_absolute: Option<bool>) -> fmt::Result {
+               show_def_docs: bool, use_absolute: Option<bool>, rename: Option<&str>,
+) -> fmt::Result {
     if render_mode == RenderMode::Normal {
         let id = cx.derive_id(match i.inner_impl().trait_ {
             Some(ref t) => format!("impl-{}", small_url_encode(&format!("{:#}", t))),
@@ -3905,7 +3908,7 @@ fn render_impl(w: &mut fmt::Formatter, cx: &Context, i: &Impl, link: AssocItemLi
         if let Some(use_absolute) = use_absolute {
             write!(w, "<h3 id='{}' class='impl'><span class='in-band'><table class='table-display'>\
                        <tbody><tr><td><code>", id)?;
-            fmt_impl_for_trait_page(&i.inner_impl(), w, use_absolute)?;
+            fmt_impl_for_trait_page(&i.inner_impl(), w, use_absolute, rename)?;
             if show_def_docs {
                 for it in &i.inner_impl().items {
                     if let clean::TypedefItem(ref tydef, _) = it.inner {
@@ -3919,8 +3922,10 @@ fn render_impl(w: &mut fmt::Formatter, cx: &Context, i: &Impl, link: AssocItemLi
             write!(w, "</code>")?;
         } else {
             write!(w, "<h3 id='{}' class='impl'><span class='in-band'><table class='table-display'>\
-                       <tbody><tr><td><code>{}</code>",
-                   id, i.inner_impl())?;
+                       <tbody><tr><td><code>",
+                   id)?;
+            fmt_impl_renamed(i.inner_impl(), w, rename)?;
+            write!(w, "</code>")?;
         }
         write!(w, "<a href='#{}' class='anchor'></a>", id)?;
         write!(w, "</span></td><td><span class='out-of-band'>")?;

src/librustdoc/lib.rs

@@ -25,6 +25,7 @@
 #![feature(crate_visibility_modifier)]
 #![feature(const_fn)]
 #![feature(drain_filter)]
+#![feature(inner_deref)]
 
 #![recursion_limit="256"]
 

src/test/rustdoc/inline_local/rename.rs

@@ -0,0 +1,24 @@
+// Copyright 2018 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+mod inner {
+    pub struct SomeStruct;
+
+    impl SomeStruct {
+        pub fn new() -> SomeStruct { SomeStruct }
+    }
+}
+
+// @has rename/index.html
+// @has - '//a/@href' 'struct.MyStruct.html'
+// @has rename/struct.MyStruct.html
+// @has - '//code' 'impl MyStruct'
+// @!has - '//code' 'impl SomeStruct'
+pub use inner::SomeStruct as MyStruct;