Add support for variant and types fields for intra links

Author: GuillaumeGomez

src/librustdoc/clean/mod.rs

@@ -1013,8 +1013,7 @@ fn resolve(cx: &DocContext, path_str: &str, is_val: bool) -> Result<(Def, Option
         let ty = cx.resolver.borrow_mut()
                             .with_scope(*id,
             |resolver| {
-                resolver.resolve_str_path_error(DUMMY_SP,
-                                                &path, false)
+                resolver.resolve_str_path_error(DUMMY_SP, &path, false)
         })?;
         match ty.def {
             Def::Struct(did) | Def::Union(did) | Def::Enum(did) | Def::TyAlias(did) => {
@@ -1029,7 +1028,27 @@ fn resolve(cx: &DocContext, path_str: &str, is_val: bool) -> Result<(Def, Option
                     };
                     Ok((ty.def, Some(format!("{}.{}", out, item_name))))
                 } else {
-                    Err(())
+                    let is_enum = match ty.def {
+                        Def::Enum(_) => true,
+                        _ => false,
+                    };
+                    let elem = if is_enum {
+                        cx.tcx.adt_def(did).all_fields().find(|item| item.name == item_name)
+                    } else {
+                        cx.tcx.adt_def(did)
+                              .non_enum_variant()
+                              .fields
+                              .iter()
+                              .find(|item| item.name == item_name)
+                    };
+                    if let Some(item) = elem {
+                        Ok((ty.def,
+                            Some(format!("{}.{}",
+                                         if is_enum { "variant" } else { "structfield" },
+                                         item.name))))
+                    } else {
+                        Err(())
+                    }
                 }
             }
             Def::Trait(did) => {

src/test/rustdoc/struct-field.rs

@@ -0,0 +1,33 @@
+// 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.
+
+#![crate_name = "foo"]
+
+// ignore-tidy-linelength
+
+// @has foo/index.html '//*[@class="docblock"]/p/a[@href="../foo/struct.Foo.html#structfield.bar"]' 'Foo::bar'
+// @has foo/index.html '//*[@class="docblock"]/p/a[@href="../foo/union.Bar.html#structfield.foo"]' 'Bar::foo'
+// @has foo/index.html '//*[@class="docblock"]/p/a[@href="../foo/enum.Uniooon.html#X.v"]' 'Uniooon::X'
+
+//! Test with [Foo::bar], [Bar::foo], [Uniooon::X]
+
+pub struct Foo {
+    pub bar: usize,
+}
+
+pub union Bar {
+    pub foo: u32,
+}
+
+pub enum Uniooon {
+    F,
+    X,
+    Y,
+}