Fix various oversights in enum field treatment in trans and typeck.

Fixes #20996.

src/test/run-pass/associated-types-enum-field-named.rs

@@ -0,0 +1,43 @@
+// Copyright 2015 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.
+
+// Test associated types appearing in struct-like enum variants.
+
+use self::VarValue::*;
+
+pub trait UnifyKey {
+    type Value;
+    fn to_index(&self) -> usize;
+}
+
+pub enum VarValue<K:UnifyKey> {
+    Redirect { to: K },
+    Root { value: K::Value, rank: usize },
+}
+
+fn get<'a,K:UnifyKey<Value=Option<V>>,V>(table: &'a Vec<VarValue<K>>, key: &K) -> &'a Option<V> {
+    match table[key.to_index()] {
+        VarValue::Redirect { to: ref k } => get(table, k),
+        VarValue::Root { value: ref v, rank: _ } => v,
+    }
+}
+
+impl UnifyKey for usize {
+    type Value = Option<char>;
+    fn to_index(&self) -> usize { *self }
+}
+
+fn main() {
+    let table = vec![/* 0 */ Redirect { to: 1 },
+                     /* 1 */ Redirect { to: 3 },
+                     /* 2 */ Root { value: Some('x'), rank: 0 },
+                     /* 3 */ Redirect { to: 2 }];
+    assert_eq!(get(&table, &0), &Some('x'));
+}

src/test/run-pass/associated-types-enum-field-numbered.rs

@@ -0,0 +1,43 @@
+// Copyright 2015 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.
+
+// Test associated types appearing in tuple-like enum variants.
+
+use self::VarValue::*;
+
+pub trait UnifyKey {
+    type Value;
+    fn to_index(&self) -> usize;
+}
+
+pub enum VarValue<K:UnifyKey> {
+    Redirect(K),
+    Root(K::Value, usize),
+}
+
+fn get<'a,K:UnifyKey<Value=Option<V>>,V>(table: &'a Vec<VarValue<K>>, key: &K) -> &'a Option<V> {
+    match table[key.to_index()] {
+        VarValue::Redirect(ref k) => get(table, k),
+        VarValue::Root(ref v, _) => v,
+    }
+}
+
+impl UnifyKey for usize {
+    type Value = Option<char>;
+    fn to_index(&self) -> usize { *self }
+}
+
+fn main() {
+    let table = vec![/* 0 */ Redirect(1),
+                     /* 1 */ Redirect(3),
+                     /* 2 */ Root(Some('x'), 0),
+                     /* 3 */ Redirect(2)];
+    assert_eq!(get(&table, &0), &Some('x'));
+}