Warn unused type aliases

Author: sanxiyn

src/librustc/middle/dead.rs

@@ -413,6 +413,7 @@ impl<'a, 'tcx> DeadVisitor<'a, 'tcx> {
             hir::ItemStatic(..)
             | hir::ItemConst(..)
             | hir::ItemFn(..)
+            | hir::ItemTy(..)
             | hir::ItemEnum(..)
             | hir::ItemStruct(..)
             | hir::ItemUnion(..) => true,

src/librustc_data_structures/graph/tests.rs

@@ -11,8 +11,6 @@
 use graph::*;
 use std::fmt::Debug;
 
-type TestNode = Node<&'static str>;
-type TestEdge = Edge<&'static str>;
 type TestGraph = Graph<&'static str, &'static str>;
 
 fn create_graph() -> TestGraph {

src/test/compile-fail/issue-32119.rs

@@ -9,6 +9,7 @@
 // except according to those terms.
 
 #![feature(rustc_attrs)]
+#![allow(dead_code)]
 
 pub type T = ();
 mod foo { pub use super::T; }

src/test/compile-fail/lint-dead-code-type-alias.rs

@@ -0,0 +1,20 @@
+// Copyright 2016 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.
+
+#![deny(dead_code)]
+
+type Used = u8;
+type Unused = u8; //~ ERROR type alias is never used
+
+fn id(x: Used) -> Used { x }
+
+fn main() {
+    id(0);
+}

src/test/compile-fail/macro-tt-matchers.rs

@@ -9,6 +9,7 @@
 // except according to those terms.
 
 #![feature(rustc_attrs)]
+#![allow(dead_code)]
 
 macro_rules! foo {
     ($x:tt) => (type Alias = $x<i32>;)