Add infrastructure for compiletests

Also adds compilefail tests for some lints, closes #5646.

tests/compiletest/plugin/compile-fail/ban.rs

@@ -0,0 +1,18 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#![feature(plugin)]
+#![plugin(plugins)]
+
+extern crate js;
+
+use js::jsval::JSVal;
+use std::cell::Cell;
+
+struct Foo {
+    bar: Cell<JSVal>
+    //~^ ERROR Banned type Cell<JSVal> detected. Use MutHeap<JSVal> instead,
+}
+
+fn main() {}

tests/compiletest/plugin/compile-fail/privatize.rs

@@ -0,0 +1,16 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#![feature(plugin, custom_attribute)]
+#![plugin(plugins)]
+#![allow(dead_code)]
+
+#[privatize]
+struct Foo {
+    pub v1: i32,
+    //~^ ERROR Field v1 is public where only private fields are allowed
+    v2: i32
+}
+
+fn main() {}

tests/compiletest/plugin/compile-fail/str_to_string.rs

@@ -0,0 +1,16 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#![feature(plugin)]
+#![plugin(plugins)]
+
+
+fn main() {
+    let x = "foo".to_string();
+    //~^ ERROR str.to_owned() is more efficient than str.to_string()
+
+    let x = &x[..];
+    x.to_string();
+    //~^ ERROR str.to_owned() is more efficient than str.to_string()
+}

tests/compiletest/plugin/compile-fail/transmute_type.rs

@@ -0,0 +1,19 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#![feature(plugin)]
+#![plugin(plugins)]
+#![allow(dead_code)]
+#![deny(transmute_type_lint)]
+
+use std::mem::{self, transmute};
+
+
+fn main() {
+    let _: &[u8] = unsafe { transmute("Rust") };
+    //~^ ERROR Transmute to &[u8] from &'static str detected
+
+    let _: &[u8] = unsafe { mem::transmute("Rust") };
+    //~^ ERROR Transmute to &[u8] from &'static str detected
+}

tests/compiletest/plugin/compile-fail/unrooted_must_root.rs

@@ -0,0 +1,27 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#![feature(plugin)]
+#![plugin(plugins)]
+#![allow(dead_code)]
+
+#[must_root]
+struct Foo {
+    v: i32
+}
+
+struct Bar {
+    f: Foo
+    //~^ ERROR Type must be rooted, use #[must_root] on the struct definition to propagate
+}
+
+fn foo1(_: Foo) {} //~ ERROR Type must be rooted
+
+
+fn foo2() -> Foo { //~ ERROR Type must be rooted
+    Foo { v: 10 }
+}
+
+
+fn main() {}