Add four regression tests

src/test/compile-fail/issue-22312.rs

@@ -0,0 +1,27 @@
+// 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.
+
+use std::ops::Index;
+
+pub trait Array2D: Index<usize> {
+    fn rows(&self) -> usize;
+    fn columns(&self) -> usize;
+    fn get<'a>(&'a self, y: usize, x: usize) -> Option<&'a <Self as Index<usize>>::Output> {
+        if y >= self.rows() || x >= self.columns() {
+            return None;
+        }
+        let i = y * self.columns() + x;
+        let indexer = &(*self as &Index<usize, Output = <Self as Index<usize>>::Output>);
+        //~^ERROR non-scalar cast
+        Some(indexer.index(i))
+    }
+}
+
+fn main() {}

src/test/compile-fail/issue-23595-1.rs

@@ -0,0 +1,24 @@
+// 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.
+
+use std::ops::{Index};
+
+trait Hierarchy {
+    type Value;
+    type ChildKey;
+    type Children = Index<Self::ChildKey, Output=Hierarchy>;
+    //~^ ERROR: the value of the associated type `ChildKey`
+    //~^^ ERROR: the value of the associated type `Children`
+    //~^^^ ERROR: the value of the associated type `Value`
+
+    fn data(&self) -> Option<(Self::Value, Self::Children)>;
+}
+
+fn main() {}

src/test/compile-fail/issue-23595-2.rs

@@ -0,0 +1,18 @@
+// 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.
+
+pub struct C<AType: A> {a:AType}
+
+pub trait A {
+    type B = C<Self::anything_here_kills_it>;
+    //~^ ERROR: associated type `anything_here_kills_it` not found for `Self`
+}
+
+fn main() {}

src/test/run-pass/issue-20544.rs

@@ -0,0 +1,27 @@
+// 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.
+
+#![feature(unboxed_closures)]
+#![feature(core)]
+
+struct Fun<F>(F);
+
+impl<F, T> FnOnce<(T,)> for Fun<F> where F: Fn(T) -> T {
+    type Output = T;
+
+    extern "rust-call" fn call_once(self, (t,): (T,)) -> T {
+        (self.0)(t)
+    }
+}
+
+fn main() {
+    let fun = Fun(|i: isize| i * 2);
+    println!("{}", fun(3));
+}

src/test/run-pass/issue-21140.rs

@@ -0,0 +1,15 @@
+// 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.
+
+pub trait Trait where Self::Out: std::fmt::Display {
+    type Out;
+}
+
+fn main() {}