From b220db03bd334b2e74c4dfd62ed1318941b82a3c Mon Sep 17 00:00:00 2001
From: P1start <rewi-github@whanau.org>
Date: Fri, 29 Aug 2014 17:16:23 +1200
Subject: [PATCH 1/2] Allow `!` as the return type of proc/closure literals

Fixes #13490.
---
 src/libsyntax/parse/parser.rs       | 20 ++++++++++----------
 src/test/run-pass/closure-syntax.rs |  4 ++++
 2 files changed, 14 insertions(+), 10 deletions(-)

diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs
index 37bda15ac2c..c70a171ff7b 100644
--- a/src/libsyntax/parse/parser.rs
+++ b/src/libsyntax/parse/parser.rs
@@ -4092,20 +4092,20 @@ impl<'a> Parser<'a> {
                 (optional_unboxed_closure_kind, args)
             }
         };
-        let output = if self.eat(&token::RARROW) {
-            self.parse_ty(true)
+        let (style, output) = if self.token == token::RARROW {
+            self.parse_ret_ty()
         } else {
-            P(Ty {
+            (Return, P(Ty {
                 id: ast::DUMMY_NODE_ID,
                 node: TyInfer,
                 span: self.span,
-            })
+            }))
         };
 
         (P(FnDecl {
             inputs: inputs_captures,
             output: output,
-            cf: Return,
+            cf: style,
             variadic: false
         }), optional_unboxed_closure_kind)
     }
@@ -4118,20 +4118,20 @@ impl<'a> Parser<'a> {
                                      seq_sep_trailing_allowed(token::COMMA),
                                      |p| p.parse_fn_block_arg());
 
-        let output = if self.eat(&token::RARROW) {
-            self.parse_ty(true)
+        let (style, output) = if self.token == token::RARROW {
+            self.parse_ret_ty()
         } else {
-            P(Ty {
+            (Return, P(Ty {
                 id: ast::DUMMY_NODE_ID,
                 node: TyInfer,
                 span: self.span,
-            })
+            }))
         };
 
         P(FnDecl {
             inputs: inputs,
             output: output,
-            cf: Return,
+            cf: style,
             variadic: false
         })
     }
diff --git a/src/test/run-pass/closure-syntax.rs b/src/test/run-pass/closure-syntax.rs
index c2fbc2a4bf2..b5a94a02b34 100644
--- a/src/test/run-pass/closure-syntax.rs
+++ b/src/test/run-pass/closure-syntax.rs
@@ -78,6 +78,10 @@ fn bar<'b>() {
 
     let a = A;
     a.foo::<<'a>||>();
+
+    // issue #13490
+    let _ = || -> ! loop {};
+    let _ = proc() -> ! loop {};
 }
 
 struct B<T>;

From e5bbbbe274dff5d420f256b58ff107e619ddf86d Mon Sep 17 00:00:00 2001
From: P1start <rewi-github@whanau.org>
Date: Sat, 30 Aug 2014 20:37:11 +1200
Subject: [PATCH 2/2] Add some tests for closures that return `!`

---
 src/test/compile-fail/closure-that-fails.rs   |  3 +++
 .../compile-fail/dead-code-closure-bang.rs    | 17 ++++++++++++++++
 src/test/run-pass/closure-return-bang.rs      | 20 +++++++++++++++++++
 3 files changed, 40 insertions(+)
 create mode 100644 src/test/compile-fail/dead-code-closure-bang.rs
 create mode 100644 src/test/run-pass/closure-return-bang.rs

diff --git a/src/test/compile-fail/closure-that-fails.rs b/src/test/compile-fail/closure-that-fails.rs
index 60c80f872ec..7ce8e95a761 100644
--- a/src/test/compile-fail/closure-that-fails.rs
+++ b/src/test/compile-fail/closure-that-fails.rs
@@ -13,5 +13,8 @@ fn foo(f: || -> !) {}
 fn main() {
     // Type inference didn't use to be able to handle this:
     foo(|| fail!());
+    foo(|| -> ! fail!());
     foo(|| 22); //~ ERROR mismatched types
+    foo(|| -> ! 22); //~ ERROR mismatched types
+    let x = || -> ! 1; //~ ERROR mismatched types
 }
diff --git a/src/test/compile-fail/dead-code-closure-bang.rs b/src/test/compile-fail/dead-code-closure-bang.rs
new file mode 100644
index 00000000000..96e8378a35d
--- /dev/null
+++ b/src/test/compile-fail/dead-code-closure-bang.rs
@@ -0,0 +1,17 @@
+// Copyright 2014 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(unreachable_code)]
+
+fn main() {
+    let x: || -> ! = || fail!();
+    x();
+    println!("Foo bar"); //~ ERROR: unreachable statement
+}
diff --git a/src/test/run-pass/closure-return-bang.rs b/src/test/run-pass/closure-return-bang.rs
new file mode 100644
index 00000000000..e164aeca013
--- /dev/null
+++ b/src/test/run-pass/closure-return-bang.rs
@@ -0,0 +1,20 @@
+// Copyright 2014 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.
+
+#![allow(dead_code)]
+
+fn f(x: || -> !) -> ! {
+    x();
+}
+
+fn main() {
+    let x: || -> ! = || fail!();
+    let _y: || -> ! = || x();
+}