From 767ed1a71f07e869e07bde138845e16b320908ec Mon Sep 17 00:00:00 2001
From: Alex Crichton <alex@alexcrichton.com>
Date: Tue, 8 Apr 2014 16:59:18 -0700
Subject: [PATCH] rustc: Prevent repeated moves out of proc upvars

This fixes the categorization of the upvars of procs (represented internally
as once fns) to consider usage to require a loan. In doing so, upvars are no
longer allowed to be moved out of repeatedly in loops and such.

Closes #10398
Closes #12041
Closes #12127
---
 src/librustc/middle/borrowck/mod.rs  |  3 ++-
 src/test/compile-fail/issue-10398.rs | 19 +++++++++++++++++++
 src/test/compile-fail/issue-11925.rs |  2 +-
 src/test/compile-fail/issue-12041.rs | 21 +++++++++++++++++++++
 src/test/compile-fail/issue-12127.rs | 18 ++++++++++++++++++
 5 files changed, 61 insertions(+), 2 deletions(-)
 create mode 100644 src/test/compile-fail/issue-10398.rs
 create mode 100644 src/test/compile-fail/issue-12041.rs
 create mode 100644 src/test/compile-fail/issue-12127.rs

diff --git a/src/librustc/middle/borrowck/mod.rs b/src/librustc/middle/borrowck/mod.rs
index 6f4f2f6345eb4..cf558c6afe396 100644
--- a/src/librustc/middle/borrowck/mod.rs
+++ b/src/librustc/middle/borrowck/mod.rs
@@ -274,12 +274,13 @@ pub fn opt_loan_path(cmt: mc::cmt) -> Option<@LoanPath> {
     match cmt.cat {
         mc::cat_rvalue(..) |
         mc::cat_static_item |
-        mc::cat_copied_upvar(_) => {
+        mc::cat_copied_upvar(mc::CopiedUpvar { onceness: ast::Many, .. }) => {
             None
         }
 
         mc::cat_local(id) |
         mc::cat_arg(id) |
+        mc::cat_copied_upvar(mc::CopiedUpvar { upvar_id: id, .. }) |
         mc::cat_upvar(ty::UpvarId {var_id: id, ..}, _) => {
             Some(@LpVar(id))
         }
diff --git a/src/test/compile-fail/issue-10398.rs b/src/test/compile-fail/issue-10398.rs
new file mode 100644
index 0000000000000..a58c88737b604
--- /dev/null
+++ b/src/test/compile-fail/issue-10398.rs
@@ -0,0 +1,19 @@
+// 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.
+
+fn main() {
+    let x = ~1;
+    let f: proc() = proc() {
+        let _a = x;
+        drop(x);
+        //~^ ERROR: use of moved value: `x`
+    };
+    f();
+}
diff --git a/src/test/compile-fail/issue-11925.rs b/src/test/compile-fail/issue-11925.rs
index 06a976ecf3d30..0b8eaa5b831c0 100644
--- a/src/test/compile-fail/issue-11925.rs
+++ b/src/test/compile-fail/issue-11925.rs
@@ -11,7 +11,7 @@
 fn main() {
     let r = {
         let x = ~42;
-        let f = proc() &x; //~ ERROR: borrowed value does not live long enough
+        let f = proc() &x; //~ ERROR: `x` does not live long enough
         f()
     };
 
diff --git a/src/test/compile-fail/issue-12041.rs b/src/test/compile-fail/issue-12041.rs
new file mode 100644
index 0000000000000..9ad593673120d
--- /dev/null
+++ b/src/test/compile-fail/issue-12041.rs
@@ -0,0 +1,21 @@
+// 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.
+
+fn main() {
+    let (tx, rx) = channel();
+    spawn(proc() {
+        loop {
+            let tx = tx;
+            //~^ ERROR: use of moved value: `tx`
+            tx.send(1);
+        }
+    });
+}
+
diff --git a/src/test/compile-fail/issue-12127.rs b/src/test/compile-fail/issue-12127.rs
new file mode 100644
index 0000000000000..7889242577029
--- /dev/null
+++ b/src/test/compile-fail/issue-12127.rs
@@ -0,0 +1,18 @@
+// 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.
+
+fn main() {
+    let f = proc() {};
+    (proc() {
+        f();
+        f();
+        //~^ ERROR: use of moved value: `f`
+    })()
+}