From 56c5d4cec385ce8196ecbee0e67cf4a928c06170 Mon Sep 17 00:00:00 2001
From: Niko Matsakis <niko@alum.mit.edu>
Date: Sun, 9 Feb 2014 07:37:33 -0500
Subject: [PATCH] libsyntax -- fix unsafe sharing in closures

---
 src/libsyntax/ext/deriving/generic.rs | 10 ++++++----
 src/libsyntax/ext/deriving/rand.rs    | 11 ++++++-----
 src/libsyntax/ext/format.rs           |  1 -
 3 files changed, 12 insertions(+), 10 deletions(-)

diff --git a/src/libsyntax/ext/deriving/generic.rs b/src/libsyntax/ext/deriving/generic.rs
index 47be3067284a..9d290c93c649 100644
--- a/src/libsyntax/ext/deriving/generic.rs
+++ b/src/libsyntax/ext/deriving/generic.rs
@@ -580,10 +580,12 @@ impl<'a> MethodDef<'a> {
             ast::SelfStatic => None,
             _ => Some(ast::Arg::new_self(trait_.span, ast::MutImmutable))
         };
-        let args = arg_types.move_iter().map(|(name, ty)| {
-            cx.arg(trait_.span, name, ty)
-        });
-        let args = self_arg.move_iter().chain(args).collect();
+        let args = {
+            let args = arg_types.move_iter().map(|(name, ty)| {
+                    cx.arg(trait_.span, name, ty)
+                });
+            self_arg.move_iter().chain(args).collect()
+        };
 
         let ret_type = self.get_ret_ty(cx, trait_, generics, type_ident);
 
diff --git a/src/libsyntax/ext/deriving/rand.rs b/src/libsyntax/ext/deriving/rand.rs
index a40317286c96..ef7bd7c2bcde 100644
--- a/src/libsyntax/ext/deriving/rand.rs
+++ b/src/libsyntax/ext/deriving/rand.rs
@@ -60,7 +60,7 @@ fn rand_substructure(cx: &mut ExtCtxt, trait_span: Span, substr: &Substructure)
         cx.ident_of("Rand"),
         cx.ident_of("rand")
     ];
-    let rand_call = |span| {
+    let rand_call = |cx: &mut ExtCtxt, span| {
         cx.expr_call_global(span,
                             rand_ident.clone(),
                             ~[ rng[0] ])
@@ -111,7 +111,7 @@ fn rand_substructure(cx: &mut ExtCtxt, trait_span: Span, substr: &Substructure)
                 let i_expr = cx.expr_uint(v_span, i);
                 let pat = cx.pat_lit(v_span, i_expr);
 
-                let thing = rand_thing(cx, v_span, ident, summary, |sp| rand_call(sp));
+                let thing = rand_thing(cx, v_span, ident, summary, |cx, sp| rand_call(cx, sp));
                 cx.arm(v_span, ~[ pat ], thing)
             }).collect::<~[ast::Arm]>();
 
@@ -130,20 +130,21 @@ fn rand_substructure(cx: &mut ExtCtxt, trait_span: Span, substr: &Substructure)
                   trait_span: Span,
                   ctor_ident: Ident,
                   summary: &StaticFields,
-                  rand_call: |Span| -> @Expr)
+                  rand_call: |&mut ExtCtxt, Span| -> @Expr)
                   -> @Expr {
         match *summary {
             Unnamed(ref fields) => {
                 if fields.is_empty() {
                     cx.expr_ident(trait_span, ctor_ident)
                 } else {
-                    let exprs = fields.map(|span| rand_call(*span));
+                    let exprs = fields.map(|span| rand_call(cx, *span));
                     cx.expr_call_ident(trait_span, ctor_ident, exprs)
                 }
             }
             Named(ref fields) => {
                 let rand_fields = fields.map(|&(ident, span)| {
-                    cx.field_imm(span, ident, rand_call(span))
+                    let e = rand_call(cx, span);
+                    cx.field_imm(span, ident, e)
                 });
                 cx.expr_struct_ident(trait_span, ctor_ident, rand_fields)
             }
diff --git a/src/libsyntax/ext/format.rs b/src/libsyntax/ext/format.rs
index 35d2adbead5f..3eacce5eb1d7 100644
--- a/src/libsyntax/ext/format.rs
+++ b/src/libsyntax/ext/format.rs
@@ -21,7 +21,6 @@ use rsparse = parse;
 use std::fmt::parse;
 use std::hashmap::{HashMap, HashSet};
 use std::vec;
-use std::cell::RefCell;
 
 #[deriving(Eq)]
 enum ArgumentType {