librustc: Implement write guards for borrowing `@mut` to `&` or `&mut`. r=nmatsakis

3 files changed, 49 insertions, 32 deletions

diff --git a/src/libstd/arc.rs b/src/libstd/arc.rs
index e48dc9acaeb..4d1a8af0b1d 100644
--- a/src/libstd/arc.rs
+++ b/src/libstd/arc.rs
@@ -430,9 +430,9 @@ impl<T: Const Owned> &RWWriteMode<T> {
     /// Access the pre-downgrade RWARC in write mode.
     fn write<U>(blk: fn(x: &mut T) -> U) -> U {
         match *self {
-            RWWriteMode((data, ref token, _)) => {
+            RWWriteMode((ref data, ref token, _)) => {
                 do token.write {
-                    blk(data)
+                    blk(&mut **data)
                 }
             }
         }
@@ -440,12 +440,14 @@ impl<T: Const Owned> &RWWriteMode<T> {
     /// Access the pre-downgrade RWARC in write mode with a condvar.
     fn write_cond<U>(blk: fn(x: &x/mut T, c: &c/Condvar) -> U) -> U {
         match *self {
-            RWWriteMode((data, ref token, ref poison)) => {
+            RWWriteMode((ref data, ref token, ref poison)) => {
                 do token.write_cond |cond| {
                     let cvar = Condvar {
-                        is_mutex: false, failed: poison.failed,
-                        cond: cond };
-                    blk(data, &cvar)
+                        is_mutex: false,
+                        failed: &mut *poison.failed,
+                        cond: cond
+                    };
+                    blk(&mut **data, &cvar)
                 }
             }
         }
diff --git a/src/libstd/rope.rs b/src/libstd/rope.rs
index 153f3956884..d478970ca9f 100644
--- a/src/libstd/rope.rs
+++ b/src/libstd/rope.rs
@@ -1322,7 +1322,12 @@ mod tests {
     fn of_string2() {
         let buf = @ mut ~"1234567890";
         let mut i = 0;
-        while i < 10 { *buf = *buf + *buf; i+=1;}
+        while i < 10 {
+            let a = *buf;
+            let b = *buf;
+            *buf = a + b;
+            i+=1;
+        }
         let sample = @*buf;
         let r      = of_str(sample);
         assert char_len(r) == str::char_len(*sample);
@@ -1353,7 +1358,12 @@ mod tests {
     fn iter1() {
         let buf = @ mut ~"1234567890";
         let mut i = 0;
-        while i < 10 { *buf = *buf + *buf; i+=1;}
+        while i < 10 {
+            let a = *buf;
+            let b = *buf;
+            *buf = a + b;
+            i+=1;
+        }
         let sample = @*buf;
         let r      = of_str(sample);
 
@@ -1374,7 +1384,12 @@ mod tests {
         let init = @~"1234567890";
         let buf  = @mut * init;
         let mut i = 0;
-        while i < 8 { *buf = *buf + *buf; i+=1;}
+        while i < 8 {
+            let a = *buf;
+            let b = *buf;
+            *buf = a + b;
+            i+=1;
+        }
         let sample = @*buf;
         let r1     = of_str(sample);
         let mut r2 = of_str(init);
diff --git a/src/libstd/time.rs b/src/libstd/time.rs
index 8cc6d0245a1..d77e02f37b9 100644
--- a/src/libstd/time.rs
+++ b/src/libstd/time.rs
@@ -402,22 +402,22 @@ priv fn do_strptime(s: &str, format: &str) -> Result<Tm, ~str> {
             None => Err(~"Invalid year")
           },
           'c' => {
-            parse_type(s, pos, 'a', tm)
+            parse_type(s, pos, 'a', &mut *tm)
                 .chain(|pos| parse_char(s, pos, ' '))
-                .chain(|pos| parse_type(s, pos, 'b', tm))
+                .chain(|pos| parse_type(s, pos, 'b', &mut *tm))
                 .chain(|pos| parse_char(s, pos, ' '))
-                .chain(|pos| parse_type(s, pos, 'e', tm))
+                .chain(|pos| parse_type(s, pos, 'e', &mut *tm))
                 .chain(|pos| parse_char(s, pos, ' '))
-                .chain(|pos| parse_type(s, pos, 'T', tm))
+                .chain(|pos| parse_type(s, pos, 'T', &mut *tm))
                 .chain(|pos| parse_char(s, pos, ' '))
-                .chain(|pos| parse_type(s, pos, 'Y', tm))
+                .chain(|pos| parse_type(s, pos, 'Y', &mut *tm))
           }
           'D' | 'x' => {
-            parse_type(s, pos, 'm', tm)
+            parse_type(s, pos, 'm', &mut *tm)
                 .chain(|pos| parse_char(s, pos, '/'))
-                .chain(|pos| parse_type(s, pos, 'd', tm))
+                .chain(|pos| parse_type(s, pos, 'd', &mut *tm))
                 .chain(|pos| parse_char(s, pos, '/'))
-                .chain(|pos| parse_type(s, pos, 'y', tm))
+                .chain(|pos| parse_type(s, pos, 'y', &mut *tm))
           }
           'd' => match match_digits(s, pos, 2u, false) {
             Some(item) => { let (v, pos) = item; tm.tm_mday = v; Ok(pos) }
@@ -428,11 +428,11 @@ priv fn do_strptime(s: &str, format: &str) -> Result<Tm, ~str> {
             None => Err(~"Invalid day of the month")
           },
           'F' => {
-            parse_type(s, pos, 'Y', tm)
+            parse_type(s, pos, 'Y', &mut *tm)
                 .chain(|pos| parse_char(s, pos, '-'))
-                .chain(|pos| parse_type(s, pos, 'm', tm))
+                .chain(|pos| parse_type(s, pos, 'm', &mut *tm))
                 .chain(|pos| parse_char(s, pos, '-'))
-                .chain(|pos| parse_type(s, pos, 'd', tm))
+                .chain(|pos| parse_type(s, pos, 'd', &mut *tm))
           }
           'H' => {
             // FIXME (#2350): range check.
@@ -513,18 +513,18 @@ priv fn do_strptime(s: &str, format: &str) -> Result<Tm, ~str> {
             None => Err(~"Invalid hour")
           },
           'R' => {
-            parse_type(s, pos, 'H', tm)
+            parse_type(s, pos, 'H', &mut *tm)
                 .chain(|pos| parse_char(s, pos, ':'))
-                .chain(|pos| parse_type(s, pos, 'M', tm))
+                .chain(|pos| parse_type(s, pos, 'M', &mut *tm))
           }
           'r' => {
-            parse_type(s, pos, 'I', tm)
+            parse_type(s, pos, 'I', &mut *tm)
                 .chain(|pos| parse_char(s, pos, ':'))
-                .chain(|pos| parse_type(s, pos, 'M', tm))
+                .chain(|pos| parse_type(s, pos, 'M', &mut *tm))
                 .chain(|pos| parse_char(s, pos, ':'))
-                .chain(|pos| parse_type(s, pos, 'S', tm))
+                .chain(|pos| parse_type(s, pos, 'S', &mut *tm))
                 .chain(|pos| parse_char(s, pos, ' '))
-                .chain(|pos| parse_type(s, pos, 'p', tm))
+                .chain(|pos| parse_type(s, pos, 'p', &mut *tm))
           }
           'S' => {
             // FIXME (#2350): range check.
@@ -539,11 +539,11 @@ priv fn do_strptime(s: &str, format: &str) -> Result<Tm, ~str> {
           }
           //'s' {}
           'T' | 'X' => {
-            parse_type(s, pos, 'H', tm)
+            parse_type(s, pos, 'H', &mut *tm)
                 .chain(|pos| parse_char(s, pos, ':'))
-                .chain(|pos| parse_type(s, pos, 'M', tm))
+                .chain(|pos| parse_type(s, pos, 'M', &mut *tm))
                 .chain(|pos| parse_char(s, pos, ':'))
-                .chain(|pos| parse_type(s, pos, 'S', tm))
+                .chain(|pos| parse_type(s, pos, 'S', &mut *tm))
           }
           't' => parse_char(s, pos, '\t'),
           'u' => {
@@ -558,11 +558,11 @@ priv fn do_strptime(s: &str, format: &str) -> Result<Tm, ~str> {
             }
           }
           'v' => {
-            parse_type(s, pos, 'e', tm)
+            parse_type(s, pos, 'e', &mut *tm)
                 .chain(|pos|  parse_char(s, pos, '-'))
-                .chain(|pos| parse_type(s, pos, 'b', tm))
+                .chain(|pos| parse_type(s, pos, 'b', &mut *tm))
                 .chain(|pos| parse_char(s, pos, '-'))
-                .chain(|pos| parse_type(s, pos, 'Y', tm))
+                .chain(|pos| parse_type(s, pos, 'Y', &mut *tm))
           }
           //'W' {}
           'w' => {