---

yaml
---
r: 216510
b: refs/heads/stable
c: da03c9d
h: refs/heads/master
v: v3

Author: Ulrik Sverdrup

[refs]

@@ -29,5 +29,5 @@ refs/heads/tmp: 378a370ff2057afeb1eae86eb6e78c476866a4a6
 refs/tags/1.0.0-alpha.2: 4c705f6bc559886632d3871b04f58aab093bfa2f
 refs/tags/homu-tmp: a5286998df566e736b32f6795bfc3803bdaf453d
 refs/tags/1.0.0-beta: 8cbb92b53468ee2b0c2d3eeb8567005953d40828
-refs/heads/stable: ee48e6d192166be08a57dc4f5ba14256c072e9c3
+refs/heads/stable: da03c9df33177d77029c52f8a68a5d214a6e83c7
 refs/tags/1.0.0: 55bd4f8ff2b323f317ae89e254ce87162d52a375

branches/stable/src/libsyntax/codemap.rs

@@ -543,21 +543,17 @@ impl CodeMap {
         }
     }
 
-    pub fn new_filemap(&self, filename: FileName, src: String) -> Rc<FileMap> {
+    pub fn new_filemap(&self, filename: FileName, mut src: String) -> Rc<FileMap> {
         let mut files = self.files.borrow_mut();
         let start_pos = match files.last() {
             None => 0,
             Some(last) => last.end_pos.to_usize(),
         };
 
         // Remove utf-8 BOM if any.
-        // FIXME #12884: no efficient/safe way to remove from the start of a string
-        // and reuse the allocation.
-        let mut src = if src.starts_with("\u{feff}") {
-            String::from(&src[3..])
-        } else {
-            String::from(&src[..])
-        };
+        if src.starts_with("\u{feff}") {
+            src.drain(..3);
+        }
 
         // Append '\n' in case it's not already there.
         // This is a workaround to prevent CodeMap.lookup_filemap_idx from

branches/stable/src/libsyntax/lib.rs

@@ -27,6 +27,7 @@
 
 #![feature(associated_consts)]
 #![feature(collections)]
+#![feature(collections_drain)]
 #![feature(core)]
 #![feature(libc)]
 #![feature(rustc_private)]