Merge pull request #4672 from alexcrichton/linearmap-len-fix

Fix the len() method on LinearMap during popping

Author: catamorphism

src/libcore/hashmap.rs

@@ -220,14 +220,17 @@ pub mod linear {
                 },
             };
 
+            /* re-inserting buckets may cause changes in size, so remember what
+               our new size is ahead of time before we start insertions */
+            let size = self.size - 1;
             idx = self.next_bucket(idx, len_buckets);
             while self.buckets[idx].is_some() {
                 let mut bucket = None;
                 bucket <-> self.buckets[idx];
                 self.insert_opt_bucket(bucket);
                 idx = self.next_bucket(idx, len_buckets);
             }
-            self.size -= 1;
+            self.size = size;
 
             value
         }