std: Use util::unreachable

src/libstd/generic_os.rs

@@ -80,7 +80,7 @@ fn getenv(n: str) -> option<str> {
             ret option::some(str::from_bytes(v)); // UTF-8 or fail
         } else { nsize = res; }
     }
-    fail;
+    util::unreachable();
 }
 
 #[cfg(target_os = "win32")]

src/libstd/rope.rs

@@ -1028,7 +1028,7 @@ fn sub_bytes(node: @node, byte_offset: uint, byte_len: uint) -> @node {
               }
             }
         }
-        fail;//Note: unreachable
+        util::unreachable();
     }
 
     /*
@@ -1092,7 +1092,7 @@ fn sub_chars(node: @node, char_offset: uint, char_len: uint) -> @node {
               }
             }
         }
-        fail;
+        util::unreachable();
     }
 
     fn concat2(left: @node, right: @node) -> @node {
@@ -1176,7 +1176,7 @@ fn loop_leaves(node: @node, it: fn(leaf) -> bool) -> bool{
               }
             }
         }
-        fail;//unreachable
+        util::unreachable();
     }
 
     /*
@@ -1209,7 +1209,7 @@ fn char_at(node: @node, pos: uint) -> char {
               }
             }
         }
-        fail;//unreachable
+        util::unreachable();
     }
 
     mod leaf_iterator {
@@ -1248,7 +1248,7 @@ fn next(it: t) -> option<leaf> {
                   }
                 }
             }
-            fail;//unreachable
+            util::unreachable();
         }
     }
 
@@ -1292,7 +1292,7 @@ fn next(it: t) -> option<char> {
                   }
                 }
             }
-            fail;//unreachable
+            util::unreachable();
         }
 
         fn get_current_or_next_leaf(it: t) -> option<leaf> {