kill the old funky can_reach fn

Author: nikomatsakis

src/librustc/util/common.rs

@@ -203,49 +203,6 @@ pub fn block_query<P>(b: &ast::Block, p: P) -> bool where P: FnMut(&ast::Expr) -
     return v.flag;
 }
 
-/// K: Eq + Hash<S>, V, S, H: Hasher<S>
-///
-/// Determines whether there exists a path from `source` to `destination`.  The
-/// graph is defined by the `edges_map`, which maps from a node `S` to a list of
-/// its adjacent nodes `T`.
-///
-/// Efficiency note: This is implemented in an inefficient way because it is
-/// typically invoked on very small graphs. If the graphs become larger, a more
-/// efficient graph representation and algorithm would probably be advised.
-pub fn can_reach<T, S>(edges_map: &HashMap<T, Vec<T>, S>, source: T,
-                       destination: T) -> bool
-    where S: HashState, T: Hash + Eq + Clone,
-{
-    if source == destination {
-        return true;
-    }
-
-    // Do a little breadth-first-search here.  The `queue` list
-    // doubles as a way to detect if we've seen a particular FR
-    // before.  Note that we expect this graph to be an *extremely
-    // shallow* tree.
-    let mut queue = vec!(source);
-    let mut i = 0;
-    while i < queue.len() {
-        match edges_map.get(&queue[i]) {
-            Some(edges) => {
-                for target in edges {
-                    if *target == destination {
-                        return true;
-                    }
-
-                    if !queue.iter().any(|x| x == target) {
-                        queue.push((*target).clone());
-                    }
-                }
-            }
-            None => {}
-        }
-        i += 1;
-    }
-    return false;
-}
-
 /// Memoizes a one-argument closure using the given RefCell containing
 /// a type implementing MutableMap to serve as a cache.
 ///