remove use of unstable features altogether

Author: nikomatsakis

Cargo.toml

@@ -6,7 +6,3 @@ homepage = "https://github.com/nikomatsakis/ena"
 repository = "https://github.com/nikomatsakis/ena"
 version = "0.4.0"
 authors = ["Niko Matsakis <[email protected]>"]
-
-[features]
-default = ["unstable"]
-unstable = []

src/cc/mod.rs

@@ -2,10 +2,11 @@
 //! paper "Fast Decision Procedures Based on Congruence Closure" by Nelson
 //! and Oppen, JACM 1980.
 
-use graph::{Graph, NodeIndex};
+use graph::{self, Graph, NodeIndex};
 use std::collections::HashMap;
 use std::fmt::Debug;
 use std::hash::Hash;
+use std::iter;
 use unify::{UnifyKey, UnifyValue, InfallibleUnifyValue, UnificationTable, UnionedKeys};
 
 #[cfg(test)]
@@ -408,13 +409,15 @@ impl<'a, K: Key> Algorithm<'a, K> {
         }
     }
 
-    fn successors(&self, token: Token) -> impl Iterator<Item = Token> + 'a {
+    fn successors(&self, token: Token) -> iter::Map<graph::AdjacentTargets<'a, K, ()>,
+                                                    fn(NodeIndex) -> Token> {
         self.graph
             .successor_nodes(token.node())
             .map(Token::from_node)
     }
 
-    fn predecessors(&self, token: Token) -> impl Iterator<Item = Token> + 'a {
+    fn predecessors(&self, token: Token) -> iter::Map<graph::AdjacentSources<'a, K, ()>,
+                                                      fn(NodeIndex) -> Token> {
         self.graph
             .predecessor_nodes(token.node())
             .map(Token::from_node)

src/lib.rs

@@ -10,8 +10,6 @@
 
 #![cfg_attr(all(feature = "unstable", test), feature(test))]
 #![allow(dead_code)]
-#![cfg_attr(feature = "unstable", feature(conservative_impl_trait))]
-#![cfg_attr(feature = "unstable", feature(static_in_const))]
 
 #[macro_use]
 mod debug;