add another convenience helper (union_value) for infallible keys

Author: nikomatsakis

Cargo.toml

@@ -4,7 +4,7 @@ description = "Union-find, congruence closure, and other unification code. Based
 license = "MIT/Apache-2.0"
 homepage = "https://github.com/nikomatsakis/ena"
 repository = "https://github.com/nikomatsakis/ena"
-version = "0.7.1"
+version = "0.7.2"
 authors = ["Niko Matsakis <niko@alum.mit.edu>"]
 
 [features]

src/unify/mod.rs

@@ -453,13 +453,23 @@ impl<'tcx, K, V> UnificationTable<K>
           V: UnifyValue,
 {
     /// Unions two keys without the possibility of failure; only
-    /// applicable to InfallibleUnifyValue.
+    /// applicable when unify values use `NoError` as their error
+    /// type.
     pub fn union(&mut self, a_id: K, b_id: K)
         where V: UnifyValue<Error = NoError>
     {
         self.unify_var_var(a_id, b_id).unwrap();
     }
 
+    /// Unions a key and a value without the possibility of failure;
+    /// only applicable when unify values use `NoError` as their error
+    /// type.
+    pub fn union_value(&mut self, id: K, value: V)
+        where V: UnifyValue<Error = NoError>
+    {
+        self.unify_var_value(id, value).unwrap();
+    }
+
     /// Given two keys, indicates whether they have been unioned together.
     pub fn unioned(&mut self, a_id: K, b_id: K) -> bool {
         self.find(a_id) == self.find(b_id)