Move TreeLike impl to concrete module

When we implemented the `TreeLike` trait for the concrete `Policy` we
put it in the `iter` module, it doesn't really live there, better to put
the impl in the same place as the definition of the implementor.

Move the impl of `TreeLike` for `concrete::Policy` to the `concrete`
module.

Author: tcharding

src/iter/mod.rs

@@ -15,7 +15,7 @@ pub use tree::{
 };
 
 use crate::sync::Arc;
-use crate::{policy, Miniscript, MiniscriptKey, ScriptContext, Terminal};
+use crate::{Miniscript, MiniscriptKey, ScriptContext, Terminal};
 
 impl<'a, Pk: MiniscriptKey, Ctx: ScriptContext> TreeLike for &'a Miniscript<Pk, Ctx> {
     fn as_node(&self) -> Tree<Self> {
@@ -68,29 +68,3 @@ impl<Pk: MiniscriptKey, Ctx: ScriptContext> TreeLike for Arc<Miniscript<Pk, Ctx>
         }
     }
 }
-
-impl<'a, Pk: MiniscriptKey> TreeLike for &'a policy::Concrete<Pk> {
-    fn as_node(&self) -> Tree<Self> {
-        use policy::Concrete::*;
-        match *self {
-            Unsatisfiable | Trivial | Key(_) | After(_) | Older(_) | Sha256(_) | Hash256(_)
-            | Ripemd160(_) | Hash160(_) => Tree::Nullary,
-            And(ref subs) => Tree::Nary(subs.iter().map(Arc::as_ref).collect()),
-            Or(ref v) => Tree::Nary(v.iter().map(|(_, p)| p.as_ref()).collect()),
-            Threshold(_, ref subs) => Tree::Nary(subs.iter().map(Arc::as_ref).collect()),
-        }
-    }
-}
-
-impl<Pk: MiniscriptKey> TreeLike for Arc<policy::Concrete<Pk>> {
-    fn as_node(&self) -> Tree<Self> {
-        use policy::Concrete::*;
-        match self.as_ref() {
-            Unsatisfiable | Trivial | Key(_) | After(_) | Older(_) | Sha256(_) | Hash256(_)
-            | Ripemd160(_) | Hash160(_) => Tree::Nullary,
-            And(ref subs) => Tree::Nary(subs.iter().map(Arc::clone).collect()),
-            Or(ref v) => Tree::Nary(v.iter().map(|(_, p)| Arc::clone(p)).collect()),
-            Threshold(_, ref subs) => Tree::Nary(subs.iter().map(Arc::clone).collect()),
-        }
-    }
-}

src/policy/concrete.rs

@@ -23,7 +23,7 @@ use {
 
 use super::ENTAILMENT_MAX_TERMINALS;
 use crate::expression::{self, FromTree};
-use crate::iter::TreeLike;
+use crate::iter::{Tree, TreeLike};
 use crate::miniscript::types::extra_props::TimelockInfo;
 use crate::prelude::*;
 use crate::sync::Arc;
@@ -1114,6 +1114,34 @@ fn generate_combination<Pk: MiniscriptKey>(
     ret
 }
 
+impl<'a, Pk: MiniscriptKey> TreeLike for &'a Policy<Pk> {
+    fn as_node(&self) -> Tree<Self> {
+        use Policy::*;
+
+        match *self {
+            Unsatisfiable | Trivial | Key(_) | After(_) | Older(_) | Sha256(_) | Hash256(_)
+            | Ripemd160(_) | Hash160(_) => Tree::Nullary,
+            And(ref subs) => Tree::Nary(subs.iter().map(Arc::as_ref).collect()),
+            Or(ref v) => Tree::Nary(v.iter().map(|(_, p)| p.as_ref()).collect()),
+            Threshold(_, ref subs) => Tree::Nary(subs.iter().map(Arc::as_ref).collect()),
+        }
+    }
+}
+
+impl<Pk: MiniscriptKey> TreeLike for Arc<Policy<Pk>> {
+    fn as_node(&self) -> Tree<Self> {
+        use Policy::*;
+
+        match self.as_ref() {
+            Unsatisfiable | Trivial | Key(_) | After(_) | Older(_) | Sha256(_) | Hash256(_)
+            | Ripemd160(_) | Hash160(_) => Tree::Nullary,
+            And(ref subs) => Tree::Nary(subs.iter().map(Arc::clone).collect()),
+            Or(ref v) => Tree::Nary(v.iter().map(|(_, p)| Arc::clone(p)).collect()),
+            Threshold(_, ref subs) => Tree::Nary(subs.iter().map(Arc::clone).collect()),
+        }
+    }
+}
+
 #[cfg(all(test, feature = "compiler"))]
 mod compiler_tests {
     use core::str::FromStr;