Remove sanity_checks() from DescriptorTrait

Now that `Descriptor` no longer implements `DesciptorTrait` we can
remove the `sanity_checks` method from the trait entirely and implement
the method directly on the individual descriptors.

Author: tcharding

src/descriptor/bare.rs

@@ -61,6 +61,12 @@ impl<Pk: MiniscriptKey> Bare<Pk> {
     pub fn as_inner(&self) -> &Miniscript<Pk, BareCtx> {
         &self.ms
     }
+
+    /// Checks whether the descriptor is safe.
+    pub fn sanity_check(&self) -> Result<(), Error> {
+        self.ms.sanity_check()?;
+        Ok(())
+    }
 }
 
 impl<Pk: MiniscriptKey + ToPublicKey> Bare<Pk> {
@@ -134,11 +140,6 @@ where
 }
 
 impl<Pk: MiniscriptKey> DescriptorTrait<Pk> for Bare<Pk> {
-    fn sanity_check(&self) -> Result<(), Error> {
-        self.ms.sanity_check()?;
-        Ok(())
-    }
-
     fn script_pubkey(&self) -> Script
     where
         Pk: ToPublicKey,
@@ -336,10 +337,6 @@ where
 }
 
 impl<Pk: MiniscriptKey> DescriptorTrait<Pk> for Pkh<Pk> {
-    fn sanity_check(&self) -> Result<(), Error> {
-        Ok(())
-    }
-
     fn script_pubkey(&self) -> Script
     where
         Pk: ToPublicKey,

src/descriptor/mod.rs

@@ -79,16 +79,6 @@ pub type KeyMap = HashMap<DescriptorPublicKey, DescriptorSecretKey>;
 // because of traits cannot know underlying generic of Self.
 // Thus, we must implement additional trait for translate function
 pub trait DescriptorTrait<Pk: MiniscriptKey> {
-    /// Whether the descriptor is safe
-    /// Checks whether all the spend paths in the descriptor are possible
-    /// on the bitcoin network under the current standardness and consensus rules
-    /// Also checks whether the descriptor requires signauture on all spend paths
-    /// And whether the script is malleable.
-    /// In general, all the guarantees of miniscript hold only for safe scripts.
-    /// All the analysis guarantees of miniscript only hold safe scripts.
-    /// The signer may not be able to find satisfactions even if one exists
-    fn sanity_check(&self) -> Result<(), Error>;
-
     /// Computes the scriptpubkey of the descriptor
     fn script_pubkey(&self) -> Script
     where
@@ -433,18 +423,19 @@ impl<P: MiniscriptKey, Q: MiniscriptKey> TranslatePk<P, Q> for Descriptor<P> {
 }
 
 impl<Pk: MiniscriptKey> Descriptor<Pk> {
-    /// Whether the descriptor is safe
-    /// Checks whether all the spend paths in the descriptor are possible
-    /// on the bitcoin network under the current standardness and consensus rules
-    /// Also checks whether the descriptor requires signauture on all spend paths
-    /// And whether the script is malleable.
+    /// Checks whether the descriptor is safe.
+    ///
+    /// Checks whether all the spend paths in the descriptor are possible on the
+    /// bitcoin network under the current standardness and consensus rules. Also
+    /// checks whether the descriptor requires signatures on all spend paths and
+    /// whether the script is malleable.
+    ///
     /// In general, all the guarantees of miniscript hold only for safe scripts.
-    /// All the analysis guarantees of miniscript only hold safe scripts.
-    /// The signer may not be able to find satisfactions even if one exists
+    /// The signer may not be able to find satisfactions even if one exists.
     pub fn sanity_check(&self) -> Result<(), Error> {
         match *self {
             Descriptor::Bare(ref bare) => bare.sanity_check(),
-            Descriptor::Pkh(ref pkh) => pkh.sanity_check(),
+            Descriptor::Pkh(_) => Ok(()),
             Descriptor::Wpkh(ref wpkh) => wpkh.sanity_check(),
             Descriptor::Wsh(ref wsh) => wsh.sanity_check(),
             Descriptor::Sh(ref sh) => sh.sanity_check(),

src/descriptor/segwitv0.rs

@@ -76,6 +76,15 @@ impl<Pk: MiniscriptKey> Wsh<Pk> {
             WshInner::Ms(ref ms) => format!("wsh({})", ms),
         }
     }
+
+    /// Checks whether the descriptor is safe.
+    pub fn sanity_check(&self) -> Result<(), Error> {
+        match self.inner {
+            WshInner::SortedMulti(ref smv) => smv.sanity_check()?,
+            WshInner::Ms(ref ms) => ms.sanity_check()?,
+        }
+        Ok(())
+    }
 }
 
 impl<Pk: MiniscriptKey + ToPublicKey> Wsh<Pk> {
@@ -190,14 +199,6 @@ where
 }
 
 impl<Pk: MiniscriptKey> DescriptorTrait<Pk> for Wsh<Pk> {
-    fn sanity_check(&self) -> Result<(), Error> {
-        match self.inner {
-            WshInner::SortedMulti(ref smv) => smv.sanity_check()?,
-            WshInner::Ms(ref ms) => ms.sanity_check()?,
-        }
-        Ok(())
-    }
-
     fn script_pubkey(&self) -> Script
     where
         Pk: ToPublicKey,
@@ -348,6 +349,17 @@ impl<Pk: MiniscriptKey> Wpkh<Pk> {
     pub fn to_string_no_checksum(&self) -> String {
         format!("wpkh({})", self.pk)
     }
+
+    /// Checks whether the descriptor is safe.
+    pub fn sanity_check(&self) -> Result<(), Error> {
+        if self.pk.is_uncompressed() {
+            Err(Error::ContextError(ScriptContextError::CompressedOnly(
+                self.pk.to_string(),
+            )))
+        } else {
+            Ok(())
+        }
+    }
 }
 
 impl<Pk: MiniscriptKey + ToPublicKey> Wpkh<Pk> {
@@ -442,16 +454,6 @@ where
 }
 
 impl<Pk: MiniscriptKey> DescriptorTrait<Pk> for Wpkh<Pk> {
-    fn sanity_check(&self) -> Result<(), Error> {
-        if self.pk.is_uncompressed() {
-            Err(Error::ContextError(ScriptContextError::CompressedOnly(
-                self.pk.to_string(),
-            )))
-        } else {
-            Ok(())
-        }
-    }
-
     fn script_pubkey(&self) -> Script
     where
         Pk: ToPublicKey,

src/descriptor/sh.rs

@@ -205,6 +205,17 @@ impl<Pk: MiniscriptKey> Sh<Pk> {
             inner: ShInner::Wpkh(wpkh),
         }
     }
+
+    /// Checks whether the descriptor is safe.
+    pub fn sanity_check(&self) -> Result<(), Error> {
+        match self.inner {
+            ShInner::Wsh(ref wsh) => wsh.sanity_check()?,
+            ShInner::Wpkh(ref wpkh) => wpkh.sanity_check()?,
+            ShInner::SortedMulti(ref smv) => smv.sanity_check()?,
+            ShInner::Ms(ref ms) => ms.sanity_check()?,
+        }
+        Ok(())
+    }
 }
 
 impl<Pk: MiniscriptKey + ToPublicKey> Sh<Pk> {
@@ -264,16 +275,6 @@ impl<Pk: MiniscriptKey + ToPublicKey> Sh<Pk> {
 }
 
 impl<Pk: MiniscriptKey> DescriptorTrait<Pk> for Sh<Pk> {
-    fn sanity_check(&self) -> Result<(), Error> {
-        match self.inner {
-            ShInner::Wsh(ref wsh) => wsh.sanity_check()?,
-            ShInner::Wpkh(ref wpkh) => wpkh.sanity_check()?,
-            ShInner::SortedMulti(ref smv) => smv.sanity_check()?,
-            ShInner::Ms(ref ms) => ms.sanity_check()?,
-        }
-        Ok(())
-    }
-
     fn script_pubkey(&self) -> Script
     where
         Pk: ToPublicKey,

src/descriptor/tr.rs

@@ -271,6 +271,14 @@ impl<Pk: MiniscriptKey> Tr<Pk> {
         *self.spend_info.lock().expect("Lock poisoned") = Some(Arc::clone(&spend_info));
         spend_info
     }
+
+    /// Checks whether the descriptor is safe.
+    pub fn sanity_check(&self) -> Result<(), Error> {
+        for (_depth, ms) in self.iter_scripts() {
+            ms.sanity_check()?;
+        }
+        Ok(())
+    }
 }
 
 impl<Pk: MiniscriptKey + ToPublicKey> Tr<Pk> {
@@ -552,13 +560,6 @@ impl<Pk: MiniscriptKey> Liftable<Pk> for Tr<Pk> {
 }
 
 impl<Pk: MiniscriptKey> DescriptorTrait<Pk> for Tr<Pk> {
-    fn sanity_check(&self) -> Result<(), Error> {
-        for (_depth, ms) in self.iter_scripts() {
-            ms.sanity_check()?;
-        }
-        Ok(())
-    }
-
     fn script_pubkey(&self) -> Script
     where
         Pk: ToPublicKey,