zcash_address: Introduce UA-specific parser error type

components/zcash_address/src/encoding.rs

@@ -13,6 +13,14 @@ pub enum ParseError {
     NotZcash,
 }
 
+impl From<unified::ParseError> for ParseError {
+    fn from(e: unified::ParseError) -> Self {
+        match e {
+            unified::ParseError::InvalidEncoding => Self::InvalidEncoding,
+        }
+    }
+}
+
 impl fmt::Display for ParseError {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {

components/zcash_address/src/kind/unified.rs

@@ -1,7 +1,9 @@
 use std::convert::{TryFrom, TryInto};
+use std::error::Error;
+use std::fmt;
 use std::iter;
 
-use crate::{kind, ParseError};
+use crate::kind;
 
 mod f4jumble;
 
@@ -57,6 +59,23 @@ impl From<Typecode> for u8 {
     }
 }
 
+/// An error while attempting to parse a string as a Zcash address.
+#[derive(Debug, PartialEq)]
+pub enum ParseError {
+    /// The string is an invalid encoding.
+    InvalidEncoding,
+}
+
+impl fmt::Display for ParseError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            ParseError::InvalidEncoding => write!(f, "Invalid encoding"),
+        }
+    }
+}
+
+impl Error for ParseError {}
+
 /// The set of known Receivers for Unified Addresses.
 ///
 /// This enum is an internal-only type, and is maintained in preference order, so that the