fuzz: use FuzzPk in regression_descriptor_parse.rs

This makes the fuzztest significantly faster. If we want to search
regressions in the parsing of DescriptorPublicKey then we should have a
fuzztest specifically for that.

Author: apoelstra

fuzz/fuzz_targets/regression_descriptor_parse.rs

@@ -1,11 +1,11 @@
 use core::str::FromStr;
 
 use honggfuzz::fuzz;
-use miniscript::{Descriptor, DescriptorPublicKey};
-use old_miniscript::{Descriptor as OldDescriptor, DescriptorPublicKey as OldDescriptorPublicKey};
+use miniscript::Descriptor;
+use old_miniscript::Descriptor as OldDescriptor;
 
-type Desc = Descriptor<DescriptorPublicKey>;
-type OldDesc = OldDescriptor<OldDescriptorPublicKey>;
+type Desc = Descriptor<descriptor_fuzz::FuzzPk>;
+type OldDesc = OldDescriptor<descriptor_fuzz::FuzzPk>;
 
 fn do_test(data: &[u8]) {
     let data_str = String::from_utf8_lossy(data);
@@ -35,9 +35,5 @@ fn main() {
 #[cfg(test)]
 mod tests {
     #[test]
-    fn duplicate_crash() {
-        crate::do_test(
-            b"tr(02dddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddd,{1,unun:0})",
-        )
-    }
+    fn duplicate_crash() { crate::do_test(b"tr(d,{0,{0,0}})") }
 }

fuzz/src/lib.rs

@@ -42,6 +42,13 @@ impl MiniscriptKey for FuzzPk {
     type Hash256 = u8;
 }
 
+impl old_miniscript::MiniscriptKey for FuzzPk {
+    type Sha256 = u8;
+    type Ripemd160 = u8;
+    type Hash160 = u8;
+    type Hash256 = u8;
+}
+
 impl ToPublicKey for FuzzPk {
     fn to_public_key(&self) -> PublicKey {
         let secp_pk = secp256k1::PublicKey::from_slice(&[