Convert CPubKey to WitnessV0KeyHash directly

The round-tripping through PKHash has no effect, and is
potentially misleading as such.

src/outputtype.cpp

@@ -53,7 +53,7 @@ CTxDestination GetDestinationForKey(const CPubKey& key, OutputType type)
     case OutputType::P2SH_SEGWIT:
     case OutputType::BECH32: {
         if (!key.IsCompressed()) return PKHash(key);
-        CTxDestination witdest = WitnessV0KeyHash(PKHash(key));
+        CTxDestination witdest = WitnessV0KeyHash(key);
         CScript witprog = GetScriptForDestination(witdest);
         if (type == OutputType::P2SH_SEGWIT) {
             return ScriptHash(witprog);

src/script/standard.cpp

@@ -21,6 +21,7 @@ CScriptID::CScriptID(const CScript& in) : uint160(Hash160(in.begin(), in.end()))
 ScriptHash::ScriptHash(const CScript& in) : uint160(Hash160(in.begin(), in.end())) {}
 
 PKHash::PKHash(const CPubKey& pubkey) : uint160(pubkey.GetID()) {}
+WitnessV0KeyHash::WitnessV0KeyHash(const CPubKey& pubkey) : uint160(pubkey.GetID()) {}
 
 WitnessV0ScriptHash::WitnessV0ScriptHash(const CScript& in)
 {

src/script/standard.h

@@ -103,6 +103,7 @@ struct WitnessV0KeyHash : public uint160
 {
     WitnessV0KeyHash() : uint160() {}
     explicit WitnessV0KeyHash(const uint160& hash) : uint160(hash) {}
+    explicit WitnessV0KeyHash(const CPubKey& pubkey);
 };
 
 //! CTxDestination subtype to encode any future Witness version

src/wallet/test/ismine_tests.cpp

@@ -167,7 +167,7 @@ BOOST_AUTO_TEST_CASE(ismine_standard)
         keystore.SetupLegacyScriptPubKeyMan();
         LOCK(keystore.GetLegacyScriptPubKeyMan()->cs_KeyStore);
 
-        CScript witnessscript = GetScriptForDestination(WitnessV0KeyHash(PKHash(pubkeys[0])));
+        CScript witnessscript = GetScriptForDestination(WitnessV0KeyHash(pubkeys[0]));
         scriptPubKey = GetScriptForDestination(WitnessV0ScriptHash(witnessscript));
 
         BOOST_CHECK(keystore.GetLegacyScriptPubKeyMan()->AddCScript(witnessscript));
@@ -202,7 +202,7 @@ BOOST_AUTO_TEST_CASE(ismine_standard)
         LOCK(keystore.GetLegacyScriptPubKeyMan()->cs_KeyStore);
         BOOST_CHECK(keystore.GetLegacyScriptPubKeyMan()->AddKey(keys[0]));
 
-        scriptPubKey = GetScriptForDestination(WitnessV0KeyHash(PKHash(pubkeys[0])));
+        scriptPubKey = GetScriptForDestination(WitnessV0KeyHash(pubkeys[0]));
 
         // Keystore implicitly has key and P2SH redeemScript
         BOOST_CHECK(keystore.GetLegacyScriptPubKeyMan()->AddCScript(scriptPubKey));
@@ -217,7 +217,7 @@ BOOST_AUTO_TEST_CASE(ismine_standard)
         LOCK(keystore.GetLegacyScriptPubKeyMan()->cs_KeyStore);
         BOOST_CHECK(keystore.GetLegacyScriptPubKeyMan()->AddKey(uncompressedKey));
 
-        scriptPubKey = GetScriptForDestination(WitnessV0KeyHash(PKHash(uncompressedPubkey)));
+        scriptPubKey = GetScriptForDestination(WitnessV0KeyHash(uncompressedPubkey));
 
         // Keystore has key, but no P2SH redeemScript
         result = keystore.GetLegacyScriptPubKeyMan()->IsMine(scriptPubKey);