6 files changed, 21 insertions, 23 deletions
diff --git a/src/script/interpreter.cpp b/src/script/interpreter.cpp
index 2cdff7ee5..927b0267c 100644
--- a/src/script/interpreter.cpp
+++ b/src/script/interpreter.cpp
@@ -226,23 +226,25 @@ bool static CheckPubKeyEncoding(const valtype &vchPubKey, unsigned int flags, co
 }
 
 bool static CheckMinimalPush(const valtype& data, opcodetype opcode) {
+    // Excludes OP_1NEGATE, OP_1-16 since they are by definition minimal
+    assert(0 <= opcode && opcode <= OP_PUSHDATA4);
     if (data.size() == 0) {
-        // Could have used OP_0.
+        // Should have used OP_0.
         return opcode == OP_0;
     } else if (data.size() == 1 && data[0] >= 1 && data[0] <= 16) {
-        // Could have used OP_1 .. OP_16.
-        return opcode == OP_1 + (data[0] - 1);
+        // Should have used OP_1 .. OP_16.
+        return false;
     } else if (data.size() == 1 && data[0] == 0x81) {
-        // Could have used OP_1NEGATE.
-        return opcode == OP_1NEGATE;
+        // Should have used OP_1NEGATE.
+        return false;
     } else if (data.size() <= 75) {
-        // Could have used a direct push (opcode indicating number of bytes pushed + those bytes).
+        // Must have used a direct push (opcode indicating number of bytes pushed + those bytes).
         return opcode == data.size();
     } else if (data.size() <= 255) {
-        // Could have used OP_PUSHDATA.
+        // Must have used OP_PUSHDATA.
         return opcode == OP_PUSHDATA1;
     } else if (data.size() <= 65535) {
-        // Could have used OP_PUSHDATA2.
+        // Must have used OP_PUSHDATA2.
         return opcode == OP_PUSHDATA2;
     }
     return true;
diff --git a/src/script/interpreter.h b/src/script/interpreter.h
index e12329be7..4dad6b44c 100644
--- a/src/script/interpreter.h
+++ b/src/script/interpreter.h
@@ -104,7 +104,7 @@ enum
     //
     SCRIPT_VERIFY_MINIMALIF = (1U << 13),
 
-    // Signature(s) must be empty vector if an CHECK(MULTI)SIG operation failed
+    // Signature(s) must be empty vector if a CHECK(MULTI)SIG operation failed
     //
     SCRIPT_VERIFY_NULLFAIL = (1U << 14),
 
diff --git a/src/script/ismine.cpp b/src/script/ismine.cpp
index d0dd27255..35d794b98 100644
--- a/src/script/ismine.cpp
+++ b/src/script/ismine.cpp
@@ -13,16 +13,13 @@
 
 typedef std::vector<unsigned char> valtype;
 
-unsigned int HaveKeys(const std::vector<valtype>& pubkeys, const CKeyStore& keystore)
+static bool HaveKeys(const std::vector<valtype>& pubkeys, const CKeyStore& keystore)
 {
-    unsigned int nResult = 0;
-    for (const valtype& pubkey : pubkeys)
-    {
+    for (const valtype& pubkey : pubkeys) {
         CKeyID keyID = CPubKey(pubkey).GetID();
-        if (keystore.HaveKey(keyID))
-            ++nResult;
+        if (!keystore.HaveKey(keyID)) return false;
     }
-    return nResult;
+    return true;
 }
 
 isminetype IsMine(const CKeyStore& keystore, const CScript& scriptPubKey, SigVersion sigversion)
@@ -140,7 +137,7 @@ isminetype IsMine(const CKeyStore &keystore, const CScript& scriptPubKey, bool&
                 }
             }
         }
-        if (HaveKeys(keys, keystore) == keys.size())
+        if (HaveKeys(keys, keystore))
             return ISMINE_SPENDABLE;
         break;
     }
diff --git a/src/script/ismine.h b/src/script/ismine.h
index b54879cc1..c1338c3a8 100644
--- a/src/script/ismine.h
+++ b/src/script/ismine.h
@@ -29,7 +29,7 @@ enum isminetype
 typedef uint8_t isminefilter;
 
 /* isInvalid becomes true when the script is found invalid by consensus or policy. This will terminate the recursion
- * and return a ISMINE_NO immediately, as an invalid script should never be considered as "mine". This is needed as
+ * and return ISMINE_NO immediately, as an invalid script should never be considered as "mine". This is needed as
  * different SIGVERSION may have different network rules. Currently the only use of isInvalid is indicate uncompressed
  * keys in SIGVERSION_WITNESS_V0 script, but could also be used in similar cases in the future
  */
diff --git a/src/script/script.h b/src/script/script.h
index bedf5f9be..591777672 100644
--- a/src/script/script.h
+++ b/src/script/script.h
@@ -568,7 +568,7 @@ public:
             pc += nSize;
         }
 
-        opcodeRet = (opcodetype)opcode;
+        opcodeRet = static_cast<opcodetype>(opcode);
         return true;
     }
 
diff --git a/src/script/sign.cpp b/src/script/sign.cpp
index 838e502a0..aaba5e592 100644
--- a/src/script/sign.cpp
+++ b/src/script/sign.cpp
@@ -140,10 +140,9 @@ static CScript PushAll(const std::vector<valtype>& values)
 
 bool ProduceSignature(const BaseSignatureCreator& creator, const CScript& fromPubKey, SignatureData& sigdata)
 {
-    CScript script = fromPubKey;
     std::vector<valtype> result;
     txnouttype whichType;
-    bool solved = SignStep(creator, script, result, whichType, SIGVERSION_BASE);
+    bool solved = SignStep(creator, fromPubKey, result, whichType, SIGVERSION_BASE);
     bool P2SH = false;
     CScript subscript;
     sigdata.scriptWitness.stack.clear();
@@ -153,8 +152,8 @@ bool ProduceSignature(const BaseSignatureCreator& creator, const CScript& fromPu
         // Solver returns the subscript that needs to be evaluated;
         // the final scriptSig is the signatures from that
         // and then the serialized subscript:
-        script = subscript = CScript(result[0].begin(), result[0].end());
-        solved = solved && SignStep(creator, script, result, whichType, SIGVERSION_BASE) && whichType != TX_SCRIPTHASH;
+        subscript = CScript(result[0].begin(), result[0].end());
+        solved = solved && SignStep(creator, subscript, result, whichType, SIGVERSION_BASE) && whichType != TX_SCRIPTHASH;
         P2SH = true;
     }