Merge #18612: script: Remove undocumented and unused operator+

ccccd51908 script: Remove undocumented and unused operator+ (MarcoFalke)

Pull request description:

  This operator has no documented use case and is also unused outside of test code. The test code and all other (imaginary) code that might use this operator is written more clear and concise by the existing CScript push operators for opcodes and data.

  Removing the operator is also going to protect against accidentally reintroducing bugs like this 6ff5f718b6 (diff-8458adcedc17d046942185cb709ff5c3L1135) (last time it was used).

ACKs for top commit:
  laanwj:
    ACK ccccd51908

Tree-SHA512: 43898ac77e4d9643d9f8ac6f8f65497a4f0bbb1fb5dcaecc839c3719aa36181ba77befb213e59a9f33a20a29e0173a0e9c4763b1930940b32c3d1598b3e39af9

src/script/script.h

@@ -419,28 +419,15 @@ public:
         READWRITEAS(CScriptBase, *this);
     }
 
-    CScript& operator+=(const CScript& b)
-    {
-        reserve(size() + b.size());
-        insert(end(), b.begin(), b.end());
-        return *this;
-    }
-
-    friend CScript operator+(const CScript& a, const CScript& b)
-    {
-        CScript ret = a;
-        ret += b;
-        return ret;
-    }
-
     explicit CScript(int64_t b) { operator<<(b); }
-
     explicit CScript(opcodetype b)     { operator<<(b); }
     explicit CScript(const CScriptNum& b) { operator<<(b); }
     // delete non-existent constructor to defend against future introduction
     // e.g. via prevector
     explicit CScript(const std::vector<unsigned char>& b) = delete;
 
+    /** Delete non-existent operator to defend against future introduction */
+    CScript& operator<<(const CScript& b) = delete;
 
     CScript& operator<<(int64_t b) { return push_int64(b); }
 
@@ -487,15 +474,6 @@ public:
         return *this;
     }
 
-    CScript& operator<<(const CScript& b)
-    {
-        // I'm not sure if this should push the script or concatenate scripts.
-        // If there's ever a use for pushing a script onto a script, delete this member fn
-        assert(!"Warning: Pushing a CScript onto a CScript with << is probably not intended, use + to concatenate!");
-        return *this;
-    }
-
-
     bool GetOp(const_iterator& pc, opcodetype& opcodeRet, std::vector<unsigned char>& vchRet) const
     {
         return GetScriptOp(pc, end(), opcodeRet, &vchRet);
@@ -506,7 +484,6 @@ public:
         return GetScriptOp(pc, end(), opcodeRet, nullptr);
     }
 
-
     /** Encode/decode small integers: */
     static int DecodeOP_N(opcodetype opcode)
     {