diff --git a/src/arith_uint256.h b/src/arith_uint256.h
index 8ef40c9c56..09a8ddf19e 100644
--- a/src/arith_uint256.h
+++ b/src/arith_uint256.h
@@ -1,311 +1,323 @@
 // Copyright (c) 2009-2010 Satoshi Nakamoto
 // Copyright (c) 2009-2016 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #ifndef BITCOIN_ARITH_UINT256_H
 #define BITCOIN_ARITH_UINT256_H
 
 #include <cassert>
 #include <cstdint>
 #include <cstring>
 #include <limits>
 #include <stdexcept>
 #include <string>
 #include <vector>
 
 class uint256;
 
 class uint_error : public std::runtime_error {
 public:
     explicit uint_error(const std::string &str) : std::runtime_error(str) {}
 };
 
 /** Template base class for unsigned big integers. */
 template <unsigned int BITS> class base_uint {
 protected:
     static constexpr int WIDTH = BITS / 32;
     uint32_t pn[WIDTH];
 
 public:
     base_uint() {
         static_assert(
             BITS / 32 > 0 && BITS % 32 == 0,
             "Template parameter BITS must be a positive multiple of 32.");
 
-        for (int i = 0; i < WIDTH; i++)
+        for (int i = 0; i < WIDTH; i++) {
             pn[i] = 0;
+        }
     }
 
     base_uint(const base_uint &b) {
         static_assert(
             BITS / 32 > 0 && BITS % 32 == 0,
             "Template parameter BITS must be a positive multiple of 32.");
 
-        for (int i = 0; i < WIDTH; i++)
+        for (int i = 0; i < WIDTH; i++) {
             pn[i] = b.pn[i];
+        }
     }
 
     base_uint &operator=(const base_uint &b) {
-        for (int i = 0; i < WIDTH; i++)
+        for (int i = 0; i < WIDTH; i++) {
             pn[i] = b.pn[i];
+        }
         return *this;
     }
 
     base_uint(uint64_t b) {
         static_assert(
             BITS / 32 > 0 && BITS % 32 == 0,
             "Template parameter BITS must be a positive multiple of 32.");
 
         pn[0] = (unsigned int)b;
         pn[1] = (unsigned int)(b >> 32);
-        for (int i = 2; i < WIDTH; i++)
+        for (int i = 2; i < WIDTH; i++) {
             pn[i] = 0;
+        }
     }
 
     explicit base_uint(const std::string &str);
 
     const base_uint operator~() const {
         base_uint ret;
-        for (int i = 0; i < WIDTH; i++)
+        for (int i = 0; i < WIDTH; i++) {
             ret.pn[i] = ~pn[i];
+        }
         return ret;
     }
 
     const base_uint operator-() const {
         base_uint ret;
-        for (int i = 0; i < WIDTH; i++)
+        for (int i = 0; i < WIDTH; i++) {
             ret.pn[i] = ~pn[i];
+        }
         ++ret;
         return ret;
     }
 
     double getdouble() const;
 
     base_uint &operator=(uint64_t b) {
         pn[0] = (unsigned int)b;
         pn[1] = (unsigned int)(b >> 32);
-        for (int i = 2; i < WIDTH; i++)
+        for (int i = 2; i < WIDTH; i++) {
             pn[i] = 0;
+        }
         return *this;
     }
 
     base_uint &operator^=(const base_uint &b) {
-        for (int i = 0; i < WIDTH; i++)
+        for (int i = 0; i < WIDTH; i++) {
             pn[i] ^= b.pn[i];
+        }
         return *this;
     }
 
     base_uint &operator&=(const base_uint &b) {
-        for (int i = 0; i < WIDTH; i++)
+        for (int i = 0; i < WIDTH; i++) {
             pn[i] &= b.pn[i];
+        }
         return *this;
     }
 
     base_uint &operator|=(const base_uint &b) {
-        for (int i = 0; i < WIDTH; i++)
+        for (int i = 0; i < WIDTH; i++) {
             pn[i] |= b.pn[i];
+        }
         return *this;
     }
 
     base_uint &operator^=(uint64_t b) {
         pn[0] ^= (unsigned int)b;
         pn[1] ^= (unsigned int)(b >> 32);
         return *this;
     }
 
     base_uint &operator|=(uint64_t b) {
         pn[0] |= (unsigned int)b;
         pn[1] |= (unsigned int)(b >> 32);
         return *this;
     }
 
     base_uint &operator<<=(unsigned int shift);
     base_uint &operator>>=(unsigned int shift);
 
     base_uint &operator+=(const base_uint &b) {
         uint64_t carry = 0;
         for (int i = 0; i < WIDTH; i++) {
             uint64_t n = carry + pn[i] + b.pn[i];
             pn[i] = n & 0xffffffff;
             carry = n >> 32;
         }
         return *this;
     }
 
     base_uint &operator-=(const base_uint &b) {
         *this += -b;
         return *this;
     }
 
     base_uint &operator+=(uint64_t b64) {
         base_uint b;
         b = b64;
         *this += b;
         return *this;
     }
 
     base_uint &operator-=(uint64_t b64) {
         base_uint b;
         b = b64;
         *this += -b;
         return *this;
     }
 
     base_uint &operator*=(uint32_t b32);
     base_uint &operator*=(const base_uint &b);
     base_uint &operator/=(const base_uint &b);
 
     base_uint &operator++() {
         // prefix operator
         int i = 0;
-        while (i < WIDTH && ++pn[i] == 0)
+        while (i < WIDTH && ++pn[i] == 0) {
             i++;
+        }
         return *this;
     }
 
     const base_uint operator++(int) {
         // postfix operator
         const base_uint ret = *this;
         ++(*this);
         return ret;
     }
 
     base_uint &operator--() {
         // prefix operator
         int i = 0;
-        while (i < WIDTH && --pn[i] == std::numeric_limits<uint32_t>::max())
+        while (i < WIDTH && --pn[i] == std::numeric_limits<uint32_t>::max()) {
             i++;
+        }
         return *this;
     }
 
     const base_uint operator--(int) {
         // postfix operator
         const base_uint ret = *this;
         --(*this);
         return ret;
     }
 
     int CompareTo(const base_uint &b) const;
     bool EqualTo(uint64_t b) const;
 
     friend inline const base_uint operator+(const base_uint &a,
                                             const base_uint &b) {
         return base_uint(a) += b;
     }
     friend inline const base_uint operator-(const base_uint &a,
                                             const base_uint &b) {
         return base_uint(a) -= b;
     }
     friend inline const base_uint operator*(const base_uint &a,
                                             const base_uint &b) {
         return base_uint(a) *= b;
     }
     friend inline const base_uint operator/(const base_uint &a,
                                             const base_uint &b) {
         return base_uint(a) /= b;
     }
     friend inline const base_uint operator|(const base_uint &a,
                                             const base_uint &b) {
         return base_uint(a) |= b;
     }
     friend inline const base_uint operator&(const base_uint &a,
                                             const base_uint &b) {
         return base_uint(a) &= b;
     }
     friend inline const base_uint operator^(const base_uint &a,
                                             const base_uint &b) {
         return base_uint(a) ^= b;
     }
     friend inline const base_uint operator>>(const base_uint &a, int shift) {
         return base_uint(a) >>= shift;
     }
     friend inline const base_uint operator<<(const base_uint &a, int shift) {
         return base_uint(a) <<= shift;
     }
     friend inline const base_uint operator*(const base_uint &a, uint32_t b) {
         return base_uint(a) *= b;
     }
     friend inline bool operator==(const base_uint &a, const base_uint &b) {
         return memcmp(a.pn, b.pn, sizeof(a.pn)) == 0;
     }
     friend inline bool operator!=(const base_uint &a, const base_uint &b) {
         return memcmp(a.pn, b.pn, sizeof(a.pn)) != 0;
     }
     friend inline bool operator>(const base_uint &a, const base_uint &b) {
         return a.CompareTo(b) > 0;
     }
     friend inline bool operator<(const base_uint &a, const base_uint &b) {
         return a.CompareTo(b) < 0;
     }
     friend inline bool operator>=(const base_uint &a, const base_uint &b) {
         return a.CompareTo(b) >= 0;
     }
     friend inline bool operator<=(const base_uint &a, const base_uint &b) {
         return a.CompareTo(b) <= 0;
     }
     friend inline bool operator==(const base_uint &a, uint64_t b) {
         return a.EqualTo(b);
     }
     friend inline bool operator!=(const base_uint &a, uint64_t b) {
         return !a.EqualTo(b);
     }
 
     std::string GetHex() const;
     void SetHex(const char *psz);
     void SetHex(const std::string &str);
     std::string ToString() const;
 
     unsigned int size() const { return sizeof(pn); }
 
     /**
      * Returns the position of the highest bit set plus one, or zero if the
      * value is zero.
      */
     unsigned int bits() const;
 
     uint64_t GetLow64() const {
         static_assert(WIDTH >= 2, "Assertion WIDTH >= 2 failed (WIDTH = BITS / "
                                   "32). BITS is a template parameter.");
-        return pn[0] | (uint64_t)pn[1] << 32;
+        return pn[0] | uint64_t(pn[1]) << 32;
     }
 };
 
 /** 256-bit unsigned big integer. */
 class arith_uint256 : public base_uint<256> {
 public:
     arith_uint256() {}
     arith_uint256(const base_uint<256> &b) : base_uint<256>(b) {}
     arith_uint256(uint64_t b) : base_uint<256>(b) {}
     explicit arith_uint256(const std::string &str) : base_uint<256>(str) {}
 
     /**
      * The "compact" format is a representation of a whole number N using an
      * unsigned 32bit number similar to a floating point format.
      * The most significant 8 bits are the unsigned exponent of base 256.
      * This exponent can be thought of as "number of bytes of N".
      * The lower 23 bits are the mantissa.
      * Bit number 24 (0x800000) represents the sign of N.
      * N = (-1^sign) * mantissa * 256^(exponent-3)
      *
      * Satoshi's original implementation used BN_bn2mpi() and BN_mpi2bn().
      * MPI uses the most significant bit of the first byte as sign.
      * Thus 0x1234560000 is compact (0x05123456)
      * and  0xc0de000000 is compact (0x0600c0de)
      *
      * Bitcoin only uses this "compact" format for encoding difficulty targets,
      * which are unsigned 256bit quantities. Thus, all the complexities of the
      * sign bit and using base 256 are probably an implementation accident.
      */
     arith_uint256 &SetCompact(uint32_t nCompact, bool *pfNegative = nullptr,
                               bool *pfOverflow = nullptr);
     uint32_t GetCompact(bool fNegative = false) const;
 
     friend uint256 ArithToUint256(const arith_uint256 &);
     friend arith_uint256 UintToArith256(const uint256 &);
 };
 
 uint256 ArithToUint256(const arith_uint256 &);
 arith_uint256 UintToArith256(const uint256 &);
 
 #endif // BITCOIN_ARITH_UINT256_H