commit 3cc77d5d635c2411f327cc4f262f37abb66ff43c
Author: Zhihao Yuan <lichray@gmail.com>
Date:   Wed Jan 18 16:16:07 2017 -0600

    Treat signed-unsigned conversions as errors.

diff --git a/include/rapidjson/encodedstream.h b/include/rapidjson/encodedstream.h
index 14506838..223601c0 100644
--- a/include/rapidjson/encodedstream.h
+++ b/include/rapidjson/encodedstream.h
@@ -200,7 +200,7 @@ private:
         // xx xx xx xx  UTF-8
 
         if (!hasBOM_) {
-            unsigned pattern = (c[0] ? 1 : 0) | (c[1] ? 2 : 0) | (c[2] ? 4 : 0) | (c[3] ? 8 : 0);
+            int pattern = (c[0] ? 1 : 0) | (c[1] ? 2 : 0) | (c[2] ? 4 : 0) | (c[3] ? 8 : 0);
             switch (pattern) {
             case 0x08: type_ = kUTF32BE; break;
             case 0x0A: type_ = kUTF16BE; break;
diff --git a/include/rapidjson/encodings.h b/include/rapidjson/encodings.h
index baa7c2b1..ed7d44d3 100644
--- a/include/rapidjson/encodings.h
+++ b/include/rapidjson/encodings.h
@@ -157,7 +157,7 @@ struct UTF8 {
         if (type >= 32) {
             *codepoint = 0;
         } else {
-            *codepoint = (0xFF >> type) & static_cast<unsigned char>(c);
+            *codepoint = (0xFFu >> type) & static_cast<unsigned char>(c);
         }
         bool result = true;
         switch (type) {
@@ -283,7 +283,7 @@ struct UTF16 {
             RAPIDJSON_ASSERT(codepoint <= 0x10FFFF);
             unsigned v = codepoint - 0x10000;
             os.Put(static_cast<typename OutputStream::Ch>((v >> 10) | 0xD800));
-            os.Put((v & 0x3FF) | 0xDC00);
+            os.Put(static_cast<typename OutputStream::Ch>((v & 0x3FF) | 0xDC00));
         }
     }
 
@@ -299,7 +299,7 @@ struct UTF16 {
             RAPIDJSON_ASSERT(codepoint <= 0x10FFFF);
             unsigned v = codepoint - 0x10000;
             PutUnsafe(os, static_cast<typename OutputStream::Ch>((v >> 10) | 0xD800));
-            PutUnsafe(os, (v & 0x3FF) | 0xDC00);
+            PutUnsafe(os, static_cast<typename OutputStream::Ch>((v & 0x3FF) | 0xDC00));
         }
     }
 
diff --git a/include/rapidjson/internal/dtoa.h b/include/rapidjson/internal/dtoa.h
index 8d6350e6..bf2e9b2e 100644
--- a/include/rapidjson/internal/dtoa.h
+++ b/include/rapidjson/internal/dtoa.h
@@ -41,7 +41,7 @@ inline void GrisuRound(char* buffer, int len, uint64_t delta, uint64_t rest, uin
     }
 }
 
-inline unsigned CountDecimalDigit32(uint32_t n) {
+inline int CountDecimalDigit32(uint32_t n) {
     // Simple pure C++ implementation was faster than __builtin_clz version in this situation.
     if (n < 10) return 1;
     if (n < 100) return 2;
@@ -63,7 +63,7 @@ inline void DigitGen(const DiyFp& W, const DiyFp& Mp, uint64_t delta, char* buff
     const DiyFp wp_w = Mp - W;
     uint32_t p1 = static_cast<uint32_t>(Mp.f >> -one.e);
     uint64_t p2 = Mp.f & (one.f - 1);
-    unsigned kappa = CountDecimalDigit32(p1); // kappa in [0, 9]
+    int kappa = CountDecimalDigit32(p1); // kappa in [0, 9]
     *len = 0;
 
     while (kappa > 0) {
@@ -102,8 +102,8 @@ inline void DigitGen(const DiyFp& W, const DiyFp& Mp, uint64_t delta, char* buff
         kappa--;
         if (p2 < delta) {
             *K += kappa;
-            int index = -static_cast<int>(kappa);
-            GrisuRound(buffer, *len, delta, p2, one.f, wp_w.f * (index < 9 ? kPow10[-static_cast<int>(kappa)] : 0));
+            int index = -kappa;
+            GrisuRound(buffer, *len, delta, p2, one.f, wp_w.f * (index < 9 ? kPow10[index] : 0));
             return;
         }
     }
diff --git a/include/rapidjson/internal/ieee754.h b/include/rapidjson/internal/ieee754.h
index 82bb0b99..c2684ba2 100644
--- a/include/rapidjson/internal/ieee754.h
+++ b/include/rapidjson/internal/ieee754.h
@@ -48,13 +48,13 @@ public:
     int IntegerExponent() const { return (IsNormal() ? Exponent() : kDenormalExponent) - kSignificandSize; }
     uint64_t ToBias() const { return (u_ & kSignMask) ? ~u_ + 1 : u_ | kSignMask; }
 
-    static unsigned EffectiveSignificandSize(int order) {
+    static int EffectiveSignificandSize(int order) {
         if (order >= -1021)
             return 53;
         else if (order <= -1074)
             return 0;
         else
-            return static_cast<unsigned>(order) + 1074;
+            return order + 1074;
     }
 
 private:
diff --git a/include/rapidjson/internal/regex.h b/include/rapidjson/internal/regex.h
index 936b7144..1369ea26 100644
--- a/include/rapidjson/internal/regex.h
+++ b/include/rapidjson/internal/regex.h
@@ -688,8 +688,8 @@ private:
             bool matched = AddState(l, s.out);
             return AddState(l, s.out1) || matched;
         }
-        else if (!(stateSet_[index >> 5] & (1 << (index & 31)))) {
-            stateSet_[index >> 5] |= (1 << (index & 31));
+        else if (!(stateSet_[index >> 5] & (1u << (index & 31)))) {
+            stateSet_[index >> 5] |= (1u << (index & 31));
             *l.template PushUnsafe<SizeType>() = index;
         }
         return s.out == kRegexInvalidState; // by using PushUnsafe() above, we can ensure s is not validated due to reallocation.
diff --git a/include/rapidjson/internal/strtod.h b/include/rapidjson/internal/strtod.h
index 289c413b..adf49e34 100644
--- a/include/rapidjson/internal/strtod.h
+++ b/include/rapidjson/internal/strtod.h
@@ -140,8 +140,8 @@ inline bool StrtodDiyFp(const char* decimals, size_t length, size_t decimalPosit
         significand++;
 
     size_t remaining = length - i;
-    const unsigned kUlpShift = 3;
-    const unsigned kUlp = 1 << kUlpShift;
+    const int kUlpShift = 3;
+    const int kUlp = 1 << kUlpShift;
     int64_t error = (remaining == 0) ? 0 : kUlp / 2;
 
     DiyFp v(significand, 0);
@@ -177,17 +177,17 @@ inline bool StrtodDiyFp(const char* decimals, size_t length, size_t decimalPosit
     v = v.Normalize();
     error <<= oldExp - v.e;
 
-    const unsigned effectiveSignificandSize = Double::EffectiveSignificandSize(64 + v.e);
-    unsigned precisionSize = 64 - effectiveSignificandSize;
+    const int effectiveSignificandSize = Double::EffectiveSignificandSize(64 + v.e);
+    int precisionSize = 64 - effectiveSignificandSize;
     if (precisionSize + kUlpShift >= 64) {
-        unsigned scaleExp = (precisionSize + kUlpShift) - 63;
+        int scaleExp = (precisionSize + kUlpShift) - 63;
         v.f >>= scaleExp;
         v.e += scaleExp; 
-        error = (error >> scaleExp) + 1 + static_cast<int>(kUlp);
+        error = (error >> scaleExp) + 1 + kUlp;
         precisionSize -= scaleExp;
     }
 
-    DiyFp rounded(v.f >> precisionSize, v.e + static_cast<int>(precisionSize));
+    DiyFp rounded(v.f >> precisionSize, v.e + precisionSize);
     const uint64_t precisionBits = (v.f & ((uint64_t(1) << precisionSize) - 1)) * kUlp;
     const uint64_t halfWay = (uint64_t(1) << (precisionSize - 1)) * kUlp;
     if (precisionBits >= halfWay + static_cast<unsigned>(error)) {
diff --git a/include/rapidjson/istreamwrapper.h b/include/rapidjson/istreamwrapper.h
index f5fe2897..8639c8c3 100644
--- a/include/rapidjson/istreamwrapper.h
+++ b/include/rapidjson/istreamwrapper.h
@@ -54,7 +54,7 @@ public:
 
     Ch Peek() const { 
         typename StreamType::int_type c = stream_.peek();
-        return RAPIDJSON_LIKELY(c != StreamType::traits_type::eof()) ? static_cast<Ch>(c) : '\0';
+        return RAPIDJSON_LIKELY(c != StreamType::traits_type::eof()) ? static_cast<Ch>(c) : static_cast<Ch>('\0');
     }
 
     Ch Take() { 
diff --git a/include/rapidjson/pointer.h b/include/rapidjson/pointer.h
index 4d6391f9..bc7acfd0 100644
--- a/include/rapidjson/pointer.h
+++ b/include/rapidjson/pointer.h
@@ -274,7 +274,7 @@ public:
         else {
             Ch name[21];
             for (size_t i = 0; i <= length; i++)
-                name[i] = buffer[i];
+                name[i] = static_cast<Ch>(buffer[i]);
             Token token = { name, length, index };
             return Append(token, allocator);
         }
@@ -1029,8 +1029,8 @@ private:
             unsigned char u = static_cast<unsigned char>(c);
             static const char hexDigits[16] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };
             os_.Put('%');
-            os_.Put(hexDigits[u >> 4]);
-            os_.Put(hexDigits[u & 15]);
+            os_.Put(static_cast<typename OutputStream::Ch>(hexDigits[u >> 4]));
+            os_.Put(static_cast<typename OutputStream::Ch>(hexDigits[u & 15]));
         }
     private:
         OutputStream& os_;
diff --git a/include/rapidjson/schema.h b/include/rapidjson/schema.h
index 4760d1b4..3f81d9bb 100644
--- a/include/rapidjson/schema.h
+++ b/include/rapidjson/schema.h
@@ -1263,7 +1263,7 @@ struct TokenHelper {
         char buffer[21];
         size_t length = static_cast<size_t>((sizeof(SizeType) == 4 ? u32toa(index, buffer) : u64toa(index, buffer)) - buffer);
         for (size_t i = 0; i < length; i++)
-            *documentStack.template Push<Ch>() = buffer[i];
+            *documentStack.template Push<Ch>() = static_cast<Ch>(buffer[i]);
     }
 };
 
diff --git a/include/rapidjson/writer.h b/include/rapidjson/writer.h
index 8f6e174f..874c555c 100644
--- a/include/rapidjson/writer.h
+++ b/include/rapidjson/writer.h
@@ -352,7 +352,7 @@ protected:
         char* end = internal::dtoa(d, buffer, maxDecimalPlaces_);
         PutReserve(*os_, static_cast<size_t>(end - buffer));
         for (char* p = buffer; p != end; ++p)
-            PutUnsafe(*os_, static_cast<typename TargetEncoding::Ch>(*p));
+            PutUnsafe(*os_, static_cast<typename OutputStream::Ch>(*p));
         return true;
     }