Merge pull request #2051 from nlohmann/clang10warnings

Fix Clang compiler warnings

include/nlohmann/detail/conversions/to_chars.hpp

@@ -1006,7 +1006,7 @@ inline char* format_buffer(char* buf, int len, int decimal_exponent,
 
         std::memmove(buf + (static_cast<size_t>(n) + 1), buf + n, static_cast<size_t>(k) - static_cast<size_t>(n));
         buf[n] = '.';
-        return buf + (static_cast<size_t>(k) + 1);
+        return buf + (static_cast<size_t>(k) + 1U);
     }
 
     if (min_exp < n and n <= 0)
@@ -1018,7 +1018,7 @@ inline char* format_buffer(char* buf, int len, int decimal_exponent,
         buf[0] = '0';
         buf[1] = '.';
         std::memset(buf + 2, '0', static_cast<size_t>(-n));
-        return buf + (2 + static_cast<size_t>(-n) + k);
+        return buf + (2U + static_cast<size_t>(-n) + static_cast<size_t>(k));
     }
 
     if (k == 1)

include/nlohmann/detail/output/serializer.hpp

@@ -259,8 +259,7 @@ class serializer
                     {
                         dump_integer(*i);
                         o->write_character(',');
-                        int index = i - val.m_value.binary->cbegin();
-                        if (index % 16 == 0)
+                        if (std::distance(val.m_value.binary->cbegin(), i) % 16 == 0)
                         {
                             o->write_character('\n');
                         }

single_include/nlohmann/json.hpp

@@ -14543,7 +14543,7 @@ inline char* format_buffer(char* buf, int len, int decimal_exponent,
 
         std::memmove(buf + (static_cast<size_t>(n) + 1), buf + n, static_cast<size_t>(k) - static_cast<size_t>(n));
         buf[n] = '.';
-        return buf + (static_cast<size_t>(k) + 1);
+        return buf + (static_cast<size_t>(k) + 1U);
     }
 
     if (min_exp < n and n <= 0)
@@ -14555,7 +14555,7 @@ inline char* format_buffer(char* buf, int len, int decimal_exponent,
         buf[0] = '0';
         buf[1] = '.';
         std::memset(buf + 2, '0', static_cast<size_t>(-n));
-        return buf + (2 + static_cast<size_t>(-n) + k);
+        return buf + (2U + static_cast<size_t>(-n) + static_cast<size_t>(k));
     }
 
     if (k == 1)
@@ -14892,8 +14892,7 @@ class serializer
                     {
                         dump_integer(*i);
                         o->write_character(',');
-                        int index = i - val.m_value.binary->cbegin();
-                        if (index % 16 == 0)
+                        if (std::distance(val.m_value.binary->cbegin(), i) % 16 == 0)
                         {
                             o->write_character('\n');
                         }

test/src/unit-deserialization.cpp

@@ -76,7 +76,7 @@ struct SaxEventLogger : public nlohmann::json_sax<json>
         return true;
     }
 
-    bool binary(std::vector<std::uint8_t>& val)
+    bool binary(std::vector<std::uint8_t>& val) override
     {
         std::string binary_contents = "binary(";
         std::string comma_space = "";