Switched VS build to -W4, and fixed all resulting warnings.

Change-Id: I654217cbd01a3a449503d95753e19b672ec7ec23
Tested: on Windows, Linux

src/idl_gen_cpp.cpp

@@ -135,7 +135,7 @@ static void GenComment(const std::string &dc,
       code += " - " + enum_def.name + "_" + enum_def.vals.vec.front()->name;
     code += "]; }\n\n";
   }
-  
+
   if (enum_def.is_union) {
     // Generate a verifier function for this union that can be called by the
     // table verifier functions. It uses a switch case to select a specific
@@ -274,6 +274,8 @@ static void GenTable(StructDef &struct_def, std::string *code_ptr) {
   code += "  " + struct_def.name;
   code += "Builder(flatbuffers::FlatBufferBuilder &_fbb) : fbb_(_fbb) ";
   code += "{ start_ = fbb_.StartTable(); }\n";
+  code += "  " + struct_def.name + "Builder &operator=(const ";
+  code += struct_def.name + "Builder &);\n";
   code += "  flatbuffers::Offset<" + struct_def.name;
   code += "> Finish() { return flatbuffers::Offset<" + struct_def.name;
   code += ">(fbb_.EndTable(start_, ";

src/idl_gen_java.cpp

@@ -78,9 +78,12 @@ static void GenComment(const std::string &dc,
 static std::string MakeCamel(const std::string &in, bool first = true) {
   std::string s;
   for (size_t i = 0; i < in.length(); i++) {
-    if (!i && first) s += toupper(in[0]);
-    else if (in[i] == '_' && i + 1 < in.length()) s += toupper(in[++i]);
-    else s += in[i];
+    if (!i && first)
+      s += static_cast<char>(toupper(in[0]));
+    else if (in[i] == '_' && i + 1 < in.length())
+      s += static_cast<char>(toupper(in[++i]));
+    else
+      s += in[i];
   }
   return s;
 }
@@ -373,7 +376,7 @@ static bool SaveClass(const Parser &parser, const Definition &def,
 
 bool GenerateJava(const Parser &parser,
                   const std::string &path,
-                  const std::string &file_name) {
+                  const std::string & /*file_name*/) {
   using namespace java;
 
   for (auto it = parser.enums_.vec.begin();

src/idl_gen_text.cpp

@@ -34,8 +34,9 @@ const char *NewLine(int indent_step) {
 // Print (and its template specialization below for pointers) generate text
 // for a single FlatBuffer value into JSON format.
 // The general case for scalars:
-template<typename T> void Print(T val, Type type, int indent, int indent_step,
-                                StructDef * /*union_sd*/, std::string *_text) {
+template<typename T> void Print(T val, Type /*type*/, int /*indent*/,
+                                int /*indent_step*/, StructDef * /*union_sd*/,
+                                std::string *_text) {
   std::string &text = *_text;
   text += NumToString(val);
 }

src/idl_parser.cpp

@@ -287,7 +287,7 @@ FieldDef &Parser::AddField(StructDef &struct_def,
     // the largest scalar
     struct_def.minalign = std::max(struct_def.minalign, alignment);
     struct_def.PadLastField(alignment);
-    field.value.offset = static_cast<uoffset_t>(struct_def.bytesize);
+    field.value.offset = static_cast<voffset_t>(struct_def.bytesize);
     struct_def.bytesize += size;
   }
   if (struct_def.fields.Add(name, &field))