[core] address nits

src/mbgl/programs/program_parameters.cpp

@@ -11,7 +11,7 @@ ProgramParameters::ProgramParameters(const float pixelRatio,
           result.reserve(32);
           result += "#define DEVICE_PIXEL_RATIO ";
           result += util::toString(pixelRatio, true);
-          result += "\n";
+          result += '\n';
           if (overdraw) {
               result += "#define OVERDRAW_INSPECTOR\n";
           }
@@ -33,7 +33,7 @@ optional<std::string> ProgramParameters::cachePath(const char* name) const {
         result += *cacheDir;
         result += "/com.mapbox.gl.shader.";
         result += name;
-        result += ".";
+        result += '.';
         result += util::toHex(std::hash<std::string>()(defines));
         result += ".pbf";
         return result;

src/mbgl/shaders/shaders.cpp

@@ -18,7 +18,7 @@ std::string vertexSource(const ProgramParameters& parameters, const char* vertex
 
 std::string programIdentifier(const std::string& vertexSource, const std::string& fragmentSource) {
     std::string result;
-    result.reserve(sizeof(size_t) * 2 * 2 + 2 + 1);
+    result.reserve((sizeof(size_t) * 2) * 2 + 2); // 2 size_t hex values + "v2"
     result += util::toHex(std::hash<std::string>()(vertexSource));
     result += util::toHex(std::hash<std::string>()(fragmentSource));
     result += "v2";

src/mbgl/util/hash.hpp

@@ -8,12 +8,12 @@ namespace mbgl {
 namespace util {
 
 template <class T>
-inline void hash_combine(std::size_t& seed, const T& v) {
+void hash_combine(std::size_t& seed, const T& v) {
     seed ^= std::hash<T>()(v) + 0x9e3779b9 + (seed << 6) + (seed >> 2);
 }
 
 template <class... Args>
-inline std::size_t hash(Args&&... args) {
+std::size_t hash(Args&&... args) {
     std::size_t seed = 0;
     ignore({ (hash_combine(seed, args), 0)... });
     return seed;