[core] Don't use optional unique_ptr in function coversion code

Since unique_ptr is already nullable there is no need to wrap it in an
optional<>.

1 files changed, 7 insertions, 7 deletions

diff --git a/include/mbgl/style/expression/dsl.hpp b/include/mbgl/style/expression/dsl.hpp
index dc0f1ab90f..bcab999ab2 100644
--- a/include/mbgl/style/expression/dsl.hpp
+++ b/include/mbgl/style/expression/dsl.hpp
@@ -32,20 +32,20 @@ std::unique_ptr<Expression> literal(std::initializer_list<double> value);
 std::unique_ptr<Expression> literal(std::initializer_list<const char *> value);
 
 std::unique_ptr<Expression> assertion(type::Type, std::unique_ptr<Expression>,
-                                      optional<std::unique_ptr<Expression>> def = {});
+                                      std::unique_ptr<Expression> def = nullptr);
 std::unique_ptr<Expression> number(std::unique_ptr<Expression>,
-                                   optional<std::unique_ptr<Expression>> def = {});
+                                   std::unique_ptr<Expression> def = nullptr);
 std::unique_ptr<Expression> string(std::unique_ptr<Expression>,
-                                   optional<std::unique_ptr<Expression>> def = {});
+                                   std::unique_ptr<Expression> def = nullptr);
 std::unique_ptr<Expression> boolean(std::unique_ptr<Expression>,
-                                    optional<std::unique_ptr<Expression>> def = {});
+                                    std::unique_ptr<Expression> def = nullptr);
 
 std::unique_ptr<Expression> toColor(std::unique_ptr<Expression>,
-                                    optional<std::unique_ptr<Expression>> def = {});
+                                    std::unique_ptr<Expression> def = nullptr);
 std::unique_ptr<Expression> toString(std::unique_ptr<Expression>,
-                                     optional<std::unique_ptr<Expression>> def = {});
+                                     std::unique_ptr<Expression> def = nullptr);
 std::unique_ptr<Expression> toFormatted(std::unique_ptr<Expression>,
-                                        optional<std::unique_ptr<Expression>> def = {});
+                                        std::unique_ptr<Expression> def = nullptr);
     
 std::unique_ptr<Expression> get(const char* value);
 std::unique_ptr<Expression> get(std::unique_ptr<Expression>);