[build] Clang-3.8: Explicit mbgl::style::expression::Result default ctorupstream/qt-ci-buildfix

1 files changed, 4 insertions, 0 deletions

diff --git a/include/mbgl/style/expression/expression.hpp b/include/mbgl/style/expression/expression.hpp
index 1954d8b090..dc9fdb3d7a 100644
--- a/include/mbgl/style/expression/expression.hpp
+++ b/include/mbgl/style/expression/expression.hpp
@@ -44,6 +44,8 @@ public:
     using variant<EvaluationError, T>::variant;
     using Value = T;
     
+    constexpr Result() = default;
+
     explicit operator bool () const {
         return this->template is<T>();
     }
@@ -80,6 +82,8 @@ class EvaluationResult : public Result<Value> {
 public:
     using Result::Result; // NOLINT
     
+    constexpr EvaluationResult() = default;
+
     EvaluationResult(const std::array<double, 4>& arr) :
         Result(toExpressionValue(arr))
     {}