Fix implicit conversions in UIntView
diff --git a/runtime/cpp/emboss_prelude.h b/runtime/cpp/emboss_prelude.h
index a47b8b5..0fbaff4 100644
--- a/runtime/cpp/emboss_prelude.h
+++ b/runtime/cpp/emboss_prelude.h
@@ -145,7 +145,7 @@
   ~UIntView() = default;
 
   ValueType Read() const {
-    ValueType result = buffer_.ReadUInt();
+    ValueType result = static_cast<ValueType>(buffer_.ReadUInt());
     EMBOSS_CHECK(Parameters::ValueIsOk(result));
     return result;
   }
@@ -197,7 +197,7 @@
   bool TryToWrite(IntT value) const {
     if (!CouldWriteValue(value)) return false;
     if (!IsComplete()) return false;
-    buffer_.WriteUInt(value);
+    buffer_.WriteUInt(static_cast<ValueType>(value));
     return true;
   }