diff --git a/libs/gui/FrameTimestamps.cpp b/libs/gui/FrameTimestamps.cpp
index 85ae433..8a14359 100644
--- a/libs/gui/FrameTimestamps.cpp
+++ b/libs/gui/FrameTimestamps.cpp
@@ -158,7 +158,7 @@
 namespace {
 
 struct FrameNumberEqual {
-    FrameNumberEqual(uint64_t frameNumber) : mFrameNumber(frameNumber) {}
+    explicit FrameNumberEqual(uint64_t frameNumber) : mFrameNumber(frameNumber) {}
     bool operator()(const FrameEvents& frame) {
         return frame.valid && mFrameNumber == frame.frameNumber;
     }