diff --git a/src/simulator/high-precision-cairo.h b/src/simulator/high-precision-cairo.h
index c16e2c0bf..1f5abd88e 100644
--- a/src/simulator/high-precision-cairo.h
+++ b/src/simulator/high-precision-cairo.h
@@ -45,7 +45,7 @@ class HighPrecision
 {
 public:
   inline HighPrecision ();
-  inline HighPrecision (int64_t value, bool dummy);
+  explicit inline HighPrecision (int64_t value, bool dummy);
   explicit inline HighPrecision (double value);
 
   inline int64_t GetInteger (void) const;