diff --git a/gtsam/sam/BearingRangeFactor.h b/gtsam/sam/BearingRangeFactor.h
index da352f2e98..9874760c46 100644
--- a/gtsam/sam/BearingRangeFactor.h
+++ b/gtsam/sam/BearingRangeFactor.h
@@ -79,9 +79,8 @@ class BearingRangeFactor
   {
     std::vector<Matrix> Hs(2);
     const auto &keys = Factor::keys();
-    const Vector error = unwhitenedError(
-      {{keys[0], genericValue(a1)}, {keys[1], genericValue(a2)}}, 
-      Hs);
+    const Vector error = this->unwhitenedError(
+        {{keys[0], genericValue(a1)}, {keys[1], genericValue(a2)}}, Hs);
     if (H1) *H1 = Hs[0];
     if (H2) *H2 = Hs[1];
     return error;