diff --git a/clang/lib/Format/TokenAnnotator.cpp b/clang/lib/Format/TokenAnnotator.cpp
--- a/clang/lib/Format/TokenAnnotator.cpp
+++ b/clang/lib/Format/TokenAnnotator.cpp
@@ -229,7 +229,19 @@
     }
 
     if (Left->is(TT_OverloadedOperatorLParen)) {
-      Contexts.back().IsExpression = false;
+      // Find the previous kw_operator token
+      FormatToken *Prev = Left;
+      while (!Prev->is(tok::kw_operator)) {
+        Prev = Prev->Previous;
+        assert(Prev);
+      }
+
+      // If faced with "a.operator*(argument)" or "a->operator*(argument)"
+      // i.e. the operator is called as a member function
+      // then the argument must be an expression
+      bool OperatorCalledAsMemberFunction =
+          Prev->Previous && Prev->Previous->isOneOf(tok::period, tok::arrow);
+      Contexts.back().IsExpression = OperatorCalledAsMemberFunction;
     } else if (Style.Language == FormatStyle::LK_JavaScript &&
                (Line.startsWith(Keywords.kw_type, tok::identifier) ||
                 Line.startsWith(tok::kw_export, Keywords.kw_type,
diff --git a/clang/unittests/Format/FormatTest.cpp b/clang/unittests/Format/FormatTest.cpp
--- a/clang/unittests/Format/FormatTest.cpp
+++ b/clang/unittests/Format/FormatTest.cpp
@@ -8761,6 +8761,11 @@
                "operator()() && {}");
   verifyGoogleFormat("template <typename T>\n"
                      "auto x() & -> int {}");
+
+  // Should be binary operators when used as an argument expression (overloaded
+  // operator invoked as a member function)
+  verifyFormat("void f() { a.operator()(a * a); }");
+  verifyFormat("void f() { a->operator()(a & a); }");
 }
 
 TEST_F(FormatTest, UnderstandsAttributes) {