Index: clang/lib/Format/TokenAnnotator.cpp
===================================================================
--- clang/lib/Format/TokenAnnotator.cpp
+++ clang/lib/Format/TokenAnnotator.cpp
@@ -317,7 +317,7 @@
     // void (^ObjCBlock)(void);
     bool MightBeFunctionType = !Contexts[Contexts.size() - 2].IsExpression;
     bool ProbablyFunctionType =
-        CurrentToken->isOneOf(tok::star, tok::amp, tok::caret);
+        CurrentToken->isOneOf(tok::star, tok::amp, tok::ampamp, tok::caret);
     bool HasMultipleLines = false;
     bool HasMultipleParametersOnALine = false;
     bool MightBeObjCForRangeLoop =
Index: clang/unittests/Format/FormatTest.cpp
===================================================================
--- clang/unittests/Format/FormatTest.cpp
+++ clang/unittests/Format/FormatTest.cpp
@@ -9659,6 +9659,11 @@
   verifyFormat("void f() { a->operator()(*a * *a); }");
 }
 
+TEST_F(FormatTest, AmpAmpOperator) {
+  verifyFormat("int operator()(T (&&)[N]) { return 1; }");
+  verifyFormat("int operator()(T (&)[N]) { return 0; }");
+}
+
 TEST_F(FormatTest, UnderstandsAttributes) {
   verifyFormat("SomeType s __attribute__((unused)) (InitValue);");
   verifyFormat("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa __attribute__((unused))\n"
@@ -21871,7 +21876,7 @@
   verifyFormat("Foo::operator()(void &&);", Style);
   verifyFormat("Foo::operator&&(void &&);", Style);
   verifyFormat("Foo::operator&&();", Style);
-  verifyFormat("operator&&(int(&&)(), class Foo);", Style);
+  verifyFormat("operator&&(int (&&)(), class Foo);", Style);
   verifyFormat("operator const nsTArrayRight<E> &()", Style);
   verifyFormat("[[nodiscard]] operator const nsTArrayRight<E, Allocator> &()",
                Style);
@@ -21932,7 +21937,7 @@
   verifyFormat("Foo::operator()(void&&);", Style);
   verifyFormat("Foo::operator&&(void&&);", Style);
   verifyFormat("Foo::operator&&();", Style);
-  verifyFormat("operator&&(int(&&)(), class Foo);", Style);
+  verifyFormat("operator&&(int (&&)(), class Foo);", Style);
   verifyFormat("operator const nsTArrayLeft<E>&()", Style);
   verifyFormat("[[nodiscard]] operator const nsTArrayLeft<E, Allocator>&()",
                Style);
@@ -21973,7 +21978,7 @@
   verifyFormat("Foo::operator()(void &&);", Style);
   verifyFormat("Foo::operator&&(void &&);", Style);
   verifyFormat("Foo::operator&&();", Style);
-  verifyFormat("operator&&(int(&&)(), class Foo);", Style);
+  verifyFormat("operator&&(int (&&)(), class Foo);", Style);
 }
 
 TEST_F(FormatTest, OperatorPassedAsAFunctionPtr) {