diff --git a/cpp/ql/src/jsf/4.21 Operators/AV Rule 165.ql b/cpp/ql/src/jsf/4.21 Operators/AV Rule 165.ql
index ba2e452eade8..e657be1844e7 100644
--- a/cpp/ql/src/jsf/4.21 Operators/AV Rule 165.ql	
+++ b/cpp/ql/src/jsf/4.21 Operators/AV Rule 165.ql	
@@ -11,6 +11,6 @@ import cpp
 // see MISRA Rule 5-3-2
 
 from UnaryMinusExpr ume
-where ume.getOperand().getUnderlyingType().(IntegralType).isUnsigned()
+where ume.getOperand().getExplicitlyConverted().getUnderlyingType().(IntegralType).isUnsigned()
       and not ume.getOperand() instanceof Literal
 select ume, "The unary minus operator should not be applied to an unsigned expression."
diff --git a/cpp/ql/test/query-tests/jsf/4.21 Operators/AV Rule 165/AV Rule 165.expected b/cpp/ql/test/query-tests/jsf/4.21 Operators/AV Rule 165/AV Rule 165.expected
new file mode 100644
index 000000000000..5a6e6a66eefc
--- /dev/null
+++ b/cpp/ql/test/query-tests/jsf/4.21 Operators/AV Rule 165/AV Rule 165.expected	
@@ -0,0 +1,9 @@
+| test.c:6:6:6:8 | - ... | The unary minus operator should not be applied to an unsigned expression. |
+| test.c:9:7:9:9 | - ... | The unary minus operator should not be applied to an unsigned expression. |
+| test.c:12:7:12:9 | - ... | The unary minus operator should not be applied to an unsigned expression. |
+| test.c:16:6:16:21 | - ... | The unary minus operator should not be applied to an unsigned expression. |
+| test.c:19:7:19:23 | - ... | The unary minus operator should not be applied to an unsigned expression. |
+| test.c:22:8:22:11 | - ... | The unary minus operator should not be applied to an unsigned expression. |
+| test.c:23:8:23:11 | - ... | The unary minus operator should not be applied to an unsigned expression. |
+| test.c:24:6:24:7 | - ... | The unary minus operator should not be applied to an unsigned expression. |
+| test.c:25:7:25:9 | - ... | The unary minus operator should not be applied to an unsigned expression. |
diff --git a/cpp/ql/test/query-tests/jsf/4.21 Operators/AV Rule 165/AV Rule 165.qlref b/cpp/ql/test/query-tests/jsf/4.21 Operators/AV Rule 165/AV Rule 165.qlref
new file mode 100644
index 000000000000..a6ee879dfe95
--- /dev/null
+++ b/cpp/ql/test/query-tests/jsf/4.21 Operators/AV Rule 165/AV Rule 165.qlref	
@@ -0,0 +1 @@
+jsf/4.21 Operators/AV Rule 165.ql
diff --git a/cpp/ql/test/query-tests/jsf/4.21 Operators/AV Rule 165/test.c b/cpp/ql/test/query-tests/jsf/4.21 Operators/AV Rule 165/test.c
new file mode 100644
index 000000000000..26d53e5a0c35
--- /dev/null
+++ b/cpp/ql/test/query-tests/jsf/4.21 Operators/AV Rule 165/test.c	
@@ -0,0 +1,27 @@
+
+typedef unsigned int TUI;
+
+void f(int i, unsigned int ui, signed int si, TUI tui, volatile unsigned int vui, unsigned u, unsigned short us) {
+	i = -i;
+	i = -ui; // BAD
+	i = -si;
+	ui = -i;
+	ui = -ui; // BAD
+	ui = -si;
+	si = -i;
+	si = -ui; // BAD
+	si = -si;
+
+	i = -(int)i;
+	i = -(unsigned int)i; // BAD
+	i = -(signed int)i;
+	ui = -(int)ui;
+	ui = -(unsigned int)ui; // BAD
+	ui = -(signed int)ui;
+
+	tui = -tui; // BAD
+	vui = -vui; // BAD
+	u = -u; // BAD
+	us = -us; // BAD
+	ui = -(5U); // BAD [NOT DETECTED]
+}