diff --git a/rhino/src/test/java/org/mozilla/javascript/SuperTest.java b/rhino/src/test/java/org/mozilla/javascript/SuperTest.java
index 6dd22df461..ea3d8e0f69 100644
--- a/rhino/src/test/java/org/mozilla/javascript/SuperTest.java
+++ b/rhino/src/test/java/org/mozilla/javascript/SuperTest.java
@@ -115,6 +115,36 @@ void byIndex() {
             Utils.assertWithAllOptimizationLevelsES6(1, script);
         }
 
+        @Test
+        void byIndexNegative() {
+            String script =
+                    ""
+                            + "var a = { [-1]: 1 };"
+                            + "var b = {\n"
+                            + "  f() {\n"
+                            + "    return super[-1];\n"
+                            + "  }\n"
+                            + "};\n"
+                            + "Object.setPrototypeOf(b, a);\n"
+                            + "b.f();";
+            Utils.assertWithAllOptimizationLevelsES6(1, script);
+        }
+
+        @Test
+        void byIndexFractional() {
+            String script =
+                    ""
+                            + "var a = { [0.1]: 1 };"
+                            + "var b = {\n"
+                            + "  f() {\n"
+                            + "    return super[0.1];\n"
+                            + "  }\n"
+                            + "};\n"
+                            + "Object.setPrototypeOf(b, a);\n"
+                            + "b.f();";
+            Utils.assertWithAllOptimizationLevelsES6(1, script);
+        }
+
         @Test
         void byElementString() {
             String script =
@@ -399,6 +429,35 @@ void propertyNotFoundInSuper() {
             Utils.assertWithAllOptimizationLevelsES6(Undefined.instance, script);
         }
 
+        @Test
+        void propertyNotFoundInSuperByElement() {
+            // super is implicitly Object.prototype here
+            String script =
+                    ""
+                            + "const xAsString = 'x';\n"
+                            + "const o = {\n"
+                            + "  f() {\n"
+                            + "    return super[xAsString];\n"
+                            + "  }"
+                            + "};\n"
+                            + "o.f();";
+            Utils.assertWithAllOptimizationLevelsES6(Undefined.instance, script);
+        }
+
+        @Test
+        void propertyNotFoundInSuperByIndex() {
+            // super is implicitly Object.prototype here
+            String script =
+                    ""
+                            + "const o = {\n"
+                            + "  f() {\n"
+                            + "    return super[2];\n"
+                            + "  }"
+                            + "};\n"
+                            + "o.f();";
+            Utils.assertWithAllOptimizationLevelsES6(Undefined.instance, script);
+        }
+
         @Test
         void prototypeIsNull() {
             String script =
@@ -463,6 +522,36 @@ void byIndex() {
             Utils.assertWithAllOptimizationLevelsES6("new:proto", script);
         }
 
+        @Test
+        void byIndexNegative() {
+            String script =
+                    ""
+                            + "var proto = { [-1]: 'proto' };"
+                            + "var object = {\n"
+                            + "  [-1]: 'obj',\n"
+                            + "  f() { super[-1] = 'new'; }\n"
+                            + "};\n"
+                            + "Object.setPrototypeOf(object, proto);\n"
+                            + "object.f();"
+                            + "object[-1] + ':' + proto[-1]";
+            Utils.assertWithAllOptimizationLevelsES6("new:proto", script);
+        }
+
+        @Test
+        void byIndexFractional() {
+            String script =
+                    ""
+                            + "var proto = { [0.1]: 'proto' };"
+                            + "var object = {\n"
+                            + "  [0.1]: 'obj',\n"
+                            + "  f() { super[0.1] = 'new'; }\n"
+                            + "};\n"
+                            + "Object.setPrototypeOf(object, proto);\n"
+                            + "object.f();"
+                            + "object[0.1] + ':' + proto[0.1]";
+            Utils.assertWithAllOptimizationLevelsES6("new:proto", script);
+        }
+
         @Test
         void byElementString() {
             String script =