Add m-esr52 at 52.6.0

1 files changed, 45 insertions, 0 deletions

diff --git a/js/src/tests/ecma_6/Class/superPropSkips.js b/js/src/tests/ecma_6/Class/superPropSkips.js
new file mode 100644
index 000000000..c9587c72f
--- /dev/null
+++ b/js/src/tests/ecma_6/Class/superPropSkips.js
@@ -0,0 +1,45 @@
+// Ensure that super lookups and sets skip over properties on the |this| object.
+// That is, super lookups start with the superclass, not the current class.
+
+// The whole point: an empty superclass
+class base {
+    constructor() { }
+}
+
+class derived extends base {
+    constructor() { super(); this.prop = "flamingo"; }
+
+    toString() { throw "No!"; }
+
+    testSkipGet() {
+        assertEq(super.prop, undefined);
+    }
+
+    testSkipDerivedOverrides() {
+        assertEq(super["toString"](), Object.prototype.toString.call(this));
+    }
+
+    testSkipSet() {
+        // since there's no prop on the chain, we should set the data property
+        // on the receiver, |this|
+        super.prop = "rat";
+        assertEq(this.prop, "rat");
+
+        // Since the receiver is the instance, we can overwrite inherited
+        // properties of the instance, even non-writable ones, as they could be
+        // skipped in the super lookup.
+        assertEq(this.nonWritableProp, "pony");
+        super.nonWritableProp = "bear";
+        assertEq(this.nonWritableProp, "bear");
+    }
+}
+
+Object.defineProperty(derived.prototype, "nonWritableProp", { writable: false, value: "pony" });
+
+let instance = new derived();
+instance.testSkipGet();
+instance.testSkipDerivedOverrides();
+instance.testSkipSet();
+
+if (typeof reportCompare === 'function')
+    reportCompare(0,0,"OK");