1 files changed, 34 insertions, 0 deletions
diff --git a/js/src/jit-test/tests/debug/Environment-setVariable-15.js b/js/src/jit-test/tests/debug/Environment-setVariable-15.js
new file mode 100644
index 0000000000..abb8a9687c
--- /dev/null
+++ b/js/src/jit-test/tests/debug/Environment-setVariable-15.js
@@ -0,0 +1,34 @@
+// Debugger.Environment should throw trying to setVariable on a const binding.
+
+load(libdir + "asserts.js");
+
+var g = newGlobal({newCompartment: true});
+var dbg = new Debugger;
+dbg.addDebuggee(g);
+
+dbg.onEnterFrame = (frame) => {
+  frame.onStep = () => {
+    if (frame.environment.getVariable("x") === 42) {
+      assertThrowsInstanceOf(() => frame.environment.setVariable("x", 43), TypeError);
+      assertEq(frame.environment.getVariable("x"), 42);
+    }
+  };
+};
+
+const unaliased = g.parseModule(`
+  const x = 42;
+  assertEq(x, 42);
+`);
+moduleLink(unaliased);
+moduleEvaluate(unaliased);
+
+const aliased = g.parseModule(`
+  const x = 42;
+  assertEq(x, 42);
+
+  function closedOver() {
+    return x;
+  }
+`);
+moduleLink(aliased);
+moduleEvaluate(aliased);