1 files changed, 50 insertions, 0 deletions
diff --git a/js/src/jit-test/tests/debug/error-cause-copied.js b/js/src/jit-test/tests/debug/error-cause-copied.js
new file mode 100644
index 0000000000..b36c8de164
--- /dev/null
+++ b/js/src/jit-test/tests/debug/error-cause-copied.js
@@ -0,0 +1,50 @@
+// Test that the ErrorCopier copies the optional "cause" property of error objects.
+
+let g = newGlobal({newCompartment: true});
+let dbg = new Debugger(g);
+let hits = 0;
+dbg.onDebuggerStatement = function (frame) {
+  hits++;
+
+  // Use |getVariable()| so we can easily throw our custom error from the
+  // with-statement scope.
+  let caught;
+  try {
+    frame.environment.getVariable("x");
+  } catch (e) {
+    caught = e;
+  }
+
+  // The ErrorCopier copied error, so |caught| isn't equal to |g.error|.
+  assertEq(caught !== g.error, true);
+
+  // Ensure the "cause" property is correctly copied.
+  assertEq(caught.cause, g.cause);
+};
+
+// The error must be same-compartment with the debugger compartment for the
+// ErrorCopier.
+g.eval(`
+  var cause = new Object();
+  var error = new Error("", {cause});
+`);
+
+// Scope must be outside of debugger compartment to avoid triggering a
+// DebuggeeWouldRun error.
+let scope = {
+  get x() {
+    throw g.error;
+  }
+};
+
+g.eval(`
+  function f(scope) {
+    with (scope) {
+      debugger;
+    }
+  }
+`);
+
+g.f(scope);
+
+assertEq(hits, 1);