1 files changed, 19 insertions, 0 deletions
diff --git a/js/src/tests/non262/Function/parameter-redeclaration.js b/js/src/tests/non262/Function/parameter-redeclaration.js
new file mode 100644
index 0000000000..74e55e3aa9
--- /dev/null
+++ b/js/src/tests/non262/Function/parameter-redeclaration.js
@@ -0,0 +1,19 @@
+// 'var' is allowed to redeclare parameters.
+function f1(a = 0) {
+  var a;
+}
+
+// 'let' and 'const' at body-level are not allowed to redeclare parameters.
+assertThrowsInstanceOf(() => {
+  eval(`function f2(a = 0) {
+    let a;
+  }`);
+}, SyntaxError);
+assertThrowsInstanceOf(() => {
+  eval(`function f3(a = 0) {
+    const a;
+  }`);
+}, SyntaxError);
+
+if (typeof reportCompare === "function")
+  reportCompare(true, true);