1 files changed, 52 insertions, 0 deletions
diff --git a/js/src/jit-test/tests/basic/spread-call-length.js b/js/src/jit-test/tests/basic/spread-call-length.js
new file mode 100644
index 0000000000..1d84d046d8
--- /dev/null
+++ b/js/src/jit-test/tests/basic/spread-call-length.js
@@ -0,0 +1,52 @@
+load(libdir + 'iteration.js');
+
+let makeCall    = farg => Function("f", "arg", "return f(" + farg + ");");
+let makeFunCall = farg => Function("f", "arg", "return f.call(null, " + farg + ");");
+let makeNew     = farg => Function("f", "arg", "return new f(" + farg + ").length;");
+
+function checkLength(f, makeFn) {
+  assertEq(makeFn("...[1, 2, 3]")(f), 3);
+  assertEq(makeFn("1, ...[2], 3")(f), 3);
+  assertEq(makeFn("1, ...[2], ...[3]")(f), 3);
+  assertEq(makeFn("1, ...[2, 3]")(f), 3);
+  assertEq(makeFn("1, ...[], 2, 3")(f), 3);
+
+  assertEq(makeFn("...[1]")(f), 1);
+  assertEq(makeFn("...[1, 2]")(f), 2);
+  assertEq(makeFn("...[1, 2, 3, 4]")(f), 4);
+  assertEq(makeFn("1, ...[2, 3, 4], 5")(f), 5);
+
+  assertEq(makeFn("...[undefined]")(f), 1);
+
+  // other iterable objects
+  assertEq(makeFn("...arg")(f, new Int32Array([1, 2, 3])), 3);
+  assertEq(makeFn("...arg")(f, "abc"), 3);
+  assertEq(makeFn("...arg")(f, [1, 2, 3][Symbol.iterator]()), 3);
+  assertEq(makeFn("...arg")(f, new Set([1, 2, 3])), 3);
+  assertEq(makeFn("...arg")(f, new Map([["a", "A"], ["b", "B"], ["c", "C"]])), 3);
+  let itr = {};
+  itr[Symbol.iterator] = function() {
+      return {
+          i: 1,
+          next: function() {
+              if (this.i < 4)
+                  return { value: this.i++, done: false };
+              else
+                  return { value: undefined, done: true };
+          }
+      };
+  }
+  assertEq(makeFn("...arg")(f, itr), 3);
+  function* gen() {
+      for (let i = 1; i < 4; i ++)
+          yield i;
+  }
+  assertEq(makeFn("...arg")(f, gen()), 3);
+}
+
+checkLength(function(x) { return arguments.length; }, makeCall);
+checkLength(function(x) { return arguments.length; }, makeFunCall);
+function lengthClass(x) {
+  this.length = arguments.length;
+}
+checkLength(lengthClass, makeNew);