Make let variables fresh in each iteration of a for-loop.

test/mjsunit/harmony/block-for.js

Index: test/mjsunit/harmony/block-for.js
diff --git a/test/mjsunit/harmony/block-for.js b/test/mjsunit/harmony/block-for.js
index e84f0d2fee852ce05c0e797d59b98b8dbd0c3260..2c112467bb708a14f265feb68abd8a0c38f836dd 100644
--- a/test/mjsunit/harmony/block-for.js
+++ b/test/mjsunit/harmony/block-for.js
@@ -102,7 +102,7 @@ assertThrows("function foo() { 'use strict'; for (let x, y = 4 in {}) { } }", Sy
 assertThrows("function foo() { 'use strict'; for (let x = 3, y = 4 in {}) { } }", SyntaxError);
 
 
-// In a normal for statement the iteration variable is not
+// In a normal for statement the iteration variable is
 // freshly allocated for each iteration.
 function closures1() {
   let a = [];
@@ -110,7 +110,7 @@ function closures1() {
     a.push(function () { return i; });
   }
   for (let j = 0; j < 5; ++j) {
-    assertEquals(5, a[j]());
+    assertEquals(j, a[j]());
   }
 }
 closures1();
@@ -123,13 +123,45 @@ function closures2() {
     b.push(function () { return j; });
   }
   for (let k = 0; k < 5; ++k) {
-    assertEquals(5, a[k]());
-    assertEquals(15, b[k]());
+    assertEquals(k, a[k]());
+    assertEquals(k + 10, b[k]());
   }
 }
 closures2();
 
 
+function closure_in_for_init() {
+  let a = [];
+  for (let i = 0, f = function() { return i }; i < 5; ++i) {
+    a.push(f);
+  }
+  for (let k = 0; k < 5; ++k) {
+    assertEquals(0, a[k]());
+  }
+}
+closure_in_for_init();
+
+
+function closure_in_for_cond() {
+  let a = [];
+  for (let i = 0; a.push(function () { return i; }), i < 5; ++i) { }
+  for (let k = 0; k < 5; ++k) {
+    assertEquals(k, a[k]());
+  }
+}
+closure_in_for_next();
+
+
+function closure_in_for_next() {
+  let a = [];
+  for (let i = 0; i < 5; a.push(function () { return i; }), ++i) { }
+  for (let k = 0; k < 5; ++k) {
+    assertEquals(k + 1, a[k]());
+  }
+}
+closure_in_for_next();
+
+
 // In a for-in statement the iteration variable is fresh
 // for earch iteration.
 function closures3(x) {