Ship ES2015 sloppy-mode function hoisting, let, class

test/mjsunit/regress/regress-crbug-323936.js

Index: test/mjsunit/regress/regress-crbug-323936.js
diff --git a/test/mjsunit/regress/regress-crbug-323936.js b/test/mjsunit/regress/regress-crbug-323936.js
index c1d0f7d9311f732d62ac6f769153a04254c83bc5..6e75729c1819e3fec4a4609535c81ac740317993 100644
--- a/test/mjsunit/regress/regress-crbug-323936.js
+++ b/test/mjsunit/regress/regress-crbug-323936.js
@@ -17,7 +17,7 @@ function listener(event, exec_state, event_data, data) {
       exec_state.frame(0).evaluate("write_0('foo')");
       exec_state.frame(0).evaluate("write_1('modified')");
     } else {
-      assertEquals("foo", exec_state.frame(0).evaluate("e").value());
+      assertEquals("argument", exec_state.frame(0).evaluate("e").value());
       exec_state.frame(0).evaluate("write_2('bar')");
     }
     step++;
@@ -33,12 +33,14 @@ function f(e, x) {
   try {
     throw "error";
   } catch(e) {
-    // 'e' and 'x' bind to the argument due to hoisting
+    // In ES2015 hoisting semantics, 'x' binds to the argument
+    // and 'e' binds to the exception.
     function write_0(v) { e = v }
     function write_1(v) { x = v }
     debugger;
-    assertEquals("error", e);
+    assertEquals("foo", e);  // overwritten by the debugger
   }
+  assertEquals("argument", e);  // debugger did not overwrite

[adamk, 2016/01/05 19:19:05]

Do you understand if this test still testing the thing it was built for? It's
hard for me to tell..

[Dan Ehrenberg, 2016/01/06 00:27:57]

The original bug was about the debugger being able to observe the correct values
within the nested, overlapping scope and interact with that code with correct,
consistent semantics. I think the test changes maintain that, with the current
semantics, and that this is more useful than turning on an obsolete flag.

   function write_2(v) { e = v }
   debugger;
   assertEquals("bar", e);