Fixes a few different issues related to block scope.

Fixes a few different issues related to block scope.
This was breaking the spirodraw sample, on a line like:
  int gcg = gcf(wrUnits, ru)

I'll check in tests separately to the bleeding_edge branch.
TBR=jimhug

Committed: https://code.google.com/p/dart/source/detail?r=1066

[Jennifer Messerly, 2011-11-02 03:23:19]

Submitting.

FYI, the test I'm planning to add for this is below. It's passing in the VM. We
were failing pretty much all of these before.


// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

foo() => 123;

void testShadowingScope1() {
  var foo = foo();
  Expect.equals(123, foo);
}

void testShadowingScope2() {
  {
    var foo = foo() + 444;
    Expect.equals(567, foo);
  }
  Expect.equals(123, foo());
}

void testShadowingCapture1() {
  var f;
  {
    var foo = 888;
    f = () => foo;
  }
  var foo = -888;
  Expect.equals(888, f());
}

void testShadowingCapture2() {
  var f = null;
  // this one uses a reentrent block
  for (int i = 0; i < 2; i++) {
    var foo = i + 888;
    if (f == null) f = () => foo;
  } while(false);
  var foo = -888;

  // this could break if it doesn't bind the right "foo"
  Expect.equals(888, f());
}

class BlockScopeTest1 {
  void testShadowingInstanceVar() {
    if (true) {
      var foo = foo() + 444;
      Expect.equals(1221, foo);
    }
    Expect.equals(777, foo());
  }
  static void testShadowingStatic() {
    if (true) {
      var bar = bar() + 444;
      Expect.equals(1221, bar);
    }
    Expect.equals(777, bar());
  }

  foo() => 777;
  static bar() => 777;
}

main() {
  testShadowingScope1();
  testShadowingScope2();
  testShadowingCapture1();
  testShadowingCapture2();
  new BlockScopeTest1().testShadowingInstanceVar();
  BlockScopeTest1.testShadowingStatic();
}

http://codereview.chromium.org/8437043/diff/1/gen.dart
File gen.dart (left):

http://codereview.chromium.org/8437043/diff/1/gen.dart#oldcode416
gen.dart:416: // TODO(jmesserly): we also need to check that no scope in the
method
this TODO is one of the issues addressed

[jimhug, 2011-11-07 21:30:32]

The changes to frogsh look really ugly to me, and I don't understand why most of
them are needed.  Are you being overly agressive with renaming, or am I missing
something important?

[jimhug, 2011-11-07 21:40:20]

lgtm

[Jennifer Messerly, 2011-11-07 21:41:09]

On 2011/11/07 21:30:32, jimhug wrote:
> The changes to frogsh look really ugly to me, and I don't understand why most
of
> them are needed.  Are you being overly agressive with renaming, or am I
missing
> something important?

Yeah, for the parameters & fields we can generate better code. I'll take a look.