simplify function coercions -- DDC can generate function types in place

test/codegen/expect/collection/src/priority_queue.js

 dart_library.library('collection/src/priority_queue', null, /* Imports */[
   'dart/_runtime',
   'dart/core',
   'dart/collection'
 ], /* Lazy imports */[
 ], function(exports, dart, core, collection) {
   'use strict';
   let dartx = dart.dartx;
   const PriorityQueue$ = dart.generic(function(E) {
     class PriorityQueue extends core.Object {
@@ skipping 82 matching lines @@
         let last = this[_removeLast]();
         if (dart.notNull(this[_length]) > 0) {
           this[_bubbleDown](last, 0);
         }
         return result;
       }
       toList() {
         let list = core.List$(E).new();
         list[dartx.length] = this[_length];
         list[dartx.setRange](0, this[_length], this[_queue]);
-        list[dartx.sort](dart.as(this.comparison, __CastType0));
+        list[dartx.sort](dart.as(this.comparison, dart.functionType(core.int, [E, E])));

[Jennifer Messerly, 2016/03/12 00:36:56]

looks like a bug fix. We weren't instantiating the typedef with E.

         return list;
       }
       toSet() {
         let set = new (collection.SplayTreeSet$(E))(dart.as(this.comparison, dart.functionType(core.int, [E, E])));
         for (let i = 0; i < dart.notNull(this[_length]); i++) {
           set.add(this[_queue][dartx.get](i));
         }
         return set;
       }
       toString() {
@@ skipping 114 matching lines @@
         [_removeLast]: [E, []],
         [_bubbleUp]: [dart.void, [E, core.int]],
         [_bubbleDown]: [dart.void, [E, core.int]],
         [_grow]: [dart.void, []]
       })
     });
     HeapPriorityQueue._INITIAL_CAPACITY = 7;
     return HeapPriorityQueue;
   });
   let HeapPriorityQueue = HeapPriorityQueue$();
-  const __CastType0$ = dart.generic(function(E) {
-    const __CastType0 = dart.typedef('__CastType0', () => dart.functionType(core.int, [E, E]));
-    return __CastType0;
-  });
-  let __CastType0 = __CastType0$();
   // Exports:
   exports.PriorityQueue$ = PriorityQueue$;
   exports.PriorityQueue = PriorityQueue;
   exports.HeapPriorityQueue$ = HeapPriorityQueue$;
   exports.HeapPriorityQueue = HeapPriorityQueue;
 });