Fix crash generating facades for loasd. Fix bug in how we handle TypePredicates. Add test for TypeP…

test/function_test.ts

Index: test/function_test.ts
diff --git a/test/function_test.ts b/test/function_test.ts
index 01c869603f9859dc9a8ae5ac4ae0d5b33e7ef913..9208fe7f39145e932d658ed1fccdd95f7f517b47 100644
--- a/test/function_test.ts
+++ b/test/function_test.ts
@@ -23,6 +23,14 @@ external x(p1, [num a, num b, p2]);`);
 external x();`);
   });
 
+  it('supports type predicates', () => {
+    expectTranslate('function isArrayBuffer(value?: any): value is ArrayBuffer;')
+        .to.equal(`import "dart:typed_data" show ByteBuffer;
+
+@JS()
+external bool /*value is ByteBuffer*/ isArrayBuffer([dynamic value]);`);
+  });
+
   it('polyfill var args', () => {
     expectTranslate('function x(...a: number[]) { return 42; }').to.equal(`@JS()
 external x([num a1, num a2, num a3, num a4, num a5]);`);