Fasta type inference prototype #2

pkg/front_end/test/fasta/inference/closure_body_async_upwards_local.dart.direct.expect

+library;
+import self as self;
+import "dart:async" as asy;
+import "dart:core" as core;
+
+static method main() → dynamic {
+  () → asy::Future<core::int> x = () → asy::Future<core::int> /* originally async */ {
+    final asy::Completer<core::int> :completer = asy::Completer::sync<core::int>();
+    core::int :return_value;
+    dynamic :async_op_then;
+    dynamic :async_op_error;
+    dynamic :await_jump_var = 0;
+    dynamic :await_ctx_var;
+    function :async_op([dynamic :result, dynamic :exception, dynamic :stack_trace]) → dynamic yielding 
+      try {
+        #L1:
+        {
+          :return_value = 1;
+          break #L1;
+        }
+        :completer.complete(:return_value);
+        return;
+      }
+      on dynamic catch(dynamic :exception, dynamic :stack_trace) {
+        :completer.completeError(:exception, :stack_trace);
+      }
+    :async_op_then = asy::_asyncThenWrapperHelper(:async_op);
+    :async_op_error = asy::_asyncErrorWrapperHelper(:async_op);
+    asy::Future::microtask<dynamic>(:async_op);
+    return :completer.future;
+  };
+}