AST nodes for function-typed parameters.

dart/frog/leg/tree/nodes.dart

Index: dart/frog/leg/tree/nodes.dart
diff --git a/dart/frog/leg/tree/nodes.dart b/dart/frog/leg/tree/nodes.dart
index 1c86371f6e09847e9216988239b816f2e9a48458..3d6cb3464ca102b0a9533d94e25b9facaaf5790b 100644
--- a/dart/frog/leg/tree/nodes.dart
+++ b/dart/frog/leg/tree/nodes.dart
@@ -83,7 +83,8 @@ class Node implements Hashable {
     Unparser unparser = new Unparser();
     try {
       return unparser.unparse(this);
-    } catch (var e) {
+    } catch (var e, var trace) {
+      print(trace);
       return '<<unparse error: ${getObjectDescription()}: ${unparser.sb}>>';
     }
   }
@@ -523,7 +524,9 @@ class FunctionExpression extends Expression {
     return firstBeginToken(returnType, name);
   }
 
-  Token getEndToken() => body.getEndToken();
+  Token getEndToken() {
+    return (body === null) ? parameters.getEndToken() : body.getEndToken();
+  }
 }
 
 typedef void DecodeErrorHandler(Token token, var error);