Fix some strong mode issues.

lib/text/ast_to_text.dart

Index: lib/text/ast_to_text.dart
diff --git a/lib/text/ast_to_text.dart b/lib/text/ast_to_text.dart
index 46850b765d50f4f7460b0f44a7103c7dae5e694f..84255dbde1639ce848ebb578d9b63d5d2a1fa9fc 100644
--- a/lib/text/ast_to_text.dart
+++ b/lib/text/ast_to_text.dart
@@ -679,7 +679,7 @@ class Printer extends Visitor<Null> {
       writeExpression(node.initializer);
     }
     if ((node.enclosingClass == null &&
-        node.enclosingLibrary.fileUri != node.fileUri) ||
+            node.enclosingLibrary.fileUri != node.fileUri) ||
         (node.enclosingClass != null &&
             node.enclosingClass.fileUri != node.fileUri)) {
       writeWord("/* from ${node.fileUri} */");
@@ -1327,7 +1327,8 @@ class Printer extends Visitor<Null> {
       writeSymbol('>');
     }
     writeSymbol('(');
-    var allArgs = [node.positional, node.named].expand((x) => x);
+    var allArgs =
+        <List<TreeNode>>[node.positional, node.named].expand((x) => x);
     writeList(allArgs, writeNode);
     writeSymbol(')');
   }