Fix some strong mode issues.

lib/text/ast_to_text.dart

 // Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 library kernel.ast_to_text;
 
 import '../ast.dart';
 import '../import_table.dart';
 import '../type_propagation/type_propagation.dart';
 
 class Namer<T> {
@@ skipping 661 matching lines @@
     }
     writeWord('field');
     writeSpace();
     writeAnnotatedType(node.type, annotator?.annotateField(this, node));
     writeName(getMemberName(node));
     if (node.initializer != null) {
       writeSpaced('=');
       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} */");
     }
     endLine(';');
   }
 
   visitProcedure(Procedure node) {
     writeAnnotationList(node.annotations);
     writeIndentation();
@@ skipping 627 matching lines @@
     }
   }
 
   visitArguments(Arguments node) {
     if (node.types.isNotEmpty) {
       writeSymbol('<');
       writeList(node.types, writeType);
       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(')');
   }
 
   visitNamedExpression(NamedExpression node) {
     writeWord(node.name);
     writeComma(':');
     writeExpression(node.value);
   }
 
@@ skipping 208 matching lines @@
   }
   throw 'illegal ProcedureKind: $kind';
 }
 
 class ExpressionPrinter {
   final Printer writeer;
   final int minimumPrecedence;
 
   ExpressionPrinter(this.writeer, this.minimumPrecedence);
 }