Split before "deferred" if present.

lib/src/source_visitor.dart

 // Copyright (c) 2014, 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 dart_style.src.source_visitor;
 
 import 'package:analyzer/analyzer.dart';
 import 'package:analyzer/src/generated/scanner.dart';
 import 'package:analyzer/src/generated/source.dart';
 
@@ skipping 950 matching lines @@
     _visitCombinator(node.implementsKeyword, node.interfaces);
   }
 
   visitImportDirective(ImportDirective node) {
     visitDeclarationMetadata(node.metadata);
 
     _simpleStatement(node, () {
       token(node.keyword);
       space();
       visit(node.uri);
-      token(node.deferredKeyword, before: space);
-      token(node.asKeyword, before: soloSplit, after: space);
-      visit(node.prefix);
+
+      if (node.asKeyword != null) {
+        soloSplit();
+        token(node.deferredKeyword, after: space);
+        token(node.asKeyword);
+        space();
+        visit(node.prefix);
+      }
 
       builder.startRule(new CombinatorRule());
       visitNodes(node.combinators);
       builder.endRule();
     });
   }
 
   visitIndexExpression(IndexExpression node) {
     builder.nestExpression();
 
@@ skipping 1139 matching lines @@
   /// Gets the 1-based line number that the beginning of [token] lies on.
   int _startLine(Token token) => _lineInfo.getLocation(token.offset).lineNumber;
 
   /// Gets the 1-based line number that the end of [token] lies on.
   int _endLine(Token token) => _lineInfo.getLocation(token.end).lineNumber;
 
   /// Gets the 1-based column number that the beginning of [token] lies on.
   int _startColumn(Token token) =>
       _lineInfo.getLocation(token.offset).columnNumber;
 }