Change the way hard splits are handled.

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 289 matching lines @@
     builder.startBlockArgumentNesting();
 
     // If the cascade sections have consistent names they can be broken
     // normally otherwise they always get their own line.
     if (_allowInlineCascade(node.cascadeSections)) {
       builder.startRule();
       zeroSplit();
       visitNodes(node.cascadeSections, between: zeroSplit);
       builder.endRule();
     } else {
-      builder.startRule(new HardSplitRule());
+      builder.startRule(new Rule.hard());
       zeroSplit();
       visitNodes(node.cascadeSections, between: zeroSplit);
       builder.endRule();
     }
 
     builder.endBlockArgumentNesting();
     builder.unnest();
 
     if (node.target is MethodInvocation) builder.unnest();
   }
@@ skipping 1399 matching lines @@
     // level when they are actually unrelated. Splitting at "=>" forces:
     //
     //     someFunction(parameter,
     //             parameter) =>
     //         function(
     //             argument);
     if (body is ExpressionFunctionBody) {
       builder.nestExpression();
 
       // This rule is ended by visitExpressionFunctionBody().
-      builder.startLazyRule(new SimpleRule(Cost.arrow));
+      builder.startLazyRule(new Rule(Cost.arrow));
     }
 
     if (parameters != null) {
       builder.nestExpression();
       visit(parameters);
       builder.unnest();
 
       if (afterParameters != null) afterParameters();
     }
 
@@ skipping 80 matching lines @@
     }
 
     // Add this collection to the stack.
     _collectionSplits.add(false);
 
     _startLiteralBody(leftBracket);
 
     // Always use a hard rule to split the elements. The parent chunk of
     // the collection will handle the unsplit case, so this only comes
     // into play when the collection is split.
-    var rule = new HardSplitRule();
+    var rule = new Rule.hard();
     builder.startRule(rule);
 
     // If a collection contains a line comment, we assume it's a big complex
     // blob of data with some documented structure. In that case, the user
     // probably broke the elements into lines deliberately, so preserve those.
     var preserveNewlines = _containsLineComments(elements, rightBracket);
 
     for (var element in elements) {
       if (element != elements.first) {
         if (preserveNewlines) {
@@ skipping 269 matching lines @@
   /// Returns the chunk the split was applied to.
   Chunk split() => builder.split(space: true);
 
   /// Writes a zero-space split owned by the current rule.
   ///
   /// Returns the chunk the split was applied to.
   Chunk zeroSplit() => builder.split();
 
   /// Writes a single space split with its own rule.
   void soloSplit([int cost]) {
-    builder.startRule(new SimpleRule(cost));
+    builder.startRule(new Rule(cost));
     split();
     builder.endRule();
   }
 
   /// Writes a zero-space split with its own rule.
   void soloZeroSplit() {
     builder.startRule();
     builder.split();
     builder.endRule();
   }
@@ skipping 200 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;
 }