Code formatter transform for empty constructor bodys (a la Style guide).

pkg/analyzer_experimental/lib/src/services/formatter_impl.dart

 // Copyright (c) 2013, 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 formatter_impl;
 
 import 'dart:math';
 
 import 'package:analyzer_experimental/analyzer.dart';
 import 'package:analyzer_experimental/src/generated/parser.dart';
@@ skipping 247 matching lines @@
         return true;
       }
     }
     // '>' '>' => '>>'
     if (isGT(token1) && isGT(token1.next)) {
       if (isGT_GT(token2)) {
         token1 = token1.next;
         return true;
       }
     }
+    // Cons(){} => Cons();
+    if (isOPEN_CURLY_BRACKET(token1) && isCLOSE_CURLY_BRACKET(token1.next)) {
+      if (isSEMICOLON(token2)) {
+        token1 = token1.next;
+        advance();
+        return true;
+      }
+    }
     // Advance past synthetic { } tokens
     if (isOPEN_CURLY_BRACKET(token2) || isCLOSE_CURLY_BRACKET(token2)) {
       token2 = token2.next;
       return checkTokens();
     }
 
     return false;
   }
 
 }
@@ skipping 26 matching lines @@
     tokenIs(token, TokenType.CLOSE_CURLY_BRACKET);
 
 /// Test if this token is a OPEN_SQUARE_BRACKET token.
 bool isOPEN_SQ_BRACKET(Token token) =>
     tokenIs(token, TokenType.OPEN_SQUARE_BRACKET);
 
 /// Test if this token is a CLOSE_SQUARE_BRACKET token.
 bool isCLOSE_SQUARE_BRACKET(Token token) =>
     tokenIs(token, TokenType.CLOSE_SQUARE_BRACKET);
 
+/// Test if this token is a SEMICOLON token.
+bool isSEMICOLON(Token token) =>
+    tokenIs(token, TokenType.SEMICOLON);
+
 
 /// An AST visitor that drives formatting heuristics.
 class SourceVisitor implements ASTVisitor {
 
   static final OPEN_CURLY = syntheticToken(TokenType.OPEN_CURLY_BRACKET, '{');
   static final CLOSE_CURLY = syntheticToken(TokenType.CLOSE_CURLY_BRACKET, '}');
+  static final SEMI_COLON = syntheticToken(TokenType.SEMICOLON, ';');
 
   static const SYNTH_OFFSET = -13;
 
   static StringToken syntheticToken(TokenType type, String value) =>
       new StringToken(type, value, SYNTH_OFFSET);
 
   static bool isSynthetic(Token token) => token.offset == SYNTH_OFFSET;
 
   /// The writer to which the source is to be written.
   final SourceWriter writer;
@@ skipping 222 matching lines @@
 
     // Check for redirects or initializer lists
     if (node.separator != null) {
       if (node.redirectedConstructor != null) {
         visitConstructorRedirects(node);
       } else {
         visitConstructorInitializers(node);
       }
     }
 
-    visitPrefixedBody(space, node.body);
+    var body = node.body;
+    if (codeTransforms && body is BlockFunctionBody) {
+      if (body.block.statements.isEmpty) {
+        token(SEMI_COLON);
+        newlines();
+        return;
+      }
+    }
+
+    visitPrefixedBody(space, body);
   }
 
   visitConstructorInitializers(ConstructorDeclaration node) {
     newlines();
     indent(2);
     token(node.separator /* : */);
     space();
     for (var i = 0; i < node.initializers.length; i++) {
       if (i > 0) {
         comma();
@@ skipping 927 matching lines @@
     var lastLine =
         lineInfo.getLocation(lastOffset).lineNumber;
     var currentLine =
         lineInfo.getLocation(currentOffset).lineNumber;
     return currentLine - lastLine;
   }
 
   String toString() => writer.toString();
 
 }