fix to run against latest analyzer

lib/src/codegen/ast_builder.dart

Index: lib/src/codegen/ast_builder.dart
diff --git a/lib/src/codegen/ast_builder.dart b/lib/src/codegen/ast_builder.dart
index 45c3c12eb8ac09c9b3fef4652c184033949c1006..f2d448e7a225ce783301d5470e76ebea4d78d6d0 100644
--- a/lib/src/codegen/ast_builder.dart
+++ b/lib/src/codegen/ast_builder.dart
@@ -525,6 +525,11 @@ class RawAstBuilder {
     return new ExpressionFunctionBody(null, null, body, semi);
   }
 
+  static ExpressionStatement expressionStatement(Expression expression) {
+    Token semi = new Token(TokenType.SEMICOLON, 0);
+    return new ExpressionStatement(expression, semi);
+  }
+
   static FunctionDeclaration functionDeclaration(
       TypeName rt, SimpleIdentifier f, FunctionExpression fexp) {
     return new FunctionDeclaration(null, null, null, rt, null, f, fexp);