diff --git a/lib/src/file.dart b/lib/src/file.dart
index 97a2f65..717a4d4 100644
--- a/lib/src/file.dart
+++ b/lib/src/file.dart
@@ -214,7 +214,7 @@
   ///
   /// If [end] isn't passed, it defaults to the end of the file.
   String getText(int start, [int end]) =>
-      String.fromCharCodes(_decodedChars, start, end);
+      String.fromCharCodes(_decodedChars.sublist(start, end));
 }
 
 /// A [SourceLocation] within a [SourceFile].