Dart SDK Spelling b, c, and d.

pkg/compiler/lib/src/io/position_information.dart

 // Copyright (c) 2015, 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.
 
 /// Source information system mapping that attempts a semantic mapping between
 /// offsets of JavaScript code points to offsets of Dart code points.
 
 library dart2js.source_information.position;
 
 import '../common.dart';
@@ skipping 676 matching lines @@
   ///           ^             // the subexpression offset of the `*.bar()` call
   ///               ^         // the subexpression offset of the `baz()` call
   ///
   /// Here, even though the JavaScript node for the `*.bar()` call contains
   /// the `foo()` its execution is identified by the `bar` identifier more than
   /// the foo identifier.
   ///
   final int subexpressionOffset;
 
   /// The `left-to-right` offset of the step. This is like [subexpressionOffset]
-  /// bute restricted so that the offset of each subexpression in execution
+  /// but restricted so that the offset of each subexpression in execution
   /// order is monotonically increasing.
   ///
   /// For instance:
   ///
   ///     foo().bar(baz());
   ///     ^                   // the left-to-right offset of the `foo()` call
   ///           ^             // the left-to-right offset of the `*.bar()` call
   ///     ^                   // the left-to-right offset of the `baz()` call
   ///
   /// Here, `baz()` is executed before `foo()` so we need to use 'f' as its best
@@ skipping 628 matching lines @@
 
   @override
   CodePosition operator [](js.Node node) {
     CodePosition codePosition = codePositions[node];
     if (codePosition == null) {
       coverage.registerNodesWithoutOffset(node);
     }
     return codePosition;
   }
 }