[kernel] Offsets on loops

pkg/kernel/lib/ast.dart

 // Copyright (c) 2016, 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.
 
 /// -----------------------------------------------------------------------
 ///                           ERROR HANDLING
 /// -----------------------------------------------------------------------
 ///
 /// As a rule of thumb, errors that can be detected statically are handled by
 /// the frontend, typically by translating the erroneous code into a 'throw' or
@@ skipping 3414 matching lines @@
     }
     transformList(updates, v, this);
     if (body != null) {
       body = body.accept(v);
       body?.parent = this;
     }
   }
 }
 
 class ForInStatement extends Statement {
+  /// Offset in the source file it comes from.
+  ///
+  /// Valid values are from 0 and up, or -1 ([TreeNode.noOffset]) if the file
+  /// offset is not available (this is the default if none is specifically set).
+  int bodyOffset = TreeNode.noOffset;

[ahe, 2017/08/08 11:38:50]

Why is the bodyOffset different from body.fileOffset?

[jensj, 2017/08/08 11:54:53]

As I recall I had to add that because we don't have offsets on everything. So
body.fileOffset might not go into the dill file, but we need the position to
reproduce the debugging behavior of the non-kernel pipeline.

[ahe, 2017/08/08 11:58:03]

Can't we make sure that we have positions on all those other things? It seems
like a bug if we have statements that lack a position, or am I missing
something?

+
   VariableDeclaration variable; // Has no initializer.
   Expression iterable;
   Statement body;
   bool isAsync; // True if this is an 'await for' loop.
 
   ForInStatement(this.variable, this.iterable, this.body,
       {this.isAsync: false}) {
     variable?.parent = this;
     iterable?.parent = this;
     body?.parent = this;
@@ skipping 1295 matching lines @@
   if (typedef_.canonicalName == null) {
     throw '$typedef_ has no canonical name';
   }
   return typedef_.canonicalName;
 }
 
 /// Annotation describing information which is not part of Dart semantics; in
 /// other words, if this information (or any information it refers to) changes,
 /// static analysis and runtime behavior of the library are unaffected.
 const informative = null;