{
  "$type": "site.standard.document",
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  "path": "/t/exception-annotations-lay-of-the-land/14056#post_2",
  "publishedAt": "2026-05-09T09:22:16.000Z",
  "site": "https://discourse.haskell.org",
  "tags": [
    "issue"
  ],
  "textContent": "Great overview, thanks!\n\nAbout the issue of whether, in the `Exception` instance for `SomeException`, the definition of `toException` should clear the context.\n\nIf it clears the context (as it does currently) this code\n\n\n    catchAndThrow :: IO a -> IO a\n    catchAndThrow = handle $ \\(e :: SomeException) -> throwIO e\n\n\nwill lose the existing anotations in `e`, instead adding backtrace information (say, an `IPE` backtrace) corresponding to the `throwIO`, correct?\n\nIf we modify `SomeException`’s `toException` to keep the context, wouldn’t that same code result in _two_ unrelated backtraces, one for the original exception, another for the `throwIO` call site?",
  "title": "Exception Annotations: Lay of the Land"
}