idris-lang/Idris-dev — pull request #775 by david-christiansen (2014-01-10 14:06:52+00:00)
Title: Preliminary support for error reflection

Error reflection allows Idris errors to be decorated by user code. This has at least the following potential uses:
* Nice error messages for embedded DSLs
* Improving confusing special cases of errors in the stdlib and suggesting how to fix them

See test/test037 for an example of their use.