A Revised Haskell 2010 Language Report

The current Haskell 2010 language report does not reflect the language as it is used today. Engineers who rely on the report for precise syntax or semantics must instead trace proposals and discussions to understand what compilers actually accept. This extra step increases the chance of writing code that is incompatible with GHC or MicroHS. The mismatch also forces developers to remember which parts of the report are outdated.

The proposal is to create a revised Haskell 2010 report that incorporates the accepted changes such as Functor-Applicative-Monad, MonadFail, Foldable-Traversable and Monad-of-no-return. Because these changes are already non-contentious, a lightweight decision process can be used to assemble the report. The revised version would be treated as a retcon of the original Haskell 2010 specification, so no new language version is introduced.

Adopting the revised report gives the community an authoritative reference that matches compiler behavior, removing the need to warn readers about inaccurate sections. The work involved is primarily editorial: updating the source text, generating PDF and HTML outputs, and ensuring the build process does not suffer from long LaTeX compile times. No changes are required to compilers or existing codebases, so there is no version churn for toolchains.

The revised report does not add new features beyond those already adopted, so it cannot anticipate future extensions; any later proposals would require another update. Its usefulness depends on the completeness of the discrepancy list in the GHC user guide; undocumented differences between compilers and the report would persist. Thus the effort improves current documentation but does not eliminate the need for ongoing maintenance.