Comment on WildP and undone attempt to fix 819.
Factored out function checkAbsurdLambda.
Refactor: use LensHiding (function visible).
Factored out checkExtendedLambda.
Factored out checkRecordExpression and checkRecordUpdate.
Removed a stale comment.
Unified 4 definitions of unScope.
Refactor: fused checkMeta and inferMeta into checkOrInferMeta.
Comment and type signature for domainFree.
Fixed issue 807 (connected to issue 655).
Problem was a circumvention of the code that generates helper
functions for coinduction when checking an alias.
New solution for 655:
Added new flag envExpandLast to type checking context, which is turned
off when checking aliases.
Another test case for issue 807.
Fixed issue 821: invalid IMPOSSIBLE in comparison of spines.
Reactivated flexible function arity (issue 727).
Compilers probably need to be updated to this feature.
Release notes for flexible function arity.
Russels paradox with --type-in-type, by Paolo Capriotti.