#15601: Unexpected compile error on type level lists with a single element -------------------------------------+------------------------------------- Reporter: erikd | Owner: (none) Type: bug | Status: closed Priority: normal | Milestone: 8.6.1 Component: Compiler | Version: 8.4.3 Resolution: invalid | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Incorrect | Unknown/Multiple error/warning at compile-time | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by monoidal): * status: new => closed * resolution: => invalid Comment: This is unfortunately by design. When type-level lists were added, the syntax `[a]` was already taken. For example `[Integer]` is a list of integers, kind `*`. It's not a type-level list with one entry, which would be kind `[*]`. If we could start Haskell from scratch I would vote for having `['a', 'b'] :: List Char` instead of `['a', 'b'] :: [Char]` but it's too late to change. See https://downloads.haskell.org/~ghc/latest/docs/html/users_guide/glasgow_exts... #promoted-list-and-tuple-types -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/15601#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler