Unlifted types and pattern synonym signatures
The following program is rejected by ghc-8.0.1:
{-# LANGUAGE MagicHash #-}
{-# LANGUAGE PatternSynonyms #-}
module Foo where
import GHC.Exts (Int#)
pattern Zero :: Int# -- commenting out this line works
pattern Zero <- 0#
% ghc-stage2 unlifted-pattern-synonym.hs
[1 of 1] Compiling Foo ( unlifted-pattern-synonym.hs, unlifted-pattern-synonym.o )
unlifted-pattern-synonym.hs:7:17: error:
• Expecting a lifted type, but ‘Int#’ is unlifted
• In the type ‘Int#’
Commenting out the type signature removes the error.
GHC 7.10.3 accepts this program, with and without the type signature.
Trac metadata
Trac field | Value |
---|---|
Version | 8.0.1 |
Type | Bug |
TypeOfFailure | OtherFailure |
Priority | normal |
Resolution | Unresolved |
Component | Compiler (Type checker) |
Test case | |
Differential revisions | |
BlockedBy | |
Related | |
Blocking | |
CC | |
Operating system | |
Architecture |