HEAD panic: tcSyntaxOp "noSyntaxExpr"
The following program triggers a bug in 8.2.2 and 8.5.20171215.
-- Checks that the ordering constraint on the groupWith function is respected
{-# OPTIONS_GHC -XMonadComprehensions -XTransformListComp #-}
module ShouldFail where
import GHC.Exts (groupWith)
data Unorderable = Gnorf | Pinky | Brain
foo = [ ()
| Gnorf <- [Gnorf, Brain]
, then group by x using groupWith
]Reproduce:
ghc bug.hsOutput:
` [1 of 1] Compiling ShouldFail ( bug.hs, bug.o ) ghc: panic! (the 'impossible' happened) (GHC version 8.5.20171215 for x86_64-unknown-linux): tcSyntaxOp "noSyntaxExpr" Call stack: CallStack (from HasCallStack): callStackDoc, called at compiler/utils/Outputable.hs:1150:37 in ghc:Outputable pprPanic, called at compiler/typecheck/TcExpr.hs:1436:31 in ghc:TcExpr
Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug`
Trac metadata
| Trac field | Value |
|---|---|
| Version | 8.2.2 |
| Type | Bug |
| TypeOfFailure | OtherFailure |
| Priority | normal |
| Resolution | Unresolved |
| Component | Compiler |
| Test case | |
| Differential revisions | |
| BlockedBy | |
| Related | |
| Blocking | |
| CC | |
| Operating system | |
| Architecture |