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.hs
Output:
` [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 | |
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Blocking | |
CC | |
Operating system | |
Architecture |