Underconstrained typed holes are non-performant
With a fresh build of 8.5:
GHCi, version 8.5.20180323: http://www.haskell.org/ghc/ :? for help
Loaded GHCi configuration from /Users/leo/.ghci
Prelude> 3 _ 4
ghc-stage2: panic! (the 'impossible' happened)
(GHC version 8.5.20180323 for x86_64-apple-darwin):
ASSERT failed!
2
1
t_a4j6[tau:1]
Maybe a_a4j7[tau:2]
Call stack:
CallStack (from HasCallStack):
callStackDoc, called at compiler/utils/Outputable.hs:1157:37 in ghc:Outputable
pprPanic, called at compiler/utils/Outputable.hs:1213:5 in ghc:Outputable
assertPprPanic, called at compiler/typecheck/TcMType.hs:720:54 in ghc:TcMType
I believe this fails in earlier versions as well, but I haven't tested it.
Trac metadata
Trac field | Value |
---|---|
Version | 8.5 |
Type | Bug |
TypeOfFailure | OtherFailure |
Priority | normal |
Resolution | Unresolved |
Component | Compiler |
Test case | |
Differential revisions | |
BlockedBy | |
Related | |
Blocking | |
CC | |
Operating system | |
Architecture |