#5395: Context reduction stack overflow without undecidable instances
---------------------------------+------------------------------------------
Reporter: guest | Owner:
Type: bug | Status: new
Priority: normal | Component: Compiler
Version: 7.0.4 | Keywords: type family, termination
Testcase: | Blockedby:
Os: Unknown/Multiple | Blocking:
Architecture: Unknown/Multiple | Failure: GHC rejects valid program
---------------------------------+------------------------------------------
When using type families whose reduction surely terminates (and which are
accepted without undecidable instances) GHC still seems to set the context
stack reduction limit. See the included code.
The fixed limit on context stack size prevents us from doing type-level
arithmetic on arbitrarily-sized type-level numerals.
If the context-size limit is applied whether undecidable instance
extension is used or not, one may wonder of the purpose of the
undecidable instance extension.
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/5395>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler
_______________________________________________
Glasgow-haskell-bugs mailing list
[email protected]
http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs
