#7748: Runtime <<loop>> due to incorrect inferred type
----------------------------------------+-----------------------------------
Reporter: jbransen | Owner:
Type: bug | Status: new
Priority: normal | Component: Compiler (Type
checker)
Version: 7.6.2 | Keywords:
Os: Unknown/Multiple | Architecture: Unknown/Multiple
Failure: GHC accepts invalid program | Blockedby:
Blocking: | Related:
----------------------------------------+-----------------------------------
There is a bug in the type checker of 7.6.1 and 7.6.2, which accepts an
incorrect type resulting in <<loop>> at runtime. Furthermore, 7.6.2 even
automatically infers this incorrect type. Hence, the attached code has the
following behavior:
- No explicit type: Code works in 7.6.1, loops in 7.6.2
- Correct explicit type: Code works fine in 7.6.1 and 7.6.2
- Incorrect explicit type: Code loops in 7.6.1 and 7.6.2
The incorrect type has a parameter that is too polymorphic, i.e. an "a"
type is accepted while the function does a pattern match on the parameter
from which it is clear that it should be a Maybe type. In 7.4.* versions
this incorrect type is not accepted.
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7748>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler
_______________________________________________
ghc-tickets mailing list
[email protected]
http://www.haskell.org/mailman/listinfo/ghc-tickets
