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Opened by Ian Lynagh <igloo@earth.li>@trac-igloo

Impredicativity bug: Church2 test gives a rather confusing error with the HEAD

The Church2 test gives a rather confusing error with the HEAD:

Church2.hs:27:14:
    Couldn't match expected type `CNat'
           against inferred type `(a -> a) -> a -> a'
      Expected type: CNat -> CNat
      Inferred type: CNat -> CNat
    In the first argument of `n', namely `(mul m)'
    In the expression: n (mul m) n1

In particular the lines

      Expected type: CNat -> CNat
      Inferred type: CNat -> CNat

are confusing, and I'm not sure why it's giving two expected/inferred pairs of types.

Trac metadata
Trac field Value
Version 6.7
Type Bug
TypeOfFailure OtherFailure
Priority normal
Resolution Unresolved
Component Compiler (Type checker)
Test case
Differential revisions
BlockedBy
Related
Blocking
CC
Operating system Unknown
Architecture Unknown
Edited by Simon Peyton Jones