wiki:UndecidableInstances

Version 4 (modified by ross@…, 8 years ago) (diff)

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Allow Undecidable Instances

Ticket(s)

Brief Explanation

There are no restrictions on the form of instance declarations (see FlexibleInstances). As a result, context reduction need not terminate, so implementations impose some limit on the depth of inference.

References

Pros

  • offered by GHC and Hugs with appropriate options
  • flexible

Cons

  • no clear boundary