Simplify type signatures when using type families?

Simplify type signatures when using type families?

References

Reference NO 1

http://stackoverflow.com/questions/15201365/simplify-type-signatures-when-using-type-families

Reference NO 2

http://stackoverflow.com/questions/16926579/incomprehensible-error-message-with-type-families

Reference NO 3

http://www.haskell.org/haskellwiki/GHC/Type_families

Reference NO 4

http://typesandkinds.wordpress.com/2013/04/29/coincident-overlap-in-type-families/

Reference NO 5

http://research.microsoft.com/en-us/um/people/simonpj/papers/ext-f/axioms-extended.pdf

Reference NO 6

http://research.microsoft.com/~simonpj/papers/constraints/jfp-outsidein.pdf

Reference NO 7

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Reference NO 8

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