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# Liberal Type Synonyms
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## Brief Explanation
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See the [ GHC Documentation](http://www.haskell.org/ghc/docs/latest/html/users_guide/type-extensions.html#type-synonyms) on this extension.
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The basic idea is that type validity checking is done *after expanding type synonyms*. This means that type synonyms can be written unsaturated, as long as the result of expanding synonyms leaves everything saturated. This is sometimes quite useful.
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There are also interactions with [RankNTypes](rank-n-types) - a type synonym may expand to a quantified type.
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## Proposal
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Adopt GHC's approach to type synonym expansion.
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## References
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- [ GHC Documentation](http://www.haskell.org/ghc/docs/latest/html/users_guide/type-extensions.html#type-synonyms)
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## Tickets
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<table><tr><th>[\#102](https://gitlab.haskell.org//haskell/prime/issues/102)</th>
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<td>add Liberal Type Synonyms</td></tr></table>
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## Pros
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- Small generalisation
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- Easily specified
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- Quite handy
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## Cons
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- any? |
