<div dir="ltr"><div class="gmail_extra">Hello,</div><div class="gmail_extra"><br></div><div class="gmail_extra">Have a look at: <a href="https://downloads.haskell.org/~ghc/latest/docs/html/users_guide/other-type-extensions.html#scoped-type-variables">https://downloads.haskell.org/~ghc/latest/docs/html/users_guide/other-type-extensions.html#scoped-type-variables</a></div><div class="gmail_extra"><br></div><div class="gmail_extra">TL;DR - pattern type signatures are not the same kind of an animal that declaration signatures are. This kind of an animal has already bitten me in the bottom, so I'm glad I can share the insight :)</div><div class="gmail_extra"><br></div><div class="gmail_extra">Best regards,</div><div class="gmail_extra">Marcin Mrotek</div></div>