title: equal sign with haskell literals
body: <p>What exactly happens in GHCi when I load a file with a line that says: 0=1 ?</p>
  
  <p>I was expecting that this would give an error but it doesn't seem to do anything at all. Does it do anything? </p>
  
  <p>I assume it's equivalent in GHCi to just saying "let 0=1". What does that do?</p>