Remove implicit Bit type signature on rhs of property declarations.

Fixes #224.

It might be desirable to add some other check for `property` declarations
to make sure that their types are predicates of some arity.

src/Cryptol/Parser/ParserUtils.hs

@@ -331,7 +331,7 @@ mkPoly rng terms = mk 0 (map fromInteger bits)
 mkProperty :: LPName -> [Pattern PName] -> Expr PName -> Decl PName
 mkProperty f ps e = DBind Bind { bName       = f
                                , bParams     = reverse ps
-                               , bDef        = at e (Located emptyRange (DExpr (ETyped e TBit)))
+                               , bDef        = at e (Located emptyRange (DExpr e))
                                , bSignature  = Nothing
                                , bPragmas    = [PragmaProperty]
                                , bMono       = False

tests/issues/issue312.icry.fails

@@ -1 +0,0 @@
-https://github.com/GaloisInc/cryptol/issues/224

tests/parser/docs.cry

@@ -18,7 +18,7 @@ test3 x = x
 /**
  * Test that doc strings work on property declarations
  */
-property test4 x = x
+property test4 x = (x : Bit)
 
 /**
  * Test that doc strings work on fixity declarations