infix-type-constructors.md

@@ -77,6 +77,43 @@ And `type` gets an extra production:
    data a `Bar` b = a `BAR` b
   ```
 
+## Issues
+
+
+The second proposal—-to treat all infix operators as type constructors—-leads to an ambiguity in import/export declarations:
+
+```wiki
+module Test ( (+) ) where
+```
+
+
+This export declaration is ambiguous because it is not clear if we mean to export the value operator (+), the type constructor (+), or both.
+A similar issue arises with imports.
+
+
+One possible solution is to state that, when written on their own, infix operators in import/export specifications refer to the value level.
+So in the above example we would be exporting the value operator (+).
+
+
+To import/export the type constructor one would have to use an explicit (possibly empty) sub-ordinate list:
+
+```wiki
+module Test ( (+)() ) where
+```
+
+
+Unfortunately, such specifications look rather odd.
+
+
+Another solution would be to introduce a new piece of syntax which would translate to the same thing.  Perhaps:
+
+```wiki
+module Test ( type (+) ) where
+```
+
+
+The intention here is that `type` specifies the namespace of the following name, and not that it is a type synonym.
+
 ## References
 
 - [ Infix type constructors, classes, and type variables](http://www.haskell.org/ghc/docs/latest/html/users_guide/type-extensions.html#infix-tycons) in the GHC User's Guide.