[clean-list] Synonym type and Universal type

[lethevert]

Hello,


I have a question about synonym type and universal type.


Section 5.3 in Clean Language Report version 2.1 says

============================
SynonymTypeDef = ::TypeLhs :== [UniversalQuantVariables]Type ;
============================

However I found some problem on using synonym type and universal type together.

The following program

============================
Start = f id 1 "a"

id a = a

::Id :== A.a: a -> a

f :: Id Int String -> (Int, String)
f g i s = (g i, g s)
============================

produces type unification errors.

============================
Compiling Main
Type error [Main.icl,11,f]: near g : cannot unify types:
 v5 -> String
 Id
Type error [Main.icl,5,Start]:"argument 1 of f" cannot unify types:
 Id
 v1 -> v1
============================

But if we modify the first program as the following way

============================
::Id a :== a -> a

f :: (A.a: Id a) Int String -> (Int, String)
f g i s = (g i, g s)
============================

it doesn't produce any errors.



Why this happens?


-- 
lethevert
lethevert at users.sourceforge.net