X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2Fprelude%2Fprimops.txt.pp;h=49f7a97a61d699b34fb19e2e162d3eda049d831c;hp=7d80db4fcc3df3e49e401a8e74c3e2a05b41980a;hb=e11c554e94c39223ea55991a552ccb244dfe4364;hpb=51bbdda993815fc0c3e55cbfcc60ffd512b9d4bd

diff --git a/compiler/prelude/primops.txt.pp b/compiler/prelude/primops.txt.pp
index 7d80db4..49f7a97 100644
--- a/compiler/prelude/primops.txt.pp
+++ b/compiler/prelude/primops.txt.pp
@@ -1738,9 +1738,19 @@ primtype Any a
 	    but never enters a function value.  
 
 	It's also used to instantiate un-constrained type variables after type
-	checking.  For example
+	checking.  For example, {\tt length} has type
 
-	{\tt length Any []}
+	{\tt length :: forall a. [a] -> Int}
+
+	and the list datacon for the empty list has type
+
+	{\tt [] :: forall a. [a]}
+
+	In order to compose these two terms as {\tt length []} a type
+	application is required, but there is no constraint on the
+	choice.  In this situation GHC uses {\tt Any}:
+
+	{\tt length Any ([] Any)}
 
 	Annoyingly, we sometimes need {\tt Any}s of other kinds, such as {\tt (* -> *)} etc.
 	This is a bit like tuples.   We define a couple of useful ones here,