X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2Ftypes%2FTypeRep.lhs;h=b0b5c63c81fae87a827d85ebecf516b795f0d4df;hp=544b822f28ac49eed7b7b6601ee14e4a9280adab;hb=bda859adc28cc7f9b5292fb7f93a0d8fc763ad08;hpb=0b86bc9b022a5965d2b35f143ff4b919f784e676

diff --git a/compiler/types/TypeRep.lhs b/compiler/types/TypeRep.lhs
index 544b822..b0b5c63 100644
--- a/compiler/types/TypeRep.lhs
+++ b/compiler/types/TypeRep.lhs
@@ -192,8 +192,11 @@ data Type
 	TyVar
 	Type	
 
-  | PredTy		-- A high level source type 
-	PredType	-- ...can be expanded to a representation type...
+  | PredTy		-- The type of evidence for a type predictate
+	PredType	-- Can be expanded to a representation type.
+	-- NB: A PredTy (EqPred _ _) can appear only as the kind
+	--     of a coercion variable; never as the argument or result
+	--     of a FunTy (unlike ClassP, IParam)
 
   | NoteTy 		-- A type with a note attached
 	TyNote