diff --git a/src/GF/GFCC/Generate.hs b/src/GF/GFCC/Generate.hs
index 8baaf12d7..64ef5d5cf 100644
--- a/src/GF/GFCC/Generate.hs
+++ b/src/GF/GFCC/Generate.hs
@@ -25,7 +25,7 @@ generate gfcc cat = concatMap (\i -> gener i cat) [0..]
 
 -- generate an infinite list of trees randomly
 genRandom :: StdGen -> GFCC -> CId -> [Exp]
-genRandom gen gfcc cat = genTrees (randomRs (0.0, 1.0) gen) cat where
+genRandom gen gfcc cat = genTrees (randomRs (0.0, 1.0 :: Double) gen) cat where
 
   timeout = 47 -- give up