[when let-shrinking a tail, be sure to optimize function bodies
John Meacham <john@repetae.net>**20100812054500
 Ignore-this: eb1b56f28287a98b67bcd9c29d50ba82
] hunk ./src/Grin/SSimplify.hs 242
-                return (updateLetProps lt { expBody = e } :>>= l :-> r)
+                return (updateLetProps lt { expBody = e, expDefs = defs } :>>= l :-> r)