X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2Frename%2FRnExpr.lhs;h=1b2700497b837495d7fc88b117b7ef696fcd77af;hb=94356abffa2d8389d85b012bfd316a89459f8fa0;hp=59d0dd180fdf58b020dba225d4a8a9fffbe2aa19;hpb=6a821057e7b641888b57485625ffa80b1c4158b9;p=ghc-hetmet.git

diff --git a/ghc/compiler/rename/RnExpr.lhs b/ghc/compiler/rename/RnExpr.lhs
index 59d0dd1..1b27004 100644
--- a/ghc/compiler/rename/RnExpr.lhs
+++ b/ghc/compiler/rename/RnExpr.lhs
@@ -952,7 +952,8 @@ segsToStmts :: [Segment [LStmt Name]] -> ([LStmt Name], FreeVars)
 
 segsToStmts [] = ([], emptyFVs)
 segsToStmts ((defs, uses, fwds, ss) : segs)
-  = (new_stmt : later_stmts, later_uses `plusFV` uses)
+  = ASSERT( not (null ss) )
+    (new_stmt : later_stmts, later_uses `plusFV` uses)
   where
     (later_stmts, later_uses) = segsToStmts segs
     new_stmt | non_rec	 = head ss