diff --git a/parser-typechecker/src/Unison/PatternMatchCoverage/GrdTree.hs b/parser-typechecker/src/Unison/PatternMatchCoverage/GrdTree.hs
index 681382f5d..7644cacf3 100644
--- a/parser-typechecker/src/Unison/PatternMatchCoverage/GrdTree.hs
+++ b/parser-typechecker/src/Unison/PatternMatchCoverage/GrdTree.hs
@@ -84,3 +84,5 @@ pattern Grd x rest = Fix (GrdF x rest)
 
 pattern Fork :: NonEmpty (GrdTree n l) -> GrdTree n l
 pattern Fork alts = Fix (ForkF alts)
+
+{-# COMPLETE Leaf, Grd, Fork #-}