diff --git a/dev-haskell/mono-traversable/mono-traversable-1.0.15.1.ebuild b/dev-haskell/mono-traversable/mono-traversable-1.0.15.1.ebuild
index 1951801ea8f23..8087ede033a9b 100644
--- a/dev-haskell/mono-traversable/mono-traversable-1.0.15.1.ebuild
+++ b/dev-haskell/mono-traversable/mono-traversable-1.0.15.1.ebuild
@@ -23,7 +23,7 @@ RDEPEND="dev-haskell/hashable:=[profile?]
 	>=dev-haskell/unordered-containers-0.2:=[profile?]
 	>=dev-haskell/vector-0.10:=[profile?]
 	>=dev-haskell/vector-algorithms-0.6:=[profile?]
-	>=dev-lang/ghc-8.2.1:=
+	>=dev-lang/ghc-8.2.1:= <dev-lang/ghc-9.1
 "
 DEPEND="${RDEPEND}
 	>=dev-haskell/cabal-2.0.0.2