diff --git a/mk/warnings.mk b/mk/warnings.mk
index d604f9ae2d1fe9b029340ac8e5c0cd5480c63efe..f8db8fd35d852fbb012e68f209ba67e054ce3ca1 100644
--- a/mk/warnings.mk
+++ b/mk/warnings.mk
@@ -32,6 +32,8 @@ SRC_CC_WARNING_OPTS += -Wno-unknown-pragmas
 
 endif
 
+SRC_HC_WARNING_OPTS_STAGE1 += -fwarn-noncanonical-monad-instances
+SRC_HC_WARNING_OPTS_STAGE2 += -fwarn-noncanonical-monad-instances
 
 
 ######################################################################
diff --git a/utils/haddock b/utils/haddock
index 42b2cfc595f1ee62d1c1b8513c5df1d92709c06a..a6deefad581cbeb62048826bc1d626c41a0dd56c 160000
--- a/utils/haddock
+++ b/utils/haddock
@@ -1 +1 @@
-Subproject commit 42b2cfc595f1ee62d1c1b8513c5df1d92709c06a
+Subproject commit a6deefad581cbeb62048826bc1d626c41a0dd56c