diff --git a/lib/backend-lalr/src/Happy/Backend/LALR.hs b/lib/backend-lalr/src/Happy/Backend/LALR.hs
index ca144464..78bf47d7 100644
--- a/lib/backend-lalr/src/Happy/Backend/LALR.hs
+++ b/lib/backend-lalr/src/Happy/Backend/LALR.hs
@@ -35,7 +35,7 @@ importsToInject debug = concat ["\n", import_array, import_bits, import_glaexts,
                            "import Control.Monad (ap)\n"
 
 langExtsToInject :: [String]
-langExtsToInject = ["MagicHash", "BangPatterns", "TypeSynonymInstances", "FlexibleInstances", "NoStrictData"]
+langExtsToInject = ["MagicHash", "BangPatterns", "TypeSynonymInstances", "FlexibleInstances", "PatternGuards", "NoStrictData"]
 
 defines :: Bool -> Bool -> String
 defines debug coerce = unlines [ "#define " ++ d ++ " 1" | d <- vars_to_define ]
diff --git a/tests/Makefile b/tests/Makefile
index 17765d7d..3fd483de 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -5,7 +5,7 @@
 # [2021-07-14, PR #196](https://github.com/haskell/happy/pull/196)
 #
 HC ?= ghc
-HC_OPTS=-package array -Wall -Werror
+HC_OPTS=-package array -Wall -Werror -XHaskell98
 
 # NOTE: `cabal test` will take care to build the local `happy`
 # executable and place it into $PATH for us to pick up.