diff --git a/src/Lexer.hs b/src/Lexer.hs
index 3e98cce..273a0fe 100644
--- a/src/Lexer.hs
+++ b/src/Lexer.hs
@@ -221,7 +221,7 @@ link :: Lexer
 link = do
     pos <- getPosition
     l <- linkRaw
-    -- "unconsume" the last token
+    -- register the position of the last token
     pos' <- flip incSourceColumn (-1) <$> getPosition
     pure $ (pos, LinkOpen) : l <> [(pos', LinkClose)]
 
diff --git a/test/Spec.hs b/test/Spec.hs
index 8207b77..a09489e 100644
--- a/test/Spec.hs
+++ b/test/Spec.hs
@@ -11,6 +11,7 @@ import Types
 import Data.String (IsString (..))
 import Data.Text (Text)
 import Text.Parsec.Pos
+import GHC.Stack
 
 main :: IO ()
 main = hspec $ do
@@ -186,6 +187,7 @@ instance IsString (Doc String) where
 
 shouldLexTo :: String -> [(Int, Int, Token)] -> Expectation
 shouldLexTo input expected =
+   withFrozenCallStack $
     case lexer input of
         Right tokens -> do
             let actual = map (\(pos, tok) -> (sourceLine pos, sourceColumn pos, tok)) tokens