hpack or cabal (or both) is a janky POS

package.yaml

@@ -76,7 +76,9 @@ library:
         - unsupported-ghc-version > 1 && < 1
 
     - condition: flag(error-messages)
-      then: {}
+      then:
+        # dummy value because cabal is stupid
+        cpp-options: -DCABAL_SERIOUSLY_CMON_MATE
       else:
         cpp-options: -DNO_ERROR_MESSAGES
 

polysemy.cabal

@@ -4,7 +4,7 @@ cabal-version: 1.12
 --
 -- see: https://github.com/sol/hpack
 --
--- hash: 022b4ccf6d38c802d8cbfa8835a7e832c23eba47ccf428861ac5016b7ad596d8
+-- hash: 5871506acb960e1595dcd500e8680727e555c25cfbd825e98b767b01c91cffc9
 
 name:           polysemy
 version:        0.5.0.0
@@ -91,6 +91,7 @@ library
     build-depends:
         unsupported-ghc-version >1 && <1
   if flag(error-messages)
+    cpp-options: -DCABAL_SERIOUSLY_CMON_MATE
   else
     cpp-options: -DNO_ERROR_MESSAGES
   default-language: Haskell2010