Issue 5775 seems to be fixed, let's see

cabal-testsuite/PackageTests/NewBuild/CmdRun/Script/cabal.test.hs

 import Test.Cabal.Prelude
 
 main = cabalTest $ do
-    expectBroken 5775 $ cabal' "v2-run" ["script.hs"]
-    return ()
+    res <- cabal' "v2-run" ["script.lhs"]
+    assertOutputContains "Hello World" res

cabal-testsuite/PackageTests/NewBuild/CmdRun/Script/script.hs

@@ -8,4 +8,4 @@ build-depends: base ^>= 4.0
 import Prelude
 
 main :: IO ()
-main = return ()
+main = putStrLn "Hello World"