Add a regression test for #24029

testsuite/tests/simplCore/should_compile/T24029.hs

+{-# OPTIONS_GHC -O #-}
+module T24029 (surround) where
+
+data Buffer where
+  Buffer :: !Int -> Buffer
+
+newtype Builder = Builder (Buffer -> Buffer)
+
+c :: Builder -> Builder -> Builder
+c (Builder f) (Builder g) = Builder (\b -> f (g b))
+
+i :: Buffer -> Buffer
+i (Buffer x) = Buffer x
+
+surround :: Builder -> Builder
+surround f = f
+{-# NOINLINE [1] surround #-}
+
+{-# RULES
+"surround/surround" forall a. surround a = c (Builder (i . i)) a
+  #-}

testsuite/tests/simplCore/should_compile/all.T

@@ -502,3 +502,4 @@ test('T23938', [extra_files(['T23938A.hs'])], multimod_compile, ['T23938', '-O -
 test('T23922a', normal, compile, ['-O'])
 test('T23952', [extra_files(['T23952a.hs'])], multimod_compile, ['T23952', '-v0 -O'])
 test('T24014', normal, compile, ['-dcore-lint'])
+test('T24029', normal, compile, [''])