Add minimal example for reproducing PIR simplifier bug

plutus-tx-plugin/app/SimplifierBugMinimalExample.hs

@@ -0,0 +1,45 @@
+-- editorconfig-checker-disable-file
+{-# LANGUAGE BangPatterns          #-}
+{-# LANGUAGE DataKinds             #-}
+{-# LANGUAGE MultiParamTypeClasses #-}
+{-# LANGUAGE NamedFieldPuns        #-}
+{-# LANGUAGE NoImplicitPrelude     #-}
+{-# LANGUAGE PackageImports        #-}
+{-# LANGUAGE ScopedTypeVariables   #-}
+{-# LANGUAGE TemplateHaskell       #-}
+{-# LANGUAGE TypeApplications      #-}
+{-# LANGUAGE ViewPatterns          #-}
+
+-- Comment out in order to reproduce the compilation issue.
+-- WATCH OUT: THIS IS PROBABLY GOING TO OOO YOUR MACHINE
+{-# OPTIONS_GHC -fplugin-opt PlutusTx.Plugin:max-simplifier-iterations-pir=1 #-}
+
+module Main where
+
+import PlutusTx qualified
+import PlutusTx.Prelude hiding (Semigroup (..), unless)
+import Prelude qualified as H
+
+main :: H.IO ()
+main = do
+  H.pure ()
+
+data C = A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R
+
+PlutusTx.makeIsDataIndexed ''C [ ('A, 0) , ('B, 1) , ('C, 2) , ('D, 3) , ('E, 4) , ('F, 5) , ('G, 6) , ('H, 7) , ('I, 8) , ('J, 9) , ('K, 10) , ('L, 11) , ('M, 12) , ('N, 13) , ('O, 14) , ('P, 15) , ('Q, 16) , ('R, 17) ]
+
+{-# INLINABLE validator #-}
+validator ::
+  BuiltinData
+  -> BuiltinData
+  -> BuiltinData
+  -> Bool
+validator d _ _ =
+  let !_ = PlutusTx.unsafeFromBuiltinData @C d
+   in True
+
+unappliedValidator ::
+  PlutusTx.CompiledCode (PlutusTx.BuiltinData -> PlutusTx.BuiltinData -> PlutusTx.BuiltinData -> BuiltinUnit)
+unappliedValidator =
+   $$(PlutusTx.compile [|| \d r c -> check $ validator d r c ||])
+

plutus-tx-plugin/plutus-tx-plugin.cabal

@@ -116,6 +116,18 @@ executable gen-plugin-opts-doc
 
   default-language: Haskell2010
 
+executable simplifier-bug-minimal-example
+  import:           lang, ghc-version-support
+  main-is:          SimplifierBugMinimalExample.hs
+  hs-source-dirs:   app
+  ghc-options:      -threaded -rtsopts -with-rtsopts=-N
+  build-depends:
+    , base              >=4.7   && <5
+    , plutus-tx
+    , plutus-tx-plugin  ^>=1.29
+
+  default-language: Haskell2010
+
 test-suite plutus-tx-plugin-tests
   import:             lang, ghc-version-support