From b3be0d185b6e597fa517859430cf6d54df04ca46 Mon Sep 17 00:00:00 2001
From: Simon Peyton Jones <simon.peytonjones@gmail.com>
Date: Tue, 10 Jan 2023 09:26:08 +0000
Subject: Fix finaliseArgBoxities for OPAQUE function

We never do worker wrapper for OPAQUE functions, so we must
zap the unboxing info during strictness analysis.

This patch fixes #22502
---
 testsuite/tests/simplCore/should_compile/T22502.hs | 15 +++++++++++++++
 testsuite/tests/simplCore/should_compile/all.T     |  1 +
 2 files changed, 16 insertions(+)
 create mode 100644 testsuite/tests/simplCore/should_compile/T22502.hs

(limited to 'testsuite/tests/simplCore')

diff --git a/testsuite/tests/simplCore/should_compile/T22502.hs b/testsuite/tests/simplCore/should_compile/T22502.hs
new file mode 100644
index 0000000000..396e4cab9f
--- /dev/null
+++ b/testsuite/tests/simplCore/should_compile/T22502.hs
@@ -0,0 +1,15 @@
+{-# LANGUAGE MagicHash #-}
+module M where
+
+import GHC.Exts
+import GHC.IO
+
+data T a = MkT !Bool !a
+
+fun :: T a -> IO a
+{-# OPAQUE fun #-}
+fun (MkT _ x) = IO $ \s -> noinline seq# x s
+-- evaluate/seq# should not produce its own eval for x
+-- since it is properly tagged (from a strict field)
+
+-- uses noinline to prevent caseRules from eliding the seq# in Core
diff --git a/testsuite/tests/simplCore/should_compile/all.T b/testsuite/tests/simplCore/should_compile/all.T
index e57bb4cafa..4fd57c5301 100644
--- a/testsuite/tests/simplCore/should_compile/all.T
+++ b/testsuite/tests/simplCore/should_compile/all.T
@@ -463,3 +463,4 @@ test('T22459', normal, compile, [''])
 test('T22623', normal, multimod_compile, ['T22623', '-O -v0'])
 test('T22662', normal, compile, [''])
 test('T22725', normal, compile, ['-O'])
+test('T22502', normal, compile, ['-O'])
-- 
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