From a0671e2de97c5801bfba4b12f16e498492681bc1 Mon Sep 17 00:00:00 2001
From: Simon Marlow <marlowsd@gmail.com>
Date: Thu, 28 Sep 2017 13:08:45 -0400
Subject: [PATCH] mkDataConRep: fix bug in strictness signature (#14290)
The strictness signature for a data con wrapper wasn't including any
dictionary arguments, which meant that bangs on the fields of a
constructor with an existential context would be moved to the wrong
fields. See T14290 for an example.
Test Plan:
* New test T14290
* validate
Reviewers: simonpj, niteria, austin, bgamari, erikd
Reviewed By: simonpj, bgamari
Subscribers: rwbarton, thomie
GHC Trac Issues: #14290
Differential Revision: https://phabricator.haskell.org/D4040
(cherry picked from commit 5935acdb1302263011c2023d5e7f4ec496c972c0)
---
compiler/basicTypes/MkId.hs | 6 +++++-
testsuite/tests/stranal/should_run/T14290.hs | 17 +++++++++++++++++
testsuite/tests/stranal/should_run/all.T | 1 +
3 files changed, 23 insertions(+), 1 deletion(-)
create mode 100644 testsuite/tests/stranal/should_run/T14290.hs
diff --git a/compiler/basicTypes/MkId.hs b/compiler/basicTypes/MkId.hs
index a3c82f1bd676..1ce90bb091e5 100644
--- a/compiler/basicTypes/MkId.hs
+++ b/compiler/basicTypes/MkId.hs
@@ -528,7 +528,11 @@ mkDataConRep dflags fam_envs wrap_name mb_bangs data_con
wrap_sig = mkClosedStrictSig wrap_arg_dmds (dataConCPR data_con)
- wrap_arg_dmds = map mk_dmd arg_ibangs
+ wrap_arg_dmds =
+ replicate (length theta) topDmd ++ map mk_dmd arg_ibangs
+ -- Don't forget the dictionary arguments when building
+ -- the strictness signature (#14290).
+
mk_dmd str | isBanged str = evalDmd
| otherwise = topDmd
diff --git a/testsuite/tests/stranal/should_run/T14290.hs b/testsuite/tests/stranal/should_run/T14290.hs
new file mode 100644
index 000000000000..7093239d4c22
--- /dev/null
+++ b/testsuite/tests/stranal/should_run/T14290.hs
@@ -0,0 +1,17 @@
+{-# LANGUAGE ExistentialQuantification #-}
+module Main (main) where
+
+main :: IO ()
+main = r `seq` return ()
+
+r :: Rec
+r = Rec{ a = error "xxx", b = 3, c = True }
+
+class C t
+instance C Bool
+
+data Rec = forall t. C t => Rec
+ { a :: ()
+ , b :: !Int
+ , c :: t
+ }
diff --git a/testsuite/tests/stranal/should_run/all.T b/testsuite/tests/stranal/should_run/all.T
index 076474608ef2..dada8176cbc1 100644
--- a/testsuite/tests/stranal/should_run/all.T
+++ b/testsuite/tests/stranal/should_run/all.T
@@ -15,3 +15,4 @@ test('T11555a', normal, compile_and_run, [''])
test('T12368', exit_code(1), compile_and_run, [''])
test('T12368a', exit_code(1), compile_and_run, [''])
test('T13380', [expect_broken(13380), exit_code(1)], compile_and_run, [''])
+test('T14290', normal, compile_and_run, [''])
--
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