Encode strictness in GHC generics metadata

This augments `MetaSel` with a `Bang` field, which gives generic
programmers access to the following information about each field
selector:

* `SourceUnpackedness`: whether a field was marked `{-# NOUNPACK #-}`,
  `{-# UNPACK #-}`, or not
* `SourceStrictness`: whether a field was given a strictness (`!`) or
  laziness (`~`) annotation
* `DecidedStrictness`: what strictness GHC infers for a field during
  compilation, which may be influenced by optimization levels,
  `-XStrictData`, `-funbox-strict-fields`, etc.

Unlike in Phab:D1603, generics does not grant a programmer the ability
to "splice" in metadata, so there is no issue including
`DecidedStrictness` with `Bang` (whereas in Template Haskell, it had to
be split off).

One consequence of this is that `MetaNoSel` had to be removed, since it
became redundant. The `NoSelector` empty data type was also removed for
similar reasons.

Fixes #10716.

Test Plan: ./validate

Reviewers: dreixel, goldfire, kosmikus, austin, hvr, bgamari

Reviewed By: bgamari

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D1646

GHC Trac Issues: #10716

6 files changed, 253 insertions, 86 deletions

diff --git a/testsuite/tests/generics/GFullyStrict.hs b/testsuite/tests/generics/GFullyStrict.hs
new file mode 100644
index 0000000000..7c879d9877
--- /dev/null
+++ b/testsuite/tests/generics/GFullyStrict.hs
@@ -0,0 +1,57 @@
+{-# LANGUAGE DefaultSignatures #-}
+{-# LANGUAGE DeriveAnyClass #-}
+{-# LANGUAGE DeriveGeneric #-}
+{-# LANGUAGE FlexibleContexts #-}
+{-# LANGUAGE FlexibleInstances #-}
+{-# LANGUAGE ScopedTypeVariables #-}
+{-# LANGUAGE TypeOperators #-}
+module Main where
+
+import Data.Proxy (Proxy(..))
+import GHC.Generics
+
+main :: IO ()
+main = do
+  print (fullyStrict (Proxy :: Proxy (StrictMaybe Bool)))
+  print (fullyStrict (Proxy :: Proxy (Maybe Bool)))
+
+data StrictMaybe a = StrictNothing | StrictJust !a
+  deriving (FullyStrict, Generic)
+
+instance FullyStrict Bool
+instance FullyStrict a => FullyStrict (Maybe a)
+
+class FullyStrict a where
+  fullyStrict :: proxy a -> Bool
+  default fullyStrict :: (GFullyStrict (Rep a)) => proxy a -> Bool
+  fullyStrict _ = gfullyStrict (Proxy :: Proxy (Rep a p))
+
+class GFullyStrict f where
+  gfullyStrict :: proxy (f p) -> Bool
+
+instance GFullyStrict V1 where
+  gfullyStrict _ = True
+
+instance GFullyStrict U1 where
+  gfullyStrict _ = True
+
+instance FullyStrict c => GFullyStrict (Rec0 c) where
+  gfullyStrict _ = fullyStrict (Proxy :: Proxy c)
+
+instance GFullyStrict f => GFullyStrict (D1 c f) where
+  gfullyStrict _ = gfullyStrict (Proxy :: Proxy (f p))
+
+instance GFullyStrict f => GFullyStrict (C1 c f) where
+  gfullyStrict _ = gfullyStrict (Proxy :: Proxy (f p))
+
+instance (GFullyStrict f, Selector c) => GFullyStrict (S1 c f) where
+  gfullyStrict _ = gfullyStrict (Proxy :: Proxy (f p))
+                && selDecidedStrictness (undefined :: S1 c f p) /= DecidedLazy
+
+instance (GFullyStrict f, GFullyStrict g) => GFullyStrict (f :+: g) where
+  gfullyStrict _ =
+    gfullyStrict (Proxy :: Proxy (f p)) && gfullyStrict (Proxy :: Proxy (g p))
+
+instance (GFullyStrict f, GFullyStrict g) => GFullyStrict (f :*: g) where
+  gfullyStrict _ =
+    gfullyStrict (Proxy :: Proxy (f p)) && gfullyStrict (Proxy :: Proxy (g p))
diff --git a/testsuite/tests/generics/GFullyStrict.stdout b/testsuite/tests/generics/GFullyStrict.stdout
new file mode 100644
index 0000000000..1cc8b5e10d
--- /dev/null
+++ b/testsuite/tests/generics/GFullyStrict.stdout
@@ -0,0 +1,2 @@
+True
+False
diff --git a/testsuite/tests/generics/GenDerivOutput.stderr b/testsuite/tests/generics/GenDerivOutput.stderr
index 6197da3d03..de11f431e9 100644
--- a/testsuite/tests/generics/GenDerivOutput.stderr
+++ b/testsuite/tests/generics/GenDerivOutput.stderr
@@ -109,11 +109,19 @@ GHC.Generics representation types:
                                                                            'GHC.Types.True)
                                                                         (GHC.Generics.S1
                                                                            ('GHC.Generics.MetaSel
-                                                                              "element")
+                                                                              ('GHC.Base.Just
+                                                                                 "element")
+                                                                              'GHC.Generics.NoSourceUnpackedness
+                                                                              'GHC.Generics.NoSourceStrictness
+                                                                              'GHC.Generics.DecidedLazy)
                                                                            (GHC.Generics.Rec0 a)
                                                                          GHC.Generics.:*: GHC.Generics.S1
                                                                                             ('GHC.Generics.MetaSel
-                                                                                               "rest")
+                                                                                               ('GHC.Base.Just
+                                                                                                  "rest")
+                                                                                               'GHC.Generics.NoSourceUnpackedness
+                                                                                               'GHC.Generics.NoSourceStrictness
+                                                                                               'GHC.Generics.DecidedLazy)
                                                                                             (GHC.Generics.Rec0
                                                                                                (GenDerivOutput.List
                                                                                                   a))))
@@ -131,11 +139,19 @@ GHC.Generics representation types:
                                                                         'GHC.Types.True)
                                                                      (GHC.Generics.S1
                                                                         ('GHC.Generics.MetaSel
-                                                                           "element")
+                                                                           ('GHC.Base.Just
+                                                                              "element")
+                                                                           'GHC.Generics.NoSourceUnpackedness
+                                                                           'GHC.Generics.NoSourceStrictness
+                                                                           'GHC.Generics.DecidedLazy)
                                                                         GHC.Generics.Par1
                                                                       GHC.Generics.:*: GHC.Generics.S1
                                                                                          ('GHC.Generics.MetaSel
-                                                                                            "rest")
+                                                                                            ('GHC.Base.Just
+                                                                                               "rest")
+                                                                                            'GHC.Generics.NoSourceUnpackedness
+                                                                                            'GHC.Generics.NoSourceStrictness
+                                                                                            'GHC.Generics.DecidedLazy)
                                                                                          (GHC.Generics.Rec1
                                                                                             GenDerivOutput.List)))
   type GHC.Generics.Rep (GenDerivOutput.Rose a) = GHC.Generics.D1
@@ -156,10 +172,18 @@ GHC.Generics representation types:
                                                                            'GHC.Generics.PrefixI
                                                                            'GHC.Types.False)
                                                                         (GHC.Generics.S1
-                                                                           'GHC.Generics.MetaNoSel
+                                                                           ('GHC.Generics.MetaSel
+                                                                              'GHC.Base.Nothing
+                                                                              'GHC.Generics.NoSourceUnpackedness
+                                                                              'GHC.Generics.NoSourceStrictness
+                                                                              'GHC.Generics.DecidedLazy)
                                                                            (GHC.Generics.Rec0 a)
                                                                          GHC.Generics.:*: GHC.Generics.S1
-                                                                                            'GHC.Generics.MetaNoSel
+                                                                                            ('GHC.Generics.MetaSel
+                                                                                               'GHC.Base.Nothing
+                                                                                               'GHC.Generics.NoSourceUnpackedness
+                                                                                               'GHC.Generics.NoSourceStrictness
+                                                                                               'GHC.Generics.DecidedLazy)
                                                                                             (GHC.Generics.Rec0
                                                                                                (GenDerivOutput.List
                                                                                                   (GenDerivOutput.Rose
@@ -179,10 +203,20 @@ GHC.Generics representation types:
                                                                         'GHC.Generics.PrefixI
                                                                         'GHC.Types.False)
                                                                      (GHC.Generics.S1
-                                                                        'GHC.Generics.MetaNoSel
+                                                                        ('GHC.Generics.MetaSel
+                                                                           'GHC.Base.Nothing
+                                                                           'GHC.Generics.NoSourceUnpackedness
+                                                                           'GHC.Generics.NoSourceStrictness
+                                                                           'GHC.Generics.DecidedLazy)
                                                                         GHC.Generics.Par1
                                                                       GHC.Generics.:*: GHC.Generics.S1
-                                                                                         'GHC.Generics.MetaNoSel
+                                                                                         ('GHC.Generics.MetaSel
+                                                                                            'GHC.Base.Nothing
+                                                                                            'GHC.Generics.NoSourceUnpackedness
+                                                                                            'GHC.Generics.NoSourceStrictness
+                                                                                            'GHC.Generics.DecidedLazy)
                                                                                          (GenDerivOutput.List
                                                                                           GHC.Generics.:.: GHC.Generics.Rec1
                                                                                                              GenDerivOutput.Rose)))
+
+
diff --git a/testsuite/tests/generics/GenDerivOutput1_0.stderr b/testsuite/tests/generics/GenDerivOutput1_0.stderr
index 0757b128ca..0f4df6275a 100644
--- a/testsuite/tests/generics/GenDerivOutput1_0.stderr
+++ b/testsuite/tests/generics/GenDerivOutput1_0.stderr
@@ -23,31 +23,39 @@ Derived instances:
 
 
 GHC.Generics representation types:
-    type GHC.Generics.Rep1 GenDerivOutput1_0.List = GHC.Generics.D1
+  type GHC.Generics.Rep1 GenDerivOutput1_0.List = GHC.Generics.D1
                                                     ('GHC.Generics.MetaData
                                                        "List"
                                                        "GenDerivOutput1_0"
                                                        "main"
                                                        'GHC.Types.False)
-                                                      (GHC.Generics.C1
+                                                    (GHC.Generics.C1
                                                        ('GHC.Generics.MetaCons
                                                           "Nil"
                                                           'GHC.Generics.PrefixI
                                                           'GHC.Types.False)
                                                        GHC.Generics.U1
-                                                       GHC.Generics.:+: GHC.Generics.C1
+                                                     GHC.Generics.:+: GHC.Generics.C1
                                                                         ('GHC.Generics.MetaCons
                                                                            "Cons"
                                                                            'GHC.Generics.PrefixI
                                                                            'GHC.Types.True)
-                                                                          (GHC.Generics.S1
+                                                                        (GHC.Generics.S1
                                                                            ('GHC.Generics.MetaSel
-                                                                              "element")
-                                                                             GHC.Generics.Par1
-                                                                           GHC.Generics.:*: GHC.Generics.S1
+                                                                              ('GHC.Base.Just
+                                                                                 "element")
+                                                                              'GHC.Generics.NoSourceUnpackedness
+                                                                              'GHC.Generics.NoSourceStrictness
+                                                                              'GHC.Generics.DecidedLazy)
+                                                                           GHC.Generics.Par1
+                                                                         GHC.Generics.:*: GHC.Generics.S1
                                                                                             ('GHC.Generics.MetaSel
-                                                                                               "rest")
-                                                                                              (GHC.Generics.Rec1
-                                                                                                 GenDerivOutput1_0.List)))
+                                                                                               ('GHC.Base.Just
+                                                                                                  "rest")
+                                                                                               'GHC.Generics.NoSourceUnpackedness
+                                                                                               'GHC.Generics.NoSourceStrictness
+                                                                                               'GHC.Generics.DecidedLazy)
+                                                                                            (GHC.Generics.Rec1
+                                                                                               GenDerivOutput1_0.List)))
 
 
diff --git a/testsuite/tests/generics/GenDerivOutput1_1.stderr b/testsuite/tests/generics/GenDerivOutput1_1.stderr
index 736637f6c2..d76d6bb593 100644
--- a/testsuite/tests/generics/GenDerivOutput1_1.stderr
+++ b/testsuite/tests/generics/GenDerivOutput1_1.stderr
@@ -155,7 +155,7 @@ Derived instances:
 
 
 GHC.Generics representation types:
-    type GHC.Generics.Rep1 CanDoRep1_1.Dd = GHC.Generics.D1
+  type GHC.Generics.Rep1 CanDoRep1_1.Dd = GHC.Generics.D1
                                             ('GHC.Generics.MetaData
                                                "Dd" "CanDoRep1_1" "main" 'GHC.Types.False)
                                             (GHC.Generics.C1
@@ -167,15 +167,23 @@ GHC.Generics representation types:
                                                                    "D1d"
                                                                    'GHC.Generics.PrefixI
                                                                    'GHC.Types.True)
-                                                                  (GHC.Generics.S1
-                                                                   ('GHC.Generics.MetaSel "d11d")
-                                                                     GHC.Generics.Par1
-                                                                   GHC.Generics.:*: GHC.Generics.S1
+                                                                (GHC.Generics.S1
+                                                                   ('GHC.Generics.MetaSel
+                                                                      ('GHC.Base.Just "d11d")
+                                                                      'GHC.Generics.NoSourceUnpackedness
+                                                                      'GHC.Generics.NoSourceStrictness
+                                                                      'GHC.Generics.DecidedLazy)
+                                                                   GHC.Generics.Par1
+                                                                 GHC.Generics.:*: GHC.Generics.S1
                                                                                     ('GHC.Generics.MetaSel
-                                                                                       "d12d")
-                                                                                      (GHC.Generics.Rec1
-                                                                                         CanDoRep1_1.Dd)))
-    type GHC.Generics.Rep (CanDoRep1_1.Dd a) = GHC.Generics.D1
+                                                                                       ('GHC.Base.Just
+                                                                                          "d12d")
+                                                                                       'GHC.Generics.NoSourceUnpackedness
+                                                                                       'GHC.Generics.NoSourceStrictness
+                                                                                       'GHC.Generics.DecidedLazy)
+                                                                                    (GHC.Generics.Rec1
+                                                                                       CanDoRep1_1.Dd)))
+  type GHC.Generics.Rep (CanDoRep1_1.Dd a) = GHC.Generics.D1
                                                ('GHC.Generics.MetaData
                                                   "Dd" "CanDoRep1_1" "main" 'GHC.Types.False)
                                                (GHC.Generics.C1
@@ -187,16 +195,24 @@ GHC.Generics representation types:
                                                                       "D1d"
                                                                       'GHC.Generics.PrefixI
                                                                       'GHC.Types.True)
-                                                                     (GHC.Generics.S1
-                                                                      ('GHC.Generics.MetaSel "d11d")
-                                                                        (GHC.Generics.Rec0 a)
-                                                                      GHC.Generics.:*: GHC.Generics.S1
+                                                                   (GHC.Generics.S1
+                                                                      ('GHC.Generics.MetaSel
+                                                                         ('GHC.Base.Just "d11d")
+                                                                         'GHC.Generics.NoSourceUnpackedness
+                                                                         'GHC.Generics.NoSourceStrictness
+                                                                         'GHC.Generics.DecidedLazy)
+                                                                      (GHC.Generics.Rec0 a)
+                                                                    GHC.Generics.:*: GHC.Generics.S1
                                                                                        ('GHC.Generics.MetaSel
-                                                                                          "d12d")
-                                                                                         (GHC.Generics.Rec0
-                                                                                            (CanDoRep1_1.Dd
-                                                                                               a))))
-    type GHC.Generics.Rep (CanDoRep1_1.Dc a) = GHC.Generics.D1
+                                                                                          ('GHC.Base.Just
+                                                                                             "d12d")
+                                                                                          'GHC.Generics.NoSourceUnpackedness
+                                                                                          'GHC.Generics.NoSourceStrictness
+                                                                                          'GHC.Generics.DecidedLazy)
+                                                                                       (GHC.Generics.Rec0
+                                                                                          (CanDoRep1_1.Dd
+                                                                                             a))))
+  type GHC.Generics.Rep (CanDoRep1_1.Dc a) = GHC.Generics.D1
                                                ('GHC.Generics.MetaData
                                                   "Dc" "CanDoRep1_1" "main" 'GHC.Types.False)
                                                (GHC.Generics.C1
@@ -208,16 +224,24 @@ GHC.Generics representation types:
                                                                       "D1c"
                                                                       'GHC.Generics.PrefixI
                                                                       'GHC.Types.True)
-                                                                     (GHC.Generics.S1
-                                                                      ('GHC.Generics.MetaSel "d11c")
-                                                                        (GHC.Generics.Rec0 a)
-                                                                      GHC.Generics.:*: GHC.Generics.S1
+                                                                   (GHC.Generics.S1
+                                                                      ('GHC.Generics.MetaSel
+                                                                         ('GHC.Base.Just "d11c")
+                                                                         'GHC.Generics.NoSourceUnpackedness
+                                                                         'GHC.Generics.NoSourceStrictness
+                                                                         'GHC.Generics.DecidedLazy)
+                                                                      (GHC.Generics.Rec0 a)
+                                                                    GHC.Generics.:*: GHC.Generics.S1
                                                                                        ('GHC.Generics.MetaSel
-                                                                                          "d12c")
-                                                                                         (GHC.Generics.Rec0
-                                                                                            (CanDoRep1_1.Dc
-                                                                                               a))))
-    type GHC.Generics.Rep1 CanDoRep1_1.Db = GHC.Generics.D1
+                                                                                          ('GHC.Base.Just
+                                                                                             "d12c")
+                                                                                          'GHC.Generics.NoSourceUnpackedness
+                                                                                          'GHC.Generics.NoSourceStrictness
+                                                                                          'GHC.Generics.DecidedLazy)
+                                                                                       (GHC.Generics.Rec0
+                                                                                          (CanDoRep1_1.Dc
+                                                                                             a))))
+  type GHC.Generics.Rep1 CanDoRep1_1.Db = GHC.Generics.D1
                                             ('GHC.Generics.MetaData
                                                "Db" "CanDoRep1_1" "main" 'GHC.Types.False)
                                             (GHC.Generics.C1
@@ -229,15 +253,23 @@ GHC.Generics representation types:
                                                                    "D1b"
                                                                    'GHC.Generics.PrefixI
                                                                    'GHC.Types.True)
-                                                                  (GHC.Generics.S1
-                                                                   ('GHC.Generics.MetaSel "d11b")
-                                                                     GHC.Generics.Par1
-                                                                   GHC.Generics.:*: GHC.Generics.S1
+                                                                (GHC.Generics.S1
+                                                                   ('GHC.Generics.MetaSel
+                                                                      ('GHC.Base.Just "d11b")
+                                                                      'GHC.Generics.NoSourceUnpackedness
+                                                                      'GHC.Generics.NoSourceStrictness
+                                                                      'GHC.Generics.DecidedLazy)
+                                                                   GHC.Generics.Par1
+                                                                 GHC.Generics.:*: GHC.Generics.S1
                                                                                     ('GHC.Generics.MetaSel
-                                                                                       "d12b")
-                                                                                      (GHC.Generics.Rec1
-                                                                                         CanDoRep1_1.Db)))
-    type GHC.Generics.Rep (CanDoRep1_1.Da a) = GHC.Generics.D1
+                                                                                       ('GHC.Base.Just
+                                                                                          "d12b")
+                                                                                       'GHC.Generics.NoSourceUnpackedness
+                                                                                       'GHC.Generics.NoSourceStrictness
+                                                                                       'GHC.Generics.DecidedLazy)
+                                                                                    (GHC.Generics.Rec1
+                                                                                       CanDoRep1_1.Db)))
+  type GHC.Generics.Rep (CanDoRep1_1.Da a) = GHC.Generics.D1
                                                ('GHC.Generics.MetaData
                                                   "Da" "CanDoRep1_1" "main" 'GHC.Types.False)
                                                (GHC.Generics.C1
@@ -249,16 +281,24 @@ GHC.Generics representation types:
                                                                       "D1"
                                                                       'GHC.Generics.PrefixI
                                                                       'GHC.Types.True)
-                                                                     (GHC.Generics.S1
-                                                                      ('GHC.Generics.MetaSel "d11a")
-                                                                        (GHC.Generics.Rec0 a)
-                                                                      GHC.Generics.:*: GHC.Generics.S1
+                                                                   (GHC.Generics.S1
+                                                                      ('GHC.Generics.MetaSel
+                                                                         ('GHC.Base.Just "d11a")
+                                                                         'GHC.Generics.NoSourceUnpackedness
+                                                                         'GHC.Generics.NoSourceStrictness
+                                                                         'GHC.Generics.DecidedLazy)
+                                                                      (GHC.Generics.Rec0 a)
+                                                                    GHC.Generics.:*: GHC.Generics.S1
                                                                                        ('GHC.Generics.MetaSel
-                                                                                          "d12a")
-                                                                                         (GHC.Generics.Rec0
-                                                                                            (CanDoRep1_1.Da
-                                                                                               a))))
-    type GHC.Generics.Rep1 CanDoRep1_1.Da = GHC.Generics.D1
+                                                                                          ('GHC.Base.Just
+                                                                                             "d12a")
+                                                                                          'GHC.Generics.NoSourceUnpackedness
+                                                                                          'GHC.Generics.NoSourceStrictness
+                                                                                          'GHC.Generics.DecidedLazy)
+                                                                                       (GHC.Generics.Rec0
+                                                                                          (CanDoRep1_1.Da
+                                                                                             a))))
+  type GHC.Generics.Rep1 CanDoRep1_1.Da = GHC.Generics.D1
                                             ('GHC.Generics.MetaData
                                                "Da" "CanDoRep1_1" "main" 'GHC.Types.False)
                                             (GHC.Generics.C1
@@ -270,15 +310,23 @@ GHC.Generics representation types:
                                                                    "D1"
                                                                    'GHC.Generics.PrefixI
                                                                    'GHC.Types.True)
-                                                                  (GHC.Generics.S1
-                                                                   ('GHC.Generics.MetaSel "d11a")
-                                                                     GHC.Generics.Par1
-                                                                   GHC.Generics.:*: GHC.Generics.S1
+                                                                (GHC.Generics.S1
+                                                                   ('GHC.Generics.MetaSel
+                                                                      ('GHC.Base.Just "d11a")
+                                                                      'GHC.Generics.NoSourceUnpackedness
+                                                                      'GHC.Generics.NoSourceStrictness
+                                                                      'GHC.Generics.DecidedLazy)
+                                                                   GHC.Generics.Par1
+                                                                 GHC.Generics.:*: GHC.Generics.S1
                                                                                     ('GHC.Generics.MetaSel
-                                                                                       "d12a")
-                                                                                      (GHC.Generics.Rec1
-                                                                                         CanDoRep1_1.Da)))
-    type GHC.Generics.Rep (CanDoRep1_1.Db a) = GHC.Generics.D1
+                                                                                       ('GHC.Base.Just
+                                                                                          "d12a")
+                                                                                       'GHC.Generics.NoSourceUnpackedness
+                                                                                       'GHC.Generics.NoSourceStrictness
+                                                                                       'GHC.Generics.DecidedLazy)
+                                                                                    (GHC.Generics.Rec1
+                                                                                       CanDoRep1_1.Da)))
+  type GHC.Generics.Rep (CanDoRep1_1.Db a) = GHC.Generics.D1
                                                ('GHC.Generics.MetaData
                                                   "Db" "CanDoRep1_1" "main" 'GHC.Types.False)
                                                (GHC.Generics.C1
@@ -290,16 +338,24 @@ GHC.Generics representation types:
                                                                       "D1b"
                                                                       'GHC.Generics.PrefixI
                                                                       'GHC.Types.True)
-                                                                     (GHC.Generics.S1
-                                                                      ('GHC.Generics.MetaSel "d11b")
-                                                                        (GHC.Generics.Rec0 a)
-                                                                      GHC.Generics.:*: GHC.Generics.S1
+                                                                   (GHC.Generics.S1
+                                                                      ('GHC.Generics.MetaSel
+                                                                         ('GHC.Base.Just "d11b")
+                                                                         'GHC.Generics.NoSourceUnpackedness
+                                                                         'GHC.Generics.NoSourceStrictness
+                                                                         'GHC.Generics.DecidedLazy)
+                                                                      (GHC.Generics.Rec0 a)
+                                                                    GHC.Generics.:*: GHC.Generics.S1
                                                                                        ('GHC.Generics.MetaSel
-                                                                                          "d12b")
-                                                                                         (GHC.Generics.Rec0
-                                                                                            (CanDoRep1_1.Db
-                                                                                               a))))
-    type GHC.Generics.Rep1 CanDoRep1_1.Dc = GHC.Generics.D1
+                                                                                          ('GHC.Base.Just
+                                                                                             "d12b")
+                                                                                          'GHC.Generics.NoSourceUnpackedness
+                                                                                          'GHC.Generics.NoSourceStrictness
+                                                                                          'GHC.Generics.DecidedLazy)
+                                                                                       (GHC.Generics.Rec0
+                                                                                          (CanDoRep1_1.Db
+                                                                                             a))))
+  type GHC.Generics.Rep1 CanDoRep1_1.Dc = GHC.Generics.D1
                                             ('GHC.Generics.MetaData
                                                "Dc" "CanDoRep1_1" "main" 'GHC.Types.False)
                                             (GHC.Generics.C1
@@ -311,13 +367,21 @@ GHC.Generics representation types:
                                                                    "D1c"
                                                                    'GHC.Generics.PrefixI
                                                                    'GHC.Types.True)
-                                                                  (GHC.Generics.S1
-                                                                   ('GHC.Generics.MetaSel "d11c")
-                                                                     GHC.Generics.Par1
-                                                                   GHC.Generics.:*: GHC.Generics.S1
+                                                                (GHC.Generics.S1
+                                                                   ('GHC.Generics.MetaSel
+                                                                      ('GHC.Base.Just "d11c")
+                                                                      'GHC.Generics.NoSourceUnpackedness
+                                                                      'GHC.Generics.NoSourceStrictness
+                                                                      'GHC.Generics.DecidedLazy)
+                                                                   GHC.Generics.Par1
+                                                                 GHC.Generics.:*: GHC.Generics.S1
                                                                                     ('GHC.Generics.MetaSel
-                                                                                       "d12c")
-                                                                                      (GHC.Generics.Rec1
-                                                                                         CanDoRep1_1.Dc)))
+                                                                                       ('GHC.Base.Just
+                                                                                          "d12c")
+                                                                                       'GHC.Generics.NoSourceUnpackedness
+                                                                                       'GHC.Generics.NoSourceStrictness
+                                                                                       'GHC.Generics.DecidedLazy)
+                                                                                    (GHC.Generics.Rec1
+                                                                                       CanDoRep1_1.Dc)))
 
 
diff --git a/testsuite/tests/generics/all.T b/testsuite/tests/generics/all.T
index cbf70cf8bf..32534834f2 100644
--- a/testsuite/tests/generics/all.T
+++ b/testsuite/tests/generics/all.T
@@ -17,6 +17,8 @@ test('GenCannotDoRep1_6', normal, compile_fail, [''])
 test('GenCannotDoRep1_7', normal, compile_fail, [''])
 test('GenCannotDoRep1_8', normal, compile_fail, [''])
 
+test('GFullyStrict', normal, compile_and_run, [''])
+
 test('T5462Yes1', outputdir('out_T5462Yes1')
     , multimod_compile_and_run, ['T5462Yes1', '-iGEq -iGEnum -iGFunctor'])
 test('T5462Yes2', outputdir('out_T5462Yes2')