Typecheck remaining ValArgs in rebuildHsApps

This patch refactors hasFixedRuntimeRep_remainingValArgs, renaming it
to tcRemainingValArgs. The logic is moved to rebuildHsApps, which
ensures consistent behaviour across tcApp and quickLookArg1/tcEValArg.

This patch also refactors the treatment of stupid theta for data
constructors, changing the place we drop stupid theta arguments
from dsConLike to mkDataConRep (now the datacon wrapper drops these
arguments).

We decided not to implement PHASE 2 of the FixedRuntimeRep plan for
these remaining ValArgs. Future directions are outlined on the wiki:
  https://gitlab.haskell.org/ghc/ghc/-/wikis/Remaining-ValArgs

Fixes #21544 and #21650

21 files changed, 212 insertions, 118 deletions

diff --git a/testsuite/tests/linear/should_compile/LinearDataConSections.hs b/testsuite/tests/linear/should_compile/LinearDataConSections.hs
index 8a71a494c8..b00fabced5 100644
--- a/testsuite/tests/linear/should_compile/LinearDataConSections.hs
+++ b/testsuite/tests/linear/should_compile/LinearDataConSections.hs
@@ -14,4 +14,4 @@ foo :: Char %Many -> D
 foo = (True `MkD`)
 
 bar :: Bool %Many -> D
-bar = (`MkD` 'y')
\ No newline at end of file
+bar = (`MkD` 'y')
diff --git a/testsuite/tests/rename/should_fail/rnfail055.stderr b/testsuite/tests/rename/should_fail/rnfail055.stderr
index 5034a85ec2..787009a4c6 100644
--- a/testsuite/tests/rename/should_fail/rnfail055.stderr
+++ b/testsuite/tests/rename/should_fail/rnfail055.stderr
@@ -52,6 +52,7 @@ RnFail055.hs-boot:15:1: error:
     The roles do not match.
     Roles on abstract types default to ‘representational’ in boot files.
     The datatype contexts do not match
+    The constructors do not match: The types for ‘T2’ differ
 
 RnFail055.hs-boot:17:11: error:
     ‘T3’ is exported by the hs-boot file, but not exported by the module
diff --git a/testsuite/tests/rep-poly/EtaExpandDataCon.hs b/testsuite/tests/rep-poly/EtaExpandDataCon.hs
index fb4618578a..9f31b7f452 100644
--- a/testsuite/tests/rep-poly/EtaExpandDataCon.hs
+++ b/testsuite/tests/rep-poly/EtaExpandDataCon.hs
@@ -39,7 +39,6 @@ newtype N3 a where
 
 foo3 :: (a %1 -> N3 a) -> N3 a
 foo3 = MkN3
-
 type D4 :: TYPE FloatRep -> Type -> Type
 data D4 a b = MkD4 a b b
 
diff --git a/testsuite/tests/rep-poly/EtaExpandDataFamily.hs b/testsuite/tests/rep-poly/EtaExpandDataFamily.hs
deleted file mode 100644
index 02475f6cb1..0000000000
--- a/testsuite/tests/rep-poly/EtaExpandDataFamily.hs
+++ /dev/null
@@ -1,29 +0,0 @@
-
-{-# LANGUAGE DataKinds #-}
-{-# LANGUAGE DatatypeContexts #-}
-{-# LANGUAGE MagicHash #-}
-{-# LANGUAGE PolyKinds #-}
-{-# LANGUAGE StandaloneKindSignatures #-}
-{-# LANGUAGE TypeFamilies #-}
-{-# LANGUAGE UnliftedNewtypes #-}
-
-module EtaExpandDataFamily where
-
-import Data.Kind
-import GHC.Exts
-
-
-type N :: forall (r :: RuntimeRep) -> TYPE r -> TYPE r
-data family N r a
-newtype instance N r a = MkN a
-
-foo :: Int# -> N IntRep Int#
-foo = MkN
-
-
-type N :: forall (r :: RuntimeRep) -> TYPE r -> Type -> Type -> Type -> TYPE r
-data family N r a i
-newtype instance Ord b => N r a Int b c = MkN a
-
-foo :: Ord b => Int# -> N IntRep Int# Int b c
-foo = MkN
diff --git a/testsuite/tests/rep-poly/RepPolyMagic.stderr b/testsuite/tests/rep-poly/RepPolyMagic.stderr
index f99d0c740a..47e7ba81d3 100644
--- a/testsuite/tests/rep-poly/RepPolyMagic.stderr
+++ b/testsuite/tests/rep-poly/RepPolyMagic.stderr
@@ -4,23 +4,15 @@ RepPolyMagic.hs:12:7: error:
       The second argument of ‘seq’
       does not have a fixed runtime representation.
       Its type is:
-        b0 :: TYPE c1
-      Cannot unify ‘r’ with the type variable ‘c1’
-      because it is not a concrete ‘RuntimeRep’.
+        b :: TYPE r
     • In the expression: seq
       In an equation for ‘foo’: foo = seq
-    • Relevant bindings include
-        foo :: a -> b -> b (bound at RepPolyMagic.hs:12:1)
 
 RepPolyMagic.hs:15:7: error:
     • Unsaturated use of a representation-polymorphic primitive function.
       The second argument of ‘oneShot’
       does not have a fixed runtime representation.
       Its type is:
-        a0 :: TYPE c0
-      Cannot unify ‘r’ with the type variable ‘c0’
-      because it is not a concrete ‘RuntimeRep’.
+        a :: TYPE r
     • In the expression: oneShot
       In an equation for ‘bar’: bar = oneShot
-    • Relevant bindings include
-        bar :: (a -> a) -> a -> a (bound at RepPolyMagic.hs:15:1)
diff --git a/testsuite/tests/rep-poly/RepPolyRightSection.stderr b/testsuite/tests/rep-poly/RepPolyRightSection.stderr
index fdc7a399fa..62c0bdcd8d 100644
--- a/testsuite/tests/rep-poly/RepPolyRightSection.stderr
+++ b/testsuite/tests/rep-poly/RepPolyRightSection.stderr
@@ -4,10 +4,6 @@ RepPolyRightSection.hs:14:11: error:
       The third argument of ‘rightSection’
       does not have a fixed runtime representation.
       Its type is:
-        a :: TYPE c0
-      Cannot unify ‘r’ with the type variable ‘c0’
-      because it is not a concrete ‘RuntimeRep’.
+        a :: TYPE r
     • In the expression: `g` undefined
       In an equation for ‘test2’: test2 = (`g` undefined)
-    • Relevant bindings include
-        test2 :: a -> a (bound at RepPolyRightSection.hs:14:1)
diff --git a/testsuite/tests/rep-poly/RepPolyTuple2.hs b/testsuite/tests/rep-poly/RepPolyTuple2.hs
new file mode 100644
index 0000000000..43e590587b
--- /dev/null
+++ b/testsuite/tests/rep-poly/RepPolyTuple2.hs
@@ -0,0 +1,21 @@
+{-# LANGUAGE MagicHash #-}
+{-# LANGUAGE DataKinds #-}
+{-# LANGUAGE PolyKinds #-}
+{-# LANGUAGE ScopedTypeVariables #-}
+{-# LANGUAGE TypeFamilies #-}
+{-# LANGUAGE UnboxedTuples #-}
+
+module RepPolyTuple2 where
+
+import GHC.Exts
+
+type RR :: RuntimeRep
+type family RR where { RR = FloatRep }
+type F :: TYPE RR
+type family F where { F = Float# }
+
+{-# NOINLINE expensive #-}
+expensive :: Float -> Float
+expensive x = cos x ** 123.45
+
+tup x = (# , #) @LiftedRep @RR (expensive x)
diff --git a/testsuite/tests/rep-poly/RepPolyTuple2.stderr b/testsuite/tests/rep-poly/RepPolyTuple2.stderr
new file mode 100644
index 0000000000..558e1bf1bb
--- /dev/null
+++ b/testsuite/tests/rep-poly/RepPolyTuple2.stderr
@@ -0,0 +1,10 @@
+
+RepPolyTuple2.hs:21:9: error:
+    • Unsaturated use of a representation-polymorphic data constructor.
+      The second argument of ‘(#,#)’
+      does not have a fixed runtime representation.
+      Its type is:
+        b :: TYPE RR
+    • In the expression: (#,#) @LiftedRep @RR (expensive x)
+      In an equation for ‘tup’:
+          tup x = (#,#) @LiftedRep @RR (expensive x)
diff --git a/testsuite/tests/rep-poly/RepPolyUnliftedNewtype.hs b/testsuite/tests/rep-poly/RepPolyUnliftedNewtype.hs
new file mode 100644
index 0000000000..65a1fea656
--- /dev/null
+++ b/testsuite/tests/rep-poly/RepPolyUnliftedNewtype.hs
@@ -0,0 +1,55 @@
+{-# LANGUAGE DataKinds #-}
+{-# LANGUAGE DatatypeContexts #-}
+{-# LANGUAGE LinearTypes #-}
+{-# LANGUAGE MagicHash #-}
+{-# LANGUAGE PartialTypeSignatures #-}
+{-# LANGUAGE PolyKinds #-}
+{-# LANGUAGE StandaloneKindSignatures #-}
+{-# LANGUAGE TypeApplications #-}
+{-# LANGUAGE UnliftedNewtypes #-}
+
+module RepPolyUnliftedNewtype where
+
+import GHC.Exts
+import GHC.Types (Multiplicity(..))
+
+type C :: forall (r :: RuntimeRep). TYPE r -> Constraint
+class C a
+instance C Int#
+
+type N :: forall (r :: RuntimeRep). TYPE r -> TYPE r
+newtype C a => N a = MkN a
+
+f1, f2, f3, f4, f5, f6, f7 :: Int# %Many -> N Int#
+f1 = MkN
+f2 = MkN @_
+f3 = MkN @IntRep
+f4 = MkN @_      @_
+f5 = MkN @_      @Int#
+f6 = MkN @IntRep @_
+f7 = MkN @IntRep @Int#
+
+g1, g2, g3, g4, g5, g6, g7 :: Int# %Many -> N Int#
+g1 x = MkN               x
+g2 x = MkN @_            x
+g3 x = MkN @IntRep       x
+g4 x = MkN @_      @_    x
+g5 x = MkN @_      @Int# x
+g6 x = MkN @IntRep @_    x
+g7 x = MkN @IntRep @Int# x
+
+h3, h5, h6, h7 :: _ => _ %Many -> N _
+h3 = MkN @IntRep
+h5 = MkN @_      @Int#
+h6 = MkN @IntRep @_
+h7 = MkN @IntRep @Int#
+
+k1 (x :: Int#) = MkN               x
+k2 (x :: Int#) = MkN @_            x
+k3  x          = MkN @IntRep       x
+k4 (x :: Int#) = MkN @_      @_    x
+k5  x          = MkN @_      @Int# x
+k6  x          = MkN @IntRep @_    x
+k7  x          = MkN @IntRep @Int# x
+
+l1 = (MkN :: Int# %Many -> N Int#)
diff --git a/testsuite/tests/rep-poly/T13233.stderr b/testsuite/tests/rep-poly/T13233.stderr
index 5b083ea6c7..c7e6be02fc 100644
--- a/testsuite/tests/rep-poly/T13233.stderr
+++ b/testsuite/tests/rep-poly/T13233.stderr
@@ -1,24 +1,30 @@
 
 T13233.hs:14:11: error:
-    • The data constructor argument in second position
-      does not have a fixed runtime representation.
-      Its type is:
-        b1 :: TYPE c3
-      Cannot unify ‘rep’ with the type variable ‘c3’
-      because it is not a concrete ‘RuntimeRep’.
+    • • Unsaturated use of a representation-polymorphic data constructor.
+        The second argument of ‘(#,#)’
+        does not have a fixed runtime representation.
+        Its type is:
+          a :: TYPE rep
+      • Unsaturated use of a representation-polymorphic data constructor.
+        The first argument of ‘(#,#)’
+        does not have a fixed runtime representation.
+        Its type is:
+          a :: TYPE rep
     • In the first argument of ‘bar’, namely ‘(#,#)’
       In the expression: bar (#,#)
       In an equation for ‘baz’: baz = bar (#,#)
-    • Relevant bindings include
-        baz :: a -> a -> (# a, a #) (bound at T13233.hs:14:1)
 
 T13233.hs:22:16: error:
-    • The data constructor argument in second position
-      does not have a fixed runtime representation.
-      Its type is:
-        b0 :: TYPE c1
-      Cannot unify ‘rep2’ with the type variable ‘c1’
-      because it is not a concrete ‘RuntimeRep’.
+    • • Unsaturated use of a representation-polymorphic data constructor.
+        The second argument of ‘(#,#)’
+        does not have a fixed runtime representation.
+        Its type is:
+          b :: TYPE rep2
+      • Unsaturated use of a representation-polymorphic data constructor.
+        The first argument of ‘(#,#)’
+        does not have a fixed runtime representation.
+        Its type is:
+          a :: TYPE rep1
     • In the first argument of ‘obscure’, namely ‘(#,#)’
       In the expression: obscure (#,#)
       In an equation for ‘quux’: quux = obscure (#,#)
diff --git a/testsuite/tests/rep-poly/T14561.stderr b/testsuite/tests/rep-poly/T14561.stderr
index 8f102143eb..3c372e689c 100644
--- a/testsuite/tests/rep-poly/T14561.stderr
+++ b/testsuite/tests/rep-poly/T14561.stderr
@@ -4,10 +4,6 @@ T14561.hs:12:9: error:
       The first argument of ‘unsafeCoerce#’
       does not have a fixed runtime representation.
       Its type is:
-        a0 :: TYPE c0
-      Cannot unify ‘r’ with the type variable ‘c0’
-      because it is not a concrete ‘RuntimeRep’.
+        a :: TYPE r
     • In the expression: unsafeCoerce#
       In an equation for ‘badId’: badId = unsafeCoerce#
-    • Relevant bindings include
-        badId :: a -> a (bound at T14561.hs:12:1)
diff --git a/testsuite/tests/rep-poly/T14561b.stderr b/testsuite/tests/rep-poly/T14561b.stderr
index bbc72d01d8..7af3b05511 100644
--- a/testsuite/tests/rep-poly/T14561b.stderr
+++ b/testsuite/tests/rep-poly/T14561b.stderr
@@ -4,10 +4,6 @@ T14561b.hs:12:9: error:
       The first argument of ‘coerce’
       does not have a fixed runtime representation.
       Its type is:
-        a0 :: TYPE c0
-      Cannot unify ‘r’ with the type variable ‘c0’
-      because it is not a concrete ‘RuntimeRep’.
+        a :: TYPE r
     • In the expression: coerce
       In an equation for ‘badId’: badId = coerce
-    • Relevant bindings include
-        badId :: a -> a (bound at T14561b.hs:12:1)
diff --git a/testsuite/tests/rep-poly/T17817.stderr b/testsuite/tests/rep-poly/T17817.stderr
index 4fb45622bc..7acdec120a 100644
--- a/testsuite/tests/rep-poly/T17817.stderr
+++ b/testsuite/tests/rep-poly/T17817.stderr
@@ -4,15 +4,6 @@ T17817.hs:16:10: error:
       The first argument of ‘mkWeak#’
       does not have a fixed runtime representation.
       Its type is:
-        a0 :: TYPE ('BoxedRep c0)
-      Cannot unify ‘l’ with the type variable ‘c0’
-      because it is not a concrete ‘Levity’.
+        a :: TYPE ('BoxedRep l)
     • In the expression: mkWeak#
       In an equation for ‘primop’: primop = mkWeak#
-    • Relevant bindings include
-        primop :: a
-                  -> b
-                  -> (State# RealWorld -> (# State# RealWorld, c #))
-                  -> State# RealWorld
-                  -> (# State# RealWorld, Weak# b #)
-          (bound at T17817.hs:16:1)
diff --git a/testsuite/tests/rep-poly/T21544.hs b/testsuite/tests/rep-poly/T21544.hs
new file mode 100644
index 0000000000..38793c8a15
--- /dev/null
+++ b/testsuite/tests/rep-poly/T21544.hs
@@ -0,0 +1,29 @@
+
+{-# LANGUAGE DataKinds #-}
+{-# LANGUAGE DatatypeContexts #-}
+{-# LANGUAGE MagicHash #-}
+{-# LANGUAGE PolyKinds #-}
+{-# LANGUAGE StandaloneKindSignatures #-}
+{-# LANGUAGE TypeFamilies #-}
+{-# LANGUAGE UnliftedNewtypes #-}
+
+module T21544 where
+
+import Data.Kind
+import GHC.Exts
+
+
+type N1 :: forall (r :: RuntimeRep) -> TYPE r -> TYPE r
+data family N1 r a
+newtype instance N1 r a = MkN1 a
+
+foo1 :: Int# -> N1 IntRep Int#
+foo1 = MkN1
+
+
+type N2 :: forall (r :: RuntimeRep) -> TYPE r -> Type -> Type -> Type -> TYPE r
+data family N2 r a i
+newtype instance Ord b => N2 r a Int b c = MkN2 a
+
+foo2 :: Ord b => Int# -> N2 IntRep Int# Int b c
+foo2 = MkN2
diff --git a/testsuite/tests/rep-poly/EtaExpandNewtypeTF.hs b/testsuite/tests/rep-poly/T21650_a.hs
index 9145e796b2..2c3e6aacb4 100644
--- a/testsuite/tests/rep-poly/EtaExpandNewtypeTF.hs
+++ b/testsuite/tests/rep-poly/T21650_a.hs
@@ -1,6 +1,6 @@
 {-# LANGUAGE DataKinds, DatatypeContexts, MagicHash, UnliftedNewtypes, TypeFamilies #-}
 
-module EtaExpandNewtypeTF where
+module T21650_a where
 
 import Data.Kind
 import GHC.Exts
diff --git a/testsuite/tests/rep-poly/T21650_a.stderr b/testsuite/tests/rep-poly/T21650_a.stderr
new file mode 100644
index 0000000000..628dbced5a
--- /dev/null
+++ b/testsuite/tests/rep-poly/T21650_a.stderr
@@ -0,0 +1,18 @@
+
+T21650_a.hs:25:8: error:
+    • Unsaturated use of a representation-polymorphic newtype constructor.
+      The first argument of ‘MkN’
+      does not have a fixed runtime representation.
+      Its type is:
+        F Float :: TYPE (R Float)
+    • In the expression: MkN
+      In an equation for ‘foo1’: foo1 = MkN
+
+T21650_a.hs:28:10: error:
+    • Unsaturated use of a representation-polymorphic newtype constructor.
+      The first argument of ‘MkN’
+      does not have a fixed runtime representation.
+      Its type is:
+        F Double :: TYPE (R Double)
+    • In the expression: MkN
+      In an equation for ‘foo2’: foo2 _ = MkN
diff --git a/testsuite/tests/rep-poly/EtaExpandNewtypeTF2.hs b/testsuite/tests/rep-poly/T21650_b.hs
index ba973ae1f9..7274db8863 100644
--- a/testsuite/tests/rep-poly/EtaExpandNewtypeTF2.hs
+++ b/testsuite/tests/rep-poly/T21650_b.hs
@@ -7,7 +7,7 @@
 {-# LANGUAGE UnliftedNewtypes #-}
 {-# LANGUAGE LinearTypes #-}
 
-module EtaExpandNewtypeTF2 where
+module T21650_b where
 
 import Data.Kind
 import GHC.Exts
diff --git a/testsuite/tests/rep-poly/T21650_b.stderr b/testsuite/tests/rep-poly/T21650_b.stderr
new file mode 100644
index 0000000000..5b2ceb0b5c
--- /dev/null
+++ b/testsuite/tests/rep-poly/T21650_b.stderr
@@ -0,0 +1,18 @@
+
+T21650_b.hs:34:7: error:
+    • Unsaturated use of a representation-polymorphic newtype constructor.
+      The first argument of ‘MkN’
+      does not have a fixed runtime representation.
+      Its type is:
+        a :: TYPE (RR T1 t2)
+    • In the expression: MkN
+      In an equation for ‘foo’: foo = MkN
+
+T21650_b.hs:37:7: error:
+    • Unsaturated use of a representation-polymorphic newtype constructor.
+      The first argument of ‘MkN’
+      does not have a fixed runtime representation.
+      Its type is:
+        a :: TYPE (RR T1 t2)
+    • In the expression: MkN
+      In an equation for ‘bar’: bar = MkN
diff --git a/testsuite/tests/rep-poly/UnliftedNewtypesCoerceFail.stderr b/testsuite/tests/rep-poly/UnliftedNewtypesCoerceFail.stderr
index cbb03c1d27..3484650c73 100644
--- a/testsuite/tests/rep-poly/UnliftedNewtypesCoerceFail.stderr
+++ b/testsuite/tests/rep-poly/UnliftedNewtypesCoerceFail.stderr
@@ -4,10 +4,6 @@ UnliftedNewtypesCoerceFail.hs:14:8: error:
       The first argument of ‘coerce’
       does not have a fixed runtime representation.
       Its type is:
-        a0 :: TYPE c0
-      Cannot unify ‘rep’ with the type variable ‘c0’
-      because it is not a concrete ‘RuntimeRep’.
+        x :: TYPE rep
     • In the expression: coerce
       In an equation for ‘goof’: goof = coerce
-    • Relevant bindings include
-        goof :: x -> y (bound at UnliftedNewtypesCoerceFail.hs:14:1)
diff --git a/testsuite/tests/rep-poly/UnliftedNewtypesLevityBinder.stderr b/testsuite/tests/rep-poly/UnliftedNewtypesLevityBinder.stderr
index bd4b2ba2ca..e0bdaa5e8c 100644
--- a/testsuite/tests/rep-poly/UnliftedNewtypesLevityBinder.stderr
+++ b/testsuite/tests/rep-poly/UnliftedNewtypesLevityBinder.stderr
@@ -1,12 +1,9 @@
 
 UnliftedNewtypesLevityBinder.hs:15:7: error:
-    • The newtype constructor argument
+    • Unsaturated use of a representation-polymorphic newtype constructor.
+      The first argument of ‘IdentC’
       does not have a fixed runtime representation.
       Its type is:
-        a0 :: TYPE c0
-      Cannot unify ‘r’ with the type variable ‘c0’
-      because it is not a concrete ‘RuntimeRep’.
+        a :: TYPE r
     • In the expression: IdentC
       In an equation for ‘bad’: bad = IdentC
-    • Relevant bindings include
-        bad :: a -> Ident a (bound at UnliftedNewtypesLevityBinder.hs:15:1)
diff --git a/testsuite/tests/rep-poly/all.T b/testsuite/tests/rep-poly/all.T
index c37289e568..39c9bed7ae 100644
--- a/testsuite/tests/rep-poly/all.T
+++ b/testsuite/tests/rep-poly/all.T
@@ -28,11 +28,9 @@ test('T20423', normal, compile_fail, [''])
 test('T20423b', normal, compile_fail, [''])
 test('T20426', normal, compile_fail, [''])
 test('T21239', normal, compile, [''])
+test('T21544', normal, compile, ['-Wno-deprecated-flags'])
 
 test('EtaExpandDataCon', normal, compile, ['-O'])
-test('EtaExpandDataFamily', expect_broken(21544), compile, [''])
-test('EtaExpandNewtypeTF', expect_broken(21650), compile, ['-Wno-deprecated-flags'])
-test('EtaExpandNewtypeTF2', expect_broken(21650), compile, ['-Wno-deprecated-flags'])
 test('EtaExpandStupid1', normal, compile, ['-Wno-deprecated-flags'])
 test('EtaExpandStupid2', normal, compile_fail, ['-Wno-deprecated-flags'])
 test('LevPolyLet', normal, compile_fail, [''])
@@ -83,31 +81,35 @@ test('RepPolyTupleSection', normal, compile_fail, [''])
 test('RepPolyUnboxedPatterns', normal, compile_fail, [''])
 test('RepPolyUnliftedDatatype', normal, compile, [''])
 test('RepPolyUnliftedDatatype2', normal, compile, ['-O'])
+test('RepPolyUnliftedNewtype', normal, compile,
+     ['-fno-warn-partial-type-signatures -fno-warn-deprecated-flags'])
 test('RepPolyWildcardPattern', normal, compile_fail, [''])
 test('RepPolyWrappedVar', normal, compile_fail, [''])
 test('RepPolyWrappedVar2', normal, compile, [''])
 test('UnliftedNewtypesCoerceFail', normal, compile_fail, [''])
 test('UnliftedNewtypesLevityBinder', normal, compile_fail, [''])
 
-######################################################################
-## The following tests require rewriting in RuntimeReps,            ##
-## i.e. PHASE 2 of the FixedRuntimeRep plan.                        ##
-##                                                                  ##
-## These tests work!                                                ##
-                                                                    ##
-test('T13105', normal, compile, [''])                               ##
-test('T17536b', normal, compile, [''])                              ##
-                                                                    ##
-## These don't!                                                     ##
-## For the moment, we check that we get the expected error message, ##
-## as we want to reject these in the typechecker instead of getting ##
-## a compiler crash.                                                ##
-                                                                    ##
-test('T17021', normal, compile_fail, [''])                          ##
-test('T20363', normal, compile_fail, [''])                          ##
-test('T20363_show_co', normal, compile_fail                         ##
-    , ['-fprint-explicit-coercions'])                               ##
-test('T20363b', normal, compile_fail, [''])                         ##
-test('RepPolyCase2', normal, compile_fail, [''])                    ##
-test('RepPolyRule3', normal, compile_fail, [''])                    ##
-######################################################################
+###############################################################################
+## The following tests require rewriting in RuntimeReps,                     ##
+## i.e. PHASE 2 of the FixedRuntimeRep plan.                                 ##
+##                                                                           ##
+## These tests work!                                                         ##
+                                                                             ##
+test('T13105', normal, compile, [''])                                        ##
+test('T17536b', normal, compile, [''])                                       ##
+                                                                             ##
+## These don't!                                                              ##
+## For the moment, we check that we get the expected error message,          ##
+## as we want to reject these in the typechecker instead of getting          ##
+## a compiler crash.                                                         ##
+                                                                             ##
+test('T17021', normal, compile_fail, [''])                                   ##
+test('T20363', normal, compile_fail, [''])                                   ##
+test('T20363_show_co', normal, compile_fail, ['-fprint-explicit-coercions']) ##
+test('T20363b', normal, compile_fail, [''])                                  ##
+test('RepPolyCase2', normal, compile_fail, [''])                             ##
+test('RepPolyRule3', normal, compile_fail, [''])                             ##
+test('RepPolyTuple2', normal, compile_fail, ['']) ## see #21683              ##
+test('T21650_a', normal, compile_fail, ['-Wno-deprecated-flags'])            ##
+test('T21650_b', normal, compile_fail, ['-Wno-deprecated-flags'])            ##
+###############################################################################