Assume at least one evaluation for nested SubDemands (#21081, #21133)wip/T21081

See the new `Note [SubDemand denotes at least one evaluation]`.

A demand `n :* sd` on a let binder `x=e` now means

> "`x` was evaluated `n` times and in any program trace it is evaluated, `e` is
>  evaluated deeply in sub-demand `sd`."

The "any time it is evaluated" premise is what this patch adds. As a result,
we get better nested strictness. For example (T21081)
```hs
f :: (Bool, Bool) -> (Bool, Bool)
f pr = (case pr of (a,b) -> a /= b, True)
-- before: <MP(L,L)>
-- after:  <MP(SL,SL)>

g :: Int -> (Bool, Bool)
g x = let y = let z = odd x in (z,z) in f y
```
The change in demand signature "before" to "after" allows us to case-bind `z`
here.

Similarly good things happen for the `sd` in call sub-demands `Cn(sd)`, which
allows for more eta-reduction (which is only sound with `-fno-pedantic-bottoms`,
albeit).

We also fix #21085, a surprising inconsistency with `Poly` to `Call` sub-demand
expansion.

In an attempt to fix a regression caused by less inlining due to eta-reduction
in T15426, I eta-expanded the definition of `elemIndex` and `elemIndices`, thus
fixing #21345 on the go.

The main point of this patch is that it fixes #21081 and #21133.

Annoyingly, I discovered that more precise demand signatures for join points can
transform a program into a lazier program if that join point gets floated to the
top-level, see #21392. There is no simple fix at the moment, but !5349 might.
Thus, we accept a ~5% regression in `MultiLayerModulesTH_OneShot`, where #21392
bites us in `addListToUniqDSet`. T21392 reliably reproduces the issue.

Surprisingly, ghc/alloc perf on Windows improves much more than on other jobs, by
0.4% in the geometric mean and by 2% in T16875.

Metric Increase:
    MultiLayerModulesTH_OneShot
Metric Decrease:
    T16875

44 files changed, 456 insertions, 327 deletions

diff --git a/testsuite/tests/arityanal/should_compile/Arity01.stderr b/testsuite/tests/arityanal/should_compile/Arity01.stderr
index c5c5a24a9a..40d65fe4ea 100644
--- a/testsuite/tests/arityanal/should_compile/Arity01.stderr
+++ b/testsuite/tests/arityanal/should_compile/Arity01.stderr
@@ -1,11 +1,11 @@
 
 ==================== Tidy Core ====================
-Result size of Tidy Core = {terms: 61, types: 43, coercions: 0, joins: 0/0}
+Result size of Tidy Core = {terms: 65, types: 41, coercions: 0, joins: 0/0}
 
--- RHS size: {terms: 1, types: 0, coercions: 0, joins: 0/0}
+-- RHS size: {terms: 2, types: 0, coercions: 0, joins: 0/0}
 F1.f2 :: Integer
-[GblId, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 100 0}]
-F1.f2 = 1
+[GblId, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 10 10}]
+F1.f2 = GHC.Num.Integer.IS 1#
 
 Rec {
 -- RHS size: {terms: 18, types: 4, coercions: 0, joins: 0/0}
@@ -13,16 +13,16 @@ F1.f1_h1 [Occ=LoopBreaker] :: Integer -> Integer -> Integer -> Integer
 [GblId, Arity=3, Str=<SL><SL><SL>, Unf=OtherCon []]
 F1.f1_h1
   = \ (n :: Integer) (x :: Integer) (eta :: Integer) ->
-      case GHC.Num.Integer.integerLt# x n of {
-        __DEFAULT -> eta;
-        1# -> F1.f1_h1 n (GHC.Num.Integer.integerAdd x F1.f2) (GHC.Num.Integer.integerAdd x eta)
+      case GHC.Num.Integer.integerLt x n of {
+        False -> eta;
+        True -> F1.f1_h1 n (GHC.Num.Integer.integerAdd x F1.f2) (GHC.Num.Integer.integerAdd x eta)
       }
 end Rec }
 
--- RHS size: {terms: 1, types: 0, coercions: 0, joins: 0/0}
+-- RHS size: {terms: 2, types: 0, coercions: 0, joins: 0/0}
 F1.f3 :: Integer
-[GblId, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 100 0}]
-F1.f3 = 5
+[GblId, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 10 10}]
+F1.f3 = GHC.Num.Integer.IS 5#
 
 -- RHS size: {terms: 4, types: 0, coercions: 0, joins: 0/0}
 f1 :: Integer
@@ -34,20 +34,20 @@ g :: Integer -> Integer -> Integer -> Integer -> Integer -> Integer
 [GblId, Arity=5, Str=<1L><SL><SL><SL><SL>, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [0 0 0 0 0] 120 0}]
 g = \ (x1 :: Integer) (x2 :: Integer) (x3 :: Integer) (x4 :: Integer) (x5 :: Integer) -> GHC.Num.Integer.integerAdd (GHC.Num.Integer.integerAdd (GHC.Num.Integer.integerAdd (GHC.Num.Integer.integerAdd x1 x2) x3) x4) x5
 
--- RHS size: {terms: 1, types: 0, coercions: 0, joins: 0/0}
+-- RHS size: {terms: 2, types: 0, coercions: 0, joins: 0/0}
 F1.s1 :: Integer
-[GblId, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 100 0}]
-F1.s1 = 3
+[GblId, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 10 10}]
+F1.s1 = GHC.Num.Integer.IS 3#
 
--- RHS size: {terms: 8, types: 8, coercions: 0, joins: 0/0}
+-- RHS size: {terms: 8, types: 7, coercions: 0, joins: 0/0}
 s :: forall {t1} {t2}. Num t1 => (t1 -> t2) -> t2
-[GblId, Arity=2, Str=<MP(A,A,A,A,A,A,MCM(L))><1C1(L)>, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [30 60] 50 0}]
+[GblId, Arity=2, Str=<MP(A,A,A,A,A,A,1C1(L))><1C1(L)>, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [30 60] 50 0}]
 s = \ (@t) (@t1) ($dNum :: Num t) (f :: t -> t1) -> f (fromInteger @t $dNum F1.s1)
 
--- RHS size: {terms: 1, types: 0, coercions: 0, joins: 0/0}
+-- RHS size: {terms: 2, types: 0, coercions: 0, joins: 0/0}
 F1.h1 :: Integer
-[GblId, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 100 0}]
-F1.h1 = 24
+[GblId, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 10 10}]
+F1.h1 = GHC.Num.Integer.IS 24#
 
 -- RHS size: {terms: 4, types: 1, coercions: 0, joins: 0/0}
 h :: Integer -> Integer
diff --git a/testsuite/tests/arityanal/should_compile/Arity05.stderr b/testsuite/tests/arityanal/should_compile/Arity05.stderr
index 7045daa0f1..91c909ecc6 100644
--- a/testsuite/tests/arityanal/should_compile/Arity05.stderr
+++ b/testsuite/tests/arityanal/should_compile/Arity05.stderr
@@ -1,44 +1,44 @@
 
 ==================== Tidy Core ====================
-Result size of Tidy Core = {terms: 54, types: 87, coercions: 0, joins: 0/0}
+Result size of Tidy Core = {terms: 56, types: 87, coercions: 0, joins: 0/0}
 
--- RHS size: {terms: 1, types: 0, coercions: 0, joins: 0/0}
+-- RHS size: {terms: 2, types: 0, coercions: 0, joins: 0/0}
 F5.f5g1 :: Integer
-[GblId, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 100 0}]
-F5.f5g1 = 1
+[GblId, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 10 10}]
+F5.f5g1 = GHC.Num.Integer.IS 1#
 
 -- RHS size: {terms: 12, types: 9, coercions: 0, joins: 0/0}
 f5g :: forall {a} {t}. Num a => (t -> a) -> t -> a
 [GblId,
  Arity=3,
- Str=<SP(1C1(C1(L)),A,A,A,A,A,MCM(L))><MCM(L)><L>,
+ Str=<SP(1C1(C1(L)),A,A,A,A,A,MC1(L))><MC1(L)><L>,
  Unf=Unf{Src=InlineStable, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=ALWAYS_IF(arity=3,unsat_ok=True,boring_ok=False)
          Tmpl= \ (@a) (@t) ($dNum :: Num a) (h [Occ=Once1!] :: t -> a) (z [Occ=Once1] :: t) -> + @a $dNum (h z) (fromInteger @a $dNum F5.f5g1)}]
 f5g = \ (@a) (@t) ($dNum :: Num a) (h :: t -> a) (z :: t) -> + @a $dNum (h z) (fromInteger @a $dNum F5.f5g1)
 
 -- RHS size: {terms: 15, types: 12, coercions: 0, joins: 0/0}
 F5.$wf5h [InlPrag=[2]] :: forall {a} {t}. (a -> a -> a) -> (Integer -> a) -> (t -> a) -> t -> (t -> a) -> a
-[GblId, Arity=5, Str=<SCS(C1(L))><MCM(L)><MCM(L)><L><MCM(L)>, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [60 60 60 0 60] 120 0}]
-F5.$wf5h = \ (@a) (@t) (ww :: a -> a -> a) (ww1 :: Integer -> a) (w :: t -> a) (w1 :: t) (w2 :: t -> a) -> ww (w w1) (ww (w2 w1) (ww1 F5.f5g1))
+[GblId, Arity=5, Str=<SCS(C1(L))><MC1(L)><MC1(L)><L><MC1(L)>, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [60 60 60 0 60] 120 0}]
+F5.$wf5h = \ (@a) (@t) (ww :: a -> a -> a) (ww1 :: Integer -> a) (f :: t -> a) (x :: t) (g :: t -> a) -> ww (f x) (ww (g x) (ww1 F5.f5g1))
 
 -- RHS size: {terms: 15, types: 30, coercions: 0, joins: 0/0}
 f5h [InlPrag=[2]] :: forall {a} {t}. Num a => (t -> a) -> t -> (t -> a) -> a
 [GblId,
  Arity=4,
- Str=<1P(SCS(C1(L)),A,A,A,A,A,MCM(L))><MCM(L)><L><MCM(L)>,
+ Str=<1P(SCS(C1(L)),A,A,A,A,A,MC1(L))><MC1(L)><L><MC1(L)>,
  Unf=Unf{Src=InlineStable, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=ALWAYS_IF(arity=4,unsat_ok=True,boring_ok=False)
-         Tmpl= \ (@a) (@t) (w [Occ=Once1!] :: Num a) (w1 [Occ=Once1] :: t -> a) (w2 [Occ=Once1] :: t) (w3 [Occ=Once1] :: t -> a) -> case w of { GHC.Num.C:Num ww [Occ=Once1] _ [Occ=Dead] _ [Occ=Dead] _ [Occ=Dead] _ [Occ=Dead] _ [Occ=Dead] ww6 [Occ=Once1] -> F5.$wf5h @a @t ww ww6 w1 w2 w3 }}]
-f5h = \ (@a) (@t) (w :: Num a) (w1 :: t -> a) (w2 :: t) (w3 :: t -> a) -> case w of { GHC.Num.C:Num ww ww1 ww2 ww3 ww4 ww5 ww6 -> F5.$wf5h @a @t ww ww6 w1 w2 w3 }
+         Tmpl= \ (@a) (@t) ($dNum [Occ=Once1!] :: Num a) (f [Occ=Once1] :: t -> a) (x [Occ=Once1] :: t) (g [Occ=Once1] :: t -> a) -> case $dNum of { GHC.Num.C:Num ww [Occ=Once1] _ [Occ=Dead] _ [Occ=Dead] _ [Occ=Dead] _ [Occ=Dead] _ [Occ=Dead] ww6 [Occ=Once1] -> F5.$wf5h @a @t ww ww6 f x g }}]
+f5h = \ (@a) (@t) ($dNum :: Num a) (f :: t -> a) (x :: t) (g :: t -> a) -> case $dNum of { GHC.Num.C:Num ww ww1 ww2 ww3 ww4 ww5 ww6 -> F5.$wf5h @a @t ww ww6 f x g }
 
 -- RHS size: {terms: 4, types: 1, coercions: 0, joins: 0/0}
 f5y :: Integer -> Integer
 [GblId, Arity=1, Str=<1L>, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [0] 30 0}]
 f5y = \ (y :: Integer) -> GHC.Num.Integer.integerAdd y F5.f5g1
 
--- RHS size: {terms: 1, types: 0, coercions: 0, joins: 0/0}
+-- RHS size: {terms: 2, types: 0, coercions: 0, joins: 0/0}
 f5 :: Integer
-[GblId, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 100 0}]
-f5 = 3
+[GblId, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 10 10}]
+f5 = GHC.Num.Integer.IS 3#
 
 
 
diff --git a/testsuite/tests/arityanal/should_compile/Arity08.stderr b/testsuite/tests/arityanal/should_compile/Arity08.stderr
index 406b5c6bdf..9885d5f158 100644
--- a/testsuite/tests/arityanal/should_compile/Arity08.stderr
+++ b/testsuite/tests/arityanal/should_compile/Arity08.stderr
@@ -1,10 +1,10 @@
 
 ==================== Tidy Core ====================
-Result size of Tidy Core = {terms: 23, types: 20, coercions: 0, joins: 0/0}
+Result size of Tidy Core = {terms: 24, types: 18, coercions: 0, joins: 0/0}
 
--- RHS size: {terms: 20, types: 11, coercions: 0, joins: 0/0}
+-- RHS size: {terms: 20, types: 10, coercions: 0, joins: 0/0}
 f8f :: forall {p}. Num p => Bool -> p -> p -> p
-[GblId, Arity=4, Str=<LP(LCL(C1(L)),A,MCM(C1(L)),A,A,A,A)><1L><L><L>, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [90 30 0 0] 140 0}]
+[GblId, Arity=4, Str=<LP(SCS(C1(L)),A,MC1(C1(L)),A,A,A,A)><1L><L><L>, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [90 30 0 0] 140 0}]
 f8f
   = \ (@p) ($dNum :: Num p) (b :: Bool) (x :: p) (y :: p) ->
       case b of {
@@ -12,10 +12,10 @@ f8f
         True -> y
       }
 
--- RHS size: {terms: 1, types: 0, coercions: 0, joins: 0/0}
+-- RHS size: {terms: 2, types: 0, coercions: 0, joins: 0/0}
 f8 :: Integer
-[GblId, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 100 0}]
-f8 = 2
+[GblId, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 10 10}]
+f8 = GHC.Num.Integer.IS 2#
 
 
 
diff --git a/testsuite/tests/arityanal/should_compile/Arity11.stderr b/testsuite/tests/arityanal/should_compile/Arity11.stderr
index 48b37a13db..7c7451a6d7 100644
--- a/testsuite/tests/arityanal/should_compile/Arity11.stderr
+++ b/testsuite/tests/arityanal/should_compile/Arity11.stderr
@@ -1,59 +1,77 @@
 
 ==================== Tidy Core ====================
-Result size of Tidy Core = {terms: 129, types: 98, coercions: 0, joins: 0/5}
+Result size of Tidy Core = {terms: 149, types: 104, coercions: 0, joins: 2/7}
 
--- RHS size: {terms: 1, types: 0, coercions: 0, joins: 0/0}
-F11.fib1 :: Integer
-[GblId, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 100 0}]
-F11.fib1 = 0
-
--- RHS size: {terms: 1, types: 0, coercions: 0, joins: 0/0}
+-- RHS size: {terms: 2, types: 0, coercions: 0, joins: 0/0}
 F11.fib3 :: Integer
-[GblId, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 100 0}]
-F11.fib3 = 1
+[GblId, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 10 10}]
+F11.fib3 = GHC.Num.Integer.IS 1#
 
--- RHS size: {terms: 1, types: 0, coercions: 0, joins: 0/0}
+-- RHS size: {terms: 2, types: 0, coercions: 0, joins: 0/0}
 F11.fib2 :: Integer
-[GblId, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 100 0}]
-F11.fib2 = 2
+[GblId, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 10 10}]
+F11.fib2 = GHC.Num.Integer.IS 2#
 
 Rec {
--- RHS size: {terms: 24, types: 3, coercions: 0, joins: 0/0}
+-- RHS size: {terms: 38, types: 13, coercions: 0, joins: 2/2}
 F11.f11_fib [Occ=LoopBreaker] :: Integer -> Integer
 [GblId, Arity=1, Str=<SL>, Unf=OtherCon []]
 F11.f11_fib
   = \ (ds :: Integer) ->
-      case GHC.Num.Integer.integerEq# ds F11.fib1 of {
-        __DEFAULT ->
-          case GHC.Num.Integer.integerEq# ds F11.fib3 of {
-            __DEFAULT -> GHC.Num.Integer.integerAdd (F11.f11_fib (GHC.Num.Integer.integerSub ds F11.fib3)) (F11.f11_fib (GHC.Num.Integer.integerSub ds F11.fib2));
-            1# -> F11.fib3
+      join {
+        $j [Dmd=ML] :: Integer
+        [LclId[JoinId(0)(Nothing)]]
+        $j
+          = join {
+              $j1 [Dmd=ML] :: Integer
+              [LclId[JoinId(0)(Nothing)]]
+              $j1 = GHC.Num.Integer.integerAdd (F11.f11_fib (GHC.Num.Integer.integerSub ds F11.fib3)) (F11.f11_fib (GHC.Num.Integer.integerSub ds F11.fib2)) } in
+            case ds of {
+              GHC.Num.Integer.IS x1 ->
+                case x1 of {
+                  __DEFAULT -> jump $j1;
+                  1# -> F11.fib3
+                };
+              GHC.Num.Integer.IP x1 -> jump $j1;
+              GHC.Num.Integer.IN x1 -> jump $j1
+            } } in
+      case ds of {
+        GHC.Num.Integer.IS x1 ->
+          case x1 of {
+            __DEFAULT -> jump $j;
+            0# -> F11.fib3
           };
-        1# -> F11.fib3
+        GHC.Num.Integer.IP x1 -> jump $j;
+        GHC.Num.Integer.IN x1 -> jump $j
       }
 end Rec }
 
--- RHS size: {terms: 52, types: 27, coercions: 0, joins: 0/5}
+-- RHS size: {terms: 2, types: 0, coercions: 0, joins: 0/0}
+F11.fib1 :: Integer
+[GblId, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 10 10}]
+F11.fib1 = GHC.Num.Integer.IS 0#
+
+-- RHS size: {terms: 52, types: 26, coercions: 0, joins: 0/5}
 F11.$wfib [InlPrag=[2]] :: forall {t} {a}. (t -> t -> Bool) -> (Num t, Num a) => t -> a
-[GblId, Arity=4, Str=<SCS(C1(L))><LP(A,LCL(C1(L)),A,A,A,A,L)><LP(LCL(C1(L)),A,A,A,A,A,MCM(L))><L>, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [60 150 60 0] 460 0}]
+[GblId, Arity=4, Str=<SCS(C1(L))><LP(A,LCS(C1(L)),A,A,A,A,LCS(L))><LP(LCS(C1(L)),A,A,A,A,A,MC1(L))><L>, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [60 150 60 0] 460 0}]
 F11.$wfib
-  = \ (@t) (@a) (ww :: t -> t -> Bool) (w :: Num t) (w1 :: Num a) (w2 :: t) ->
+  = \ (@t) (@a) (ww :: t -> t -> Bool) ($dNum :: Num t) ($dNum1 :: Num a) (eta :: t) ->
       let {
         lvl :: t
         [LclId]
-        lvl = fromInteger @t w F11.fib3 } in
+        lvl = fromInteger @t $dNum F11.fib3 } in
       let {
         lvl1 :: t
         [LclId]
-        lvl1 = fromInteger @t w F11.fib2 } in
+        lvl1 = fromInteger @t $dNum F11.fib2 } in
       let {
         lvl2 :: a
         [LclId]
-        lvl2 = fromInteger @a w1 F11.fib3 } in
+        lvl2 = fromInteger @a $dNum1 F11.fib3 } in
       let {
         lvl3 :: t
         [LclId]
-        lvl3 = fromInteger @t w F11.fib1 } in
+        lvl3 = fromInteger @t $dNum F11.fib1 } in
       letrec {
         fib4 [Occ=LoopBreaker, Dmd=SCS(L)] :: t -> a
         [LclId, Arity=1, Str=<L>, Unf=OtherCon []]
@@ -62,26 +80,26 @@ F11.$wfib
               case ww ds lvl3 of {
                 False ->
                   case ww ds lvl of {
-                    False -> + @a w1 (fib4 (- @t w ds lvl)) (fib4 (- @t w ds lvl1));
+                    False -> + @a $dNum1 (fib4 (- @t $dNum ds lvl)) (fib4 (- @t $dNum ds lvl1));
                     True -> lvl2
                   };
                 True -> lvl2
               }; } in
-      fib4 w2
+      fib4 eta
 
--- RHS size: {terms: 14, types: 20, coercions: 0, joins: 0/0}
+-- RHS size: {terms: 14, types: 19, coercions: 0, joins: 0/0}
 fib [InlPrag=[2]] :: forall {t} {a}. (Eq t, Num t, Num a) => t -> a
 [GblId,
  Arity=4,
- Str=<1!P(SCS(C1(L)),A)><LP(A,LCL(C1(L)),A,A,A,A,L)><LP(LCL(C1(L)),A,A,A,A,A,L)><L>,
+ Str=<1P(SCS(C1(L)),A)><LP(A,LCS(C1(L)),A,A,A,A,LCS(L))><LP(LCS(C1(L)),A,A,A,A,A,LCS(L))><L>,
  Unf=Unf{Src=InlineStable, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=ALWAYS_IF(arity=4,unsat_ok=True,boring_ok=False)
-         Tmpl= \ (@t) (@a) (w [Occ=Once1!] :: Eq t) (w1 [Occ=Once1] :: Num t) (w2 [Occ=Once1] :: Num a) (w3 [Occ=Once1] :: t) -> case w of { GHC.Classes.C:Eq ww [Occ=Once1] _ [Occ=Dead] -> F11.$wfib @t @a ww w1 w2 w3 }}]
-fib = \ (@t) (@a) (w :: Eq t) (w1 :: Num t) (w2 :: Num a) (w3 :: t) -> case w of { GHC.Classes.C:Eq ww ww1 -> F11.$wfib @t @a ww w1 w2 w3 }
+         Tmpl= \ (@t) (@a) ($dEq [Occ=Once1!] :: Eq t) ($dNum [Occ=Once1] :: Num t) ($dNum1 [Occ=Once1] :: Num a) (eta [Occ=Once1] :: t) -> case $dEq of { GHC.Classes.C:Eq ww [Occ=Once1] _ [Occ=Dead] -> F11.$wfib @t @a ww $dNum $dNum1 eta }}]
+fib = \ (@t) (@a) ($dEq :: Eq t) ($dNum :: Num t) ($dNum1 :: Num a) (eta :: t) -> case $dEq of { GHC.Classes.C:Eq ww ww1 -> F11.$wfib @t @a ww $dNum $dNum1 eta }
 
--- RHS size: {terms: 1, types: 0, coercions: 0, joins: 0/0}
+-- RHS size: {terms: 2, types: 0, coercions: 0, joins: 0/0}
 F11.f3 :: Integer
-[GblId, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 100 0}]
-F11.f3 = 1000
+[GblId, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 10 10}]
+F11.f3 = GHC.Num.Integer.IS 1000#
 
 -- RHS size: {terms: 2, types: 0, coercions: 0, joins: 0/0}
 F11.f11_x :: Integer
@@ -98,20 +116,20 @@ f11f :: forall {p}. p -> Integer -> Integer
 [GblId, Arity=2, Str=<A><SL>, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=ALWAYS_IF(arity=1,unsat_ok=True,boring_ok=True)}]
 f11f = \ (@p) _ [Occ=Dead] -> F11.f11f1
 
--- RHS size: {terms: 1, types: 0, coercions: 0, joins: 0/0}
+-- RHS size: {terms: 2, types: 0, coercions: 0, joins: 0/0}
 F11.f5 :: Integer
-[GblId, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 100 0}]
-F11.f5 = 6
+[GblId, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 10 10}]
+F11.f5 = GHC.Num.Integer.IS 6#
 
 -- RHS size: {terms: 3, types: 0, coercions: 0, joins: 0/0}
 F11.f4 :: Integer
 [GblId, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=False, ConLike=False, WorkFree=False, Expandable=False, Guidance=IF_ARGS [] 30 0}]
 F11.f4 = GHC.Num.Integer.integerAdd F11.f11_x F11.f5
 
--- RHS size: {terms: 1, types: 0, coercions: 0, joins: 0/0}
+-- RHS size: {terms: 2, types: 0, coercions: 0, joins: 0/0}
 F11.f2 :: Integer
-[GblId, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 100 0}]
-F11.f2 = 8
+[GblId, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 10 10}]
+F11.f2 = GHC.Num.Integer.IS 8#
 
 -- RHS size: {terms: 3, types: 0, coercions: 0, joins: 0/0}
 F11.f1 :: Integer
diff --git a/testsuite/tests/arityanal/should_compile/Arity14.stderr b/testsuite/tests/arityanal/should_compile/Arity14.stderr
index efd90363c6..fec1b63641 100644
--- a/testsuite/tests/arityanal/should_compile/Arity14.stderr
+++ b/testsuite/tests/arityanal/should_compile/Arity14.stderr
@@ -1,26 +1,26 @@
 
 ==================== Tidy Core ====================
-Result size of Tidy Core = {terms: 56, types: 87, coercions: 0, joins: 0/3}
+Result size of Tidy Core = {terms: 57, types: 81, coercions: 0, joins: 0/3}
 
--- RHS size: {terms: 3, types: 3, coercions: 0, joins: 0/0}
+-- RHS size: {terms: 3, types: 2, coercions: 0, joins: 0/0}
 F14.f1 :: forall {t}. t -> t
 [GblId, Arity=1, Str=<1L>, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=ALWAYS_IF(arity=1,unsat_ok=True,boring_ok=True)}]
 F14.f1 = \ (@t) (y :: t) -> y
 
--- RHS size: {terms: 1, types: 0, coercions: 0, joins: 0/0}
+-- RHS size: {terms: 2, types: 0, coercions: 0, joins: 0/0}
 F14.f2 :: Integer
-[GblId, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 100 0}]
-F14.f2 = 1
+[GblId, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [] 10 10}]
+F14.f2 = GHC.Num.Integer.IS 1#
 
--- RHS size: {terms: 35, types: 24, coercions: 0, joins: 0/3}
+-- RHS size: {terms: 35, types: 23, coercions: 0, joins: 0/3}
 F14.$wf14 [InlPrag=[2]] :: forall {t}. (t -> t -> Bool) -> Num t => t -> t -> t -> t
-[GblId, Arity=4, Str=<SCS(C1(L))><LP(LCL(C1(L)),A,A,A,A,A,MCM(L))><L><L>, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [60 90 0 0] 300 0}]
+[GblId, Arity=4, Str=<SCS(C1(L))><LP(LCS(C1(L)),A,A,A,A,A,MC1(L))><L><L>, Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=IF_ARGS [60 90 0 0] 300 0}]
 F14.$wf14
-  = \ (@t) (ww :: t -> t -> Bool) (w :: Num t) (w1 :: t) (w2 :: t) ->
+  = \ (@t) (ww :: t -> t -> Bool) ($dNum :: Num t) (eta :: t) (eta1 :: t) ->
       let {
         lvl :: t
         [LclId]
-        lvl = fromInteger @t w F14.f2 } in
+        lvl = fromInteger @t $dNum F14.f2 } in
       letrec {
         f3 [Occ=LoopBreaker, Dmd=SCS(C1(L))] :: t -> t -> t -> t
         [LclId, Arity=2, Str=<L><L>, Unf=OtherCon []]
@@ -30,21 +30,21 @@ F14.$wf14
                 False -> F14.f1 @t;
                 True ->
                   let {
-                    v :: t -> t
+                    v [Dmd=LCS(L)] :: t -> t
                     [LclId]
-                    v = f3 n (+ @t w x lvl) } in
-                  \ (y :: t) -> v (+ @t w x y)
+                    v = f3 n (+ @t $dNum x lvl) } in
+                  \ (y :: t) -> v (+ @t $dNum x y)
               }; } in
-      f3 w1 w2
+      f3 eta eta1
 
--- RHS size: {terms: 13, types: 34, coercions: 0, joins: 0/0}
+-- RHS size: {terms: 13, types: 33, coercions: 0, joins: 0/0}
 f14 [InlPrag=[2]] :: forall {t}. (Ord t, Num t) => t -> t -> t -> t
 [GblId,
  Arity=4,
- Str=<1!P(A,A,SCS(C1(L)),A,A,A,A,A)><LP(LCL(C1(L)),A,A,A,A,A,L)><L><L>,
+ Str=<1P(A,A,SCS(C1(L)),A,A,A,A,A)><LP(LCS(C1(L)),A,A,A,A,A,LCS(L))><L><L>,
  Unf=Unf{Src=InlineStable, TopLvl=True, Value=True, ConLike=True, WorkFree=True, Expandable=True, Guidance=ALWAYS_IF(arity=4,unsat_ok=True,boring_ok=False)
-         Tmpl= \ (@t) (w [Occ=Once1!] :: Ord t) (w1 [Occ=Once1] :: Num t) (w2 [Occ=Once1] :: t) (w3 [Occ=Once1] :: t) -> case w of { GHC.Classes.C:Ord _ [Occ=Dead] _ [Occ=Dead] ww2 [Occ=Once1] _ [Occ=Dead] _ [Occ=Dead] _ [Occ=Dead] _ [Occ=Dead] _ [Occ=Dead] -> F14.$wf14 @t ww2 w1 w2 w3 }}]
-f14 = \ (@t) (w :: Ord t) (w1 :: Num t) (w2 :: t) (w3 :: t) -> case w of { GHC.Classes.C:Ord ww ww1 ww2 ww3 ww4 ww5 ww6 ww7 -> F14.$wf14 @t ww2 w1 w2 w3 }
+         Tmpl= \ (@t) ($dOrd [Occ=Once1!] :: Ord t) ($dNum [Occ=Once1] :: Num t) (eta [Occ=Once1] :: t) (eta1 [Occ=Once1] :: t) -> case $dOrd of { GHC.Classes.C:Ord _ [Occ=Dead] _ [Occ=Dead] ww2 [Occ=Once1] _ [Occ=Dead] _ [Occ=Dead] _ [Occ=Dead] _ [Occ=Dead] _ [Occ=Dead] -> F14.$wf14 @t ww2 $dNum eta eta1 }}]
+f14 = \ (@t) ($dOrd :: Ord t) ($dNum :: Num t) (eta :: t) (eta1 :: t) -> case $dOrd of { GHC.Classes.C:Ord ww ww1 ww2 ww3 ww4 ww5 ww6 ww7 -> F14.$wf14 @t ww2 $dNum eta eta1 }
 
 
 
diff --git a/testsuite/tests/arityanal/should_compile/Arity16.stderr b/testsuite/tests/arityanal/should_compile/Arity16.stderr
index 8f750b6d04..eb9f0a5ffe 100644
--- a/testsuite/tests/arityanal/should_compile/Arity16.stderr
+++ b/testsuite/tests/arityanal/should_compile/Arity16.stderr
@@ -1,11 +1,11 @@
 
 ==================== Tidy Core ====================
-Result size of Tidy Core = {terms: 52, types: 75, coercions: 0, joins: 0/0}
+Result size of Tidy Core = {terms: 53, types: 71, coercions: 0, joins: 0/0}
 
 Rec {
 -- RHS size: {terms: 15, types: 15, coercions: 0, joins: 0/0}
 map2 [Occ=LoopBreaker] :: forall {t} {a}. (t -> a) -> [t] -> [a]
-[GblId, Arity=2, Str=<L><1L>, Unf=OtherCon []]
+[GblId, Arity=2, Str=<LCS(L)><1L>, Unf=OtherCon []]
 map2
   = \ (@t) (@a) (f :: t -> a) (ds :: [t]) ->
       case ds of {
@@ -19,26 +19,26 @@ lvl :: GHC.Prim.Addr#
 [GblId, Unf=OtherCon []]
 lvl = "Arity16.hs:(6,1)-(7,47)|function zipWith2"#
 
--- RHS size: {terms: 3, types: 4, coercions: 0, joins: 0/0}
-lvl1 :: forall {a}. [a]
+-- RHS size: {terms: 2, types: 2, coercions: 0, joins: 0/0}
+lvl1 :: ()
 [GblId, Str=b, Cpr=b]
-lvl1 = \ (@a) -> Control.Exception.Base.patError @'GHC.Types.LiftedRep @[a] lvl
+lvl1 = Control.Exception.Base.patError @GHC.Types.LiftedRep @() lvl
 
 Rec {
--- RHS size: {terms: 29, types: 32, coercions: 0, joins: 0/0}
+-- RHS size: {terms: 31, types: 32, coercions: 0, joins: 0/0}
 zipWith2 [Occ=LoopBreaker] :: forall {t1} {t2} {a}. (t1 -> t2 -> a) -> [t1] -> [t2] -> [a]
-[GblId, Arity=3, Str=<LCL(C1(L))><1L><1L>, Unf=OtherCon []]
+[GblId, Arity=3, Str=<LCS(C1(L))><1L><1L>, Unf=OtherCon []]
 zipWith2
   = \ (@t) (@t1) (@a) (f :: t -> t1 -> a) (ds :: [t]) (ds1 :: [t1]) ->
       case ds of {
         [] ->
           case ds1 of {
             [] -> GHC.Types.[] @a;
-            : ipv ipv1 -> lvl1 @a
+            : ipv ipv1 -> case lvl1 of wild2 { }
           };
         : a1 x ->
           case ds1 of {
-            [] -> lvl1 @a;
+            [] -> case lvl1 of wild2 { };
             : b y -> GHC.Types.: @a (f a1 b) (zipWith2 @t @t1 @a f x y)
           }
       }
diff --git a/testsuite/tests/simplCore/should_compile/OpaqueNoSpecialise.stderr b/testsuite/tests/simplCore/should_compile/OpaqueNoSpecialise.stderr
index b3d76cde24..a534137d14 100644
--- a/testsuite/tests/simplCore/should_compile/OpaqueNoSpecialise.stderr
+++ b/testsuite/tests/simplCore/should_compile/OpaqueNoSpecialise.stderr
@@ -12,7 +12,7 @@ lvl = GHC.Num.Integer.IS 1#
 f [InlPrag=OPAQUE] :: forall {t}. Num t => t -> [t]
 [GblId,
  Arity=2,
- Str=<LP(A,LCL(C1(L)),A,A,A,A,MCM(L))><L>,
+ Str=<LP(A,LCS(C1(L)),A,A,A,A,MC1(L))><L>,
  Unf=OtherCon []]
 f = \ (@t) ($dNum :: Num t) (eta :: t) ->
       let {
@@ -72,3 +72,6 @@ OpaqueNoSpecialise.$trModule :: GHC.Types.Module
 OpaqueNoSpecialise.$trModule
   = GHC.Types.Module
       OpaqueNoSpecialise.$trModule3 OpaqueNoSpecialise.$trModule1
+
+
+
diff --git a/testsuite/tests/simplCore/should_compile/T18013.stderr b/testsuite/tests/simplCore/should_compile/T18013.stderr
index fe48290c49..b94cec212b 100644
--- a/testsuite/tests/simplCore/should_compile/T18013.stderr
+++ b/testsuite/tests/simplCore/should_compile/T18013.stderr
@@ -138,7 +138,7 @@ mapMaybeRule [InlPrag=[2]]
   :: forall a b. Rule IO a b -> Rule IO (Maybe a) (Maybe b)
 [GblId,
  Arity=1,
- Str=<1!P(L,LCL(C1(C1(P(L,1L)))))>,
+ Str=<1!P(L,LCS(C1(C1(P(L,1L)))))>,
  Unf=Unf{Src=InlineStable, TopLvl=True, Value=True, ConLike=True,
          WorkFree=True, Expandable=True,
          Guidance=ALWAYS_IF(arity=1,unsat_ok=True,boring_ok=False)
diff --git a/testsuite/tests/simplCore/should_compile/T21261.hs b/testsuite/tests/simplCore/should_compile/T21261.hs
index ae39c4b7d4..95fe678682 100644
--- a/testsuite/tests/simplCore/should_compile/T21261.hs
+++ b/testsuite/tests/simplCore/should_compile/T21261.hs
@@ -34,14 +34,18 @@ f5 c = Just (c 1 2 + c 3 4)
 yes2_lazy :: (Int -> Int -> Int) -> Maybe Int
 yes2_lazy c = f5 (\x y -> c x y)
 
-f6 :: (Int -> Int -> Int) -> Maybe Int
-f6 c = Just (c 1 `seq` c 3 4)
+-- These last two here are disallowed in T21261_pedantic.hs, which activates
+-- -fpedantic-bottoms. It would be unsound to eta reduce these bindings with
+-- -fpedantic-bottoms, but without it's fine to eta reduce:
+
+f6 :: (Int -> Int -> Int) -> Int
+f6 c = c 1 `seq` c 2 3
 {-# NOINLINE f6 #-}
-no2_lazy :: (Int -> Int -> Int) -> Maybe Int
-no2_lazy c = f6 (\x y -> c x y)
+yes_non_pedantic :: (Int -> Int -> Int) -> Int
+yes_non_pedantic c = f6 (\x y -> c x y)
 
-f7 :: (Int -> Int -> Int) -> Int
-f7 c = c 1 `seq` c 2 3
+f7 :: (Int -> Int -> Int) -> Maybe Int
+f7 c = Just (c 1 `seq` c 3 4)
 {-# NOINLINE f7 #-}
-not_quite_eta :: (Int -> Int -> Int) -> Int
-not_quite_eta c = f7 (\x y -> c x y)
+yes_non_pedantic_lazy :: (Int -> Int -> Int) -> Maybe Int
+yes_non_pedantic_lazy c = f7 (\x y -> c x y)
diff --git a/testsuite/tests/simplCore/should_compile/T21261.stderr b/testsuite/tests/simplCore/should_compile/T21261.stderr
index 779f769e43..691045b23a 100644
--- a/testsuite/tests/simplCore/should_compile/T21261.stderr
+++ b/testsuite/tests/simplCore/should_compile/T21261.stderr
@@ -1,7 +1,7 @@
 
 ==================== Tidy Core ====================
 Result size of Tidy Core
-  = {terms: 192, types: 201, coercions: 0, joins: 0/0}
+  = {terms: 166, types: 176, coercions: 0, joins: 0/0}
 
 lvl = I# 3#
 
@@ -27,16 +27,15 @@ no3
   = \ c ->
       case $wf4 (\ x y z -> c x y z) of ww { __DEFAULT -> I# ww }
 
-$wf6 = \ c -> (# case c lvl2 of { __DEFAULT -> c lvl lvl1 } #)
+f6 = \ c -> case c lvl2 of { __DEFAULT -> c lvl3 lvl }
 
-f6 = \ c -> case $wf6 c of { (# ww #) -> Just ww }
+yes_non_pedantic = f6
 
-no2_lazy
-  = \ c -> case $wf6 (\ x y -> c x y) of { (# ww #) -> Just ww }
+$wf7 = \ c -> (# case c lvl2 of { __DEFAULT -> c lvl lvl1 } #)
 
-f7 = \ c -> case c lvl2 of { __DEFAULT -> c lvl3 lvl }
+f7 = \ c -> case $wf7 c of { (# ww #) -> Just ww }
 
-not_quite_eta = \ c -> f7 (\ x y -> c x y)
+yes_non_pedantic_lazy = f7
 
 $wf5
   = \ c ->
@@ -46,8 +45,7 @@ $wf5
 
 f5 = \ c -> case $wf5 c of { (# ww #) -> Just ww }
 
-yes2_lazy
-  = \ c -> case $wf5 (\ x y -> c x y) of { (# ww #) -> Just ww }
+yes2_lazy = f5
 
 $wf3
   = \ c ->
diff --git a/testsuite/tests/simplCore/should_compile/T21261_pedantic.hs b/testsuite/tests/simplCore/should_compile/T21261_pedantic.hs
new file mode 100644
index 0000000000..b63d90558b
--- /dev/null
+++ b/testsuite/tests/simplCore/should_compile/T21261_pedantic.hs
@@ -0,0 +1,18 @@
+{-# OPTIONS_GHC -fpedantic-bottoms #-} -- This flag must inhibit eta reduction based on demands
+
+module T21261_pedantic where
+
+-- README: See T21261. These examples absolutely should not eta reduce with
+-- -fpedantic-bottoms.
+
+f1 :: (Int -> Int -> Int) -> Int
+f1 c = c 1 `seq` c 2 3
+{-# NOINLINE f1 #-}
+no2 :: (Int -> Int -> Int) -> Int
+no2 c = f1 (\x y -> c x y)
+
+f2 :: (Int -> Int -> Int) -> Maybe Int
+f2 c = Just (c 1 `seq` c 3 4)
+{-# NOINLINE f2 #-}
+no2_lazy :: (Int -> Int -> Int) -> Maybe Int
+no2_lazy c = f2 (\x y -> c x y)
diff --git a/testsuite/tests/simplCore/should_compile/T21261_pedantic.stderr b/testsuite/tests/simplCore/should_compile/T21261_pedantic.stderr
new file mode 100644
index 0000000000..fdd7de05df
--- /dev/null
+++ b/testsuite/tests/simplCore/should_compile/T21261_pedantic.stderr
@@ -0,0 +1,26 @@
+
+==================== Tidy Core ====================
+Result size of Tidy Core
+  = {terms: 59, types: 63, coercions: 0, joins: 0/0}
+
+lvl = I# 2#
+
+lvl1 = I# 3#
+
+lvl2 = I# 1#
+
+f1 = \ c -> case c lvl2 of { __DEFAULT -> c lvl lvl1 }
+
+no2 = \ c -> f1 (\ x y -> c x y)
+
+lvl3 = I# 4#
+
+$wf2 = \ c -> (# case c lvl2 of { __DEFAULT -> c lvl1 lvl3 } #)
+
+f2 = \ c -> case $wf2 c of { (# ww #) -> Just ww }
+
+no2_lazy
+  = \ c -> case $wf2 (\ x y -> c x y) of { (# ww #) -> Just ww }
+
+
+
diff --git a/testsuite/tests/simplCore/should_compile/T21392.hs b/testsuite/tests/simplCore/should_compile/T21392.hs
new file mode 100644
index 0000000000..8b60aba580
--- /dev/null
+++ b/testsuite/tests/simplCore/should_compile/T21392.hs
@@ -0,0 +1,37 @@
+module T21392 (f) where
+
+import Data.List (foldl', insertBy)
+import Data.Ord
+
+newtype Unique = U { unU :: Int }
+class Uniquable u where getKey :: u -> Unique
+instance Uniquable Int where getKey = U
+data UMap a = UMap { unS :: ![(Unique,a)], unI :: !Int }
+
+addOne :: Uniquable u => UMap a -> u -> a -> UMap a
+addOne (UMap set n) x v = UMap (insertBy (comparing (unU . fst)) (getKey x,v) set) (n+1)
+
+newtype USet u = USet (UMap u)
+
+insertOne :: Uniquable u => USet u -> u -> USet u
+insertOne (USet s) x = USet (addOne s x x)
+
+insertMany :: Uniquable u => USet u -> [u] -> USet u
+insertMany s vs = foldl' insertOne s (reverse (reverse vs))
+
+seq' = seq
+{-# NOINLINE seq' #-}
+
+blah s@(USet m) = unS m `seq'` s
+{-# NOINLINE blah #-}
+
+end (USet m) = unS m
+{-# NOINLINE end #-}
+
+f :: USet Int -> [Int] -> [(Unique,Int)]
+f !xs ys
+  | length ys == 13 = end $ blah t
+  | length ys == 23 = reverse $ end $ blah t
+  | otherwise       = []
+  where
+    t = insertMany xs (reverse $ reverse $ reverse $ reverse ys)
diff --git a/testsuite/tests/simplCore/should_compile/T4908.stderr b/testsuite/tests/simplCore/should_compile/T4908.stderr
index 9cfd79d1e0..307c9fb728 100644
--- a/testsuite/tests/simplCore/should_compile/T4908.stderr
+++ b/testsuite/tests/simplCore/should_compile/T4908.stderr
@@ -59,7 +59,7 @@ end Rec }
 f [InlPrag=[2]] :: Int -> (Int, Int) -> Bool
 [GblId,
  Arity=2,
- Str=<1!P(1L)><MP(A,MP(ML))>,
+ Str=<1!P(1L)><MP(A,1P(1L))>,
  Cpr=2,
  Unf=Unf{Src=InlineStable, TopLvl=True, Value=True, ConLike=True,
          WorkFree=True, Expandable=True,
diff --git a/testsuite/tests/simplCore/should_compile/all.T b/testsuite/tests/simplCore/should_compile/all.T
index 3b78531e5e..0c52c80480 100644
--- a/testsuite/tests/simplCore/should_compile/all.T
+++ b/testsuite/tests/simplCore/should_compile/all.T
@@ -394,15 +394,17 @@ test('T21144',  normal, compile, ['-O'])
 # Key here is that the argument to ifoldl' is eta-reduced in Core to
 #   `/\m. f @(S m)`
 # which will erase completely in STG
-test('T20040', [ grep_errmsg(r'ifoldl\''), expect_broken(20040) ], compile, ['-O -ddump-stg-final -dno-typeable-binds -dsuppress-all -dsuppress-uniques'])
+test('T20040', [ grep_errmsg(r'ifoldl\'') ], compile, ['-O -ddump-stg-final -dno-typeable-binds -dsuppress-all -dsuppress-uniques'])
 
 # Key here is that yes* become visibly trivial due to eta-reduction, while no* are not eta-reduced.
-test('T21261', [ grep_errmsg(r'^(yes|no)') ], compile, ['-O -ddump-simpl -dno-typeable-binds -dsuppress-all -dsuppress-uniques'])
+test('T21261',          [ grep_errmsg(r'^(yes|no)') ], compile, ['-O -ddump-simpl -dno-typeable-binds -dsuppress-all -dsuppress-uniques'])
+test('T21261_pedantic', [ grep_errmsg(r'^(yes|no)') ], compile, ['-O -ddump-simpl -dno-typeable-binds -dsuppress-all -dsuppress-uniques'])
 
 # We expect to see a SPEC rule for $cm
 test('T17966',  [ grep_errmsg(r'SPEC') ], compile, ['-O -ddump-spec'])
 # We expect to see a SPEC rule for $cm
 test('T19644',  [ grep_errmsg(r'SPEC') ], compile, ['-O -ddump-spec'])
-
 test('T21391', normal, compile, ['-O -dcore-lint'])
 test('T21391a', normal, compile, ['-O -dcore-lint'])
+# We don't want to see a thunk allocation for the insertBy expression after CorePrep.
+test('T21392', [ grep_errmsg(r'sat.* :: \[\(.*Unique, .*Int\)\]'), expect_broken(21392) ], compile, ['-O -ddump-prep -dno-typeable-binds -dsuppress-uniques'])
diff --git a/testsuite/tests/stranal/should_compile/T18894.stderr b/testsuite/tests/stranal/should_compile/T18894.stderr
index 22888e53a2..6027112cb4 100644
--- a/testsuite/tests/stranal/should_compile/T18894.stderr
+++ b/testsuite/tests/stranal/should_compile/T18894.stderr
@@ -46,7 +46,7 @@ lvl :: Int
 lvl = GHC.Types.I# 0#
 
 -- RHS size: {terms: 42, types: 15, coercions: 0, joins: 0/1}
-g2 [InlPrag=NOINLINE, Dmd=LCL(C1(!P(M!P(L),1!P(L))))]
+g2 [InlPrag=NOINLINE, Dmd=LCS(C1(!P(M!P(L),1!P(L))))]
   :: Int -> Int -> (Int, Int)
 [LclId,
  Arity=2,
@@ -147,7 +147,7 @@ lvl :: (Int, Int)
 lvl = (lvl, lvl)
 
 -- RHS size: {terms: 36, types: 10, coercions: 0, joins: 0/1}
-g1 [InlPrag=NOINLINE, Dmd=LCL(!P(L,L))] :: Int -> (Int, Int)
+g1 [InlPrag=NOINLINE, Dmd=LCS(!P(L,L))] :: Int -> (Int, Int)
 [LclId,
  Arity=1,
  Str=<1!P(1L)>,
@@ -201,7 +201,7 @@ h1 :: Int -> Int
          WorkFree=True, Expandable=True, Guidance=IF_ARGS [20] 111 10}]
 h1
   = \ (ds [Dmd=1!P(SL)] :: Int) ->
-      case ds of wild [Dmd=M!P(ML)] { GHC.Types.I# ds [Dmd=SL] ->
+      case ds of wild [Dmd=M!P(1L)] { GHC.Types.I# ds [Dmd=SL] ->
       case ds of {
         __DEFAULT ->
           case g1 wild of { (x [Dmd=1!P(L)], ds [Dmd=1!P(L)]) ->
@@ -264,7 +264,7 @@ lvl :: Int
 lvl = GHC.Types.I# 0#
 
 -- RHS size: {terms: 39, types: 17, coercions: 0, joins: 0/1}
-$wg2 [InlPrag=NOINLINE, Dmd=LCL(C1(!P(M!P(L),1!P(L))))]
+$wg2 [InlPrag=NOINLINE, Dmd=LCS(C1(!P(M!P(L),1!P(L))))]
   :: Int -> GHC.Prim.Int# -> (# Int, Int #)
 [LclId,
  Arity=2,
@@ -328,7 +328,7 @@ h2
       }
 
 -- RHS size: {terms: 34, types: 14, coercions: 0, joins: 0/1}
-$wg1 [InlPrag=NOINLINE, Dmd=LCL(!P(L,L))]
+$wg1 [InlPrag=NOINLINE, Dmd=LCS(!P(L,L))]
   :: GHC.Prim.Int# -> (# GHC.Prim.Int#, Int #)
 [LclId,
  Arity=1,
@@ -366,7 +366,7 @@ lvl :: (Int, Int)
 lvl = case $wg1 2# of { (# ww, ww #) -> (GHC.Types.I# ww, ww) }
 
 -- RHS size: {terms: 22, types: 16, coercions: 0, joins: 0/0}
-$wh1 [InlPrag=[2], Dmd=LCL(!P(L))] :: GHC.Prim.Int# -> Int
+$wh1 [InlPrag=[2], Dmd=LCS(!P(L))] :: GHC.Prim.Int# -> Int
 [LclId,
  Arity=1,
  Str=<1L>,
diff --git a/testsuite/tests/stranal/should_compile/T18903.stderr b/testsuite/tests/stranal/should_compile/T18903.stderr
index d237e7434f..8110312a8b 100644
--- a/testsuite/tests/stranal/should_compile/T18903.stderr
+++ b/testsuite/tests/stranal/should_compile/T18903.stderr
@@ -56,7 +56,7 @@ h :: Int -> Int
 h = \ (m :: Int) ->
       case m of wild { GHC.Types.I# ds ->
       let {
-        $wg [InlPrag=NOINLINE, Dmd=MCM(!P(M!P(L),1!P(L)))]
+        $wg [InlPrag=NOINLINE, Dmd=MC1(!P(M!P(L),1!P(L)))]
           :: GHC.Prim.Int# -> (# Int, Int #)
         [LclId, Arity=1, Str=<1L>, Unf=OtherCon []]
         $wg
diff --git a/testsuite/tests/stranal/sigs/BottomFromInnerLambda.stderr b/testsuite/tests/stranal/sigs/BottomFromInnerLambda.stderr
index 075a819db8..1c944f8520 100644
--- a/testsuite/tests/stranal/sigs/BottomFromInnerLambda.stderr
+++ b/testsuite/tests/stranal/sigs/BottomFromInnerLambda.stderr
@@ -1,20 +1,17 @@
 
 ==================== Strictness signatures ====================
-BottomFromInnerLambda.$trModule:
 BottomFromInnerLambda.expensive: <1!P(SL)>
 BottomFromInnerLambda.f: <1!P(SL)>
 
 
 
 ==================== Cpr signatures ====================
-BottomFromInnerLambda.$trModule:
 BottomFromInnerLambda.expensive: 1
 BottomFromInnerLambda.f:
 
 
 
 ==================== Strictness signatures ====================
-BottomFromInnerLambda.$trModule:
 BottomFromInnerLambda.expensive: <1!P(1L)>
 BottomFromInnerLambda.f: <1!P(1L)>
 
diff --git a/testsuite/tests/stranal/sigs/DmdAnalGADTs.stderr b/testsuite/tests/stranal/sigs/DmdAnalGADTs.stderr
index 2ed48eed70..2f7b6376f0 100644
--- a/testsuite/tests/stranal/sigs/DmdAnalGADTs.stderr
+++ b/testsuite/tests/stranal/sigs/DmdAnalGADTs.stderr
@@ -1,9 +1,5 @@
 
 ==================== Strictness signatures ====================
-DmdAnalGADTs.$tc'A:
-DmdAnalGADTs.$tc'B:
-DmdAnalGADTs.$tcD:
-DmdAnalGADTs.$trModule:
 DmdAnalGADTs.diverges: b
 DmdAnalGADTs.f: <1L>
 DmdAnalGADTs.f': <1L>
@@ -14,10 +10,6 @@ DmdAnalGADTs.hasStrSig: <1!P(L)>
 
 
 ==================== Cpr signatures ====================
-DmdAnalGADTs.$tc'A:
-DmdAnalGADTs.$tc'B:
-DmdAnalGADTs.$tcD:
-DmdAnalGADTs.$trModule:
 DmdAnalGADTs.diverges: b
 DmdAnalGADTs.f:
 DmdAnalGADTs.f': 1
@@ -28,10 +20,6 @@ DmdAnalGADTs.hasStrSig: 1
 
 
 ==================== Strictness signatures ====================
-DmdAnalGADTs.$tc'A:
-DmdAnalGADTs.$tc'B:
-DmdAnalGADTs.$tcD:
-DmdAnalGADTs.$trModule:
 DmdAnalGADTs.diverges: b
 DmdAnalGADTs.f: <1L>
 DmdAnalGADTs.f': <1L>
diff --git a/testsuite/tests/stranal/sigs/HyperStrUse.stderr b/testsuite/tests/stranal/sigs/HyperStrUse.stderr
index 08caf32af4..23c437158e 100644
--- a/testsuite/tests/stranal/sigs/HyperStrUse.stderr
+++ b/testsuite/tests/stranal/sigs/HyperStrUse.stderr
@@ -1,18 +1,15 @@
 
 ==================== Strictness signatures ====================
-HyperStrUse.$trModule:
 HyperStrUse.f: <1!P(1!P(L),A)><1L>
 
 
 
 ==================== Cpr signatures ====================
-HyperStrUse.$trModule:
 HyperStrUse.f: 1
 
 
 
 ==================== Strictness signatures ====================
-HyperStrUse.$trModule:
 HyperStrUse.f: <1!P(1!P(L),A)><1L>
 
 
diff --git a/testsuite/tests/stranal/sigs/NewtypeArity.stderr b/testsuite/tests/stranal/sigs/NewtypeArity.stderr
index 45bc691802..7190bedc35 100644
--- a/testsuite/tests/stranal/sigs/NewtypeArity.stderr
+++ b/testsuite/tests/stranal/sigs/NewtypeArity.stderr
@@ -1,26 +1,17 @@
 
 ==================== Strictness signatures ====================
-Test.$tc'MkT:
-Test.$tcT:
-Test.$trModule:
 Test.t: <1!P(L)><1!P(L)>
 Test.t2: <1!P(L)><1!P(L)>
 
 
 
 ==================== Cpr signatures ====================
-Test.$tc'MkT:
-Test.$tcT:
-Test.$trModule:
 Test.t: 1
 Test.t2: 1
 
 
 
 ==================== Strictness signatures ====================
-Test.$tc'MkT:
-Test.$tcT:
-Test.$trModule:
 Test.t: <1!P(L)><1!P(L)>
 Test.t2: <1!P(L)><1!P(L)>
 
diff --git a/testsuite/tests/stranal/sigs/StrAnalExample.stderr b/testsuite/tests/stranal/sigs/StrAnalExample.stderr
index 80855b392e..08485e735a 100644
--- a/testsuite/tests/stranal/sigs/StrAnalExample.stderr
+++ b/testsuite/tests/stranal/sigs/StrAnalExample.stderr
@@ -1,18 +1,15 @@
 
 ==================== Strictness signatures ====================
-StrAnalExample.$trModule:
 StrAnalExample.foo: <1L>
 
 
 
 ==================== Cpr signatures ====================
-StrAnalExample.$trModule:
 StrAnalExample.foo:
 
 
 
 ==================== Strictness signatures ====================
-StrAnalExample.$trModule:
 StrAnalExample.foo: <1L>
 
 
diff --git a/testsuite/tests/stranal/sigs/T12370.stderr b/testsuite/tests/stranal/sigs/T12370.stderr
index dc7dbdd2e5..3070069a1a 100644
--- a/testsuite/tests/stranal/sigs/T12370.stderr
+++ b/testsuite/tests/stranal/sigs/T12370.stderr
@@ -1,20 +1,17 @@
 
 ==================== Strictness signatures ====================
-T12370.$trModule:
 T12370.bar: <1!P(L)><1!P(L)>
 T12370.foo: <1!P(1!P(L),1!P(L))>
 
 
 
 ==================== Cpr signatures ====================
-T12370.$trModule:
 T12370.bar: 1
 T12370.foo: 1
 
 
 
 ==================== Strictness signatures ====================
-T12370.$trModule:
 T12370.bar: <1!P(L)><1!P(L)>
 T12370.foo: <1!P(1!P(L),1!P(L))>
 
diff --git a/testsuite/tests/stranal/sigs/T13331.stderr b/testsuite/tests/stranal/sigs/T13331.stderr
index 78cccb7fe4..feebb4eaa1 100644
--- a/testsuite/tests/stranal/sigs/T13331.stderr
+++ b/testsuite/tests/stranal/sigs/T13331.stderr
@@ -1,27 +1,15 @@
 
 ==================== Strictness signatures ====================
-T13331.$tc'Bin:
-T13331.$tc'Tip:
-T13331.$tcMap:
-T13331.$trModule:
 T13331.naiveInsertInt: <1L><L><1L>
 
 
 
 ==================== Cpr signatures ====================
-T13331.$tc'Bin:
-T13331.$tc'Tip:
-T13331.$tcMap:
-T13331.$trModule:
 T13331.naiveInsertInt:
 
 
 
 ==================== Strictness signatures ====================
-T13331.$tc'Bin:
-T13331.$tc'Tip:
-T13331.$tcMap:
-T13331.$trModule:
 T13331.naiveInsertInt: <1L><L><1L>
 
 
diff --git a/testsuite/tests/stranal/sigs/T13380f.stderr b/testsuite/tests/stranal/sigs/T13380f.stderr
index 4b17ceae85..1da38aeeee 100644
--- a/testsuite/tests/stranal/sigs/T13380f.stderr
+++ b/testsuite/tests/stranal/sigs/T13380f.stderr
@@ -1,6 +1,5 @@
 
 ==================== Strictness signatures ====================
-T13380f.$trModule:
 T13380f.f: <1!P(L)><1!P(L)><L>
 T13380f.g: <1!P(L)><ML><L>
 T13380f.h: <1!P(L)><ML><L>
@@ -11,7 +10,6 @@ T13380f.unsafeCall: <L>
 
 
 ==================== Cpr signatures ====================
-T13380f.$trModule:
 T13380f.f: 1(, 1)
 T13380f.g: 1(, 1)
 T13380f.h: 1(, 1)
@@ -22,7 +20,6 @@ T13380f.unsafeCall: 1(, 1)
 
 
 ==================== Strictness signatures ====================
-T13380f.$trModule:
 T13380f.f: <1!P(L)><1!P(L)><L>
 T13380f.g: <1!P(L)><ML><L>
 T13380f.h: <1!P(L)><ML><L>
diff --git a/testsuite/tests/stranal/sigs/T16197b.stderr b/testsuite/tests/stranal/sigs/T16197b.stderr
index ec45df4202..d4c250b44a 100644
--- a/testsuite/tests/stranal/sigs/T16197b.stderr
+++ b/testsuite/tests/stranal/sigs/T16197b.stderr
@@ -1,30 +1,15 @@
 
 ==================== Strictness signatures ====================
-T16197b.$tc'Box:
-T16197b.$tc'T:
-T16197b.$tcBox:
-T16197b.$tcT:
-T16197b.$trModule:
 T16197b.f: <1!P(L)>
 
 
 
 ==================== Cpr signatures ====================
-T16197b.$tc'Box:
-T16197b.$tc'T:
-T16197b.$tcBox:
-T16197b.$tcT:
-T16197b.$trModule:
 T16197b.f: 1
 
 
 
 ==================== Strictness signatures ====================
-T16197b.$tc'Box:
-T16197b.$tc'T:
-T16197b.$tcBox:
-T16197b.$tcT:
-T16197b.$trModule:
 T16197b.f: <1!P(L)>
 
 
diff --git a/testsuite/tests/stranal/sigs/T16859.stderr b/testsuite/tests/stranal/sigs/T16859.stderr
index 37718134a2..6dd199c07c 100644
--- a/testsuite/tests/stranal/sigs/T16859.stderr
+++ b/testsuite/tests/stranal/sigs/T16859.stderr
@@ -1,11 +1,5 @@
 
 ==================== Strictness signatures ====================
-T16859.$tc'External:
-T16859.$tc'Internal:
-T16859.$tc'Name:
-T16859.$tcName:
-T16859.$tcNameSort:
-T16859.$trModule:
 T16859.bar: <1!A><L>
 T16859.baz: <1L><1!P(L)><1C1(L)>
 T16859.buz: <1!P(L,L)>
@@ -19,12 +13,6 @@ T16859.n_uniq: <1!P(A,A,L,A)>
 
 
 ==================== Cpr signatures ====================
-T16859.$tc'External:
-T16859.$tc'Internal:
-T16859.$tc'Name:
-T16859.$tcName:
-T16859.$tcNameSort:
-T16859.$trModule:
 T16859.bar: 1
 T16859.baz: 1
 T16859.buz: 1
@@ -38,12 +26,6 @@ T16859.n_uniq: 1
 
 
 ==================== Strictness signatures ====================
-T16859.$tc'External:
-T16859.$tc'Internal:
-T16859.$tc'Name:
-T16859.$tcName:
-T16859.$tcNameSort:
-T16859.$trModule:
 T16859.bar: <1!A><L>
 T16859.baz: <L><1!P(L)><1C1(L)>
 T16859.buz: <1!P(L,L)>
diff --git a/testsuite/tests/stranal/sigs/T17932.stderr b/testsuite/tests/stranal/sigs/T17932.stderr
index dadd60b491..52b365bcc2 100644
--- a/testsuite/tests/stranal/sigs/T17932.stderr
+++ b/testsuite/tests/stranal/sigs/T17932.stderr
@@ -1,30 +1,15 @@
 
 ==================== Strictness signatures ====================
-T17932.$tc'Options:
-T17932.$tc'X:
-T17932.$tcOptions:
-T17932.$tcX:
-T17932.$trModule:
 T17932.flags: <1!P(1L,1L)>
 
 
 
 ==================== Cpr signatures ====================
-T17932.$tc'Options:
-T17932.$tc'X:
-T17932.$tcOptions:
-T17932.$tcX:
-T17932.$trModule:
 T17932.flags:
 
 
 
 ==================== Strictness signatures ====================
-T17932.$tc'Options:
-T17932.$tc'X:
-T17932.$tcOptions:
-T17932.$tcX:
-T17932.$trModule:
 T17932.flags: <1!P(1L,1L)>
 
 
diff --git a/testsuite/tests/stranal/sigs/T18086.stderr b/testsuite/tests/stranal/sigs/T18086.stderr
index 1748a0c145..ce14711025 100644
--- a/testsuite/tests/stranal/sigs/T18086.stderr
+++ b/testsuite/tests/stranal/sigs/T18086.stderr
@@ -1,20 +1,17 @@
 
 ==================== Strictness signatures ====================
-T18086.$trModule:
 T18086.m: <L>x
 T18086.panic: <L>x
 
 
 
 ==================== Cpr signatures ====================
-T18086.$trModule:
 T18086.m: b
 T18086.panic: b
 
 
 
 ==================== Strictness signatures ====================
-T18086.$trModule:
 T18086.m: <L>x
 T18086.panic: <L>x
 
diff --git a/testsuite/tests/stranal/sigs/T18907.stderr b/testsuite/tests/stranal/sigs/T18907.stderr
index 9d9aff99c8..235872a8eb 100644
--- a/testsuite/tests/stranal/sigs/T18907.stderr
+++ b/testsuite/tests/stranal/sigs/T18907.stderr
@@ -1,8 +1,5 @@
 
 ==================== Strictness signatures ====================
-T18907.$tc'H:
-T18907.$tcHuge:
-T18907.$trModule:
 T18907.f: <1L>
 T18907.g: <1P(SL,L,L,L,L)>
 T18907.h: <1!A><1L>
@@ -11,9 +8,6 @@ T18907.m: <1!B>b
 
 
 ==================== Cpr signatures ====================
-T18907.$tc'H:
-T18907.$tcHuge:
-T18907.$trModule:
 T18907.f:
 T18907.g:
 T18907.h:
@@ -22,9 +16,6 @@ T18907.m: b
 
 
 ==================== Strictness signatures ====================
-T18907.$tc'H:
-T18907.$tcHuge:
-T18907.$trModule:
 T18907.f: <1L>
 T18907.g: <1P(SL,L,L,L,L)>
 T18907.h: <1!A><1L>
diff --git a/testsuite/tests/stranal/sigs/T18957.hs b/testsuite/tests/stranal/sigs/T18957.hs
index 8f4550696d..b49ed1a4b8 100644
--- a/testsuite/tests/stranal/sigs/T18957.hs
+++ b/testsuite/tests/stranal/sigs/T18957.hs
@@ -28,5 +28,7 @@ h1 f x = f `seq'` if x < 100 then f x else 200
 h2 :: (Int -> Int) -> Int -> Int
 h2 f x = f `seq` if x < 100 then f x else 200
 
+-- | The first argument is evaluated lazily and multiple times, but called every
+-- time it's evaluated.
 h3 :: (Int -> Int) -> Int -> Int
 h3 f x = if x < 100 then f x + f (x+1) else 200
diff --git a/testsuite/tests/stranal/sigs/T18957.stderr b/testsuite/tests/stranal/sigs/T18957.stderr
index 3d730ce9fc..04937d4028 100644
--- a/testsuite/tests/stranal/sigs/T18957.stderr
+++ b/testsuite/tests/stranal/sigs/T18957.stderr
@@ -1,16 +1,14 @@
 
 ==================== Strictness signatures ====================
-T18957.$trModule:
-T18957.g: <MCM(L)><1L>
+T18957.g: <MC1(L)><1L>
 T18957.h1: <SCM(L)><1L>
 T18957.h2: <1CM(L)><1L>
-T18957.h3: <L><1L>
+T18957.h3: <LCS(L)><1L>
 T18957.seq': <1A><1L>
 
 
 
 ==================== Cpr signatures ====================
-T18957.$trModule:
 T18957.g:
 T18957.h1:
 T18957.h2:
@@ -20,11 +18,10 @@ T18957.seq':
 
 
 ==================== Strictness signatures ====================
-T18957.$trModule:
-T18957.g: <MCM(L)><1L>
+T18957.g: <MC1(L)><1L>
 T18957.h1: <SCM(L)><1L>
 T18957.h2: <1CM(L)><1L>
-T18957.h3: <L><1L>
+T18957.h3: <LCS(L)><1L>
 T18957.seq': <1A><1L>
 
 
diff --git a/testsuite/tests/stranal/sigs/T19407.stderr b/testsuite/tests/stranal/sigs/T19407.stderr
index 8d4045700a..a855d89810 100644
--- a/testsuite/tests/stranal/sigs/T19407.stderr
+++ b/testsuite/tests/stranal/sigs/T19407.stderr
@@ -1,23 +1,13 @@
 
 ==================== Strictness signatures ====================
-T19407.$tc'Huge:
-T19407.$tc'T:
-T19407.$tcHuge:
-T19407.$tcT:
-T19407.$trModule:
 T19407.f: <SP(1P(1L,A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,A),ML)>
-T19407.g: <1!P(1L,A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,A)><MP(A,ML)>
+T19407.g: <1!P(1L,A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,A)><MP(A,1L)>
 T19407.h: <1!P(1L,A)>
 T19407.n: <1!P(A,1!P(L))>
 
 
 
 ==================== Cpr signatures ====================
-T19407.$tc'Huge:
-T19407.$tc'T:
-T19407.$tcHuge:
-T19407.$tcT:
-T19407.$trModule:
 T19407.f:
 T19407.g:
 T19407.h:
@@ -26,13 +16,8 @@ T19407.n: 1
 
 
 ==================== Strictness signatures ====================
-T19407.$tc'Huge:
-T19407.$tc'T:
-T19407.$tcHuge:
-T19407.$tcT:
-T19407.$trModule:
 T19407.f: <1P(1P(1L,A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,A),ML)>
-T19407.g: <1!P(1L,A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,A)><MP(A,ML)>
+T19407.g: <1!P(1L,A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,A,A)><MP(A,1L)>
 T19407.h: <1!P(1L,A)>
 T19407.n: <1!P(A,1!P(L))>
 
diff --git a/testsuite/tests/stranal/sigs/T19871.stderr b/testsuite/tests/stranal/sigs/T19871.stderr
index f8f465fd82..13e67a2805 100644
--- a/testsuite/tests/stranal/sigs/T19871.stderr
+++ b/testsuite/tests/stranal/sigs/T19871.stderr
@@ -1,8 +1,5 @@
 
 ==================== Strictness signatures ====================
-T19871.$tc'Huge:
-T19871.$tcHuge:
-T19871.$trModule:
 T19871.absent: <1P(1L,ML,A,A,A,A,A,A,A,A,A,A)>
 T19871.ann: <1P(SL,L,L,L,L,L,L,L,L,L,L,L)>
 T19871.f1: <1!P(1L,A,A,A,A,A,A,A,A,A,A,A)>
@@ -17,16 +14,13 @@ T19871.f6: <1!P(A,A,A,A,A,1L,A,A,A,A,A,A)>
 T19871.f7: <1!P(A,A,A,A,A,A,1L,A,A,A,A,A)>
 T19871.f8: <1!P(A,A,A,A,A,A,A,1L,A,A,A,A)>
 T19871.f9: <1!P(A,A,A,A,A,A,A,A,1L,A,A,A)>
-T19871.guarded: <MCM(L)><1P(SL,L,L,L,L,L,L,L,L,L,L,L)>
+T19871.guarded: <MC1(L)><1P(SL,L,L,L,L,L,L,L,L,L,L,L)>
 T19871.sumIO: <1!P(1L)><1!P(L)><L>
 T19871.update: <1P(SL,L,L,L,L,L,L,L,L,L,L,L)>
 
 
 
 ==================== Cpr signatures ====================
-T19871.$tc'Huge:
-T19871.$tcHuge:
-T19871.$trModule:
 T19871.absent: 1
 T19871.ann: 1
 T19871.f1:
@@ -48,9 +42,6 @@ T19871.update: 1
 
 
 ==================== Strictness signatures ====================
-T19871.$tc'Huge:
-T19871.$tcHuge:
-T19871.$trModule:
 T19871.absent: <1P(1L,ML,A,A,A,A,A,A,A,A,A,A)>
 T19871.ann: <1P(SL,L,L,L,L,L,L,L,L,L,L,L)>
 T19871.f1: <1!P(1L,A,A,A,A,A,A,A,A,A,A,A)>
@@ -65,7 +56,7 @@ T19871.f6: <1!P(A,A,A,A,A,1L,A,A,A,A,A,A)>
 T19871.f7: <1!P(A,A,A,A,A,A,1L,A,A,A,A,A)>
 T19871.f8: <1!P(A,A,A,A,A,A,A,1L,A,A,A,A)>
 T19871.f9: <1!P(A,A,A,A,A,A,A,A,1L,A,A,A)>
-T19871.guarded: <MCM(L)><1P(SL,L,L,L,L,L,L,L,L,L,L,L)>
+T19871.guarded: <MC1(L)><1P(SL,L,L,L,L,L,L,L,L,L,L,L)>
 T19871.sumIO: <1!P(1L)><1!P(L)><L>
 T19871.update: <1P(SL,L,L,L,L,L,L,L,L,L,L,L)>
 
diff --git a/testsuite/tests/stranal/sigs/T20746.stderr b/testsuite/tests/stranal/sigs/T20746.stderr
index b0656cd13d..5be614867a 100644
--- a/testsuite/tests/stranal/sigs/T20746.stderr
+++ b/testsuite/tests/stranal/sigs/T20746.stderr
@@ -1,21 +1,18 @@
 
 ==================== Strictness signatures ====================
-Foo.$trModule:
-Foo.f: <MP(A,MCM(L),A)><L>
+Foo.f: <MP(A,1C1(L),A)><L>
 Foo.foogle: <L><L>
 
 
 
 ==================== Cpr signatures ====================
-Foo.$trModule:
 Foo.f: 1
 Foo.foogle: 1
 
 
 
 ==================== Strictness signatures ====================
-Foo.$trModule:
-Foo.f: <MP(A,MCM(L),A)><L>
+Foo.f: <MP(A,1C1(L),A)><L>
 Foo.foogle: <L><L>
 
 
diff --git a/testsuite/tests/stranal/sigs/T20746b.stderr b/testsuite/tests/stranal/sigs/T20746b.stderr
index bd23944c61..7e6fada4e5 100644
--- a/testsuite/tests/stranal/sigs/T20746b.stderr
+++ b/testsuite/tests/stranal/sigs/T20746b.stderr
@@ -1,20 +1,17 @@
 
 ==================== Strictness signatures ====================
-T20746b.$trModule:
 T20746b.f: <1L><L><L>
 T20746b.mightThrow: <L><L>
 
 
 
 ==================== Cpr signatures ====================
-T20746b.$trModule:
 T20746b.f: 1
 T20746b.mightThrow: 1
 
 
 
 ==================== Strictness signatures ====================
-T20746b.$trModule:
 T20746b.f: <1L><L><L>
 T20746b.mightThrow: <L><L>
 
diff --git a/testsuite/tests/stranal/sigs/T21081.hs b/testsuite/tests/stranal/sigs/T21081.hs
new file mode 100644
index 0000000000..e07ec410bc
--- /dev/null
+++ b/testsuite/tests/stranal/sigs/T21081.hs
@@ -0,0 +1,123 @@
+{-# LANGUAGE BangPatterns #-}
+
+module T21081 where
+
+-- | Should put demand `MP(SL,SL)` or `MP(1L,1L)` on `pr`, telling us that `f`
+-- will evaluate both components of `pr` whenever it evaluates `pr` lazily.
+f :: (Bool, Bool) -> (Bool, Bool)
+f pr = (case pr of (a,b) -> a /= b, True)
+{-# NOINLINE f #-}
+-- | If `f` gets the correct signature, we can case-bind `z` here (not tested)
+g :: Int -> (Bool, Bool)
+g x = let y = let z = odd x in (z,z) in f y
+
+-- | Should put demand `LCS(C1(L))` on `f`, telling us that whenever `myfoldl`
+-- evaluates `f`, it will also call it at least once (`S`) and then always call
+-- it with a second argument (`1`).
+-- This in turn allows us to eta-reduce `(\a b -> f a b)` to `f` (not tested,
+-- but there's T20040 which tests an even more complicated case).
+myfoldl :: (a -> b -> a) -> a -> [b] -> a
+myfoldl f z [] = z
+myfoldl f !z (x:xs) = myfoldl (\a b -> f a b) (f z x) xs
+
+-- | Should put demand `LCL(C1(L))` on `f`
+blah :: (Int -> Int -> Int) -> Int -> Int
+blah f 0 = 0
+blah f 1 = f `seq` 1
+blah f x = f (x+1) (x+2) + f (x+3) (x+4)
+{-# NOINLINE blah #-}
+-- | It's not safe to eta-reduce the lambda here, because `do_blah undefined`
+-- would crash.
+do_blah :: (Int -> Int -> Int) -> Int
+do_blah f = blah (\a b -> f a b) 1
+
+-- | Should put demand `MP(ML,ML)` on `p`, not `MP(L,L)`.
+h :: (Int, Int) -> Int -> Int
+h p 0 = 0
+h p 1 = fst p
+h p y = snd p + y
+{-# NOINLINE h #-}
+-- | We want to use call-by-name for `a` and `b`, justified by the used-once
+-- info on `p` in `h`.
+blurg :: Int -> Int
+blurg x =
+  let a = sum [0..x]
+      b = sum [1..x]
+  in h (a,b) x
+
+-- | But we still need `p` to have demand `MP(L,L)` or simply `L` here.
+-- NOT `MP(ML,ML)`. This demonstrates that product usage demands stay absolute.
+h2 :: (Int, Int) -> Int -> Int
+h2 p y = h p y + h p (y+1)
+{-# NOINLINE h2 #-}
+-- | Otherwise we'd use call-by-name for `a` and `b` here, although they are
+-- evaluated multiple times in `h2`.
+blurg2 :: Int -> Int
+blurg2 x =
+  let a = sum [0..x]
+      b = sum [1..x]
+  in h2 (a,b) x
+
+-- | Must not put demand `MP(1L,1L)` on `x` (e.g., strict in the components).
+-- This demonstrates that `plusDmd` must fall back to `lubSubDemand` when both
+-- Demands are lazy.
+i :: Bool -> Bool -> (Int, Int) -> Int
+i b b' x = (if b then fst x else 3) + (if b' then snd x else 4)
+
+fst' :: (a,b) -> a
+fst' (x,_) = x
+{-# NOINLINE fst' #-}
+
+snd' :: (a,b) -> b
+snd' (_,x) = x
+{-# NOINLINE snd' #-}
+
+-- | We want `SP(1L,1L)`, even if neither `fst'` nor `snd'` are strict in both
+-- components. This dictates that `plusDmd` has to do `plusSubDemand` when both
+-- Demands are strict. Which differs in a crucial way from the situation in `i`!
+j :: (Integer, Integer) -> Integer
+j p = fst' p + snd' p
+
+
+-- A few examples from a call between Simon and me
+
+call1 :: (Bool,Bool) -> (Bool, Bool)
+call1 x = (x `seq` case x of (a,b) -> a, True)
+--  call1 :: <MP(1L,A)>
+-- x may not be evald at all, but
+--   if `x` is evaluated at all, then
+--   then `a` is evaluated exactly once (in total)
+
+call2 :: (Bool,Bool) -> (Bool, Bool)
+call2 x = (x `seq` case x of (a,b) -> a, case x of (a,b) -> a)
+--  call2 :: LP(SL,A)
+-- If x is evaluated, then `a` is (in total) evaluated
+-- maybe as much as twice
+
+call3 :: (Bool,Bool) -> (Bool, ())
+call3 x = (x `seq` case x of (a,b) -> a, x `seq` ())
+--  call3 :: LP(ML,A)
+-- If x is evaluated, then `a` may not be evaluated at all.
+
+call4 :: (Bool,Bool) -> Bool -> (Bool, Bool)
+call4 x y = y `seq` (case x of (a,b) -> a, True)
+--  call4 :: <MP(1L,A)><1A>
+-- What is demand on x in (call4 x x)?
+-- NOT SP(1L,A)!!
+
+call5 :: (Bool,Bool) -> Bool -> (Bool, ())
+call5 x y = (case x of (a,b) -> a, y `seq` ())
+--  call5 :: <MP(1L,A)><MA>
+-- What is demand on x in `snd (call5 x x)`?
+-- Not LP(1L,A)!!  call5 might evaluate second argument but not first
+-- Lub because we might evaluate one OR the other.
+
+call6 :: (Int,Int) -> (Int,Int) -> Bool -> Int
+call6 x y True  = 42
+call6 x y False = case y of (a, _) -> case x of (b, _) -> a + b
+--  call6 :: <MP(1L)><MP(1L)><1L>
+-- What is demand on x in `call6 x x`?
+-- Not LP(1L)!! It's LP(SL)
+-- call6 might evaluate both its arguments and, in each case
+-- evaluate the component once.  So the component of x
+-- gets evaluated twice.
diff --git a/testsuite/tests/stranal/sigs/T21081.stderr b/testsuite/tests/stranal/sigs/T21081.stderr
new file mode 100644
index 0000000000..ec7e776ca8
--- /dev/null
+++ b/testsuite/tests/stranal/sigs/T21081.stderr
@@ -0,0 +1,69 @@
+
+==================== Strictness signatures ====================
+T21081.blah: <LCL(C1(L))><1!P(1L)>
+T21081.blurg: <S!P(SL)>
+T21081.blurg2: <S!P(SL)>
+T21081.call1: <MP(1L,A)>
+T21081.call2: <LP(SL,A)>
+T21081.call3: <LP(ML,A)>
+T21081.call4: <MP(1L,A)><1A>
+T21081.call5: <MP(1L,A)><MA>
+T21081.call6: <MP(1L,A)><MP(1L,A)><1L>
+T21081.do_blah: <LCS(C1(L))>
+T21081.f: <MP(SL,SL)>
+T21081.fst': <1!P(1L,A)>
+T21081.g: <ML>
+T21081.h: <MP(ML,ML)><1!P(1L)>
+T21081.h2: <L><S!P(SL)>
+T21081.i: <1L><1L><MP(ML,ML)>
+T21081.j: <S!P(1L,1L)>
+T21081.myfoldl: <LCS(C1(L))><1L><1L>
+T21081.snd': <1!P(A,1L)>
+
+
+
+==================== Cpr signatures ====================
+T21081.blah: 1
+T21081.blurg:
+T21081.blurg2: 1
+T21081.call1: 1(, 2)
+T21081.call2: 1
+T21081.call3: 1
+T21081.call4: 1(, 2)
+T21081.call5: 1
+T21081.call6: 1
+T21081.do_blah: 1
+T21081.f: 1(, 2)
+T21081.fst':
+T21081.g: 1(, 2)
+T21081.h:
+T21081.h2: 1
+T21081.i: 1
+T21081.j:
+T21081.myfoldl:
+T21081.snd':
+
+
+
+==================== Strictness signatures ====================
+T21081.blah: <LCL(C1(L))><1!P(1L)>
+T21081.blurg: <1!P(SL)>
+T21081.blurg2: <1!P(SL)>
+T21081.call1: <MP(1L,A)>
+T21081.call2: <LP(SL,A)>
+T21081.call3: <LP(ML,A)>
+T21081.call4: <MP(1L,A)><1A>
+T21081.call5: <MP(1L,A)><MA>
+T21081.call6: <MP(1L,A)><MP(1L,A)><1L>
+T21081.do_blah: <LCS(C1(L))>
+T21081.f: <MP(SL,SL)>
+T21081.fst': <1!P(1L,A)>
+T21081.g: <ML>
+T21081.h: <MP(ML,ML)><1!P(1L)>
+T21081.h2: <L><1!P(SL)>
+T21081.i: <1L><1L><MP(ML,ML)>
+T21081.j: <1!P(1L,1L)>
+T21081.myfoldl: <LCS(C1(L))><1L><1L>
+T21081.snd': <1!P(A,1L)>
+
+
diff --git a/testsuite/tests/stranal/sigs/T21119.stderr b/testsuite/tests/stranal/sigs/T21119.stderr
index 0a398888d0..dade4dc2a6 100644
--- a/testsuite/tests/stranal/sigs/T21119.stderr
+++ b/testsuite/tests/stranal/sigs/T21119.stderr
@@ -2,22 +2,16 @@
 ==================== Strictness signatures ====================
 T21119.$fMyShow(,): <1!A>
 T21119.$fMyShowInt: <1!A>
-T21119.$tc'C:MyShow:
-T21119.$tcMyShow:
-T21119.$trModule:
 T21119.get: <1!P(1!P(L),1!P(L))><1!P(L)><1L>
 T21119.getIO: <1P(1L,ML)><1L><ML><L>
-T21119.indexError: <1C1(L)><1!B><S!S><S!S>b
-T21119.throwIndexError: <MCM(L)><MA><L><L><L>x
+T21119.indexError: <1C1(S)><1!B><S!S><S!S>b
+T21119.throwIndexError: <MC1(L)><MA><L><L><L>x
 
 
 
 ==================== Cpr signatures ====================
 T21119.$fMyShow(,):
 T21119.$fMyShowInt:
-T21119.$tc'C:MyShow:
-T21119.$tcMyShow:
-T21119.$trModule:
 T21119.get:
 T21119.getIO: 1
 T21119.indexError: b
@@ -28,12 +22,9 @@ T21119.throwIndexError: b
 ==================== Strictness signatures ====================
 T21119.$fMyShow(,): <1!A>
 T21119.$fMyShowInt: <1!A>
-T21119.$tc'C:MyShow:
-T21119.$tcMyShow:
-T21119.$trModule:
 T21119.get: <1!P(1!P(L),1!P(L))><1!P(L)><1L>
 T21119.getIO: <1P(1L,ML)><1L><ML><L>
-T21119.indexError: <1C1(L)><1!B><S!S><S!S>b
-T21119.throwIndexError: <MCM(L)><MA><L><L><L>x
+T21119.indexError: <1C1(S)><1!B><S!S><S!S>b
+T21119.throwIndexError: <MC1(L)><MA><L><L><L>x
 
 
diff --git a/testsuite/tests/stranal/sigs/T5075.stderr b/testsuite/tests/stranal/sigs/T5075.stderr
index e367385d52..9bc8301440 100644
--- a/testsuite/tests/stranal/sigs/T5075.stderr
+++ b/testsuite/tests/stranal/sigs/T5075.stderr
@@ -1,14 +1,12 @@
 
 ==================== Strictness signatures ====================
-T5075.$trModule:
-T5075.f: <S!P(A,A,SCS(C1(L)),A,A,A,A,A)><LP(A,A,LCL(C1(L)),A,A,A,L)><L>
+T5075.f: <S!P(A,A,SCS(C1(L)),A,A,A,A,A)><LP(A,A,LCS(C1(L)),A,A,A,LCS(L))><L>
 T5075.g: <1L><S!P(L)>
 T5075.h: <S!P(L)>
 
 
 
 ==================== Cpr signatures ====================
-T5075.$trModule:
 T5075.f: 1
 T5075.g: 2
 T5075.h:
@@ -16,8 +14,7 @@ T5075.h:
 
 
 ==================== Strictness signatures ====================
-T5075.$trModule:
-T5075.f: <1P(A,A,SCS(C1(L)),A,A,A,A,A)><LP(A,A,LCL(C1(L)),A,A,A,L)><L>
+T5075.f: <1P(A,A,SCS(C1(L)),A,A,A,A,A)><LP(A,A,LCS(C1(L)),A,A,A,LCS(L))><L>
 T5075.g: <1L><S!P(L)>
 T5075.h: <1!P(L)>
 
diff --git a/testsuite/tests/stranal/sigs/T8569.stderr b/testsuite/tests/stranal/sigs/T8569.stderr
index 187047e612..0330cc6b61 100644
--- a/testsuite/tests/stranal/sigs/T8569.stderr
+++ b/testsuite/tests/stranal/sigs/T8569.stderr
@@ -1,27 +1,15 @@
 
 ==================== Strictness signatures ====================
-T8569.$tc'Rdata:
-T8569.$tc'Rint:
-T8569.$tcRep:
-T8569.$trModule:
 T8569.addUp: <1L><L>
 
 
 
 ==================== Cpr signatures ====================
-T8569.$tc'Rdata:
-T8569.$tc'Rint:
-T8569.$tcRep:
-T8569.$trModule:
 T8569.addUp:
 
 
 
 ==================== Strictness signatures ====================
-T8569.$tc'Rdata:
-T8569.$tc'Rint:
-T8569.$tcRep:
-T8569.$trModule:
 T8569.addUp: <1L><L>
 
 
diff --git a/testsuite/tests/stranal/sigs/T8598.stderr b/testsuite/tests/stranal/sigs/T8598.stderr
index 747c6a096b..00542be668 100644
--- a/testsuite/tests/stranal/sigs/T8598.stderr
+++ b/testsuite/tests/stranal/sigs/T8598.stderr
@@ -1,18 +1,15 @@
 
 ==================== Strictness signatures ====================
-T8598.$trModule:
 T8598.fun: <1!P(L)>
 
 
 
 ==================== Cpr signatures ====================
-T8598.$trModule:
 T8598.fun: 1
 
 
 
 ==================== Strictness signatures ====================
-T8598.$trModule:
 T8598.fun: <1!P(L)>
 
 
diff --git a/testsuite/tests/stranal/sigs/UnsatFun.stderr b/testsuite/tests/stranal/sigs/UnsatFun.stderr
index a9c3ca340a..c659311b22 100644
--- a/testsuite/tests/stranal/sigs/UnsatFun.stderr
+++ b/testsuite/tests/stranal/sigs/UnsatFun.stderr
@@ -1,18 +1,16 @@
 
 ==================== Strictness signatures ====================
-UnsatFun.$trModule:
 UnsatFun.f: <1!S><B>b
 UnsatFun.g: <1!S>b
-UnsatFun.g': <ML>
+UnsatFun.g': <MS>
 UnsatFun.g3: <A>
 UnsatFun.h: <1C1(L)>
-UnsatFun.h2: <1L><MCM(L)>
+UnsatFun.h2: <1L><MC1(L)>
 UnsatFun.h3: <1C1(A)>
 
 
 
 ==================== Cpr signatures ====================
-UnsatFun.$trModule:
 UnsatFun.f: b
 UnsatFun.g:
 UnsatFun.g':
@@ -24,13 +22,12 @@ UnsatFun.h3: 1
 
 
 ==================== Strictness signatures ====================
-UnsatFun.$trModule:
 UnsatFun.f: <1!S><B>b
 UnsatFun.g: <1!S>b
-UnsatFun.g': <ML>
+UnsatFun.g': <MS>
 UnsatFun.g3: <A>
 UnsatFun.h: <1C1(L)>
-UnsatFun.h2: <1L><MCM(L)>
+UnsatFun.h2: <1L><MC1(L)>
 UnsatFun.h3: <1C1(A)>
 
 
diff --git a/testsuite/tests/stranal/sigs/all.T b/testsuite/tests/stranal/sigs/all.T
index 876d2242d8..3782fa97a6 100644
--- a/testsuite/tests/stranal/sigs/all.T
+++ b/testsuite/tests/stranal/sigs/all.T
@@ -1,7 +1,7 @@
 # This directory contains tests where we annotate functions with expected
 # type signatures, and verify that these actually those found by the compiler
 
-setTestOpts(extra_hc_opts('-ddump-str-signatures -ddump-cpr-signatures'))
+setTestOpts(extra_hc_opts('-ddump-str-signatures -ddump-cpr-signatures -dno-typeable-binds'))
 
 # We are testing the result of an optimization, so no use
 # running them in various runtimes
@@ -31,5 +31,5 @@ test('T18907', normal, compile, [''])
 test('T13331', normal, compile, [''])
 test('T20746', normal, compile, [''])
 test('T20746b', normal, compile, [''])
-
+test('T21081', normal, compile, [''])
 test('T21119', normal, compile, [''])