Make CallArity make more use of many-calls

by elaborating the domain a bit.

testsuite/tests/callarity/CallArity1.hs

@@ -76,7 +76,7 @@ exprs =
                           (mkLams [y] $ Var y)
                   ) $ mkLams [z] $ Var d `mkVarApps` [x]) $
         f `mkLApps` [0] `mkApps` [go `mkLApps` [0, 0]]
-  , ("go2 (using surrounding interesting let; 'go 2' would be good!)",) $
+  , ("go2 (using surrounding interesting let)",) $
      mkLet n (f `mkLApps` [0]) $
          mkRFun go [x]
             (mkLet d (mkACase (Var go `mkVarApps` [x])
@@ -98,6 +98,38 @@ exprs =
      mkRLet n (mkACase (mkLams [y] $ mkLit 0) (Var n)) $
      mkRLet d (mkACase (mkLams [y] $ n `mkLApps` [0]) (Var d)) $
          d `mkLApps` [0]
+  , ("two thunks, one called multiple times (both arity 1 would be bad!)",) $
+     mkLet n (mkACase (mkLams [y] $ mkLit 0) (f `mkLApps` [0])) $
+     mkLet d (mkACase (mkLams [y] $ mkLit 0) (f `mkLApps` [0])) $
+         Var n `mkApps` [Var d `mkApps` [Var d `mkApps` [mkLit 0]]]
+  , ("two thunks (recursive), one called multiple times (both arity 1 would be bad!)",) $
+     mkRLet n (mkACase (mkLams [y] $ mkLit 0) (Var n)) $
+     mkRLet d (mkACase (mkLams [y] $ mkLit 0) (Var d)) $
+         Var n `mkApps` [Var d `mkApps` [Var d `mkApps` [mkLit 0]]]
+  , ("two functions, not thunks",) $
+     mkLet go  (mkLams [x] (mkACase (mkLams [y] $ mkLit 0) (Var f `mkVarApps` [x]))) $
+     mkLet go2 (mkLams [x] (mkACase (mkLams [y] $ mkLit 0) (Var f `mkVarApps` [x]))) $
+         Var go `mkApps` [go2 `mkLApps` [0,1], mkLit 0]
+  , ("a thunk, called multiple times via a forking recursion (d 1 would be bad!)",) $
+     mkLet  d   (mkACase (mkLams [y] $ mkLit 0) (f `mkLApps` [0])) $
+     mkRLet go2 (mkLams [x] (mkACase (Var go2 `mkApps` [Var go2 `mkApps` [mkLit 0, mkLit 0]]) (Var d))) $
+         go2 `mkLApps` [0,1]
+  , ("a function, one called multiple times via a forking recursion",) $
+     mkLet go   (mkLams [x] (mkACase (mkLams [y] $ mkLit 0) (Var f `mkVarApps` [x]))) $
+     mkRLet go2 (mkLams [x] (mkACase (Var go2 `mkApps` [Var go2 `mkApps` [mkLit 0, mkLit 0]]) (go `mkLApps` [0]))) $
+         go2 `mkLApps` [0,1]
+  , ("two functions (recursive)",) $
+     mkRLet go  (mkLams [x] (mkACase (mkLams [y] $ mkLit 0) (Var go `mkVarApps` [x]))) $
+     mkRLet go2 (mkLams [x] (mkACase (mkLams [y] $ mkLit 0) (Var go2 `mkVarApps` [x]))) $
+         Var go `mkApps` [go2 `mkLApps` [0,1], mkLit 0]
+  , ("mutual recursion (thunks), called mutiple times (both arity 1 would be bad!)",) $
+     Let (Rec [ (n, mkACase (mkLams [y] $ mkLit 0) (Var d))
+              , (d, mkACase (mkLams [y] $ mkLit 0) (Var n))]) $
+         Var n `mkApps` [Var d `mkApps` [Var d `mkApps` [mkLit 0]]]
+  , ("mutual recursion (functions), but no thunks (both arity 2 would be good)",) $
+     Let (Rec [ (go,  mkLams [x] (mkACase (mkLams [y] $ mkLit 0) (Var go2 `mkVarApps` [x])))
+              , (go2, mkLams [x] (mkACase (mkLams [y] $ mkLit 0) (Var go `mkVarApps` [x])))]) $
+         Var go `mkApps` [go2 `mkLApps` [0,1], mkLit 0]
   ]
 
 main = do

testsuite/tests/callarity/CallArity1.stderr

@@ -15,9 +15,9 @@ go2 (in case crut):
 go2 (in function call):
     go 2
     d 1
-go2 (using surrounding interesting let; 'go 2' would be good!):
-    go 0
-    d 0
+go2 (using surrounding interesting let):
+    go 2
+    d 1
     n 1
 go2 (using surrounding boring let):
     go 2
@@ -29,3 +29,27 @@ two recursions (both arity 1 would be good!):
 two recursions (semantically like the previous case):
     d 1
     n 1
+two thunks, one called multiple times (both arity 1 would be bad!):
+    d 0
+    n 1
+two thunks (recursive), one called multiple times (both arity 1 would be bad!):
+    d 0
+    n 1
+two functions, not thunks:
+    go 2
+    go2 2
+a thunk, called multiple times via a forking recursion (d 1 would be bad!):
+    go2 2
+    d 0
+a function, one called multiple times via a forking recursion:
+    go 2
+    go2 2
+two functions (recursive):
+    go 2
+    go2 2
+mutual recursion (thunks), called mutiple times (both arity 1 would be bad!):
+    d 0
+    n 0
+mutual recursion (functions), but no thunks (both arity 2 would be good):
+    go 0
+    go2 0