More inlining, fix issues in eval of case

src/Lib/ProcessDecl.newt

@@ -143,6 +143,8 @@ complexity (Ref _ _) = 1
 complexity (Lam _ _ _ _ sc) = 1 + complexity sc
 complexity (App _ t u) = complexity t + complexity u
 complexity (Bnd _ _) = 1
+-- These turn into a projection
+complexity (Case _ sc (CaseCons _ _ t :: Nil)) = 1 + complexity sc + complexity t
 complexity _ = 100
 
 processDef : List String → FC → String → List (Raw × Raw) → M Unit
@@ -168,12 +170,18 @@ processDef ns fc nm clauses = do
   -- TODO - make nf that expands all metas and drop zonk
   -- Idris2 doesn't expand metas for performance - a lot of these are dropped during erasure.
   -- Day1.newt is a test case
-  -- NOW - might not need this if we do it at compile time
+  -- This inlines metas and functions flagged Inline.
   tm' <- zonk top 0 Nil tm
   debug $ \ _ => "NF\n\{render 80 $ pprint Nil tm'}"
   debug $ \ _ => "Add def \{nm} \{render 90 $ pprint Nil tm'} : \{render 90 $ pprint Nil ty}"
   updateDef (QN ns nm) fc ty (Fn tm')
-  if complexity tm' < 10
+  -- putStrLn "complexity \{show (QN ns nm)} \{show $ complexity tm'}"
+  -- putStrLn $ show tm'
+  -- TODO we need some protection against inlining a function calling itself.
+  -- 14 gets us to 6.21s, higher than 11 breaks Zoo4eg.newt with a unification error (probably need to inline at the end instead)
+  -- But we need better heuristics, maybe fuel and deciding while inlining.
+  -- bind is explicit here because the complexity has a 100 in it.
+  if complexity tm' < 11 || show (QN ns nm) == "Prelude.Prelude.Monad Prelude.IO,bind"
     then setFlag (QN ns nm) fc Inline
     else pure MkUnit