fix open resolve

Add test

Author: TimWhiting

lib/std/core/unsafe.kk

@@ -10,6 +10,7 @@
 module std/core/unsafe
 
 import std/core/types
+import std/core/hnd
 
 // _Unsafe_. This function calls a function and pretends it did not have any effect at all.
 // Use with utmost care as it should not be used to dismiss user-defined effects that need

src/Core/OpenResolve.hs

@@ -177,13 +177,13 @@ resOpen (Env penv gamma) eopen effFrom effTo tpFrom tpTo@(TFun targs _ tres) exp
              in case lsFrom of
                  []  -> -- no handled effect, use cast
                         case lsTo of
-                          [] -> trace ("  no handled effect, in no handled effect context: use cast")
+                          [] | matchType tlFrom tlTo -> trace ("  no handled effect, in no handled effect context: use cast")
                                 expr
-                          _  -> trace ("  no handled effect; use none: " ++ show expr) $
-                                if (isHandlerFree expr)
-                                 then trace ("***  remove open-none") $  -- fully total with using any operations that need evidence; just leave it as is
-                                      expr
-                                else if (n <= 4)
+                          _  -> 
+                              trace ("  different effects: " ++ show (ppType penv tlFrom) ++ ", to " ++ show (ppType penv tlTo)
+                                     ++ " with effects: " ++ show (map (ppType penv) lsFrom, map (ppType penv) lsTo)) $  
+                              if isHandlerFree expr then expr
+                              else if (n <= 4)
                                  then wrapper (resolve (nameOpenNone n)) []  -- fails in perf1c with exceeded stack size if --optmaxdup < 500 (since it prevents a tailcall)
                                       -- expr  -- fails in nim as it evidence is not cleared
                                  else wrapperThunk (resolve (nameOpenNone 0)) []
@@ -236,9 +236,9 @@ isHandlerFree expr
                   -> case handlerFreeFunType (typeOf vname) of
                        Nothing  -> True
                        Just ok  -> ok
-      Var vname _ -> case handlerFreeFunType (typeOf vname) of
-                       Nothing   -> True
-                       Just ok   -> ok && (isSystemCoreName (getName vname))
+      -- Var vname _ -> case handlerFreeFunType (typeOf vname) of
+      --                  Nothing   -> True
+      --                  Just ok   -> ok && (isSystemCoreName (getName vname))
       Con{} -> True
       Lit{} -> True
       _     -> False

test/cgen/open-resolve.kk

@@ -0,0 +1,13 @@
+import std/os/path
+import std/os/env
+
+effect val package-root: path
+
+fun main()
+  println("Expecting :" ++ (cwd() / ".kokac").show)
+  with set-package-root(cwd())
+  println(package-root)
+
+noinline fun set-package-root(root: path, f: () -> <package-root,ndet|e> a): <ndet|e> a
+  with val package-root = root / ".kokac"
+  f()

test/cgen/open-resolve.kk.out

@@ -0,0 +1,2 @@
+Expecting :"@@@/@kokac"
+"@@@/@kokac"