Fix top level effect

Author: CAG2Mark

hkmc2/shared/src/main/scala/hkmc2/codegen/HandlerLowering.scala

@@ -207,6 +207,7 @@ class HandlerLowering(paths: HandlerPaths, opt: EffectHandlers)(using TL, Raise,
 
   // coalesce useless states
   def optParts(entryState: BlockState, states: Ls[BlockState]): (BlockState, Ls[BlockState]) =
+    return (entryState, states)
     val statesMap = (entryState :: states).map(state => state.id -> state).toMap
     def findEdges(state: BlockState) =
       var edges: List[BlockState] = Nil
@@ -831,15 +832,15 @@ class HandlerLowering(paths: HandlerPaths, opt: EffectHandlers)(using TL, Raise,
     val transform = new BlockTransformerShallow(SymbolSubst()):
       override def applyBlock(b: Block): Block = b match
         case ResultPlaceholder(res, uid, c, rest) => 
-          val (doUnwindCall, implct) = doUnwind match
-            case None => (topLevelCall(LinkState(res, clsSym.asPath, Value.Lit(Tree.IntLit(uid)))), true)
-            case Some(doUnwind) => (PureCall(doUnwind.get, res.asPath :: Value.Lit(Tree.IntLit(uid)) :: Nil), false)
+          val doUnwindBlk = doUnwind match
+            case None => Assign(res, topLevelCall(LinkState(res, clsSym.asPath, Value.Lit(Tree.IntLit(uid)))), End())
+            case Some(doUnwind) => Return(PureCall(doUnwind.get, res.asPath :: Value.Lit(Tree.IntLit(uid)) :: Nil), false)
           blockBuilder
             .assign(res, c)
             .ifthen(
               res.asPath,
               Case.Cls(paths.effectSigSym, paths.effectSigPath),
-              Return(doUnwindCall, implct)
+              doUnwindBlk
             )
             .rest(applyBlock(rest))
         case _ => super.applyBlock(b)

hkmc2/shared/src/test/mlscript/handlers/BadHandlers.mls

@@ -20,7 +20,7 @@ h.oops
 //│ h = new Handler$h$1();
 //│ tmp = handleBlock$();
 //│ if (tmp instanceof runtime.EffectSig.class) {
-//│   runtime.topLevelEffect(tmp, false)
+//│   tmp = runtime.topLevelEffect(tmp, false);
 //│ }
 //│ tmp
 

hkmc2/shared/src/test/mlscript/handlers/Debugging.mls

@@ -224,7 +224,6 @@ fun f() =
   print(debug.getLocals())
 //│ i = 100
 
-:fixme
 f()
 //│ > [FnLocalsInfo("‹top level›", [LocalVarInfo("i", 100)]), FnLocalsInfo("f", [LocalVarInfo("j", 200)])]
 //│ > Stack Trace:
@@ -234,4 +233,3 @@ f()
 //│ > Stack Trace:
 //│ > 	at f (Debugging.mls:223:3) with locals: j=300
 //│ > [FnLocalsInfo("‹top level›", [LocalVarInfo("i", 100)]), FnLocalsInfo("f", [LocalVarInfo("j", 300)])]
-//│ ═══[RUNTIME ERROR] RangeError: Maximum call stack size exceeded

hkmc2/shared/src/test/mlscript/handlers/Effects.mls

@@ -241,7 +241,7 @@ if true do
 //│ h11 = new Handler$h$23();
 //│ tmp11 = handleBlock$11();
 //│ if (tmp11 instanceof runtime.EffectSig.class) {
-//│   runtime.topLevelEffect(tmp11, false)
+//│   tmp11 = runtime.topLevelEffect(tmp11, false);
 //│ }
 //│ tmp11
 //│ = 3

hkmc2/shared/src/test/mlscript/handlers/RecursiveHandlers.mls

@@ -415,7 +415,7 @@ str
 //│   h11 = new Handler$h1$3();
 //│   tmp9 = handleBlock$7();
 //│   if (tmp9 instanceof runtime.EffectSig.class) {
-//│     runtime.topLevelEffect(tmp9, false)
+//│     tmp9 = runtime.topLevelEffect(tmp9, false);
 //│   }
 //│   tmp10 = tmp9;
 //│ } else {

hkmc2/shared/src/test/mlscript/handlers/ReturnInHandler.mls

@@ -40,7 +40,7 @@ let l = () =>
   return 3
   4
 //│ ╔══[ERROR] Return statements are not allowed outside of a function.
-//│ ║  l.55: 	  return 3
+//│ ║  l.40: 	  return 3
 //│ ╙──      	         ^
 //│ l = [function l]
 
@@ -58,7 +58,7 @@ let l = () =>
   4
 l()
 //│ ╔══[ERROR] Return statements are not allowed outside of a function.
-//│ ║  l.85: 	  return 3
+//│ ║  l.57: 	  return 3
 //│ ╙──      	         ^
 
 

hkmc2/shared/src/test/mlscript/handlers/SetInHandlers.mls

@@ -16,7 +16,7 @@ x
 //│   x = tmp1;
 //│   tmp2 = Predef.print(x);
 //│   if (tmp2 instanceof runtime.EffectSig.class) {
-//│     runtime.topLevelEffect(tmp2, false)
+//│     tmp2 = runtime.topLevelEffect(tmp2, false);
 //│   }
 //│   tmp = tmp2;
 //│ } finally {

hkmc2/shared/src/test/mlscript/handlers/StackSafety.mls

@@ -71,7 +71,7 @@ hi(0)
 //│ });
 //│ res = runtime.runStackSafe(5, $_stack$_safe$_body$_);
 //│ if (res instanceof runtime.EffectSig.class) {
-//│   runtime.topLevelEffect(res, false)
+//│   res = runtime.topLevelEffect(res, false);
 //│ }
 //│ res
 //│ = 0
@@ -167,7 +167,7 @@ sum(10000)
 //│ });
 //│ res1 = runtime.runStackSafe(1000, $_stack$_safe$_body$_1);
 //│ if (res1 instanceof runtime.EffectSig.class) {
-//│   runtime.topLevelEffect(res1, false)
+//│   res1 = runtime.topLevelEffect(res1, false);
 //│ }
 //│ res1
 //│ = 50005000