Add Scoped blocks

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

@@ -29,10 +29,15 @@ sealed abstract class Block extends Product:
     case _: End => true
     case _ => false
 
-  /** This variation of `definedVars` excludes the `syms` in `Scoped` blocks
-    * so that `Scoped` blocks' vars can be seen in the output js code;
-    * otherwise `blockPreamble` allocates all the `definedVars` such that
-    * we cannot see and test vars generated because of the existence of the `Scoped` blocks */
+  /** This variation of `definedVars` excludes the `syms` in `Scoped` blocks.
+    * It is used in JSBuilder now: names are allocated in JSBuilder for these `definedVarsNoScoped` symbols.
+    * This is needed now because
+    *   - there are symbols that are not collected in the `Scoped` blocks (due to later passes),
+    *     and they still need to be allocated a name in JSBuilder
+    *   - if we don't exlude the `Scoped` symbols, they may be allocated a name
+    *     prematurely and decalred in wrong places, e.g. symbols inside while bodies
+    *     may be declared in an outer level
+    */
   lazy val definedVarsNoScoped: Set[Local] = this match
     case _: Return | _: Throw => Set.empty
     case Begin(sub, rst) => sub.definedVarsNoScoped ++ rst.definedVarsNoScoped

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

@@ -304,7 +304,7 @@ class Lowering()(using Config, TL, Raise, State, Ctx):
               case (sym, params, split) =>
                 val paramLists = params :: Nil
                 val bodyBlock = inScopedBlock(ucs.Normalization(this)(split)(Ret))
-                FunDefn.withFreshSymbol(N, sym, paramLists, bodyBlock)(isTailRec = false)
+                FunDefn.withFreshSymbol(N, sym, paramLists, bodyBlock)(forceTailRec = false)
             // The return type is intended to be consistent with `gatherMembers`
             (mtds, Nil, Nil, End())
           case _ => gatherMembers(defn.body)
@@ -526,7 +526,7 @@ class Lowering()(using Config, TL, Raise, State, Ctx):
               N,
               lamSym,
               PlainParamList(Nil) :: Nil,
-              inScopedBlock(returnedTerm(arg2)))(isTailRec = false)
+              inScopedBlock(returnedTerm(arg2)))(forceTailRec = false)
             Define(
               lamDef,
               k(Call(
@@ -678,7 +678,7 @@ class Lowering()(using Config, TL, Raise, State, Ctx):
       else
         val lamSym = new BlockMemberSymbol("lambda", Nil, false)
         loweringCtx.collectScopedSym(lamSym)
-        val lamDef = FunDefn.withFreshSymbol(N, lamSym, paramLists, bodyBlock)(isTailRec = false)
+        val lamDef = FunDefn.withFreshSymbol(N, lamSym, paramLists, bodyBlock)(forceTailRec = false)
         Define(
           lamDef,
           k(lamDef.asPath))
@@ -1025,8 +1025,8 @@ class Lowering()(using Config, TL, Raise, State, Ctx):
       case Lambda(params, body) =>
         val lamSym = BlockMemberSymbol("lambda", Nil, false)
         loweringCtx.collectScopedSym(lamSym)
-        val lamDef = FunDefn.withFreshSymbol(N, lamSym, params :: Nil, body)(isTailRec = false)
-        Define(lamDef, k(Value.Ref(lamSym, N)))
+        val lamDef = FunDefn.withFreshSymbol(N, lamSym, params :: Nil, body)(forceTailRec = false)
+        Define(lamDef, k(lamDef.asPath))
       case r =>
         val l = new TempSymbol(N)
         loweringCtx.collectScopedSym(l)

hkmc2/shared/src/main/scala/hkmc2/semantics/ucs/Normalization.scala

@@ -340,6 +340,7 @@ class Normalization(lowering: Lowering)(using tl: TL)(using Raise, Ctx, State) e
         val res = new BlockMemberSymbol("while", Nil, false)
         outerCtx.collectScopedSym(res)
         res
+      lazy val tSym = TermSymbol.fromFunBms(f, N)
       val normalized = tl.scoped("ucs:normalize"):
         normalize(inputSplit)(using VarSet())
       tl.scoped("ucs:normalized"):
@@ -352,7 +353,7 @@ class Normalization(lowering: Lowering)(using tl: TL)(using Raise, Ctx, State) e
       // NOTE: `shouldRewriteWhile` is not the same as `config.rewriteWhileLoops`
       // as shouldRewriteWhile is always true when effect handler lowering is on
       lazy val loopCont = if config.shouldRewriteWhile
-        then Return(Call(Value.Ref(f, N), Nil)(true, true, false), false)
+        then Return(Call(Value.Ref(f, S(tSym)), Nil)(true, true, false), false)
         else Continue(loopLabel)
       val cont =
         if kw === `while` then
@@ -418,8 +419,8 @@ class Normalization(lowering: Lowering)(using tl: TL)(using Raise, Ctx, State) e
               Select(Value.Ref(State.runtimeSymbol), Tree.Ident("LoopEnd"))(S(State.loopEndSymbol))
             val blk = blockBuilder
               .assign(l, Value.Lit(Tree.UnitLit(false)))
-              .define(FunDefn.withFreshSymbol(N, f, PlainParamList(Nil) :: Nil, Begin(body, Return(loopEnd, false)))(isTailRec = false))
-              .assign(loopResult, Call(Value.Ref(f, N), Nil)(true, true, false))
+              .define(FunDefn(N, f, tSym, PlainParamList(Nil) :: Nil, Begin(body, Return(loopEnd, false)))(forceTailRec = false))
+              .assign(loopResult, Call(Value.Ref(f, S(tSym)), Nil)(true, true, false))
             if summon[LoweringCtx].mayRet then
               blk
                 .assign(isReturned, Call(Value.Ref(State.builtinOpsMap("!==")),

hkmc2/shared/src/test/mlscript/codegen/FieldSymbols.mls

@@ -100,7 +100,7 @@ case
 //│               modulefulness = Modulefulness of N
 //│           restParam = N
 //│       body = Scoped:
-//│         syms = HashSet($argument0$, a)
+//│         syms = HashSet(a, $argument0$)
 //│         body = Match:
 //│           scrut = Ref:
 //│             l = caseScrut
@@ -142,9 +142,9 @@ case
 //│                 value = Lit of StrLit of "match error"
 //│           rest = End of ""
 //│     rest = Return: \
-//│     res = Ref:
+//│     res = Ref{disamb=term:lambda}:
 //│       l = member:lambda
-//│       disamb = N
+//│       disamb = S of term:lambda
 //│     implct = true
 //│ = fun
 

hkmc2/shared/src/test/mlscript/codegen/RandomStuff.mls

@@ -6,8 +6,8 @@ fun foo() = if false do foo()
 //│ JS (unsanitized):
 //│ let foo;
 //│ foo = function foo() {
-//│   let scrut;
 //│   loopLabel: while (true) {
+//│     let scrut;
 //│     scrut = false;
 //│     if (scrut === true) { continue loopLabel } else { return runtime.Unit }
 //│     break;
@@ -68,7 +68,7 @@ do
 //│ JS (unsanitized):
 //│ let f, f1;
 //│ f1 = 1;
-//│ f = function f() { loopLabel: while (true) { continue loopLabel; break; } };
+//│ f = function f() { loopLabel: while (true) { let tmp; continue loopLabel; break; } };
 //│ runtime.Unit
 //│ f = 1
 

hkmc2/shared/src/test/mlscript/std/FingerTreeListTest.mls

@@ -135,8 +135,8 @@ fun popByIndex(start, end, acc, lft) =
 //│ JS (unsanitized):
 //│ let popByIndex;
 //│ popByIndex = function popByIndex(start, end, acc, lft) {
-//│   let scrut, tmp34, tmp35, tmp36;
 //│   loopLabel: while (true) {
+//│     let scrut, tmp34, tmp35, tmp36;
 //│     scrut = start >= end;
 //│     if (scrut === true) {
 //│       return acc

hkmc2/shared/src/test/mlscript/tailrec/Simple.mls

@@ -5,7 +5,7 @@
 @tailrec
 fun f = f
 //│ JS (unsanitized):
-//│ let f; f = function f() { loopLabel: while (true) { continue loopLabel; break; } };
+//│ let f; f = function f() { loopLabel: while (true) { let tmp; continue loopLabel; break; } };
 
 :fixme
 module Foo with
@@ -29,8 +29,14 @@ fun f(x) = f(f(x) + 1)
 //│ JS (unsanitized):
 //│ let f3;
 //│ f3 = function f(x) {
-//│   let tmp, tmp1;
-//│   loopLabel: while (true) { tmp = f3(x); tmp1 = tmp + 1; x = tmp1; continue loopLabel; break; }
+//│   loopLabel: while (true) {
+//│     let tmp, tmp1;
+//│     tmp = f3(x);
+//│     tmp1 = tmp + 1;
+//│     x = tmp1;
+//│     continue loopLabel;
+//│     break;
+//│   }
 //│ };
 
 module A with
@@ -44,7 +50,7 @@ module A with
 module B with
   fun g(x) = A.f(x * 2)
 //│ ╔══[WARNING] This function does not directly self-recurse, but is marked @tailrec.
-//│ ║  l.43: 	  fun f(x) = B.g(x + 1)
+//│ ║  l.49: 	  fun f(x) = B.g(x + 1)
 //│ ╙──      	      ^
 
 

hkmc2/shared/src/test/mlscript/tailrec/TailRecOpt.mls

@@ -16,16 +16,18 @@ fun f(a, b, c) =
     else c
 f(10000, 20000, 0)
 //│ JS (unsanitized):
-//│ let f, g, g_f;
+//│ let f, g;
+//│ let g_f;
 //│ g_f = function g_f(id, param0, param1, param2, param3) {
-//│   let scrut, scrut1, tmp, tmp1, tmp2;
 //│   loopLabel: while (true) {
 //│     if (id === 0) {
+//│       let tmp;
 //│       tmp = param2 + param3;
 //│       param2 = tmp;
 //│       id = 1;
 //│       continue loopLabel
 //│     } else if (id === 1) {
+//│       let scrut, scrut1, tmp1, tmp2;
 //│       scrut = param0 > 0;
 //│       if (scrut === true) {
 //│         tmp1 = param0 - 1;
@@ -72,8 +74,8 @@ A.sum(20000)
 //│     runtime.Unit;
 //│   }
 //│   static sum_impl(n, acc) {
-//│     let scrut, tmp, tmp1;
 //│     loopLabel: while (true) {
+//│       let scrut, tmp, tmp1;
 //│       scrut = Predef.equals(n, 0);
 //│       if (scrut === true) {
 //│         return acc
@@ -143,7 +145,7 @@ fun f(x) =
     @tailcall f(x)
   @tailcall g()
 //│ ╔══[ERROR] This call is not in tail position.
-//│ ║  l.142: 	    @tailcall f(x)
+//│ ║  l.144: 	    @tailcall f(x)
 //│ ╙──       	              ^
 
 :lift
@@ -161,10 +163,10 @@ module A with
     @tailcall g(x - 1)
 A.f(10000)
 //│ ╔══[ERROR] This tail call exits the current scope is not optimized.
-//│ ║  l.160: 	    fun g(x) = if x < 0 then 0 else @tailcall f(x)
+//│ ║  l.162: 	    fun g(x) = if x < 0 then 0 else @tailcall f(x)
 //│ ╙──       	                                              ^^^
 //│ ╔══[ERROR] This tail call exits the current scope is not optimized.
-//│ ║  l.161: 	    @tailcall g(x - 1)
+//│ ║  l.163: 	    @tailcall g(x - 1)
 //│ ╙──       	              ^^^^^^^^
 //│ ═══[RUNTIME ERROR] RangeError: Maximum call stack size exceeded
 
@@ -191,12 +193,12 @@ class A with
   fun g(x) = if x == 0 then 1 else @tailcall f(x - 1)
 (new A).f(10)
 //│ ╔══[ERROR] Calls from class methods cannot yet be marked @tailcall.
-//│ ║  l.190: 	  @tailrec fun f(x) = if x == 0 then 0 else @tailcall g(x - 1)
+//│ ║  l.192: 	  @tailrec fun f(x) = if x == 0 then 0 else @tailcall g(x - 1)
 //│ ╙──       	                                                      ^^^^^^^^
 //│ ╔══[ERROR] Class methods may not yet be marked @tailrec.
-//│ ║  l.190: 	  @tailrec fun f(x) = if x == 0 then 0 else @tailcall g(x - 1)
+//│ ║  l.192: 	  @tailrec fun f(x) = if x == 0 then 0 else @tailcall g(x - 1)
 //│ ╙──       	               ^
 //│ ╔══[ERROR] Calls from class methods cannot yet be marked @tailcall.
-//│ ║  l.191: 	  fun g(x) = if x == 0 then 1 else @tailcall f(x - 1)
+//│ ║  l.193: 	  fun g(x) = if x == 0 then 1 else @tailcall f(x - 1)
 //│ ╙──       	                                             ^^^^^^^^
 //│ = 0

hkmc2DiffTests/src/test/scala/hkmc2/MLsDiffMaker.scala

@@ -72,6 +72,7 @@ abstract class MLsDiffMaker extends DiffMaker:
   val importQQ = NullaryCommand("qq")
   val stageCode = NullaryCommand("staging")
   val rewriteWhile = NullaryCommand("rewriteWhile")
+  val noTailRecOpt = NullaryCommand("noTailRec")
 
   def mkConfig: Config =
     import Config.*
@@ -100,6 +101,7 @@ abstract class MLsDiffMaker extends DiffMaker:
       stageCode = stageCode.isSet,
       target = if wasm.isSet then CompilationTarget.Wasm else CompilationTarget.JS,
       rewriteWhileLoops = rewriteWhile.isSet,
+      tailRecOpt = !noTailRecOpt.isSet,
     )