Enforce module parameters to receive only module arguments

Author: FlandiaYingman

hkmc2/shared/src/main/scala/hkmc2/semantics/Elaborator.scala

@@ -232,7 +232,33 @@ extends Importer:
       term(rhs)
     case tree @ App(lhs, rhs) =>
       val sym = FlowSymbol("‹app-res›", nextUid)
-      Term.App(term(lhs), term(rhs))(tree, sym)
+      val lt = term(lhs)
+      val rt = term(rhs)
+
+      // Check module parameters
+      val args = rt match
+        case Term.Tup(fields) => S(fields)
+        case _ => N
+      val argsModFlags = args
+        .map(_.map(_.flags.mod))
+      val paramsModFlags = lt.symbol match
+        case S(sym: BlockMemberSymbol) => sym.defn match
+          case S(defn: TermDefinition) => defn.params.lift(0)
+            .map(_.params.map(_.flags.mod))
+          case _ => argsModFlags.map(_.map(_ => false))
+        case _ => argsModFlags.map(_.map(_ => false))
+      for
+        (argLists, amfs, pmfs) <- (args lazyZip argsModFlags lazyZip paramsModFlags)
+        (a, amf, pmf) <- (argLists lazyZip amfs lazyZip pmfs)
+        if amf && !pmf
+      do 
+        log(s"${a.value}")
+        raise(ErrorReport(
+        msg"Module values can only be passed to module parameters." -> a.toLoc
+        :: Nil, 
+      ))
+      
+      Term.App(lt, rt)(tree, sym)
     case Sel(pre, nme) =>
       val preTrm = term(pre)
       val sym = resolveField(nme, preTrm.symbol, nme)
@@ -325,8 +351,12 @@ extends Importer:
   def fld(tree: Tree): Ctxl[Fld] = tree match
     case InfixApp(lhs, Keyword.`:`, rhs) =>
       Fld(FldFlags.empty, term(lhs), S(term(rhs)))
-    case _ => Fld(FldFlags.empty, term(tree), N)
-  
+    case _ => 
+      val t = term(tree)
+      t.symbol.flatMap(_.asMod) match
+        case S(_) => Fld(FldFlags.module, t, N)
+        case N => Fld(FldFlags.empty, t, N)
+    
   def unit: Term.Lit = Term.Lit(UnitLit(true))
 
 

hkmc2/shared/src/main/scala/hkmc2/semantics/Term.scala

@@ -313,7 +313,7 @@ final case class Param(flags: FldFlags, sym: LocalSymbol & NamedSymbol, sign: Op
 object FldFlags { 
   val empty: FldFlags = FldFlags(false, false, false, false)
 
-  // module parameter
+  // module parameter / module argument, depending on the context
   val module: FldFlags = FldFlags(false, false, false, true)
  }
 

hkmc2/shared/src/test/mlscript/basics/ModuleMethods.mls

@@ -124,6 +124,9 @@ f1(new C)
 // Error: module values can only be passed to module parameters.
 :e
 f1(M) 
+//│ ╔══[ERROR] Module values can only be passed to module parameters.
+//│ ║  l.126: 	f1(M) 
+//│ ╙──       	   ^
 //│ Elaborated tree:
 //│ Blk:
 //│   stats = Nil
@@ -133,12 +136,11 @@ f1(M)
 //│       nme = Ident of "f1"
 //│     rhs = Tup of Ls of 
 //│       Fld:
-//│         flags = ()
+//│         flags = (module)
 //│         value = Sel:
 //│           prefix = Ref of globalThis:block#1
 //│           nme = Ident of "M"
 //│         asc = N
-//│ FAILURE: Unexpected lack of type error
 
 
 // Good: m is a module parameter, therefore the module method foo can be called on m.
@@ -206,7 +208,7 @@ f2(M)
 //│       nme = Ident of "f2"
 //│     rhs = Tup of Ls of 
 //│       Fld:
-//│         flags = ()
+//│         flags = (module)
 //│         value = Sel:
 //│           prefix = Ref of globalThis:block#1
 //│           nme = Ident of "M"
@@ -276,6 +278,9 @@ fun id[T](t: T): T = t
 // Error: Module values can only be passed to module parameters.
 :e
 id(IntMT)
+//│ ╔══[ERROR] Module values can only be passed to module parameters.
+//│ ║  l.280: 	id(IntMT)
+//│ ╙──       	   ^^^^^
 //│ Elaborated tree:
 //│ Blk:
 //│   stats = Nil
@@ -285,12 +290,11 @@ id(IntMT)
 //│       nme = Ident of "id"
 //│     rhs = Tup of Ls of 
 //│       Fld:
-//│         flags = ()
+//│         flags = (module)
 //│         value = Sel:
 //│           prefix = Ref of globalThis:block#9
 //│           nme = Ident of "IntMT"
 //│         asc = N
-//│ FAILURE: Unexpected lack of type error
 
 
 // Good: module parameters must have an explicit and concrete type. 
@@ -330,7 +334,7 @@ idMod(IntMT)
 //│       nme = Ident of "idMod"
 //│     rhs = Tup of Ls of 
 //│       Fld:
-//│         flags = ()
+//│         flags = (module)
 //│         value = Sel:
 //│           prefix = Ref of globalThis:block#9
 //│           nme = Ident of "IntMT"