Scala.js: Upgrade to Scala.js 1.18.1.

And port the changes that were made to the compiler backend.
Most notably, the changes from the following upstream PRs:

* Introduce non-nullable reference types in the IR.
  scala-js/scala-js#5018
* Opt: Remove useless *Ident indirections in the IR model.
  scala-js/scala-js#5092
* Merge the IR node This into VarRef, with a magic LocalName.
  scala-js/scala-js#5090
* Merge several IR nodes into UnaryOp.
  scala-js/scala-js#5088
* Restrict usages of StoreModule even further.
  scala-js/scala-js#5059
* Allow Return arg to be a void if the target Labeled is a void.
  scala-js/scala-js#5074
* Rename NoType to VoidType and print it as "void".
  scala-js/scala-js#5061

Author: sjrd

compiler/src/dotty/tools/backend/sjs/JSCodeGen.scala

@@ -179,8 +179,6 @@ final class JSDefinitions()(using Context) {
     def Runtime_createLocalJSClass(using Context) = Runtime_createLocalJSClassR.symbol
     @threadUnsafe lazy val Runtime_withContextualJSClassValueR = RuntimePackageClass.requiredMethodRef("withContextualJSClassValue")
     def Runtime_withContextualJSClassValue(using Context) = Runtime_withContextualJSClassValueR.symbol
-    @threadUnsafe lazy val Runtime_linkingInfoR = RuntimePackageClass.requiredMethodRef("linkingInfo")
-    def Runtime_linkingInfo(using Context) = Runtime_linkingInfoR.symbol
     @threadUnsafe lazy val Runtime_dynamicImportR = RuntimePackageClass.requiredMethodRef("dynamicImport")
     def Runtime_dynamicImport(using Context) = Runtime_dynamicImportR.symbol
 

compiler/src/dotty/tools/backend/sjs/JSDefinitions.scala

@@ -135,16 +135,13 @@ object JSEncoding {
     def freshLabelName(base: String): LabelName =
       freshLabelName(LabelName(base))
 
-    def freshLabelIdent(base: String)(implicit pos: ir.Position): js.LabelIdent =
-      js.LabelIdent(freshLabelName(base))
-
     def labelSymbolName(sym: Symbol)(using Context): LabelName =
       labelSymbolNames.getOrElseUpdate(sym, freshLabelName(sym.javaSimpleName))
 
-    def getEnclosingReturnLabel()(implicit pos: ir.Position): js.LabelIdent = {
+    def getEnclosingReturnLabel(): LabelName = {
       if (returnLabelName.isEmpty)
         returnLabelName = Some(freshLabelName("_return"))
-      js.LabelIdent(returnLabelName.get)
+      returnLabelName.get
     }
 
     /* If this `LocalNameGenerator` has a `returnLabelName` (often added in the
@@ -155,7 +152,7 @@ object JSEncoding {
         case None =>
           body
         case Some(labelName) =>
-          js.Labeled(js.LabelIdent(labelName), tpe, body)
+          js.Labeled(labelName, tpe, body)
       }
     }
   }
@@ -166,10 +163,9 @@ object JSEncoding {
 
   // Encoding methods ----------------------------------------------------------
 
-  def encodeLabelSym(sym: Symbol)(
-      implicit ctx: Context, pos: ir.Position, localNames: LocalNameGenerator): js.LabelIdent = {
+  def encodeLabelSym(sym: Symbol)(implicit ctx: Context, localNames: LocalNameGenerator): LabelName = {
     require(sym.is(Flags.Label), "encodeLabelSym called with non-label symbol: " + sym)
-    js.LabelIdent(localNames.labelSymbolName(sym))
+    localNames.labelSymbolName(sym)
   }
 
   def encodeFieldSym(sym: Symbol)(implicit ctx: Context, pos: ir.Position): js.FieldIdent =
@@ -248,11 +244,13 @@ object JSEncoding {
   private def paramOrResultTypeRef(tpe: Type)(using Context): jstpe.TypeRef =
     toParamOrResultTypeRef(toTypeRef(tpe))
 
-  def encodeLocalSym(sym: Symbol)(
-      implicit ctx: Context, pos: ir.Position, localNames: LocalNameGenerator): js.LocalIdent = {
+  def encodeLocalSym(sym: Symbol)(using Context, ir.Position, LocalNameGenerator): js.LocalIdent =
+    js.LocalIdent(encodeLocalSymName(sym))
+
+  def encodeLocalSymName(sym: Symbol)(using ctx: Context, localNames: LocalNameGenerator): LocalName = {
     require(!sym.owner.isClass && sym.isTerm && !sym.is(Flags.Method) && !sym.is(Flags.Module),
         "encodeLocalSym called with non-local symbol: " + sym)
-    js.LocalIdent(localNames.localSymbolName(sym))
+    localNames.localSymbolName(sym)
   }
 
   def encodeClassType(sym: Symbol)(using Context): jstpe.Type = {
@@ -261,7 +259,7 @@ object JSEncoding {
     else {
       assert(sym != defn.ArrayClass,
           "encodeClassType() cannot be called with ArrayClass")
-      jstpe.ClassType(encodeClassName(sym))
+      jstpe.ClassType(encodeClassName(sym), nullable = true)
     }
   }
 
@@ -324,10 +322,10 @@ object JSEncoding {
         else if (sym == defn.NullClass)
           jstpe.NullType
         else
-          jstpe.ClassType(typeRef.className)
+          jstpe.ClassType(typeRef.className, nullable = true)
 
       case typeRef: jstpe.ArrayTypeRef =>
-        jstpe.ArrayType(typeRef)
+        jstpe.ArrayType(typeRef, nullable = true)
     }
   }
 

compiler/src/dotty/tools/backend/sjs/JSEncoding.scala

@@ -652,7 +652,7 @@ final class JSExportsGen(jsCodeGen: JSCodeGen)(using Context) {
     val superClass = {
       val superClassSym = currentClassSym.asClass.superClass
       if (superClassSym.isNestedJSClass)
-        js.VarRef(js.LocalIdent(JSSuperClassParamName))(jstpe.AnyType)
+        js.VarRef(JSSuperClassParamName)(jstpe.AnyType)
       else
         js.LoadJSConstructor(encodeClassName(superClassSym))
     }
@@ -793,7 +793,7 @@ final class JSExportsGen(jsCodeGen: JSCodeGen)(using Context) {
     }
 
     // #15419 If the getter returns void, we must "box" it by returning undefined
-    if (callGetter.tpe == jstpe.NoType)
+    if (callGetter.tpe == jstpe.VoidType)
       js.Block(callGetter, js.Undefined())
     else
       callGetter
@@ -837,7 +837,7 @@ final class JSExportsGen(jsCodeGen: JSCodeGen)(using Context) {
   }
 
   private def genThrowTypeError(msg: String = "No matching overload")(implicit pos: Position): js.Tree =
-    js.Throw(js.JSNew(js.JSGlobalRef("TypeError"), js.StringLiteral(msg) :: Nil))
+    js.UnaryOp(js.UnaryOp.Throw, js.JSNew(js.JSGlobalRef("TypeError"), js.StringLiteral(msg) :: Nil))
 
   abstract class Exported(
     val sym: Symbol,
@@ -935,9 +935,9 @@ final class JSExportsGen(jsCodeGen: JSCodeGen)(using Context) {
         import dotty.tools.sjs.ir.Names
 
         (toIRType(tpe): @unchecked) match {
-          case jstpe.AnyType => NoTypeTest
+          case jstpe.AnyType | jstpe.AnyNotNullType => NoTypeTest
 
-          case jstpe.NoType      => PrimitiveTypeTest(jstpe.UndefType, 0)
+          case jstpe.VoidType    => PrimitiveTypeTest(jstpe.UndefType, 0)
           case jstpe.BooleanType => PrimitiveTypeTest(jstpe.BooleanType, 1)
           case jstpe.CharType    => PrimitiveTypeTest(jstpe.CharType, 2)
           case jstpe.ByteType    => PrimitiveTypeTest(jstpe.ByteType, 3)
@@ -947,11 +947,11 @@ final class JSExportsGen(jsCodeGen: JSCodeGen)(using Context) {
           case jstpe.FloatType   => PrimitiveTypeTest(jstpe.FloatType, 7)
           case jstpe.DoubleType  => PrimitiveTypeTest(jstpe.DoubleType, 8)
 
-          case jstpe.ClassType(Names.BoxedUnitClass)   => PrimitiveTypeTest(jstpe.UndefType, 0)
-          case jstpe.ClassType(Names.BoxedStringClass) => PrimitiveTypeTest(jstpe.StringType, 9)
-          case jstpe.ClassType(_)                      => InstanceOfTypeTest(tpe)
+          case jstpe.ClassType(Names.BoxedUnitClass, _)   => PrimitiveTypeTest(jstpe.UndefType, 0)
+          case jstpe.ClassType(Names.BoxedStringClass, _) => PrimitiveTypeTest(jstpe.StringType, 9)
+          case jstpe.ClassType(_, _)                      => InstanceOfTypeTest(tpe)
 
-          case jstpe.ArrayType(_) => InstanceOfTypeTest(tpe)
+          case jstpe.ArrayType(_, _) => InstanceOfTypeTest(tpe)
         }
     }
   }
@@ -998,7 +998,7 @@ final class JSExportsGen(jsCodeGen: JSCodeGen)(using Context) {
 
     def genArgRef(index: Int)(implicit pos: Position): js.Tree = {
       if (index < minArgc)
-        js.VarRef(js.LocalIdent(fixedParamNames(index)))(jstpe.AnyType)
+        js.VarRef(fixedParamNames(index))(jstpe.AnyType)
       else
         js.JSSelect(genRestArgRef(), js.IntLiteral(index - minArgc))
     }
@@ -1014,16 +1014,16 @@ final class JSExportsGen(jsCodeGen: JSCodeGen)(using Context) {
 
     def genRestArgRef()(implicit pos: Position): js.Tree = {
       assert(needsRestParam, s"trying to generate a reference to non-existent rest param at $pos")
-      js.VarRef(js.LocalIdent(restParamName))(jstpe.AnyType)
+      js.VarRef(restParamName)(jstpe.AnyType)
     }
 
     def genAllArgsRefsForForwarder()(implicit pos: Position): List[js.TreeOrJSSpread] = {
       val fixedArgRefs = fixedParamNames.toList.map { paramName =>
-        js.VarRef(js.LocalIdent(paramName))(jstpe.AnyType)
+        js.VarRef(paramName)(jstpe.AnyType)
       }
 
       if (needsRestParam) {
-        val restArgRef = js.VarRef(js.LocalIdent(restParamName))(jstpe.AnyType)
+        val restArgRef = js.VarRef(restParamName)(jstpe.AnyType)
         fixedArgRefs :+ js.JSSpread(restArgRef)
       } else {
         fixedArgRefs

compiler/src/dotty/tools/backend/sjs/JSExportsGen.scala

@@ -34,8 +34,7 @@ object JSPrimitives {
   inline val CREATE_INNER_JS_CLASS = CONSTRUCTOROF + 1                  // runtime.createInnerJSClass
   inline val CREATE_LOCAL_JS_CLASS = CREATE_INNER_JS_CLASS + 1          // runtime.createLocalJSClass
   inline val WITH_CONTEXTUAL_JS_CLASS_VALUE = CREATE_LOCAL_JS_CLASS + 1 // runtime.withContextualJSClassValue
-  inline val LINKING_INFO = WITH_CONTEXTUAL_JS_CLASS_VALUE + 1          // runtime.linkingInfo
-  inline val DYNAMIC_IMPORT = LINKING_INFO + 1                          // runtime.dynamicImport
+  inline val DYNAMIC_IMPORT = WITH_CONTEXTUAL_JS_CLASS_VALUE + 1        // runtime.dynamicImport
 
   inline val STRICT_EQ = DYNAMIC_IMPORT + 1                // js.special.strictEquals
   inline val IN = STRICT_EQ + 1                            // js.special.in
@@ -122,7 +121,6 @@ class JSPrimitives(ictx: Context) extends DottyPrimitives(ictx) {
     addPrimitive(jsdefn.Runtime_createInnerJSClass, CREATE_INNER_JS_CLASS)
     addPrimitive(jsdefn.Runtime_createLocalJSClass, CREATE_LOCAL_JS_CLASS)
     addPrimitive(jsdefn.Runtime_withContextualJSClassValue, WITH_CONTEXTUAL_JS_CLASS_VALUE)
-    addPrimitive(jsdefn.Runtime_linkingInfo, LINKING_INFO)
     addPrimitive(jsdefn.Runtime_dynamicImport, DYNAMIC_IMPORT)
 
     addPrimitive(jsdefn.Special_strictEquals, STRICT_EQ)

compiler/src/dotty/tools/backend/sjs/JSPrimitives.scala

@@ -1669,6 +1669,7 @@ object Build {
             "productionMode" -> sems.productionMode,
             "esVersion" -> linkerConfig.esFeatures.esVersion.edition,
             "useECMAScript2015Semantics" -> linkerConfig.esFeatures.useECMAScript2015Semantics,
+            "isWebAssembly" -> linkerConfig.experimentalUseWebAssembly,
         )
       }.taskValue,
 

project/Build.scala

@@ -6,7 +6,7 @@
 libraryDependencySchemes +=
   "org.scala-lang.modules" %% "scala-xml" % VersionScheme.Always
 
-addSbtPlugin("org.scala-js" % "sbt-scalajs" % "1.16.0")
+addSbtPlugin("org.scala-js" % "sbt-scalajs" % "1.18.1")
 
 addSbtPlugin("org.xerial.sbt" % "sbt-sonatype" % "3.9.21")
 

project/plugins.sbt

@@ -1,3 +1,5 @@
+// scalajs: --compliant-semantics
+
 object Test {
   def monitor(x: AnyRef): Unit = {x.synchronized(()); ()}
   def check(x: => Any) = try { x; sys.error("failed to throw NPE") } catch { case _: NullPointerException => }