Fix #11592: Scala.js: Handle default params of native JS classes.

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

@@ -290,12 +290,12 @@ class JSCodeGen()(using genCtx: Context) {
         "genScalaClass() must be called only for normal classes: "+sym)
     assert(sym.superClass != NoSymbol, sym)
 
-    /*if (hasDefaultCtorArgsAndRawJSModule(sym)) {
-      reporter.error(pos,
-          "Implementation restriction: constructors of " +
-          "Scala classes cannot have default parameters " +
-          "if their companion module is JS native.")
-    }*/
+    if (hasDefaultCtorArgsAndJSModule(sym)) {
+      report.error(
+          "Implementation restriction: " +
+          "constructors of Scala classes cannot have default parameters if their companion module is JS native.",
+          td)
+    }
 
     val classIdent = encodeClassNameIdent(sym)
     val originalName = originalNameOfClass(sym)
@@ -965,9 +965,8 @@ class JSCodeGen()(using genCtx: Context) {
 
     if (hasDefaultCtorArgsAndJSModule(classSym)) {
       report.error(
-          "Implementation restriction: constructors of " +
-          "non-native JS classes cannot have default parameters " +
-          "if their companion module is JS native.",
+          "Implementation restriction: " +
+          "constructors of non-native JS classes cannot have default parameters if their companion module is JS native.",
           classSym.srcPos)
       val ctorDef = js.JSMethodDef(js.MemberFlags.empty,
           js.StringLiteral("constructor"), Nil, None, js.Skip())(
@@ -1067,9 +1066,10 @@ class JSCodeGen()(using genCtx: Context) {
         Some(js.MethodDef(js.MemberFlags.empty, methodName, originalName,
             jsParams, toIRType(patchedResultType(sym)), None)(
             OptimizerHints.empty, None))
-      } else /*if (isJSNativeCtorDefaultParam(sym)) {
+      } else if (sym.isJSNativeCtorDefaultParam) {
+        // #11592
         None
-      } else if (sym.isClassConstructor && isHijackedBoxedClass(sym.owner)) {
+      } else /*if (sym.isClassConstructor && isHijackedBoxedClass(sym.owner)) {
         None
       } else*/ {
         /*def isTraitImplForwarder = dd.rhs match {

compiler/src/dotty/tools/dotc/transform/sjs/JSSymUtils.scala

@@ -158,6 +158,13 @@ object JSSymUtils {
       }
     }
 
+    /** Is this symbol a default param accessor for the constructor of a native JS class? */
+    def isJSNativeCtorDefaultParam(using Context): Boolean = {
+      sym.name.is(DefaultGetterName)
+        && sym.name.exclude(DefaultGetterName) == nme.CONSTRUCTOR
+        && sym.owner.linkedClass.hasAnnotation(jsdefn.JSNativeAnnot)
+    }
+
     def jsCallingConvention(using Context): JSCallingConvention =
       JSCallingConvention.of(sym)
 

tests/sjs-junit/test/org/scalajs/testsuite/compiler/RegressionTestScala3.scala

@@ -4,6 +4,7 @@ import org.junit.Assert.*
 import org.junit.Test
 
 import scala.scalajs.js
+import scala.scalajs.js.annotation._
 
 class RegressionTestScala3 {
   import RegressionTestScala3.*
@@ -21,6 +22,11 @@ class RegressionTestScala3 {
     assertEquals(-1, obj2.y)
     assertEquals(4, obj2.foo(5))
   }
+
+  @Test def testJSNativeDefaultCtorParamIssue11592(): Unit = {
+    assertEquals("foo", new RangeErrorIssue11592("foo").message)
+    assertEquals("", new RangeErrorIssue11592().message)
+  }
 }
 
 object RegressionTestScala3 {
@@ -33,6 +39,12 @@ object RegressionTestScala3 {
 
     def foo(x: Int): Int = new ChildClass().concreteMethod(x)
   }
+
+  @js.native
+  @JSGlobal("RangeError")
+  class RangeErrorIssue11592(msg: String = js.native) extends js.Object {
+    val message: String = js.native
+  }
 }
 
 // This class needs to be at the top-level, not in an object, to reproduce the issue