Backport "Allow export statements in AnyVal" to LTS

compiler/src/dotty/tools/dotc/ast/Desugar.scala

@@ -19,6 +19,7 @@ import printing.Formatting.hl
 import config.Printers
 
 import scala.annotation.internal.sharable
+import dotty.tools.dotc.util.SrcPos
 
 object desugar {
   import untpd.*

compiler/src/dotty/tools/dotc/typer/Checking.scala

@@ -708,7 +708,7 @@ object Checking {
         report.error(ValueClassesMayNotDefineNonParameterField(clazz, stat.symbol), stat.srcPos)
       case _: DefDef if stat.symbol.isConstructor =>
         report.error(ValueClassesMayNotDefineASecondaryConstructor(clazz, stat.symbol), stat.srcPos)
-      case _: MemberDef | _: Import | EmptyTree =>
+      case _: MemberDef | _: Import | _: Export | EmptyTree =>
       // ok
       case _ =>
         report.error(ValueClassesMayNotContainInitalization(clazz), stat.srcPos)

tests/run/export-anyval.check

@@ -0,0 +1 @@
+Hello from export

tests/run/export-anyval.scala

@@ -0,0 +1,12 @@
+class Foo(val x: String) 
+
+
+class Bar(val y: Foo) extends AnyVal:
+    export y.*
+    def foo: String = x
+end Bar
+
+@main def Test = 
+    val a = Bar(Foo("Hello from export"))
+    println(a.foo)
+