[Fix scala#13306] Print paramInfo of HKTypeLambda

Co-authored-by: Jamie Thompson <jamie.thompson@bath.edu>
Co-authored-by: Meriam Lachkar <meriam.lachkar@gmail.com>

compiler/src/dotty/tools/dotc/printing/PlainPrinter.scala

@@ -14,6 +14,7 @@ import Variances.varianceSign
 import util.SourcePosition
 import scala.util.control.NonFatal
 import scala.annotation.switch
+import Decorators._
 
 class PlainPrinter(_ctx: Context) extends Printer {
   /** The context of all public methods in Printer and subclasses.
@@ -355,8 +356,10 @@ class PlainPrinter(_ctx: Context) extends Printer {
           if lam.isDeclaredVarianceLambda then
             lam.paramNames.lazyZip(lam.declaredVariances).map((name, v) =>
               varianceSign(v) + name)
-          else lam.paramNames
-        (names.mkString("[", ", ", "]"), lam.resType)
+          else lam.paramNames.map(_.toString)
+        val infos = lam.paramInfos.map(_.show)
+        val tparamStr = names.zip(infos).map(_ + _).mkString("[", ", ", "]")
+        (tparamStr, lam.resType)
       case _ =>
         ("", tp)
     bounds match

tests/printing/i13306.check

@@ -0,0 +1,14 @@
+[[syntax trees at end of                     typer]] // tests/printing/i13306.scala
+package example {
+  class MyClass() extends Object() {}
+  class MembersContainer() extends Object() {
+    type MyType[T >: Nothing <: example.MyClass] = Comparable[T]
+  }
+  final lazy module val Exports: example.Exports = new example.Exports()
+  final module class Exports() extends Object() { this: example.Exports.type =>
+    val instance: example.MembersContainer = new example.MembersContainer()
+    export example.Exports.instance.*
+    final type MyType[T <: example.MyClass] = Comparable[T]
+  }
+}
+

tests/printing/i13306.scala

@@ -0,0 +1,12 @@
+package example
+
+class MyClass
+
+class MembersContainer {
+  type MyType[T <: MyClass] = Comparable[T]
+}
+
+object Exports {
+  val instance = new MembersContainer
+  export instance.*
+}