From a4c47671054691ec0fa19b6f73322f9b0b192b48 Mon Sep 17 00:00:00 2001
From: Adrien Piquerez <adrien.piquerez@gmail.com>
Date: Tue, 24 Aug 2021 16:18:54 +0200
Subject: [PATCH] [Fix #13306] Print paramInfo of HKTypeLambda

Co-authored-by: Jamie Thompson <jamie.thompson@bath.edu>
Co-authored-by: Meriam Lachkar <meriam.lachkar@gmail.com>
---
 .../dotty/tools/dotc/printing/PlainPrinter.scala   | 10 ++++++----
 tests/printing/i13306.check                        | 14 ++++++++++++++
 tests/printing/i13306.scala                        | 12 ++++++++++++
 3 files changed, 32 insertions(+), 4 deletions(-)
 create mode 100644 tests/printing/i13306.check
 create mode 100644 tests/printing/i13306.scala

diff --git a/compiler/src/dotty/tools/dotc/printing/PlainPrinter.scala b/compiler/src/dotty/tools/dotc/printing/PlainPrinter.scala
index 64d825ca7c26..c412afaf0487 100644
--- a/compiler/src/dotty/tools/dotc/printing/PlainPrinter.scala
+++ b/compiler/src/dotty/tools/dotc/printing/PlainPrinter.scala
@@ -348,15 +348,17 @@ class PlainPrinter(_ctx: Context) extends Printer {
     case None => "?"
   }
 
-  protected def decomposeLambdas(bounds: TypeBounds): (String, TypeBounds) =
-    def decompose(tp: Type) = tp.stripTypeVar match
+  protected def decomposeLambdas(bounds: TypeBounds): (Text, TypeBounds) =
+    def decompose(tp: Type): (Text, Type) = tp.stripTypeVar match
       case lam: HKTypeLambda =>
         val names =
           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(toText)
+        val tparams = names.zip(infos).map(_ ~ _)
+        ("[" ~ Text(tparams, ",") ~ "]", lam.resType)
       case _ =>
         ("", tp)
     bounds match
diff --git a/tests/printing/i13306.check b/tests/printing/i13306.check
new file mode 100644
index 000000000000..053d2f861cf3
--- /dev/null
+++ b/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]
+  }
+}
+
diff --git a/tests/printing/i13306.scala b/tests/printing/i13306.scala
new file mode 100644
index 000000000000..790f55018404
--- /dev/null
+++ b/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.*
+}