Fix generic signatures for nested and types

Author: Duhemm

compiler/src/dotty/tools/dotc/transform/Erasure.scala

@@ -740,7 +740,7 @@ object Erasure {
   }
 
   private def hiBounds(bounds: TypeBounds)(implicit ctx: Context): List[Type] = bounds.hi.widenDealias match {
-    case AndType(tp1, tp2) => tp1 :: tp2 :: Nil
+    case AndType(tp1, tp2) => hiBounds(tp1.bounds) ::: hiBounds(tp2.bounds)
     case tp => tp :: Nil
   }
 

tests/generic-java-signatures/andTypes.check

@@ -0,0 +1 @@
+T <: C1, T1, T2

tests/generic-java-signatures/andTypes.scala

@@ -0,0 +1,16 @@
+class C1
+trait T1
+trait T2
+
+class Foo {
+  def foo[T <: (C1 & T1) & T2] = ()
+}
+
+object Test {
+  def main(args: Array[String]): Unit = {
+    val tParams = classOf[Foo].getDeclaredMethod("foo").getTypeParameters
+    tParams.foreach { tp =>
+      println(tp.getName + " <: " + tp.getBounds.map(_.getTypeName).mkString(", "))
+    }
+  }
+}