Merge pull request scala#4701 from dotty-staging/decompile-fix-varargs

Fix printing varargs _*

library/src/scala/tasty/util/ShowSourceCode.scala

@@ -869,10 +869,15 @@ class ShowSourceCode[T <: Tasty with Singleton](tasty0: T) extends Show[T](tasty
         printRefinement(tpe)
 
       case Type.AppliedType(tp, args) =>
-        printType(tp)
-        this += "["
-        printTypesOrBounds(args, ", ")
-        this += "]"
+        tp match {
+          case Type.TypeRef("<repeated>", Types.ScalaPackage()) =>
+            this += "_*"
+          case _ =>
+            printType(tp)
+            this += "["
+            printTypesOrBounds(args, ", ")
+            this += "]"
+        }
 
       case Type.AnnotatedType(tp, annot) =>
         val Annotation(ref, args) = annot

tests/run/t889.decompiled

@@ -0,0 +1,10 @@
+/** Decompiled from out/runTestFromTasty/run/t889/Test.class */
+object Test extends dotty.runtime.LegacyApp() {
+  val a: collection.immutable.List[java.lang.String] = scala.List.apply[java.lang.String]("a")
+  Test.a match {
+    case scala.Seq("a", "b", rest: _*) =>
+      scala.Predef.println("a, b, ".+(rest))
+    case scala.Seq(first, rest: _*) =>
+      scala.Predef.println("first: ".+(first).+(", rest: ").+(rest))
+  }
+}