Fix #3273: Extend cooking to parent types

compiler/src/dotty/tools/dotc/core/classfile/ClassfileParser.scala

@@ -32,6 +32,12 @@ object ClassfileParser {
       case tp @ AppliedType(tycon, args) =>
         // disregard tycon itself, but map over it to visit the prefix
         tp.derivedAppliedType(mapOver(tycon), args.mapConserve(this))
+      case tp @ TempPolyType(_, tpe) =>
+        val tpe1 = this(tpe)
+        if (tpe1 eq tpe) tp else tp.copy(tpe = tpe1)
+      case tp @ TempClassInfoType(parents, _, _) =>
+        val parents1 = parents.mapConserve(this)
+        if (parents eq parents1) tp else tp.copy(parentTypes = parents1)
       case _ =>
         mapOver(tp)
     }
@@ -154,7 +160,7 @@ class ClassfileParser(
 
       for (i <- 0 until in.nextChar) parseMember(method = false)
       for (i <- 0 until in.nextChar) parseMember(method = true)
-      classInfo = parseAttributes(classRoot.symbol, classInfo)
+      classInfo = cook.apply(parseAttributes(classRoot.symbol, classInfo))
       if (isAnnotation) addAnnotationConstructor(classInfo)
 
       val companionClassMethod = ctx.synthesizeCompanionMethod(nme.COMPANION_CLASS_METHOD, classRoot, moduleRoot)

compiler/test/dotty/tools/dotc/CompilationTests.scala

@@ -66,6 +66,7 @@ class CompilationTests extends ParallelTesting {
       ),
       scala2Mode
     ) +
+    compileFilesInDir("../tests/pos-special/i3273", defaultOptions) +
     compileFilesInDir("../tests/pos-special/spec-t5545", defaultOptions) +
     compileFilesInDir("../tests/pos-special/strawman-collections", defaultOptions) +
     compileFile("../scala2-library/src/library/scala/collection/immutable/IndexedSeq.scala", defaultOptions) +

tests/pos-special/i3273/test/Bar_1.java

@@ -0,0 +1,8 @@
+class Bar_1 {
+	static abstract class A<X> extends B {
+		abstract B foo();
+	}
+	static abstract class B<X> {
+		abstract A bar();
+	}
+}

tests/pos-special/i3273/test/client_2.scala

@@ -0,0 +1,5 @@
+class Client {
+  val a = (_: Bar_1.A[AnyRef]).foo()
+  val b = (_: Bar_1.B[AnyRef]).bar()
+  def test(x: Bar_1.A[AnyRef]): Bar_1.B[_] = x
+}