Look up members at erasure phase for generating static forwarders

Forward-ports scala/scala@b6d7e0c42c

Author: lrytz

compiler/src/dotty/tools/backend/jvm/BCodeHelpers.scala

@@ -586,7 +586,7 @@ trait BCodeHelpers extends BCodeIdiomatic with BytecodeWriters {
         val m = if (m0.is(Bridge)) m0.nextOverriddenSymbol else m0
         if (m == NoSymbol)
           report.log(s"$m0 is a bridge method that overrides nothing, something went wrong in a previous phase.")
-        else if (m.isType || m.is(Deferred) || (m.owner eq defn.ObjectClass) || m.isConstructor || m.name.is(ExpandedName))
+        else if (m.isType || (m.owner eq defn.ObjectClass) || m.isConstructor || m.name.is(ExpandedName))
           report.debuglog(s"No forwarder for '$m' from $jclassName to '$moduleClass'")
         else if (conflictingNames(m.name))
           report.log(s"No forwarder for $m due to conflict with ${linkedClass.info.member(m.name)}")
@@ -607,7 +607,8 @@ trait BCodeHelpers extends BCodeIdiomatic with BytecodeWriters {
       val names = tp.memberNames(takeAllFilter).toSeq.sorted
       val buffer = mutable.ListBuffer[Symbol]()
       names.foreach { name =>
-        buffer ++= tp.memberBasedOnFlags(name, required, excluded)
+        // lookup members at erasure: lampepfl/dotty#12753
+        buffer ++= atPhase(erasurePhase)(tp.memberBasedOnFlags(name, required, excluded))
           .alternatives.sortBy(_.signature)(Signature.lexicographicOrdering).map(_.symbol)
       }
       buffer.toList

compiler/test/dotc/run-test-pickling.blacklist

@@ -34,3 +34,4 @@ typeclass-derivation3.scala
 varargs-abstract
 zero-arity-case-class.scala
 i12194.scala
+i12753

tests/run/i12753.check

@@ -0,0 +1,25 @@
+1
+Dbr
+1
+1
+2
+1
+1
+1
+1
+2
+1
+1
+public static java.lang.String D.bar()
+public static D D.foo(int)
+public static D D.t()
+public static int O.a()
+public static int O.b()
+public static void O.b_$eq(int)
+public static int O.c()
+public static int O.d()
+public static int O.i()
+public static int O.j()
+public static void O.j_$eq(int)
+public static int O.k()
+public static int O.l()

tests/run/i12753/C.scala

@@ -0,0 +1,34 @@
+trait C[This <: C[This]]
+
+trait COps[This <: C[This]] {
+  def t: This
+  def foo(x: Int): This = t
+  def bar: Object = "Cbr"
+}
+
+class D extends C[D] {
+  def x = 1
+}
+object D extends COps[D] {
+  def t = new D
+  override def foo(x: Int): D = super.foo(x)
+  override def bar: String = "Dbr"
+}
+
+trait T {
+  val a = 1
+  var b = 1
+  lazy val c = 1
+  def d = 1
+
+  val i: Int
+  var j: Int
+  lazy val k: Int = 1
+  def l: Int
+}
+object O extends T {
+  val i: Int = 1
+  var j: Int = 1
+  override lazy val k: Int = 1
+  def l: Int = 1
+}

tests/run/i12753/Test.java

@@ -0,0 +1,36 @@
+public class Test {
+  public static void s(Object s) {
+    System.out.println(s);
+  }
+
+  public static void statics(Class<?> c) {
+    java.lang.reflect.Method[] ms = c.getDeclaredMethods();
+    java.util.Arrays.sort(ms, (a, b) -> a.getName().compareTo(b.getName()));
+    for (java.lang.reflect.Method a : ms) {
+      if (java.lang.reflect.Modifier.isStatic(a.getModifiers()))
+        s(a);
+    }
+  }
+
+  public static void main(String[] args) {
+    s(D.foo(1).x());
+    s(D.bar());
+
+    s(O.a());
+    s(O.b());
+    O.b_$eq(2);
+    s(O.b());
+    s(O.c());
+    s(O.d());
+
+    s(O.i());
+    s(O.j());
+    O.j_$eq(2);
+    s(O.j());
+    s(O.k());
+    s(O.l());
+
+    statics(D.class);
+    statics(O.class);
+  }
+}