Fix #9392: Allow overriding a Java method when a same-named field is present

compiler/src/dotty/tools/dotc/core/SymDenotations.scala

@@ -1066,7 +1066,6 @@ object SymDenotations {
     final def isEffectivelyFinal(using Context): Boolean =
       isOneOf(EffectivelyFinalFlags)
       || is(Inline, butNot = Deferred)
-      || is(JavaDefinedVal, butNot = Method)
       || !owner.isExtensibleClass
 
     /** A class is effectively sealed if has the `final` or `sealed` modifier, or it

compiler/src/dotty/tools/dotc/typer/RefChecks.scala

@@ -778,8 +778,10 @@ object RefChecks {
         )
       def classDecls = inclazz.info.nonPrivateDecl(member.name)
 
-      (inclazz != clazz) &&
-        classDecls.hasAltWith(d => isSignatureMatch(d.symbol) && javaAccessCheck(d.symbol))
+      (inclazz != clazz) && classDecls.hasAltWith(d =>
+        isSignatureMatch(d.symbol) && javaAccessCheck(d.symbol) &&
+        !d.symbol.is(JavaDefinedVal, butNot = Method) // Java fields cannot be overriden
+      )
     }
 
     // 4. Check that every defined member with an `override` modifier overrides some other member.

tests/pos/i9392/J.java

@@ -0,0 +1,6 @@
+package pkg;
+
+public class J {
+    int i = 0;
+    public int i() { return 1; }
+}

tests/pos/i9392/S.scala

@@ -0,0 +1,17 @@
+class S1 extends pkg.J {
+  override def i(): Int = 2
+}
+
+class S2 extends pkg.J {
+  override def i: Int = 2
+}
+object Test {
+  val s1 = new S1
+
+  val i1 = s1.i
+  val i2 = s1.i()
+
+  val s2 = new S2
+
+  val i3 = s2.i
+}