In Java sources, allow a non-stable prefix for a class parent.

(If we widen Foo.this.Inner in the parents of a class to AbstractFoo#Inner, i.e. an inherited class Inner prefixed by its owner abstract class AbstractFoo, this is not considered a stable prefix for a class parent type. But in Java this is the correct type so allow it.)
scala · Feb 22, 2024 · d37857c · d37857c
1 parent e8e295a
commit d37857c
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Showing 5 changed files with 149 additions and 4 deletions.
diff --git a/compiler/src/dotty/tools/dotc/typer/Namer.scala b/compiler/src/dotty/tools/dotc/typer/Namer.scala
@@ -1542,17 +1542,19 @@ class Namer { typer: Typer =>
       end parentType
 
       /** Check parent type tree `parent` for the following well-formedness conditions:
-       *  (1) It must be a class type with a stable prefix (@see checkClassTypeWithStablePrefix)
+       *  (1) It must be a class type with a stable prefix (unless `isJava`) (@see checkClassTypeWithStablePrefix)
        *  (2) If may not derive from itself
        *  (3) The class is not final
        *  (4) If the class is sealed, it is defined in the same compilation unit as the current class
+       *
+       * @param isJava  If true, the parent type is in Java mode, and we do not require a stable prefix
        */
-      def checkedParentType(parent: untpd.Tree): Type = {
+      def checkedParentType(parent: untpd.Tree, isJava: Boolean): Type = {
         val ptype = parentType(parent)(using completerCtx.superCallContext).dealiasKeepAnnots
         if (cls.isRefinementClass) ptype
         else {
           val pt = checkClassType(ptype, parent.srcPos,
-              traitReq = parent ne parents.head, stablePrefixReq = true)
+              traitReq = parent ne parents.head, stablePrefixReq = !isJava)
           if (pt.derivesFrom(cls)) {
             val addendum = parent match {
               case Select(qual: Super, _) if Feature.migrateTo3 =>
@@ -1621,7 +1623,9 @@ class Namer { typer: Typer =>
       val parentTypes = defn.adjustForTuple(cls, cls.typeParams,
         defn.adjustForBoxedUnit(cls,
           addUsingTraits(
-            ensureFirstIsClass(cls, parents.map(checkedParentType(_)))
+            locally:
+              val isJava = ctx.isJava
+              ensureFirstIsClass(cls, parents.map(checkedParentType(_, isJava)))
           )
         )
       )

diff --git a/sbt-test/pipelining/Yjava-tasty-paths/a/InnerClassSub.java b/sbt-test/pipelining/Yjava-tasty-paths/a/InnerClassSub.java
@@ -0,0 +1,52 @@
+package a;
+
+public class InnerClassSub extends InnerClass {
+
+  public class InnerSub<U> extends Inner<U> {
+    public InnerSub(U innerField) {
+      super(innerField);
+    }
+  }
+
+  public class OuterSub<U> extends Outer<U> {
+    public OuterSub() {
+      super();
+    }
+  }
+
+  public <U> Inner<U> createInnerSub(U innerField) {
+    return new InnerSub<>(innerField);
+  }
+
+  public <U, V> Outer<U>.Nested<V> createNestedSub(U outerField, V innerField) {
+    OuterSub<U> outer = new OuterSub<>();
+    return outer.new Nested<>(outerField, innerField);
+  }
+
+  public <U> InnerClass.Inner<U> createInnerSub2(U innerField) {
+    return new InnerSub<>(innerField);
+  }
+
+  public <U, V> InnerClass.Outer<U>.Nested<V> createNestedSub2(U outerField, V innerField) {
+    OuterSub<U> outer = new OuterSub<>();
+    return outer.new Nested<>(outerField, innerField);
+  }
+
+  public static <U> InnerClass.Inner<U> createInnerStatic(U innerField) {
+    InnerClassSub innerClass = new InnerClassSub();
+    return innerClass.new Inner<>(innerField);
+  }
+
+  public static <U, V> InnerClass.Outer<U>.Nested<V> createNestedStatic(U outerField, V innerField) {
+    InnerClassSub innerClass = new InnerClassSub();
+    InnerClassSub.Outer<U> outer = innerClass.new Outer<>();
+    return outer.new Nested<>(outerField, innerField);
+  }
+
+  public static <U, V> void consumeNestedStatic(InnerClass.Outer<U>.Nested<V> nested) {
+  }
+
+  public static <U, V> void consumeNestedStatic2(Outer<U>.Nested<V> nested) {
+  }
+
+}
diff --git a/sbt-test/pipelining/Yjava-tasty-paths/b/Test.scala b/sbt-test/pipelining/Yjava-tasty-paths/b/Test.scala
@@ -3,6 +3,7 @@ package b
 import a.InnerClass
 import a.InnerClassGen
 import a.RawTypes
+import a.InnerClassSub
 
 object B {
   @main def test = {
@@ -45,6 +46,23 @@ object B {
       RawTypes.mii_Raw_Raw(cd_ii_Raw)
       RawTypes.mii_Raw_Raw2(cd_ii_Raw)
     }
+
+    locally {
+      val ici: InnerClassSub = new InnerClassSub()
+      // val ici_inner1: ici.Inner[Long] = ici.createInner[Long](47L) // error
+      val ici_inner2: InnerClass#Inner[Long] = ici.createInnerSub[Long](47L)
+      val ici_inner2_2: InnerClass#Inner[Long] = ici.createInnerSub2[Long](47L)
+      val ici_inner3: InnerClass#Inner[Long] = InnerClassSub.createInnerStatic[Long](47L)
+
+      val ici_outer: InnerClassSub#Outer[Long] = new ici.Outer[Long]()
+      val ici_nested1: InnerClassSub#Outer[Long]#Nested[Int] = new ici_outer.Nested[Int](47L, 23)
+      val ici_nested2: InnerClass#Outer[Long]#Nested[Int] = ici.createNestedSub[Long, Int](47L, 23)
+      val ici_nested2_2: InnerClass#Outer[Long]#Nested[Int] = ici.createNestedSub2[Long, Int](47L, 23)
+      val ici_nested3: InnerClass#Outer[Long]#Nested[Int] = InnerClassSub.createNestedStatic[Long, Int](47L, 23)
+
+      InnerClass.consumeNestedStatic(ici_nested3)
+      InnerClass.consumeNestedStatic2(ici_nested3)
+    }
   }
 
 }
diff --git a/tests/run/i19619/InnerClassSub.java b/tests/run/i19619/InnerClassSub.java
@@ -0,0 +1,54 @@
+// InnerClass.java
+
+package lib;
+
+public class InnerClassSub extends InnerClass {
+
+  public class InnerSub<U> extends Inner<U> {
+    public InnerSub(U innerField) {
+      super(innerField);
+    }
+  }
+
+  public class OuterSub<U> extends Outer<U> {
+    public OuterSub() {
+      super();
+    }
+  }
+
+  public <U> Inner<U> createInnerSub(U innerField) {
+    return new InnerSub<>(innerField);
+  }
+
+  public <U, V> Outer<U>.Nested<V> createNestedSub(U outerField, V innerField) {
+    OuterSub<U> outer = new OuterSub<>();
+    return outer.new Nested<>(outerField, innerField);
+  }
+
+  public <U> InnerClass.Inner<U> createInnerSub2(U innerField) {
+    return new InnerSub<>(innerField);
+  }
+
+  public <U, V> InnerClass.Outer<U>.Nested<V> createNestedSub2(U outerField, V innerField) {
+    OuterSub<U> outer = new OuterSub<>();
+    return outer.new Nested<>(outerField, innerField);
+  }
+
+  public static <U> InnerClass.Inner<U> createInnerStatic(U innerField) {
+    InnerClassSub innerClass = new InnerClassSub();
+    return innerClass.new Inner<>(innerField);
+  }
+
+  public static <U, V> InnerClass.Outer<U>.Nested<V> createNestedStatic(U outerField, V innerField) {
+    InnerClassSub innerClass = new InnerClassSub();
+    InnerClassSub.Outer<U> outer = innerClass.new Outer<>();
+    return outer.new Nested<>(outerField, innerField);
+  }
+
+  public static <U, V> void consumeNestedStatic(InnerClass.Outer<U>.Nested<V> nested) {
+  }
+
+  public static <U, V> void consumeNestedStatic2(Outer<U>.Nested<V> nested) {
+  }
+
+}
diff --git a/tests/run/i19619/Test.scala b/tests/run/i19619/Test.scala
@@ -1,6 +1,7 @@
 import lib.InnerClass
 import lib.InnerClassGen
 import lib.RawTypes
+import lib.InnerClassSub
 
 @main def Test =
 
@@ -40,3 +41,19 @@ import lib.RawTypes
 
     RawTypes.mii_Raw_Raw(cd_ii_Raw)
     RawTypes.mii_Raw_Raw2(cd_ii_Raw)
+
+  locally:
+    val ici: InnerClassSub = new InnerClassSub()
+    // val ici_inner1: ici.Inner[Long] = ici.createInner[Long](47L) // error
+    val ici_inner2: InnerClass#Inner[Long] = ici.createInnerSub[Long](47L)
+    val ici_inner2_2: InnerClass#Inner[Long] = ici.createInnerSub2[Long](47L)
+    val ici_inner3: InnerClass#Inner[Long] = InnerClassSub.createInnerStatic[Long](47L)
+
+    val ici_outer: InnerClassSub#Outer[Long] = new ici.Outer[Long]()
+    val ici_nested1: InnerClassSub#Outer[Long]#Nested[Int] = new ici_outer.Nested[Int](47L, 23)
+    val ici_nested2: InnerClass#Outer[Long]#Nested[Int] = ici.createNestedSub[Long, Int](47L, 23)
+    val ici_nested2_2: InnerClass#Outer[Long]#Nested[Int] = ici.createNestedSub2[Long, Int](47L, 23)
+    val ici_nested3: InnerClass#Outer[Long]#Nested[Int] = InnerClassSub.createNestedStatic[Long, Int](47L, 23)
+
+    InnerClass.consumeNestedStatic(ici_nested3)
+    InnerClass.consumeNestedStatic2(ici_nested3)