Add selections on self types in isAbstractMember

Author: bracevac

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

@@ -1179,7 +1179,10 @@ class Namer { typer: Typer =>
          * Check the export selects an abstract member of the current class (issue #22147).
          */
         def isAbstractMember: Boolean = sym.is(Deferred) && (expr match
-          case ths: This if ths.qual.isEmpty => true
+          case ths: This if ths.qual.isEmpty => true // access through 'this'
+          case id: Ident => id.denot.info match      // access through self type
+            case cls2: ClassInfo => cls2.cls == cls
+            case _ => false
           case _ => false
         )
         if !sym.isAccessibleFrom(pathType) then

tests/neg/exports3.scala

@@ -2,4 +2,20 @@ trait P:
   def foo: Int
 
 class A extends P:
-  export this.foo // error
+  export this.foo // error
+
+trait Q extends P:
+  def bar: Int
+
+trait R extends P:
+  def baz: Int
+  val a1: A
+  val a2: A
+
+class B extends R:
+  self =>
+    export this.baz     // error
+    export self.bar     // error
+    export this.a1.foo
+    export self.a2.foo  // error
+    export a2.foo       // error