Context for constructor error is outer context

Author: som-snytt

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

@@ -824,16 +824,16 @@ object SymDenotations {
       }
 
       /** Is protected access to target symbol permitted? */
-      def isProtectedAccessOK = {
-        def fail(str: => String): Boolean = {
-          if (whyNot != null) whyNot append str
+      def isProtectedAccessOK: Boolean =
+        def fail(str: => String): false =
+          if whyNot != null then whyNot.append(str)
           false
-        }
         val cls = owner.enclosingSubClass
-        if (!cls.exists)
+        if !cls.exists then
+          val encl = if !ctx.owner.isConstructor then ctx else ctx.outersIterator.dropWhile(_.owner.isConstructor).next()
           fail(
             i"""
-               | Access to protected $this not permitted because enclosing ${ctx.owner.enclosingClass.showLocated}
+               | Access to protected $this not permitted because enclosing ${encl.owner.enclosingClass.showLocated}
                | is not a subclass of ${owner.showLocated} where target is defined""")
         else if
           !(  isType // allow accesses to types from arbitrary subclasses fixes #4737
@@ -847,7 +847,7 @@ object SymDenotations {
                | Access to protected ${symbol.show} not permitted because prefix type ${pre.widen.show}
                | does not conform to ${cls.showLocated} where the access takes place""")
         else true
-      }
+      end isProtectedAccessOK
 
       if pre eq NoPrefix then true
       else if isAbsent() then false

tests/neg/i7709.check

@@ -0,0 +1,12 @@
+-- Error: tests/neg/i7709.scala:5:20 -----------------------------------------------------------------------------------
+5 |  class B extends X.Y // error
+  |                  ^^^
+  |                  class Y in object X cannot be accessed as a member of X.type from class B.
+  |                   Access to protected class Y not permitted because enclosing object A
+  |                   is not a subclass of object X where target is defined
+-- Error: tests/neg/i7709.scala:10:18 ----------------------------------------------------------------------------------
+10 |  def y  = new xx.Y  // error
+   |               ^^^^
+   |               class Y cannot be accessed as a member of XX from class C.
+   |                Access to protected class Y not permitted because enclosing class C
+   |                is not a subclass of class XX where target is defined

tests/neg/i7709.scala

@@ -0,0 +1,12 @@
+
+object X:
+  protected class Y
+object A:
+  class B extends X.Y // error
+class XX:
+  protected class Y
+class C:
+  def xx = new XX
+  def y  = new xx.Y  // error
+class YY extends XX:
+  def y = new Y