Merge pull request #10794 from lrytz/t13007

Avoid call to inaccessible protected java method through self type

Author: lrytz

src/compiler/scala/tools/nsc/transform/Erasure.scala

@@ -1287,9 +1287,11 @@ abstract class Erasure extends InfoTransform
 
             if (qualSym != owner)
               tree.updateAttachment(new QualTypeSymAttachment(qualSym))
-          } else if (!isJvmAccessible(owner, context)) {
+          } else if (!isJvmAccessible(owner, context) ||
+            // scala/bug#13007: isJvmAccessible is true for a protected java method, even if accessed through erased self type
+            sym.isJavaDefined && sym.isProtected && !qual.tpe.typeSymbol.isSubClass(sym.owner)) {
             val qualSym = qual.tpe.typeSymbol
-            if (qualSym != owner && isJvmAccessible(qualSym, context) && definesMemberAfterErasure(qualSym, sym))
+            if (qualSym != owner && isJvmAccessible(qualSym, context) && (definesMemberAfterErasure(qualSym, sym) || sym.overridingSymbol(qualSym).exists))
               tree.updateAttachment(new QualTypeSymAttachment(qualSym))
             else
               reporter.error(tree.pos, s"Unable to emit reference to ${sym.fullLocationString}, $owner is not accessible in ${context.enclClass.owner}")

test/files/neg/t13007.check

@@ -0,0 +1,10 @@
+Test.scala:9: error: Unable to emit reference to method j in class J, class J is not accessible in trait T
+  def t4 = j()
+           ^
+Test.scala:10: error: Unable to emit reference to method j in class J, class J is not accessible in trait T
+  def t5 = this.j()
+                ^
+Test.scala:11: error: Unable to emit reference to method j in class J, class J is not accessible in trait T
+  def t6 = self.j()
+                ^
+3 errors

test/files/neg/t13007/J.java

@@ -0,0 +1,7 @@
+package j;
+
+public class J {
+  protected boolean i() { return false; }
+  protected boolean j() { return false; }
+  public boolean k() { return false; }
+}

test/files/neg/t13007/Test.scala

@@ -0,0 +1,18 @@
+package s
+
+trait T { self: j.J =>
+  override def i(): Boolean = true
+  def t1 = i()
+  def t2 = this.i()
+  def t3 = self.i()
+
+  def t4 = j()
+  def t5 = this.j()
+  def t6 = self.j()
+
+  def t7 = k()
+  def t8 = this.k()
+  def t9 = self.k()
+}
+
+class C extends j.J with T

test/files/neg/t13307b.check

@@ -0,0 +1,9 @@
+Test.scala:8: error: Implementation restriction: trait T accesses protected method j inside a concrete trait method.
+Add an accessor in a class extending class J as a workaround.
+  def t4 = j()
+           ^
+Test.scala:9: error: Implementation restriction: trait T accesses protected method j inside a concrete trait method.
+Add an accessor in a class extending class J as a workaround.
+  def t5 = this.j()
+                ^
+2 errors

test/files/neg/t13307b/J.java

@@ -0,0 +1,7 @@
+package j;
+
+public class J {
+  protected boolean i() { return false; }
+  protected boolean j() { return false; }
+  public boolean k() { return false; }
+}

test/files/neg/t13307b/Test.scala

@@ -0,0 +1,15 @@
+package s
+
+trait T extends j.J {
+  override def i(): Boolean = true
+  def t1 = i()
+  def t2 = this.i()
+
+  def t4 = j()
+  def t5 = this.j()
+
+  def t7 = k()
+  def t8 = this.k()
+}
+
+class C extends j.J with T

test/files/run/t13007/J.java

@@ -0,0 +1,7 @@
+package j;
+
+public class J {
+  protected boolean i() { return false; }
+  protected boolean j() { return false; }
+  public boolean k() { return false; }
+}

test/files/run/t13007/Test.scala

@@ -0,0 +1,33 @@
+package s {
+
+  trait T {
+    self: j.J =>
+    override def i(): Boolean = true
+
+    def t1 = i()
+    def t2 = this.i()
+    def t3 = self.i()
+
+    // def t4 = j()
+    // def t5 = this.j()
+    // def t6 = self.j()
+
+    def t7 = k()
+    def t8 = this.k()
+    def t9 = self.k()
+  }
+
+  class C extends j.J with T
+}
+
+object Test {
+  def main(args: Array[String]): Unit = {
+    val c = new s.C
+    assert(c.t1)
+    assert(c.t2)
+    assert(c.t3)
+    assert(!c.t7)
+    assert(!c.t8)
+    assert(!c.t9)
+  }
+}

test/files/run/t13307b/J.java

@@ -0,0 +1,7 @@
+package j;
+
+public class J {
+  protected boolean i() { return false; }
+  protected boolean j() { return false; }
+  public boolean k() { return false; }
+}