Merge pull request #15703 from dotty-staging/init-super-accessor

Handle super accessors in initialization checker

compiler/src/dotty/tools/dotc/transform/init/Semantic.scala

@@ -8,6 +8,7 @@ import Symbols.*
 import Types.*
 import StdNames.*
 import NameKinds.OuterSelectName
+import NameKinds.SuperAccessorName
 
 import ast.tpd.*
 import config.Printers.init as printer
@@ -788,7 +789,9 @@ object Semantic:
             if !needResolve then
               meth
             else if superType.exists then
-              resolveSuper(ref.klass, superType, meth)
+              meth
+            else if meth.name.is(SuperAccessorName) then
+              ResolveSuper.rebindSuper(ref.klass, meth)
             else
               resolve(ref.klass, meth)
 
@@ -829,7 +832,7 @@ object Semantic:
               value.select(target, receiver, needResolve = false)
           else
             if ref.klass.isSubClass(receiver.widenSingleton.classSymbol) then
-              report.error("Unexpected resolution failure: ref.klass = " + ref.klass.show + ", meth = " + meth.show + Trace.show, Trace.position)
+              report.error("[Internal error] Unexpected resolution failure: ref.klass = " + ref.klass.show + ", meth = " + meth.show + Trace.show, Trace.position)
               Hot
             else
               // This is possible due to incorrect type cast.
@@ -1175,9 +1178,8 @@ object Semantic:
         // Note that a parameterized trait may only get parameters from the class that extends the trait.
         // A trait may not supply constructor arguments to another trait.
         if !klass.is(Flags.Trait) then
-          for parent <- klass.parentSyms if parent.hasSource do doPromote(parent.asClass, klass, isHotSegment)
-          // We still need to handle indirectly extended traits via traits, which are not in the parent list.
           val superCls = klass.superClass
+          if superCls.hasSource then doPromote(superCls.asClass, klass, isHotSegment)
           val mixins = klass.baseClasses.tail.takeWhile(_ != superCls)
           for mixin <- mixins if mixin.hasSource do doPromote(mixin.asClass, klass, isHotSegment)
       end doPromote
@@ -1768,16 +1770,3 @@ object Semantic:
     if (sym.isEffectivelyFinal || sym.isConstructor) sym
     else sym.matchingMember(cls.appliedRef)
   }
-
-  def resolveSuper(cls: ClassSymbol, superType: Type, sym: Symbol)(using Context): Symbol =
-    import annotation.tailrec
-    @tailrec def loop(bcs: List[ClassSymbol]): Symbol = bcs match {
-      case bc :: bcs1 =>
-        val cand = sym.matchingDecl(bcs.head, cls.thisType)
-          .suchThat(alt => !alt.is(Flags.Deferred)).symbol
-        if (cand.exists) cand else loop(bcs.tail)
-      case _ =>
-        NoSymbol
-    }
-    loop(cls.info.baseClasses.dropWhile(sym.owner != _))
-

tests/init/neg/super-resolution.check

@@ -0,0 +1,36 @@
+-- Error: tests/init/neg/super-resolution.scala:21:6 -------------------------------------------------------------------
+21 |  val m = 30 // error
+   |      ^
+   |      Access non-initialized value m. Calling trace:
+   |      -> class C extends A with M with N:	[ super-resolution.scala:17 ]
+   |         ^
+   |      -> foo()	[ super-resolution.scala:18 ]
+   |         ^^^^^
+   |      -> override def foo(): Int = b * super.foo()	[ super-resolution.scala:15 ]
+   |                                       ^^^^^^^^^^^
+   |      -> override def foo(): Int = a + super.foo()	[ super-resolution.scala:11 ]
+   |                                       ^^^^^^^^^^^
+   |      -> def foo(): Int = m	[ super-resolution.scala:7 ]
+   |                          ^
+-- Error: tests/init/neg/super-resolution.scala:19:6 -------------------------------------------------------------------
+19 |  val a = 10 // error
+   |      ^
+   |      Access non-initialized value a. Calling trace:
+   |      -> class C extends A with M with N:	[ super-resolution.scala:17 ]
+   |         ^
+   |      -> foo()	[ super-resolution.scala:18 ]
+   |         ^^^^^
+   |      -> override def foo(): Int = b * super.foo()	[ super-resolution.scala:15 ]
+   |                                       ^^^^^^^^^^^
+   |      -> override def foo(): Int = a + super.foo()	[ super-resolution.scala:11 ]
+   |                                   ^
+-- Error: tests/init/neg/super-resolution.scala:20:6 -------------------------------------------------------------------
+20 |  val b = 20 // error
+   |      ^
+   |      Access non-initialized value b. Calling trace:
+   |      -> class C extends A with M with N:	[ super-resolution.scala:17 ]
+   |         ^
+   |      -> foo()	[ super-resolution.scala:18 ]
+   |         ^^^^^
+   |      -> override def foo(): Int = b * super.foo()	[ super-resolution.scala:15 ]
+   |                                   ^

tests/init/neg/super-resolution.scala

@@ -0,0 +1,23 @@
+abstract class A:
+  val n: Int
+  def foo(): Int = n
+
+trait B:
+  val m: Int
+  def foo(): Int = m
+
+trait M extends A with B:
+  val a: Int
+  override def foo(): Int = a + super.foo()
+
+trait N extends A with B:
+  val b: Int
+  override def foo(): Int = b * super.foo()
+
+class C extends A with M with N:
+  foo()
+  val a = 10 // error
+  val b = 20 // error
+  val m = 30 // error
+  val n = 40
+

tests/init/neg/super-resolution2.check

@@ -0,0 +1,28 @@
+-- Error: tests/init/neg/super-resolution2.scala:19:6 ------------------------------------------------------------------
+19 |  val n = 40 // error
+   |      ^
+   |      Access non-initialized value n. Calling trace:
+   |      -> class N extends A with B:	[ super-resolution2.scala:9 ]
+   |         ^
+   |      -> new Inner	[ super-resolution2.scala:16 ]
+   |         ^^^^^^^^^
+   |      -> class Inner:	[ super-resolution2.scala:12 ]
+   |         ^
+   |      -> N.super[A].foo()	[ super-resolution2.scala:13 ]
+   |         ^^^^^^^^^^^^^^^^
+   |      -> def foo(): Int = n	[ super-resolution2.scala:3 ]
+   |                          ^
+-- Error: tests/init/neg/super-resolution2.scala:18:6 ------------------------------------------------------------------
+18 |  val m = 30 // error
+   |      ^
+   |      Access non-initialized value m. Calling trace:
+   |      -> class N extends A with B:	[ super-resolution2.scala:9 ]
+   |         ^
+   |      -> new Inner	[ super-resolution2.scala:16 ]
+   |         ^^^^^^^^^
+   |      -> class Inner:	[ super-resolution2.scala:12 ]
+   |         ^
+   |      -> N.super.foo()	[ super-resolution2.scala:14 ]
+   |         ^^^^^^^^^^^^^
+   |      -> def foo(): Int = m	[ super-resolution2.scala:7 ]
+   |                          ^

tests/init/neg/super-resolution2.scala

@@ -0,0 +1,20 @@
+abstract class A:
+  val n: Int
+  def foo(): Int = n
+
+trait B:
+  val m: Int
+  def foo(): Int = m
+
+class N extends A with B:
+  override def foo(): Int = a * super.foo()
+
+  class Inner:
+    N.super[A].foo()
+    N.super.foo()
+
+  new Inner
+
+  val m = 30 // error
+  val n = 40 // error
+  val a = 50