diff options
| -rw-r--r-- | src/compiler/scala/tools/nsc/typechecker/SuperAccessors.scala | 17 | ||||
| -rw-r--r-- | src/compiler/scala/tools/nsc/typechecker/Typers.scala | 2 | ||||
| -rw-r--r-- | test/junit/scala/lang/traits/BytecodeTest.scala | 27 |
3 files changed, 39 insertions, 7 deletions
diff --git a/src/compiler/scala/tools/nsc/typechecker/SuperAccessors.scala b/src/compiler/scala/tools/nsc/typechecker/SuperAccessors.scala index 49d892e04f..a38d21fe10 100644 --- a/src/compiler/scala/tools/nsc/typechecker/SuperAccessors.scala +++ b/src/compiler/scala/tools/nsc/typechecker/SuperAccessors.scala @@ -146,7 +146,22 @@ abstract class SuperAccessors extends transform.Transform with transform.TypingT val intermediateClasses = clazz.info.baseClasses.tail.takeWhile(_ != sym.owner) intermediateClasses.map(sym.overridingSymbol).find(s => s.isDeferred && !s.isAbstractOverride && !s.owner.isTrait).foreach { absSym => - reporter.error(sel.pos, s"${sym.fullLocationString} cannot be directly accessed from ${clazz} because ${absSym.owner} redeclares it as abstract") + reporter.error(sel.pos, s"${sym.fullLocationString} cannot be directly accessed from $clazz because ${absSym.owner} redeclares it as abstract") + } + } else if (mix != tpnme.EMPTY) { + // SD-143: a call super[T].m that resolves to A.m cannot be translated to correct bytecode if + // - A is a class (not a trait / interface), but not the direct superclass. Invokespecial + // would select an overriding method in the direct superclass, rather than A.m. + // https://docs.oracle.com/javase/specs/jvms/se8/html/jvms-6.html#jvms-6.5.invokespecial + // - A is a java-defined interface and not listed as direct parent of the class. In this + // case, `invokespecial A.m` would be invalid. + val owner = sym.owner + if (!owner.isTrait && owner != clazz.superClass) { + reporter.error(sel.pos, + s"cannot emit super call: the selected $sym is declared in $owner, which is not the direct superclass of $clazz.\n" + + s"An unqualified super call (super.${sym.name}) would be allowed.") + } else if (owner.isInterface && owner.isJavaDefined && !clazz.parentSymbols.contains(owner)) { + reporter.error(sel.pos, s"unable to emit super call unless interface ${owner.name} (which declares $sym) is directly extended by $clazz.") } } diff --git a/src/compiler/scala/tools/nsc/typechecker/Typers.scala b/src/compiler/scala/tools/nsc/typechecker/Typers.scala index a95ecd360c..bf275af24f 100644 --- a/src/compiler/scala/tools/nsc/typechecker/Typers.scala +++ b/src/compiler/scala/tools/nsc/typechecker/Typers.scala @@ -2040,7 +2040,7 @@ trait Typers extends Adaptations with Tags with TypersTracking with PatternTyper override def matches(sym: Symbol, sym1: Symbol) = if (sym.isSkolem) matches(sym.deSkolemize, sym1) else if (sym1.isSkolem) matches(sym, sym1.deSkolemize) - else super[SubstTypeMap].matches(sym, sym1) + else super.matches(sym, sym1) } // allow defaults on by-name parameters if (sym hasFlag BYNAMEPARAM) diff --git a/test/junit/scala/lang/traits/BytecodeTest.scala b/test/junit/scala/lang/traits/BytecodeTest.scala index a92d2244a2..c20fae2500 100644 --- a/test/junit/scala/lang/traits/BytecodeTest.scala +++ b/test/junit/scala/lang/traits/BytecodeTest.scala @@ -244,7 +244,6 @@ class BytecodeTest extends BytecodeTesting { @Test def sd143(): Unit = { - // this tests the status quo, which is wrong. val code = """class A { def m = 1 } |class B extends A { override def m = 2 } @@ -253,10 +252,28 @@ class BytecodeTest extends BytecodeTesting { | override def m = super[T].m // should invoke A.m |} """.stripMargin - val List(_, _, c, _) = compileClasses(code) - // even though the bytecode refers to A.m, invokespecial will resolve to B.m - assertSameCode(getMethod(c, "m"), - List(VarOp(ALOAD, 0), Invoke(INVOKESPECIAL, "A", "m", "()I", false), Op(IRETURN))) + + val err = + """cannot emit super call: the selected method m is declared in class A, which is not the direct superclass of class C. + |An unqualified super call (super.m) would be allowed.""".stripMargin + val cls = compileClasses(code, allowMessage = _.msg contains err) + assert(cls.isEmpty, cls.map(_.name)) + } + + @Test + def sd143b(): Unit = { + val jCode = List("interface A { default int m() { return 1; } }" -> "A.java") + val code = + """class B extends A { override def m = 2 } + |trait T extends A + |class C extends B with T { + | override def m = super[T].m + |} + """.stripMargin + + val err = "unable to emit super call unless interface A (which declares method m) is directly extended by class C" + val cls = compileClasses(code, jCode, allowMessage = _.msg contains err) + assert(cls.isEmpty, cls.map(_.name)) } @Test |