diff options
Diffstat (limited to 'src/compiler/scala/tools/nsc/typechecker/SuperAccessors.scala')
| -rw-r--r-- | src/compiler/scala/tools/nsc/typechecker/SuperAccessors.scala | 38 |
1 files changed, 30 insertions, 8 deletions
diff --git a/src/compiler/scala/tools/nsc/typechecker/SuperAccessors.scala b/src/compiler/scala/tools/nsc/typechecker/SuperAccessors.scala index e0d96df062..57906cfe0a 100644 --- a/src/compiler/scala/tools/nsc/typechecker/SuperAccessors.scala +++ b/src/compiler/scala/tools/nsc/typechecker/SuperAccessors.scala @@ -146,7 +146,28 @@ 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 { + // 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. + // We allow this if there are statically no intervening overrides. + // 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. + def hasClassOverride(member: Symbol, subclass: Symbol): Boolean = { + if (subclass == ObjectClass || subclass == member.owner) false + else if (member.overridingSymbol(subclass) != NoSymbol) true + else hasClassOverride(member, subclass.superClass) + } + val owner = sym.owner + if (mix != tpnme.EMPTY && !owner.isTrait && owner != clazz.superClass && hasClassOverride(sym, 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.") } } @@ -287,17 +308,18 @@ abstract class SuperAccessors extends transform.Transform with transform.TypingT val result = (localTyper.typedPos(tree.pos) { Select(Super(qual, tpnme.EMPTY) setPos qual.pos, sym.alias) }).asInstanceOf[Select] - debuglog("alias replacement: " + tree + " ==> " + result); //debug + debuglog(s"alias replacement: $sym --> ${sym.alias} / $tree ==> $result"); //debug localTyper.typed(gen.maybeMkAsInstanceOf(transformSuperSelect(result), sym.tpe, sym.alias.tpe, beforeRefChecks = true)) } else { /* * A trait which extends a class and accesses a protected member * of that class cannot implement the necessary accessor method - * because its implementation is in an implementation class (e.g. - * Foo$class) which inherits nothing, and jvm access restrictions - * require the call site to be in an actual subclass. So non-trait - * classes inspect their ancestors for any such situations and - * generate the accessors. See SI-2296. + * because jvm access restrictions require the call site to be + * in an actual subclass, and an interface cannot extend a class. + * So, non-trait classes inspect their ancestors for any such situations + * and generate the accessors. See SI-2296. + * + * TODO: anything we can improve here now that a trait compiles 1:1 to an interface? */ // FIXME - this should be unified with needsProtectedAccessor, but some // subtlety which presently eludes me is foiling my attempts. @@ -387,7 +409,7 @@ abstract class SuperAccessors extends transform.Transform with transform.TypingT val savedValid = validCurrentOwner if (owner.isClass) validCurrentOwner = true val savedLocalTyper = localTyper - localTyper = localTyper.atOwner(tree, if (owner.isModule) owner.moduleClass else owner) + localTyper = localTyper.atOwner(tree, if (owner.isModuleNotMethod) owner.moduleClass else owner) typers = typers updated (owner, localTyper) val result = super.atOwner(tree, owner)(trans) localTyper = savedLocalTyper |