summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
Diffstat
-rw-r--r--src/compiler/scala/reflect/internal/Flags.scala2
-rw-r--r--src/compiler/scala/tools/nsc/backend/jvm/GenJVM.scala34
-rw-r--r--src/compiler/scala/tools/nsc/settings/ScalaSettings.scala3
-rw-r--r--src/compiler/scala/tools/nsc/typechecker/Namers.scala5
-rw-r--r--src/compiler/scala/tools/nsc/typechecker/RefChecks.scala15
-rw-r--r--src/compiler/scala/tools/nsc/typechecker/SuperAccessors.scala3
-rw-r--r--test/files/run/finalvar.check6
-rw-r--r--test/files/run/finalvar.flags1
-rw-r--r--test/files/run/finalvar.scala37
9 files changed, 86 insertions, 20 deletions
diff --git a/src/compiler/scala/reflect/internal/Flags.scala b/src/compiler/scala/reflect/internal/Flags.scala
index 3110d73461..ce1c8d0908 100644
--- a/src/compiler/scala/reflect/internal/Flags.scala
+++ b/src/compiler/scala/reflect/internal/Flags.scala
@@ -84,7 +84,7 @@ import scala.collection.{ mutable, immutable }
*/
class ModifierFlags {
final val IMPLICIT = 0x00000200
- final val FINAL = 0x00000020
+ final val FINAL = 0x00000020 // May not be overridden. Note that java final implies much more than scala final.
final val PRIVATE = 0x00000004
final val PROTECTED = 0x00000001
diff --git a/src/compiler/scala/tools/nsc/backend/jvm/GenJVM.scala b/src/compiler/scala/tools/nsc/backend/jvm/GenJVM.scala
index 8e326c202a..b7b4212b93 100644
--- a/src/compiler/scala/tools/nsc/backend/jvm/GenJVM.scala
+++ b/src/compiler/scala/tools/nsc/backend/jvm/GenJVM.scala
@@ -871,7 +871,7 @@ abstract class GenJVM extends SubComponent with GenJVMUtil with GenAndroid with
debuglog("Adding field: " + f.symbol.fullName)
val jfield = jclass.addNewField(
- javaFlags(f.symbol) | javaFieldFlags(f.symbol),
+ javaFieldFlags(f.symbol),
javaName(f.symbol),
javaType(f.symbol.tpe)
)
@@ -1915,16 +1915,30 @@ abstract class GenJVM extends SubComponent with GenJVMUtil with GenAndroid with
val privateFlag =
sym.isPrivate || (sym.isPrimaryConstructor && isTopLevelModule(sym.owner))
- // This does not check .isFinal (which checks flags for the FINAL flag),
- // instead checking rawflags for that flag so as to exclude symbols which
- // received lateFINAL. These symbols are eligible for inlining, but to
- // avoid breaking proxy software which depends on subclassing, we avoid
- // insisting on their finality in the bytecode.
+ // Final: the only fields which can receive ACC_FINAL are eager vals.
+ // Neither vars nor lazy vals can, because:
+ //
+ // Source: http://docs.oracle.com/javase/specs/jls/se7/html/jls-17.html#jls-17.5.3
+ // "Another problem is that the specification allows aggressive
+ // optimization of final fields. Within a thread, it is permissible to
+ // reorder reads of a final field with those modifications of a final
+ // field that do not take place in the constructor."
+ //
+ // A var or lazy val which is marked final still has meaning to the
+ // scala compiler. The word final is heavily overloaded unfortunately;
+ // for us it means "not overridable". At present you can't override
+ // vars regardless; this may change.
+ //
+ // The logic does not check .isFinal (which checks flags for the FINAL flag,
+ // and includes symbols marked lateFINAL) instead inspecting rawflags so
+ // we can exclude lateFINAL. Such symbols are eligible for inlining, but to
+ // avoid breaking proxy software which depends on subclassing, we do not
+ // emit ACC_FINAL.
val finalFlag = (
((sym.rawflags & (Flags.FINAL | Flags.MODULE)) != 0)
&& !sym.enclClass.isInterface
&& !sym.isClassConstructor
- && !sym.isMutable // fix for SI-3569, it is too broad?
+ && !sym.isMutable // lazy vals and vars both
)
mkFlags(
@@ -1939,13 +1953,13 @@ abstract class GenJVM extends SubComponent with GenJVMUtil with GenAndroid with
if (sym.hasFlag(Flags.SYNCHRONIZED)) JAVA_ACC_SYNCHRONIZED else 0
)
}
- def javaFieldFlags(sym: Symbol) = {
- mkFlags(
+ def javaFieldFlags(sym: Symbol) = (
+ javaFlags(sym) | mkFlags(
if (sym hasAnnotation TransientAttr) ACC_TRANSIENT else 0,
if (sym hasAnnotation VolatileAttr) ACC_VOLATILE else 0,
if (sym.isMutable) 0 else ACC_FINAL
)
- }
+ )
def isTopLevelModule(sym: Symbol): Boolean =
afterPickler { sym.isModuleClass && !sym.isImplClass && !sym.isNestedClass }
diff --git a/src/compiler/scala/tools/nsc/settings/ScalaSettings.scala b/src/compiler/scala/tools/nsc/settings/ScalaSettings.scala
index fdde8f9990..14b3bcc8ce 100644
--- a/src/compiler/scala/tools/nsc/settings/ScalaSettings.scala
+++ b/src/compiler/scala/tools/nsc/settings/ScalaSettings.scala
@@ -31,7 +31,7 @@ trait ScalaSettings extends AbsScalaSettings
protected def defaultClasspath = sys.env.getOrElse("CLASSPATH", ".")
/** Enabled under -Xexperimental. */
- protected def experimentalSettings = List[BooleanSetting](YmethodInfer, overrideObjects)
+ protected def experimentalSettings = List[BooleanSetting](YmethodInfer, overrideObjects, overrideVars)
/** Enabled under -Xfuture. */
protected def futureSettings = List[BooleanSetting]()
@@ -117,6 +117,7 @@ trait ScalaSettings extends AbsScalaSettings
* -Y "Private" settings
*/
val overrideObjects = BooleanSetting ("-Yoverride-objects", "Allow member objects to be overridden.")
+ val overrideVars = BooleanSetting ("-Yoverride-vars", "Allow vars to be overridden.")
val Yhelp = BooleanSetting ("-Y", "Print a synopsis of private options.")
val browse = PhasesSetting ("-Ybrowse", "Browse the abstract syntax tree after")
val check = PhasesSetting ("-Ycheck", "Check the tree at the end of")
diff --git a/src/compiler/scala/tools/nsc/typechecker/Namers.scala b/src/compiler/scala/tools/nsc/typechecker/Namers.scala
index 6b27c27652..8604366bf2 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Namers.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Namers.scala
@@ -315,9 +315,10 @@ trait Namers extends MethodSynthesis {
case DefDef(_, _, _, _, _, _) => owner.newMethod(name.toTermName, pos, flags)
case ClassDef(_, _, _, _) => owner.newClassSymbol(name.toTypeName, pos, flags)
case ModuleDef(_, _, _) => owner.newModule(name, pos, flags)
- case ValDef(_, _, _, _) if isParameter => owner.newValueParameter(name, pos, flags)
case PackageDef(pid, _) => createPackageSymbol(pos, pid)
- case ValDef(_, _, _, _) => owner.newValue(name, pos, flags)
+ case ValDef(_, _, _, _) =>
+ if (isParameter) owner.newValueParameter(name, pos, flags)
+ else owner.newValue(name, pos, flags)
}
}
private def createFieldSymbol(tree: ValDef): TermSymbol =
diff --git a/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala b/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala
index 013a74da7e..9177aca656 100644
--- a/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala
@@ -394,9 +394,14 @@ abstract class RefChecks extends InfoTransform with reflect.internal.transform.R
overrideError("needs `override' modifier")
} else if (other.isAbstractOverride && other.isIncompleteIn(clazz) && !member.isAbstractOverride) {
overrideError("needs `abstract override' modifiers")
- } else if (member.isAnyOverride && (other hasFlag ACCESSOR) && other.accessed.isVariable && !other.accessed.isLazy) {
- overrideError("cannot override a mutable variable")
- } else if (member.isAnyOverride &&
+ }
+ else if (member.isAnyOverride && (other hasFlag ACCESSOR) && other.accessed.isVariable && !other.accessed.isLazy) {
+ // !?! this is not covered by the spec. We need to resolve this either by changing the spec or removing the test here.
+ // !!! is there a !?! convention? I'm !!!ing this to make sure it turns up on my searches.
+ if (!settings.overrideVars.value)
+ overrideError("cannot override a mutable variable")
+ }
+ else if (member.isAnyOverride &&
!(member.owner.thisType.baseClasses exists (_ isSubClass other.owner)) &&
!member.isDeferred && !other.isDeferred &&
intersectionIsEmpty(member.extendedOverriddenSymbols, other.extendedOverriddenSymbols)) {
@@ -1248,9 +1253,9 @@ abstract class RefChecks extends InfoTransform with reflect.internal.transform.R
}
List(tree1)
}
- case Import(_, _) => Nil
+ case Import(_, _) => Nil
case DefDef(mods, _, _, _, _, _) if (mods hasFlag MACRO) => Nil
- case _ => List(transform(tree))
+ case _ => List(transform(tree))
}
/* Check whether argument types conform to bounds of type parameters */
diff --git a/src/compiler/scala/tools/nsc/typechecker/SuperAccessors.scala b/src/compiler/scala/tools/nsc/typechecker/SuperAccessors.scala
index 4248b6f024..94733369a8 100644
--- a/src/compiler/scala/tools/nsc/typechecker/SuperAccessors.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/SuperAccessors.scala
@@ -259,7 +259,8 @@ abstract class SuperAccessors extends transform.Transform with transform.TypingT
case sel @ Select(Super(_, mix), name) =>
if (sym.isValue && !sym.isMethod || sym.hasAccessorFlag) {
- unit.error(tree.pos, "super may be not be used on "+ sym.accessedOrSelf)
+ if (!settings.overrideVars.value)
+ unit.error(tree.pos, "super may be not be used on "+ sym.accessedOrSelf)
}
else if (isDisallowed(sym)) {
unit.error(tree.pos, "super not allowed here: use this." + name.decode + " instead")
diff --git a/test/files/run/finalvar.check b/test/files/run/finalvar.check
new file mode 100644
index 0000000000..2496293972
--- /dev/null
+++ b/test/files/run/finalvar.check
@@ -0,0 +1,6 @@
+(2,2,2,2,1)
+(2,2,2,2)
+(2,2,2,2,1001)
+(2,2,2,2)
+2
+10
diff --git a/test/files/run/finalvar.flags b/test/files/run/finalvar.flags
new file mode 100644
index 0000000000..aee3039bec
--- /dev/null
+++ b/test/files/run/finalvar.flags
@@ -0,0 +1 @@
+-Yoverride-vars -Yinline \ No newline at end of file
diff --git a/test/files/run/finalvar.scala b/test/files/run/finalvar.scala
new file mode 100644
index 0000000000..010813e520
--- /dev/null
+++ b/test/files/run/finalvar.scala
@@ -0,0 +1,37 @@
+object Final {
+ class X(final var x: Int) { }
+ def f = new X(0).x += 1
+}
+
+class A {
+ var x = 1
+ def y0 = x
+ def y1 = this.x
+ def y2 = (this: A).x
+}
+
+class B extends A {
+ override def x = 2
+ def z = super.x
+}
+
+object Test {
+ def main(args: Array[String]): Unit = {
+ Final.f
+ val a = new B
+ println((a.x, a.y0, a.y1, a.y2, a.z))
+ val a0: A = a
+ println((a0.x, a0.y0, a0.y1, a0.y2))
+ a.x = 1001
+ println((a.x, a.y0, a.y1, a.y2, a.z))
+ println((a0.x, a0.y0, a0.y1, a0.y2))
+
+ val d = new D
+ println(d.w)
+ d.ten
+ println(d.w)
+ }
+}
+
+class C { var w = 1 ; def ten = this.w = 10 }
+class D extends C { override var w = 2 } \ No newline at end of file
generated by cgit v1.2.3 (git 2.39.1) at 2024-06-26 01:01:16 +0000