diff options
| -rw-r--r-- | compiler/src/dotty/tools/dotc/transform/Memoize.scala | 25 | ||||
| -rw-r--r-- | compiler/src/dotty/tools/dotc/typer/Typer.scala | 22 | ||||
| -rw-r--r-- | tests/run/final-var.check | 4 | ||||
| -rw-r--r-- | tests/run/final-var.scala | 20 |
4 files changed, 51 insertions, 20 deletions
diff --git a/compiler/src/dotty/tools/dotc/transform/Memoize.scala b/compiler/src/dotty/tools/dotc/transform/Memoize.scala index 3df9b0daa..8b5ceb0aa 100644 --- a/compiler/src/dotty/tools/dotc/transform/Memoize.scala +++ b/compiler/src/dotty/tools/dotc/transform/Memoize.scala @@ -99,26 +99,11 @@ import Decorators._ if (sym.is(Accessor, butNot = NoFieldNeeded)) if (sym.isGetter) { - def skipBlocks(t: Tree): Tree = t match { - case Block(_, t1) => skipBlocks(t1) - case _ => t - } - skipBlocks(tree.rhs) match { - case lit: Literal if sym.is(Final) && isIdempotentExpr(tree.rhs) => - // duplicating scalac behavior: for final vals that have rhs as constant, we do not create a field - // and instead return the value. This seemingly minor optimization has huge effect on initialization - // order and the values that can be observed during superconstructor call - - // see remark about idempotency in PostTyper#normalizeTree - cpy.DefDef(tree)(rhs = lit) - case _ => - var rhs = tree.rhs.changeOwnerAfter(sym, field, thisTransform) - if (isWildcardArg(rhs)) rhs = EmptyTree - - val fieldDef = transformFollowing(ValDef(field, adaptToField(rhs))) - val getterDef = cpy.DefDef(tree)(rhs = transformFollowingDeep(ref(field))(ctx.withOwner(sym), info)) - Thicket(fieldDef, getterDef) - } + var rhs = tree.rhs.changeOwnerAfter(sym, field, thisTransform) + if (isWildcardArg(rhs)) rhs = EmptyTree + val fieldDef = transformFollowing(ValDef(field, adaptToField(rhs))) + val getterDef = cpy.DefDef(tree)(rhs = transformFollowingDeep(ref(field))(ctx.withOwner(sym), info)) + Thicket(fieldDef, getterDef) } else if (sym.isSetter) { if (!sym.is(ParamAccessor)) { val Literal(Constant(())) = tree.rhs } // this is intended as an assertion field.setFlag(Mutable) // necessary for vals mixed in from Scala2 traits diff --git a/compiler/src/dotty/tools/dotc/typer/Typer.scala b/compiler/src/dotty/tools/dotc/typer/Typer.scala index b70a51d1e..a053a0b0d 100644 --- a/compiler/src/dotty/tools/dotc/typer/Typer.scala +++ b/compiler/src/dotty/tools/dotc/typer/Typer.scala @@ -1173,6 +1173,7 @@ class Typer extends Namer with TypeAssigner with Applications with Implicits wit if (sym.is(Inline, butNot = DeferredOrParamAccessor)) checkInlineConformant(rhs1, em"right-hand side of inline $sym") patchIfLazy(vdef1) + patchFinalVals(vdef1) vdef1 } @@ -1185,6 +1186,27 @@ class Typer extends Namer with TypeAssigner with Applications with Implicits wit patch(Position(toUntyped(vdef).pos.start), "@volatile ") } + /** Adds inline to final vals with idempotent rhs + * + * duplicating scalac behavior: for final vals that have rhs as constant, we do not create a field + * and instead return the value. This seemingly minor optimization has huge effect on initialization + * order and the values that can be observed during superconstructor call + * + * see remark about idempotency in PostTyper#normalizeTree + */ + private def patchFinalVals(vdef: ValDef)(implicit ctx: Context): Unit = { + def isFinalInlinableVal(sym: Symbol): Boolean = { + sym.is(Final, butNot = Mutable) && + isIdempotentExpr(vdef.rhs) /* && + ctx.scala2Mode (stay compatible with Scala2 for now) */ + } + val sym = vdef.symbol + sym.info match { + case info: ConstantType if isFinalInlinableVal(sym) && !ctx.settings.YnoInline.value => sym.setFlag(Inline) + case _ => + } + } + def typedDefDef(ddef: untpd.DefDef, sym: Symbol)(implicit ctx: Context) = track("typedDefDef") { val DefDef(name, tparams, vparamss, tpt, _) = ddef completeAnnotations(ddef, sym) diff --git a/tests/run/final-var.check b/tests/run/final-var.check new file mode 100644 index 000000000..7565230c0 --- /dev/null +++ b/tests/run/final-var.check @@ -0,0 +1,4 @@ +false +true +false +true diff --git a/tests/run/final-var.scala b/tests/run/final-var.scala new file mode 100644 index 000000000..94a6c453c --- /dev/null +++ b/tests/run/final-var.scala @@ -0,0 +1,20 @@ +object Test { + def main(args: Array[String]): Unit = { + println(Obj.myFinalVar) + Obj.myFinalVar = true + println(Obj.myFinalVar) + + val o = new Cls + println(o.myFinalVar) + o.myFinalVar = true + println(o.myFinalVar) + } +} + +object Obj { + final var myFinalVar: Boolean = false +} + +class Cls { + final var myFinalVar: Boolean = false +} |