diff options
Diffstat (limited to 'compiler/src/dotty/tools/dotc/transform/IsInstanceOfEvaluator.scala')
| -rw-r--r-- | compiler/src/dotty/tools/dotc/transform/IsInstanceOfEvaluator.scala | 27 |
1 files changed, 14 insertions, 13 deletions
diff --git a/compiler/src/dotty/tools/dotc/transform/IsInstanceOfEvaluator.scala b/compiler/src/dotty/tools/dotc/transform/IsInstanceOfEvaluator.scala index 8bc4a2aa9..ebd2ae436 100644 --- a/compiler/src/dotty/tools/dotc/transform/IsInstanceOfEvaluator.scala +++ b/compiler/src/dotty/tools/dotc/transform/IsInstanceOfEvaluator.scala @@ -7,36 +7,37 @@ import core._ import Contexts.Context, Types._, Constants._, Decorators._, Symbols._ import TypeUtils._, TypeErasure._, Flags._ - /** Implements partial evaluation of `sc.isInstanceOf[Sel]` according to: * - * +-------------+----------------------------+----------------------------+------------------+ * | Sel\sc | trait | class | final class | - * +-------------+----------------------------+----------------------------+------------------+ + * | ----------: | :------------------------: | :------------------------: | :--------------: | * | trait | ? | ? | statically known | * | class | ? | false if classes unrelated | statically known | * | final class | false if classes unrelated | false if classes unrelated | statically known | - * +-------------+----------------------------+----------------------------+------------------+ * * This is a generalized solution to raising an error on unreachable match * cases and warnings on other statically known results of `isInstanceOf`. * * Steps taken: * - * 1. evalTypeApply will establish the matrix and choose the appropriate - * handling for the case: - * 2. a) Sel/sc is a value class or scrutinee is `Any` - * b) handleStaticallyKnown - * c) falseIfUnrelated with `scrutinee <:< selector` - * d) handleFalseUnrelated - * e) leave as is (aka `happens`) - * 3. Rewrite according to step taken in `2` + * 1. `evalTypeApply` will establish the matrix and choose the appropriate + * handling for the case: + * - Sel/sc is a value class or scrutinee is `Any` + * - `handleStaticallyKnown` + * - `falseIfUnrelated` with `scrutinee <:< selector` + * - `handleFalseUnrelated` + * - leave as is (`happens`) + * 2. Rewrite according to steps taken in 1 */ class IsInstanceOfEvaluator extends MiniPhaseTransform { thisTransformer => import dotty.tools.dotc.ast.tpd._ - def phaseName = "isInstanceOfEvaluator" + val phaseName = "isInstanceOfEvaluator" + + /** Transforms a [TypeApply](dotty.tools.dotc.ast.Trees.TypeApply) in order to + * evaluate an `isInstanceOf` check according to the rules defined above. + */ override def transformTypeApply(tree: TypeApply)(implicit ctx: Context, info: TransformerInfo): Tree = { val defn = ctx.definitions |