From 4dceb2268780462823a98168d7350687d5cf27a8 Mon Sep 17 00:00:00 2001 From: Jason Zaugg Date: Wed, 23 Jan 2013 00:28:21 +0100 Subject: [backport] Fix SI-6637 (misoptimization in erasure) commit f9ef5300ab561628e53c654df9000c75f488d74a Author: Jan Niehusmann Date: Fri Nov 9 15:05:58 2012 +0100 Fix SI-6637 (misoptimization in erasure) Move the optimization one level deeper so the expression being tested with isInstanceOf is always evaluated. (cherry picked from commit b540aaee4ba30e2dd980456a44e8c6d732222df1) --- .../scala/tools/nsc/transform/Erasure.scala | 22 +++++++++++----------- test/files/run/t6637.check | 1 + test/files/run/t6637.scala | 8 ++++++++ 3 files changed, 20 insertions(+), 11 deletions(-) create mode 100644 test/files/run/t6637.check create mode 100644 test/files/run/t6637.scala diff --git a/src/compiler/scala/tools/nsc/transform/Erasure.scala b/src/compiler/scala/tools/nsc/transform/Erasure.scala index 41aada473a..889d309ba9 100644 --- a/src/compiler/scala/tools/nsc/transform/Erasure.scala +++ b/src/compiler/scala/tools/nsc/transform/Erasure.scala @@ -1057,17 +1057,17 @@ abstract class Erasure extends AddInterfaces Apply(Select(qual, cmpOp), List(gen.mkAttributedQualifier(targ.tpe))) } case RefinedType(parents, decls) if (parents.length >= 2) => - // Optimization: don't generate isInstanceOf tests if the static type - // conforms, because it always succeeds. (Or at least it had better.) - // At this writing the pattern matcher generates some instance tests - // involving intersections where at least one parent is statically known true. - // That needs fixing, but filtering the parents here adds an additional - // level of robustness (in addition to the short term fix.) - val parentTests = parents filterNot (qual.tpe <:< _) - - if (parentTests.isEmpty) Literal(Constant(true)) - else gen.evalOnce(qual, currentOwner, unit) { q => - atPos(tree.pos) { + gen.evalOnce(qual, currentOwner, unit) { q => + // Optimization: don't generate isInstanceOf tests if the static type + // conforms, because it always succeeds. (Or at least it had better.) + // At this writing the pattern matcher generates some instance tests + // involving intersections where at least one parent is statically known true. + // That needs fixing, but filtering the parents here adds an additional + // level of robustness (in addition to the short term fix.) + val parentTests = parents filterNot (qual.tpe <:< _) + + if (parentTests.isEmpty) Literal(Constant(true)) + else atPos(tree.pos) { parentTests map mkIsInstanceOf(q) reduceRight gen.mkAnd } } diff --git a/test/files/run/t6637.check b/test/files/run/t6637.check new file mode 100644 index 0000000000..9766475a41 --- /dev/null +++ b/test/files/run/t6637.check @@ -0,0 +1 @@ +ok diff --git a/test/files/run/t6637.scala b/test/files/run/t6637.scala new file mode 100644 index 0000000000..d3c380370b --- /dev/null +++ b/test/files/run/t6637.scala @@ -0,0 +1,8 @@ + +object Test extends App { + try { + class A ; class B ; List().head.isInstanceOf[A with B] + } catch { + case _ :java.util.NoSuchElementException => println("ok") + } +} -- cgit v1.2.3