diff options
Diffstat (limited to 'src/compiler/scala/tools/nsc/typechecker/PatMatVirtualiser.scala')
| -rw-r--r-- | src/compiler/scala/tools/nsc/typechecker/PatMatVirtualiser.scala | 75 |
1 files changed, 47 insertions, 28 deletions
diff --git a/src/compiler/scala/tools/nsc/typechecker/PatMatVirtualiser.scala b/src/compiler/scala/tools/nsc/typechecker/PatMatVirtualiser.scala index aff8368f75..1fd9f6fc13 100644 --- a/src/compiler/scala/tools/nsc/typechecker/PatMatVirtualiser.scala +++ b/src/compiler/scala/tools/nsc/typechecker/PatMatVirtualiser.scala @@ -8,6 +8,7 @@ package typechecker import symtab._ import Flags.{MUTABLE, METHOD, LABEL, SYNTHETIC} +import language.postfixOps /** Translate pattern matching into method calls (these methods form a zero-plus monad), similar in spirit to how for-comprehensions are compiled. * @@ -21,7 +22,7 @@ import Flags.{MUTABLE, METHOD, LABEL, SYNTHETIC} * - Array patterns * - implement spec more closely (see TODO's) * - DCE - * - use manifests for type testing + * - use TypeTags for type testing * * (longer-term) TODO: * - user-defined unapplyProd @@ -118,6 +119,7 @@ trait PatMatVirtualiser extends ast.TreeDSL { self: Analyzer => trait MatchTranslation extends MatchMonadInterface { self: TreeMakers with CodegenCore => import typer.{typed, context, silent, reallyExists} + // import typer.infer.containsUnchecked /** Implement a pattern match by turning its cases (including the implicit failure case) * into the corresponding (monadic) extractors, and combining them with the `orElse` combinator. @@ -130,10 +132,10 @@ trait PatMatVirtualiser extends ast.TreeDSL { self: Analyzer => * this could probably optimized... (but note that the matchStrategy must be solved for each nested patternmatch) */ def translateMatch(scrut: Tree, cases: List[CaseDef], pt: Type, scrutType: Type, matchFailGenOverride: Option[Tree => Tree] = None): Tree = { - // we don't transform after typers - // (that would require much more sophistication when generating trees, + // we don't transform after uncurry + // (that would require more sophistication when generating trees, // and the only place that emits Matches after typers is for exception handling anyway) - assert(phase.id <= currentRun.typerPhase.id, phase) + assert(phase.id < currentRun.uncurryPhase.id, phase) val scrutSym = freshSym(scrut.pos, pureType(scrutType)) setFlag SYNTH_CASE // pt = Any* occurs when compiling test/files/pos/annotDepMethType.scala with -Xexperimental @@ -157,12 +159,12 @@ trait PatMatVirtualiser extends ast.TreeDSL { self: Analyzer => (caseScrutSym, propagateSubstitution(translateCase(caseScrutSym, pt)(caseDef), EmptySubstitution)) } - for(cases <- emitTypeSwitch(bindersAndCases, pt) toList; + for(cases <- emitTypeSwitch(bindersAndCases, pt).toList; if cases forall treeInfo.isCatchCase; // must check again, since it's not guaranteed -- TODO: can we eliminate this? e.g., a type test could test for a trait or a non-trivial prefix, which are not handled by the back-end cse <- cases) yield fixerUpper(matchOwner, pos)(cse).asInstanceOf[CaseDef] } - val catches = if (swatches nonEmpty) swatches else { + val catches = if (swatches.nonEmpty) swatches else { val scrutSym = freshSym(pos, pureType(ThrowableClass.tpe)) val casesNoSubstOnly = caseDefs map { caseDef => (propagateSubstitution(translateCase(scrutSym, pt)(caseDef), EmptySubstitution))} @@ -819,13 +821,34 @@ class Foo(x: Other) { x._1 } // no error in this order cond } - // TODO: also need to test when erasing pt loses crucial information (and if we can recover it using a manifest) - def needsTypeTest(tp: Type, pt: Type) = !(tp <:< pt) - private def typeTest(binder: Symbol, pt: Type) = maybeWithOuterCheck(binder, pt)(codegen._isInstanceOf(binder, pt)) + // containsUnchecked: also need to test when erasing pt loses crucial information (maybe we can recover it using a TypeTag) + def needsTypeTest(tp: Type, pt: Type): Boolean = !(tp <:< pt) // || containsUnchecked(pt) + // TODO: try to find the TypeTag for the binder's type and the expected type, and if they exists, + // check that the TypeTag of the binder's type conforms to the TypeTag of the expected type + private def typeTest(binderToTest: Symbol, expectedTp: Type, disableOuterCheck: Boolean = false, dynamic: Boolean = false): Tree = { import CODE._ + // def coreTest = + if (disableOuterCheck) codegen._isInstanceOf(binderToTest, expectedTp) else maybeWithOuterCheck(binderToTest, expectedTp)(codegen._isInstanceOf(binderToTest, expectedTp)) + // if (opt.experimental && containsUnchecked(expectedTp)) { + // if (dynamic) { + // val expectedTpTagTree = findManifest(expectedTp, true) + // if (!expectedTpTagTree.isEmpty) + // ((expectedTpTagTree DOT "erasure".toTermName) DOT "isAssignableFrom".toTermName)(REF(binderToTest) DOT nme.getClass_) + // else + // coreTest + // } else { + // val expectedTpTagTree = findManifest(expectedTp, true) + // val binderTpTagTree = findManifest(binderToTest.info, true) + // if(!(expectedTpTagTree.isEmpty || binderTpTagTree.isEmpty)) + // coreTest AND (binderTpTagTree DOT nme.CONFORMS)(expectedTpTagTree) + // else + // coreTest + // } + // } else coreTest + } // need to substitute since binder may be used outside of the next extractor call (say, in the body of the case) case class TypeTestTreeMaker(prevBinder: Symbol, nextBinderTp: Type, pos: Position) extends CondTreeMaker { - val cond = typeTest(prevBinder, nextBinderTp) + val cond = typeTest(prevBinder, nextBinderTp, dynamic = true) val res = codegen._asInstanceOf(prevBinder, nextBinderTp) override def toString = "TT"+(prevBinder, nextBinderTp) } @@ -865,7 +888,7 @@ class Foo(x: Other) { x._1 } // no error in this order // TODO: `null match { x : T }` will yield a check that (indirectly) tests whether `null ne null` // don't bother (so that we don't end up with the warning "comparing values of types Null and Null using `ne' will always yield false") def genEqualsAndInstanceOf(sym: Symbol): Tree - = codegen._equals(REF(sym), patBinder) AND codegen._isInstanceOf(patBinder, pt.widen) + = codegen._equals(REF(sym), patBinder) AND typeTest(patBinder, pt.widen, disableOuterCheck = true) def isRefTp(tp: Type) = tp <:< AnyRefClass.tpe @@ -873,7 +896,7 @@ class Foo(x: Other) { x._1 } // no error in this order def isMatchUnlessNull = isRefTp(pt) && !needsTypeTest(patBinderTp, pt) // TODO: [SPEC] type test for Array - // TODO: use manifests to improve tests (for erased types we can do better when we have a manifest) + // TODO: use TypeTags to improve tests (for erased types we can do better when we have a TypeTag) pt match { case SingleType(_, sym) /*this implies sym.isStable*/ => genEqualsAndInstanceOf(sym) // TODO: [SPEC] the spec requires `eq` instead of `==` here case ThisType(sym) if sym.isModule => genEqualsAndInstanceOf(sym) // must use == to support e.g. List() == Nil @@ -1082,22 +1105,14 @@ class Foo(x: Other) { x._1 } // no error in this order def _equals(checker: Tree, binder: Symbol): Tree = checker MEMBER_== REF(binder) // NOTE: checker must be the target of the ==, that's the patmat semantics for ya def and(a: Tree, b: Tree): Tree = a AND b + // drop annotations generated by CPS plugin etc, since its annotationchecker rejects T @cps[U] <: Any + // let's assume for now annotations don't affect casts, drop them there, and bring them back using the outer Typed tree + private def mkCast(t: Tree, tp: Type) = Typed(gen.mkAsInstanceOf(t, tp.withoutAnnotations, true, false), TypeTree() setType tp) // the force is needed mainly to deal with the GADT typing hack (we can't detect it otherwise as tp nor pt need contain an abstract type, we're just casting wildly) - def _asInstanceOf(t: Tree, tp: Type, force: Boolean = false): Tree = { val tpX = /*repackExistential*/(tp) - if (!force && (t.tpe ne NoType) && t.isTyped && typesConform(t.tpe, tpX)) t //{ println("warning: emitted redundant asInstanceOf: "+(t, t.tpe, tp)); t } //.setType(tpX) - else gen.mkAsInstanceOf(t, tpX, true, false) - } - - def _isInstanceOf(b: Symbol, tp: Type): Tree = gen.mkIsInstanceOf(REF(b), /*repackExistential*/(tp), true, false) - // { val tpX = /*repackExistential*/(tp) + def _asInstanceOf(t: Tree, tp: Type, force: Boolean = false): Tree = if (!force && (t.tpe ne NoType) && t.isTyped && typesConform(t.tpe, tp)) t else mkCast(t, tp) + def _asInstanceOf(b: Symbol, tp: Type): Tree = if (typesConform(b.info, tp)) REF(b) else mkCast(REF(b), tp) + def _isInstanceOf(b: Symbol, tp: Type): Tree = gen.mkIsInstanceOf(REF(b), tp.withoutAnnotations, true, false) // if (typesConform(b.info, tpX)) { println("warning: emitted spurious isInstanceOf: "+(b, tp)); TRUE } - // else gen.mkIsInstanceOf(REF(b), tpX, true, false) - // } - - def _asInstanceOf(b: Symbol, tp: Type): Tree = { val tpX = /*repackExistential*/(tp) - if (typesConform(b.info, tpX)) REF(b) //{ println("warning: emitted redundant asInstanceOf: "+(b, b.info, tp)); REF(b) } //.setType(tpX) - else gen.mkAsInstanceOf(REF(b), tpX, true, false) - } // duplicated out of frustration with cast generation def mkZero(tp: Type): Tree = { @@ -1635,7 +1650,7 @@ class Foo(x: Other) { x._1 } // no error in this order */ def matcher(scrut: Tree, scrutSym: Symbol, restpe: Type)(cases: List[Casegen => Tree], matchFailGen: Option[Tree => Tree]): Tree = { val matchEnd = NoSymbol.newLabel(freshName("matchEnd"), NoPosition) setFlag SYNTH_CASE - val matchRes = NoSymbol.newValueParameter(newTermName("x"), NoPosition, SYNTHETIC) setInfo restpe + val matchRes = NoSymbol.newValueParameter(newTermName("x"), NoPosition, SYNTHETIC) setInfo restpe.withoutAnnotations // matchEnd setInfo MethodType(List(matchRes), restpe) def newCaseSym = NoSymbol.newLabel(freshName("case"), NoPosition) setInfo MethodType(Nil, restpe) setFlag SYNTH_CASE @@ -1649,7 +1664,11 @@ class Foo(x: Other) { x._1 } // no error in this order def catchAll = matchFailGen map { matchFailGen => val scrutRef = if(scrutSym ne NoSymbol) REF(scrutSym) else EmptyTree // for alternatives - LabelDef(nextCase, Nil, matchEnd APPLY (_asInstanceOf(matchFailGen(scrutRef), restpe))) // need to jump to matchEnd with result generated by matchFailGen (could be `FALSE` for isDefinedAt) + // must jump to matchEnd, use result generated by matchFailGen (could be `FALSE` for isDefinedAt) + LabelDef(nextCase, Nil, matchEnd APPLY (matchFailGen(scrutRef))) + // don't cast the arg to matchEnd when using PartialFun synth in uncurry, since it won't detect the throw (see gen.withDefaultCase) + // the cast is necessary when using typedMatchAnonFun-style PartialFun synth: + // (_asInstanceOf(matchFailGen(scrutRef), restpe)) } toList // catchAll.isEmpty iff no synthetic default case needed (the (last) user-defined case is a default) // if the last user-defined case is a default, it will never jump to the next case; it will go immediately to matchEnd |