diff options
Diffstat (limited to 'src/compiler/scala/tools/nsc/typechecker/Macros.scala')
| -rw-r--r-- | src/compiler/scala/tools/nsc/typechecker/Macros.scala | 1361 |
1 files changed, 1149 insertions, 212 deletions
diff --git a/src/compiler/scala/tools/nsc/typechecker/Macros.scala b/src/compiler/scala/tools/nsc/typechecker/Macros.scala index e43b1fab0b..3b270a92ad 100644 --- a/src/compiler/scala/tools/nsc/typechecker/Macros.scala +++ b/src/compiler/scala/tools/nsc/typechecker/Macros.scala @@ -3,135 +3,682 @@ package typechecker import symtab.Flags._ import scala.tools.nsc.util._ +import scala.tools.nsc.util.ClassPath._ import scala.reflect.ReflectionUtils +import scala.collection.mutable.ListBuffer +import scala.compat.Platform.EOL +import scala.reflect.makro.runtime.{Context => MacroContext} +import scala.reflect.runtime.Mirror +/** + * Code to deal with macros, namely with: + * * Compilation of macro definitions + * * Expansion of macro applications + * + * Say we have in a class C: + * + * def foo[T](xs: List[T]): T = macro fooBar + * + * Then fooBar needs to point to a static method of the following form: + * + * def fooBar[T: c.TypeTag] + * (c: scala.reflect.makro.Context) + * (xs: c.Expr[List[T]]) + * : c.mirror.Tree = { + * ... + * } + * + * Then, if foo is called in qual.foo[Int](elems), where qual: D, + * the macro application is expanded to a reflective invocation of fooBar with parameters + * + * (simpleMacroContext{ type PrefixType = D; val prefix = qual }) + * (Expr(elems)) + * (TypeTag(Int)) + */ trait Macros { self: Analyzer => import global._ import definitions._ - def macroMeth(mac: Symbol): Symbol = { - var owner = mac.owner - if (!owner.isModuleClass) owner = owner.companionModule.moduleClass - owner.info.decl(nme.macroMethodName(mac.name)) - } + val macroDebug = settings.Ymacrodebug.value + val macroCopypaste = settings.Ymacrocopypaste.value + val macroTrace = scala.tools.nsc.util.trace when macroDebug - def macroArgs(tree: Tree): (List[List[Tree]]) = tree match { - case Apply(fn, args) => - macroArgs(fn) :+ args - case TypeApply(fn, args) => - macroArgs(fn) :+ args - case Select(qual, name) => - List(List(qual)) - case _ => - List(List()) - } + val globalMacroCache = collection.mutable.Map[Any, Any]() + val perRunMacroCache = perRunCaches.newMap[Symbol, collection.mutable.Map[Any, Any]] - /** - * The definition of the method implementing a macro. Example: - * Say we have in a class C + /** A list of compatible macro implementation signatures. * - * def macro foo[T](xs: List[T]): T = expr + * In the example above: + * (c: scala.reflect.makro.Context)(xs: c.Expr[List[T]]): c.Expr[T] * - * Then the following macro method is generated for `foo`: - * - * def defmacro$foo - * (_context: scala.reflect.macro.Context) - * (_this: _context.Tree) - * (T: _context.TypeTree) - * (xs: _context.Tree): _context.Tree = { - * import _context._ // this means that all methods of Context can be used unqualified in macro's body - * expr - * } + * @param macroDef The macro definition symbol + * @param tparams The type parameters of the macro definition + * @param vparamss The value parameters of the macro definition + * @param retTpe The return type of the macro definition + */ + private def macroImplSigs(macroDef: Symbol, tparams: List[TypeDef], vparamss: List[List[ValDef]], retTpe: Type): (List[List[List[Symbol]]], Type) = { + // had to move method's body to an object because of the recursive dependencies between sigma and param + object SigGenerator { + val hasThis = macroDef.owner.isClass + val ownerTpe = macroDef.owner match { + case owner if owner.isModuleClass => new UniqueThisType(macroDef.owner) + case owner if owner.isClass => macroDef.owner.tpe + case _ => NoType + } + val hasTparams = !tparams.isEmpty + + def sigma(tpe: Type): Type = { + class SigmaTypeMap extends TypeMap { + def apply(tp: Type): Type = tp match { + case TypeRef(pre, sym, args) => + val pre1 = pre match { + case ThisType(sym) if sym == macroDef.owner => + SingleType(SingleType(SingleType(NoPrefix, paramsCtx(0)), MacroContextPrefix), ExprValue) + case SingleType(NoPrefix, sym) => + vparamss.flatten.find(_.symbol == sym) match { + case Some(macroDefParam) => + SingleType(SingleType(NoPrefix, param(macroDefParam)), ExprValue) + case _ => + pre + } + case _ => + pre + } + val args1 = args map mapOver + TypeRef(pre1, sym, args1) + case _ => + mapOver(tp) + } + } + + new SigmaTypeMap() apply tpe + } + + def makeParam(name: Name, pos: Position, tpe: Type, flags: Long = 0L) = + macroDef.newValueParameter(name, pos, flags) setInfo tpe + val ctxParam = makeParam(nme.macroContext, macroDef.pos, MacroContextClass.tpe, SYNTHETIC) + def implType(isType: Boolean, origTpe: Type): Type = + if (isRepeatedParamType(origTpe)) + appliedType( + RepeatedParamClass.typeConstructor, + List(implType(isType, sigma(origTpe.typeArgs.head)))) + else { + val tsym = getMember(MacroContextClass, if (isType) tpnme.TypeTag else tpnme.Expr) + typeRef(singleType(NoPrefix, ctxParam), tsym, List(sigma(origTpe))) + } + val paramCache = collection.mutable.Map[Symbol, Symbol]() + def param(tree: Tree): Symbol = + paramCache.getOrElseUpdate(tree.symbol, { + // [Eugene] deskolemization became necessary once I implemented inference of macro def return type + // please, verify this solution, but for now I'll leave it here - cargo cult for the win + val sym = tree.symbol.deSkolemize + val sigParam = makeParam(sym.name, sym.pos, implType(sym.isType, sym.tpe)) + if (sym.isSynthetic) sigParam.flags |= SYNTHETIC + sigParam + }) + + val paramsCtx = List(ctxParam) + val paramsThis = List(makeParam(nme.macroThis, macroDef.pos, implType(false, ownerTpe), SYNTHETIC)) + val paramsTparams = tparams map param + val paramssParams = vparamss map (_ map param) + + var paramsss = List[List[List[Symbol]]]() + // tparams are no longer part of a signature, they get into macro implementations via context bounds +// if (hasTparams && hasThis) paramsss :+= paramsCtx :: paramsThis :: paramsTparams :: paramssParams +// if (hasTparams) paramsss :+= paramsCtx :: paramsTparams :: paramssParams + // _this params are no longer part of a signature, its gets into macro implementations via Context.prefix +// if (hasThis) paramsss :+= paramsCtx :: paramsThis :: paramssParams + paramsss :+= paramsCtx :: paramssParams + + val tsym = getMember(MacroContextClass, tpnme.Expr) + val implRetTpe = typeRef(singleType(NoPrefix, ctxParam), tsym, List(sigma(retTpe))) + } + + import SigGenerator._ + macroTrace("generating macroImplSigs for: ")(macroDef) + macroTrace("tparams are: ")(tparams) + macroTrace("vparamss are: ")(vparamss) + macroTrace("retTpe is: ")(retTpe) + macroTrace("macroImplSigs are: ")(paramsss, implRetTpe) + } + + private def transformTypeTagEvidenceParams(paramss: List[List[Symbol]], transform: (Symbol, Symbol) => Option[Symbol]): List[List[Symbol]] = { + if (paramss.length == 0) + return paramss + + val wannabe = if (paramss.head.length == 1) paramss.head.head else NoSymbol + val contextParam = if (wannabe != NoSymbol && wannabe.tpe <:< definitions.MacroContextClass.tpe) wannabe else NoSymbol + + val lastParamList0 = paramss.lastOption getOrElse Nil + val lastParamList = lastParamList0 flatMap (param => param.tpe match { + case TypeRef(SingleType(NoPrefix, contextParam), sym, List(tparam)) => + var wannabe = sym + while (wannabe.isAliasType) wannabe = wannabe.info.typeSymbol + if (wannabe != definitions.TypeTagClass) + List(param) + else + transform(param, tparam.typeSymbol) map (_ :: Nil) getOrElse Nil + case _ => + List(param) + }) + + var result = paramss.dropRight(1) :+ lastParamList + if (lastParamList0.isEmpty ^ lastParamList.isEmpty) { + result = result dropRight 1 + } + + result + } + + /** As specified above, body of a macro definition must reference its implementation. + * This function verifies that the body indeed refers to a method, and that + * the referenced macro implementation is compatible with the given macro definition. * - * If macro has no type arguments, the third parameter list is omitted (it's not empty, but omitted altogether). + * This means that macro implementation (fooBar in example above) must: + * 1) Refer to a statically accessible, non-overloaded method. + * 2) Have the right parameter lists as outlined in the SIP / in the doc comment of this class. * - * To find out the desugared representation of your particular macro, compile it with -Ymacro-debug. + * @return typechecked rhs of the given macro definition */ - def macroMethDef(mdef: DefDef): Tree = { - def paramDef(name: Name, tpt: Tree) = ValDef(Modifiers(PARAM), name, tpt, EmptyTree) - val contextType = TypeTree(ReflectMacroContext.tpe) - val globParamSec = List(paramDef(nme.macroContext, contextType)) - def globSelect(name: Name) = Select(Ident(nme.macroContext), name) - def globTree = globSelect(tpnme.Tree) - def globTypeTree = globSelect(tpnme.TypeTree) - val thisParamSec = List(paramDef(newTermName(nme.macroThis), globTree)) - def tparamInMacro(tdef: TypeDef) = paramDef(tdef.name.toTermName, globTypeTree) - def vparamInMacro(vdef: ValDef): ValDef = paramDef(vdef.name, vdef.tpt match { - case tpt @ AppliedTypeTree(hk, _) if treeInfo.isRepeatedParamType(tpt) => AppliedTypeTree(hk, List(globTree)) - case _ => globTree - }) - def wrapImplicit(tree: Tree) = atPos(tree.pos) { - // implicit hasn't proven useful so far, so I'm disabling it - //val implicitDecl = ValDef(Modifiers(IMPLICIT), nme.macroContextImplicit, SingletonTypeTree(Ident(nme.macroContext)), Ident(nme.macroContext)) - val importGlob = Import(Ident(nme.macroContext), List(ImportSelector(nme.WILDCARD, -1, null, -1))) - Block(List(importGlob), tree) + def typedMacroBody(typer: Typer, ddef: DefDef): Tree = { + import typer.context + if (macroDebug) println("typechecking macro def %s at %s".format(ddef.symbol, ddef.pos)) + + implicit def augmentString(s: String) = new AugmentedString(s) + class AugmentedString(s: String) { + def abbreviateCoreAliases: String = { // hack! + var result = s + result = result.replace("c.mirror.TypeTag", "c.TypeTag") + result = result.replace("c.mirror.Expr", "c.Expr") + result + } } - var formals = (mdef.vparamss map (_ map vparamInMacro)) - if (mdef.tparams.nonEmpty) formals = (mdef.tparams map tparamInMacro) :: formals - - atPos(mdef.pos) { - new DefDef( // can't call DefDef here; need to find out why - mods = mdef.mods &~ MACRO &~ OVERRIDE, - name = nme.macroMethodName(mdef.name), - tparams = List(), - vparamss = globParamSec :: thisParamSec :: formals, - tpt = globTree, - wrapImplicit(mdef.rhs)) + + var hasErrors = false + def reportError(pos: Position, msg: String) = { + hasErrors = true + context.error(pos, msg) + } + + val macroDef = ddef.symbol + val defpos = macroDef.pos + val implpos = ddef.rhs.pos + assert(macroDef.isTermMacro, ddef) + + def invalidBodyError() = + reportError(defpos, + "macro body has wrong shape:" + + "\n required: macro <reference to implementation object>.<implementation method name>" + + "\n or : macro <implementation method name>") + def validatePreTyper(rhs: Tree): Unit = rhs match { + // we do allow macro invocations inside macro bodies + // personally I don't mind if pre-typer tree is a macro invocation + // that later resolves to a valid reference to a macro implementation + // however, I don't think that invalidBodyError() should hint at that + // let this be an Easter Egg :) + case Apply(_, _) => ; + case TypeApply(_, _) => ; + case Super(_, _) => ; + case This(_) => ; + case Ident(_) => ; + case Select(_, _) => ; + case _ => invalidBodyError() } + def validatePostTyper(rhs1: Tree): Unit = { + def loop(tree: Tree): Unit = { + def errorNotStatic() = + reportError(implpos, "macro implementation must be in statically accessible object") + + def ensureRoot(sym: Symbol) = + if (!sym.isModule && !sym.isModuleClass) errorNotStatic() + + def ensureModule(sym: Symbol) = + if (!sym.isModule) errorNotStatic() + + tree match { + case TypeApply(fun, _) => + loop(fun) + case Super(qual, _) => + ensureRoot(macroDef.owner) + loop(qual) + case This(_) => + ensureRoot(tree.symbol) + case Select(qual, name) if name.isTypeName => + loop(qual) + case Select(qual, name) if name.isTermName => + if (tree.symbol != rhs1.symbol) ensureModule(tree.symbol) + loop(qual) + case Ident(name) if name.isTypeName => + ; + case Ident(name) if name.isTermName => + if (tree.symbol != rhs1.symbol) ensureModule(tree.symbol) + case _ => + invalidBodyError() + } + } + + loop(rhs1) + } + + val rhs = ddef.rhs + validatePreTyper(rhs) + if (hasErrors) macroTrace("macro def failed to satisfy trivial preconditions: ")(macroDef) + + // we use typed1 instead of typed, because otherwise adapt is going to mess us up + // if adapt sees <qualifier>.<method>, it will want to perform eta-expansion and will fail + // unfortunately, this means that we have to manually trigger macro expansion + // because it's adapt which is responsible for automatic expansion during typechecking + def typecheckRhs(rhs: Tree): Tree = { + try { + val prevNumErrors = reporter.ERROR.count // [Eugene] funnily enough, the isErroneous check is not enough + var rhs1 = if (hasErrors) EmptyTree else typer.typed1(rhs, EXPRmode, WildcardType) + def typecheckedWithErrors = (rhs1 exists (_.isErroneous)) || reporter.ERROR.count != prevNumErrors + def rhsNeedsMacroExpansion = rhs1.symbol != null && rhs1.symbol.isTermMacro && !rhs1.symbol.isErroneous + while (!typecheckedWithErrors && rhsNeedsMacroExpansion) { + rhs1 = macroExpand1(typer, rhs1) match { + case Success(expanded) => + try { + val typechecked = typer.typed1(expanded, EXPRmode, WildcardType) + if (macroDebug) { + println("typechecked1:") + println(typechecked) + println(showRaw(typechecked)) + } + + typechecked + } finally { + openMacros = openMacros.tail + } + case Fallback(fallback) => + typer.typed1(fallback, EXPRmode, WildcardType) + case Other(result) => + result + } + } + rhs1 + } catch { + case ex: TypeError => + typer.reportTypeError(context, rhs.pos, ex) + typer.infer.setError(rhs) + } + } + + val prevNumErrors = reporter.ERROR.count // funnily enough, the isErroneous check is not enough + var rhs1 = typecheckRhs(rhs) + def typecheckedWithErrors = (rhs1 exists (_.isErroneous)) || reporter.ERROR.count != prevNumErrors + hasErrors = hasErrors || typecheckedWithErrors + if (typecheckedWithErrors) macroTrace("body of a macro def failed to typecheck: ")(ddef) + + val macroImpl = rhs1.symbol + macroDef withAnnotation AnnotationInfo(MacroImplAnnotation.tpe, List(rhs1), Nil) + if (!hasErrors) { + if (macroImpl == null) { + invalidBodyError() + } else { + if (!macroImpl.isMethod) + invalidBodyError() + if (macroImpl.isOverloaded) + reportError(implpos, "macro implementation cannot be overloaded") + if (!macroImpl.typeParams.isEmpty && (!rhs1.isInstanceOf[TypeApply])) + reportError(implpos, "macro implementation reference needs type arguments") + if (!hasErrors) + validatePostTyper(rhs1) + } + if (hasErrors) + macroTrace("macro def failed to satisfy trivial preconditions: ")(macroDef) + } + + if (!hasErrors) { + def checkCompatibility(reqparamss: List[List[Symbol]], actparamss: List[List[Symbol]], reqres: Type, actres: Type): List[String] = { + var hasErrors = false + var errors = List[String]() + def compatibilityError(msg: String) { + hasErrors = true + errors :+= msg + } + + val flatreqparams = reqparamss.flatten + val flatactparams = actparamss.flatten + val tparams = macroImpl.typeParams + val tvars = tparams map freshVar + def lengthMsg(which: String, extra: Symbol) = + "parameter lists have different length, "+which+" extra parameter "+extra.defString + if (actparamss.length != reqparamss.length) + compatibilityError("number of parameter sections differ") + + if (!hasErrors) { + try { + for ((rparams, aparams) <- reqparamss zip actparamss) { + if (rparams.length < aparams.length) + compatibilityError(lengthMsg("found", aparams(rparams.length))) + if (aparams.length < rparams.length) + compatibilityError(lengthMsg("required", rparams(aparams.length)).abbreviateCoreAliases) + } + // if the implementation signature is already deemed to be incompatible, we bail out + // otherwise, high-order type magic employed below might crash in weird ways + if (!hasErrors) { + for ((rparams, aparams) <- reqparamss zip actparamss) { + for ((rparam, aparam) <- rparams zip aparams) { + def isRepeated(param: Symbol) = param.tpe.typeSymbol == RepeatedParamClass + if (rparam.name != aparam.name && !rparam.isSynthetic) { + val rparam1 = rparam + val aparam1 = aparam + compatibilityError("parameter names differ: "+rparam.name+" != "+aparam.name) + } + if (isRepeated(rparam) && !isRepeated(aparam)) + compatibilityError("types incompatible for parameter "+rparam.name+": corresponding is not a vararg parameter") + if (!isRepeated(rparam) && isRepeated(aparam)) + compatibilityError("types incompatible for parameter "+aparam.name+": corresponding is not a vararg parameter") + if (!hasErrors) { + var atpe = aparam.tpe.substSym(flatactparams, flatreqparams).instantiateTypeParams(tparams, tvars) + + // strip the { type PrefixType = ... } refinement off the Context or otherwise we get compatibility errors + atpe = atpe match { + case RefinedType(List(tpe), Scope(sym)) if tpe == MacroContextClass.tpe && sym.allOverriddenSymbols.contains(MacroContextPrefixType) => tpe + case _ => atpe + } + + val ok = if (macroDebug) withTypesExplained(rparam.tpe <:< atpe) else rparam.tpe <:< atpe + if (!ok) { + compatibilityError("type mismatch for parameter "+rparam.name+": "+rparam.tpe.toString.abbreviateCoreAliases+" does not conform to "+atpe) + } + } + } + } + } + if (!hasErrors) { + val atpe = actres.substSym(flatactparams, flatreqparams).instantiateTypeParams(tparams, tvars) + val ok = if (macroDebug) withTypesExplained(atpe <:< reqres) else atpe <:< reqres + if (!ok) { + compatibilityError("type mismatch for return type : "+reqres.toString.abbreviateCoreAliases+" does not conform to "+(if (ddef.tpt.tpe != null) atpe.toString else atpe.toString.abbreviateCoreAliases)) + } + } + if (!hasErrors) { + val targs = solvedTypes(tvars, tparams, tparams map varianceInType(actres), false, + lubDepth(flatactparams map (_.tpe)) max lubDepth(flatreqparams map (_.tpe))) + val boundsOk = typer.silent(_.infer.checkBounds(ddef, NoPrefix, NoSymbol, tparams, targs, "")) + boundsOk match { + case SilentResultValue(true) => ; + case SilentResultValue(false) | SilentTypeError(_) => + val bounds = tparams map (tp => tp.info.instantiateTypeParams(tparams, targs).bounds) + compatibilityError("type arguments " + targs.mkString("[", ",", "]") + + " do not conform to " + tparams.head.owner + "'s type parameter bounds " + + (tparams map (_.defString)).mkString("[", ",", "]")) + } + } + } catch { + case ex: NoInstance => + compatibilityError( + "type parameters "+(tparams map (_.defString) mkString ", ")+" cannot be instantiated\n"+ + ex.getMessage) + } + } + + errors.toList + } + + var actparamss = macroImpl.paramss + actparamss = transformTypeTagEvidenceParams(actparamss, (param, tparam) => None) + + val rettpe = if (ddef.tpt.tpe != null) ddef.tpt.tpe else computeMacroDefTypeFromMacroImpl(ddef, macroDef, macroImpl) + val (reqparamsss0, reqres0) = macroImplSigs(macroDef, ddef.tparams, ddef.vparamss, rettpe) + var reqparamsss = reqparamsss0 + + // prohibit implicit params on macro implementations + // we don't have to do this, but it appears to be more clear than allowing them + val implicitParams = actparamss.flatten filter (_.isImplicit) + if (implicitParams.length > 0) { + reportError(implicitParams.head.pos, "macro implementations cannot have implicit parameters other than TypeTag evidences") + macroTrace("macro def failed to satisfy trivial preconditions: ")(macroDef) + } + + if (!hasErrors) { + val reqres = reqres0 + val actres = macroImpl.tpe.finalResultType + def showMeth(pss: List[List[Symbol]], restpe: Type, abbreviate: Boolean) = { + var argsPart = (pss map (ps => ps map (_.defString) mkString ("(", ", ", ")"))).mkString + if (abbreviate) argsPart = argsPart.abbreviateCoreAliases + var retPart = restpe.toString + if (abbreviate || ddef.tpt.tpe == null) retPart = retPart.abbreviateCoreAliases + argsPart + ": " + retPart + } + def compatibilityError(addendum: String) = + reportError(implpos, + "macro implementation has wrong shape:"+ + "\n required: "+showMeth(reqparamsss.head, reqres, true) + + (reqparamsss.tail map (paramss => "\n or : "+showMeth(paramss, reqres, true)) mkString "")+ + "\n found : "+showMeth(actparamss, actres, false)+ + "\n"+addendum) + + macroTrace("considering " + reqparamsss.length + " possibilities of compatible macro impl signatures for macro def: ")(ddef.name) + val results = reqparamsss map (checkCompatibility(_, actparamss, reqres, actres)) + if (macroDebug) (reqparamsss zip results) foreach { case (reqparamss, result) => + println("%s %s".format(if (result.isEmpty) "[ OK ]" else "[FAILED]", reqparamss)) + result foreach (errorMsg => println(" " + errorMsg)) + } + + if (results forall (!_.isEmpty)) { + var index = reqparamsss indexWhere (_.length == actparamss.length) + if (index == -1) index = 0 + val mostRelevantMessage = results(index).head + compatibilityError(mostRelevantMessage) + } else { + assert((results filter (_.isEmpty)).length == 1, results) + if (macroDebug) (reqparamsss zip results) filter (_._2.isEmpty) foreach { case (reqparamss, result) => + println("typechecked macro impl as: " + reqparamss) + } + } + } + } + + // if this macro definition is erroneous, then there's no sense in expanding its usages + // in the previous prototype macro implementations were magically generated from macro definitions + // so macro definitions and its usages couldn't be compiled in the same compilation run + // however, now definitions and implementations are decoupled, so it's everything is possible + // hence, we now use IS_ERROR flag to serve as an indicator that given macro definition is broken + if (hasErrors) { + macroDef setFlag IS_ERROR + } + + rhs1 } - def addMacroMethods(templ: Template, namer: Namer): Unit = { - for (ddef @ DefDef(mods, _, _, _, _, _) <- templ.body if mods hasFlag MACRO) { - val trace = scala.tools.nsc.util.trace when settings.Ymacrodebug.value - val sym = namer.enterSyntheticSym(trace("macro def: ")(macroMethDef(ddef))) - trace("added to "+namer.context.owner.enclClass+": ")(sym) + def computeMacroDefTypeFromMacroImpl(macroDdef: DefDef, macroDef: Symbol, macroImpl: Symbol): Type = { + // get return type from method type + def unwrapRet(tpe: Type): Type = { + def loop(tpe: Type) = tpe match { + case NullaryMethodType(ret) => ret + case mtpe @ MethodType(_, ret) => unwrapRet(ret) + case _ => tpe + } + + tpe match { + case PolyType(_, tpe) => loop(tpe) + case _ => loop(tpe) + } + } + var metaType = unwrapRet(macroImpl.tpe) + + // downgrade from metalevel-0 to metalevel-1 + def inferRuntimeType(metaType: Type): Type = metaType match { + case TypeRef(pre, sym, args) if sym.name == tpnme.Expr && args.length == 1 => + args.head + case _ => + AnyClass.tpe + } + var runtimeType = inferRuntimeType(metaType) + + // transform type parameters of a macro implementation into type parameters of a macro definition + runtimeType = runtimeType map { + case TypeRef(pre, sym, args) => + // [Eugene] not sure which of these deSkolemizes are necessary + // sym.paramPos is unreliable (see another case below) + val tparams = macroImpl.typeParams map (_.deSkolemize) + val paramPos = tparams indexOf sym.deSkolemize + val sym1 = if (paramPos == -1) sym else { + val ann = macroDef.getAnnotation(MacroImplAnnotation) + ann match { + case Some(ann) => + val TypeApply(_, implRefTargs) = ann.args(0) + val implRefTarg = implRefTargs(paramPos).tpe.typeSymbol + implRefTarg + case None => + sym + } + } + TypeRef(pre, sym1, args) + case tpe => + tpe + } + + // as stated in the spec, before being matched to macroimpl, type and value parameters of macrodef + // undergo a special transformation, sigma, that adapts them to the different metalevel macroimpl lives in + // as a result, we need to reverse this transformation when inferring macrodef ret from macroimpl ret + def unsigma(tpe: Type): Type = { + // unfortunately, we cannot dereference ``paramss'', because we're in the middle of inferring a type for ``macroDef'' +// val defParamss = macroDef.paramss + val defParamss = macroDdef.vparamss map (_ map (_.symbol)) + var implParamss = macroImpl.paramss + implParamss = transformTypeTagEvidenceParams(implParamss, (param, tparam) => None) + + val implCtxParam = if (implParamss.length > 0 && implParamss(0).length > 0) implParamss(0)(0) else null + def implParamToDefParam(implParam: Symbol): Symbol = { + val indices = (implParamss drop 1 zipWithIndex) map { case (implParams, index) => (index, implParams indexOf implParam) } filter (_._2 != -1) headOption; + val defParam = indices flatMap { + case (plistIndex, pIndex) => + if (defParamss.length <= plistIndex) None + else if (defParamss(plistIndex).length <= pIndex) None + else Some(defParamss(plistIndex)(pIndex)) + } + defParam orNull + } + + class UnsigmaTypeMap extends TypeMap { + def apply(tp: Type): Type = tp match { + case TypeRef(pre, sym, args) => + val pre1 = pre match { + case SingleType(SingleType(SingleType(NoPrefix, param), prefix), value) if param == implCtxParam && prefix == MacroContextPrefix && value == ExprValue => + ThisType(macroDef.owner) + case SingleType(SingleType(NoPrefix, param), value) if implParamToDefParam(param) != null && value == ExprValue => + val macroDefParam = implParamToDefParam(param) + SingleType(NoPrefix, macroDefParam) + case _ => + pre + } + val args1 = args map mapOver + TypeRef(pre1, sym, args1) + case _ => + mapOver(tp) + } + } + + new UnsigmaTypeMap() apply tpe } + runtimeType = unsigma(runtimeType) + + runtimeType } - lazy val mirror = new scala.reflect.runtime.Mirror { - lazy val libraryClassLoader = { - // todo. this is more or less okay, but not completely correct - // see https://issues.scala-lang.org/browse/SI-5433 for more info - val classpath = global.classPath.asURLs - var loader: ClassLoader = ScalaClassLoader.fromURLs(classpath, self.getClass.getClassLoader) - - // an heuristic to detect REPL - if (global.settings.exposeEmptyPackage.value) { - import scala.tools.nsc.interpreter._ - val virtualDirectory = global.settings.outputDirs.getSingleOutput.get - loader = new AbstractFileClassLoader(virtualDirectory, loader) {} + /** Primary mirror that is used to resolve and run macro implementations. + * Loads classes from -Xmacro-primary-classpath, or from -cp if the option is not specified. + */ + private lazy val primaryMirror: Mirror = { + if (global.forMSIL) + throw new UnsupportedOperationException("Scala reflection not available on this platform") + + val libraryClassLoader = { + if (settings.XmacroPrimaryClasspath.value != "") { + if (macroDebug) println("primary macro mirror: initializing from -Xmacro-primary-classpath: %s".format(settings.XmacroPrimaryClasspath.value)) + val classpath = toURLs(settings.XmacroFallbackClasspath.value) + ScalaClassLoader.fromURLs(classpath, self.getClass.getClassLoader) + } else { + if (macroDebug) println("primary macro mirror: initializing from -cp: %s".format(global.classPath.asURLs)) + val classpath = global.classPath.asURLs + var loader: ClassLoader = ScalaClassLoader.fromURLs(classpath, self.getClass.getClassLoader) + + // [Eugene] a heuristic to detect REPL + if (global.settings.exposeEmptyPackage.value) { + import scala.tools.nsc.interpreter._ + val virtualDirectory = global.settings.outputDirs.getSingleOutput.get + loader = new AbstractFileClassLoader(virtualDirectory, loader) {} + } + + loader } + } + + new Mirror(libraryClassLoader) { override def toString = "<primary macro mirror>" } + } - loader + /** Fallback mirror that is used to resolve and run macro implementations. + * Loads classes from -Xmacro-fallback-classpath aka "macro fallback classpath". + */ + private lazy val fallbackMirror: Mirror = { + if (global.forMSIL) + throw new UnsupportedOperationException("Scala reflection not available on this platform") + + val fallbackClassLoader = { + if (macroDebug) println("fallback macro mirror: initializing from -Xmacro-fallback-classpath: %s".format(settings.XmacroFallbackClasspath.value)) + val classpath = toURLs(settings.XmacroFallbackClasspath.value) + ScalaClassLoader.fromURLs(classpath, self.getClass.getClassLoader) } - override def defaultReflectiveClassLoader() = libraryClassLoader + new Mirror(fallbackClassLoader) { override def toString = "<fallback macro mirror>" } } - /** Return optionally address of companion object and implementation method symbol - * of given macro; or None if implementation classfile cannot be loaded or does - * not contain the macro implementation. + /** Produces a function that can be used to invoke macro implementation for a given macro definition: + * 1) Looks up macro implementation symbol in this universe. + * 2) Loads its enclosing class from the primary mirror. + * 3) Loads the companion of that enclosing class from the primary mirror. + * 4) Resolves macro implementation within the loaded companion. + * 5) If 2-4 fails, repeats them for the fallback mirror. + * + * @return Some(runtime) if macro implementation can be loaded successfully from either of the mirrors, + * None otherwise. */ - def macroImpl(mac: Symbol): Option[(AnyRef, mirror.Symbol)] = { - val debug = settings.Ymacrodebug.value - val trace = scala.tools.nsc.util.trace when debug - trace("looking for macro implementation: ")(mac.fullNameString) - - try { - val mmeth = macroMeth(mac) - trace("found implementation at: ")(mmeth.fullNameString) - - if (mmeth == NoSymbol) None - else { - trace("loading implementation class: ")(mmeth.owner.fullName) - trace("classloader is: ")("%s of type %s".format(mirror.libraryClassLoader, mirror.libraryClassLoader.getClass)) + private def macroRuntime(macroDef: Symbol): Option[List[Any] => Any] = { + macroTrace("looking for macro implementation: ")(macroDef) + macroTrace("macroDef is annotated with: ")(macroDef.annotations) + + val ann = macroDef.getAnnotation(MacroImplAnnotation) + if (ann == None) { + macroTrace("@macroImpl annotation is missing (this means that macro definition failed to typecheck)")(macroDef) + return None + } + + val macroImpl = ann.get.args(0).symbol + if (macroImpl == NoSymbol) { + macroTrace("@macroImpl annotation is malformed (this means that macro definition failed to typecheck)")(macroDef) + return None + } + + if (macroDebug) println("resolved implementation %s at %s".format(macroImpl, macroImpl.pos)) + if (macroImpl.isErroneous) { + macroTrace("macro implementation is erroneous (this means that either macro body or macro implementation signature failed to typecheck)")(macroDef) + return None + } + + def loadMacroImpl(macroMirror: Mirror): Option[(Object, macroMirror.Symbol)] = { + try { + // this logic relies on the assumptions that were valid for the old macro prototype + // namely that macro implementations can only be defined in top-level classes and modules + // with the new prototype that materialized in a SIP, macros need to be statically accessible, which is different + // for example, a macro def could be defined in a trait that is implemented by an object + // there are some more clever cases when seemingly non-static method ends up being statically accessible + // however, the code below doesn't account for these guys, because it'd take a look of time to get it right + // for now I leave it as a todo and move along to more the important stuff + + macroTrace("loading implementation class from %s: ".format(macroMirror))(macroImpl.owner.fullName) + macroTrace("classloader is: ")("%s of type %s".format(macroMirror.classLoader, if (macroMirror.classLoader != null) macroMirror.classLoader.getClass.toString else "primordial classloader")) def inferClasspath(cl: ClassLoader) = cl match { case cl: java.net.URLClassLoader => "[" + (cl.getURLs mkString ",") + "]" + case null => "[" + scala.tools.util.PathResolver.Environment.javaBootClassPath + "]" case _ => "<unknown>" } - trace("classpath is: ")(inferClasspath(mirror.libraryClassLoader)) + macroTrace("classpath is: ")(inferClasspath(macroMirror.classLoader)) - // @xeno.by: relies on the fact that macros can only be defined in static classes + // [Eugene] relies on the fact that macro implementations can only be defined in static classes + // [Martin to Eugene] There's similar logic buried in Symbol#flatname. Maybe we can refactor? def classfile(sym: Symbol): String = { def recur(sym: Symbol): String = sym match { case sym if sym.owner.isPackageClass => @@ -146,145 +693,535 @@ trait Macros { self: Analyzer => else recur(sym.enclClass) } - // @xeno.by: this doesn't work for inner classes - // neither does mmeth.owner.javaClassName, so I had to roll my own implementation - //val receiverName = mmeth.owner.fullName - val receiverName = classfile(mmeth.owner) - val receiverClass: mirror.Symbol = mirror.symbolForName(receiverName) + // [Eugene] this doesn't work for inner classes + // neither does macroImpl.owner.javaClassName, so I had to roll my own implementation + //val receiverName = macroImpl.owner.fullName + val implClassName = classfile(macroImpl.owner) + val implClassSymbol: macroMirror.Symbol = macroMirror.symbolForName(implClassName) - if (debug) { - println("receiverClass is: " + receiverClass.fullNameString) + if (macroDebug) { + println("implClassSymbol is: " + implClassSymbol.fullNameString) - val jreceiverClass = mirror.classToJava(receiverClass) - val jreceiverSource = jreceiverClass.getProtectionDomain.getCodeSource - println("jreceiverClass is %s from %s".format(jreceiverClass, jreceiverSource)) - println("jreceiverClassLoader is %s with classpath %s".format(jreceiverClass.getClassLoader, inferClasspath(jreceiverClass.getClassLoader))) + if (implClassSymbol != macroMirror.NoSymbol) { + val implClass = macroMirror.classToJava(implClassSymbol) + val implSource = implClass.getProtectionDomain.getCodeSource + println("implClass is %s from %s".format(implClass, implSource)) + println("implClassLoader is %s with classpath %s".format(implClass.getClassLoader, inferClasspath(implClass.getClassLoader))) + } } - val receiverObj = receiverClass.companionModule - trace("receiverObj is: ")(receiverObj.fullNameString) + val implObjSymbol = implClassSymbol.companionModule + macroTrace("implObjSymbol is: ")(implObjSymbol.fullNameString) - if (receiverObj == mirror.NoSymbol) None + if (implObjSymbol == macroMirror.NoSymbol) None else { - // @xeno.by: yet another reflection method that doesn't work for inner classes - //val receiver = mirror.companionInstance(receiverClass) - val clazz = java.lang.Class.forName(receiverName, true, mirror.libraryClassLoader) - val receiver = clazz getField "MODULE$" get null - - val rmeth = receiverObj.info.member(mirror.newTermName(mmeth.name.toString)) - if (debug) { - println("rmeth is: " + rmeth.fullNameString) - println("jrmeth is: " + mirror.methodToJava(rmeth)) + // yet another reflection method that doesn't work for inner classes + //val receiver = macroMirror.companionInstance(receiverClass) + val implObj = try { + val implObjClass = java.lang.Class.forName(implClassName, true, macroMirror.classLoader) + implObjClass getField "MODULE$" get null + } catch { + case ex: NoSuchFieldException => macroTrace("exception when loading implObj: ")(ex); null + case ex: NoClassDefFoundError => macroTrace("exception when loading implObj: ")(ex); null + case ex: ClassNotFoundException => macroTrace("exception when loading implObj: ")(ex); null } - if (rmeth == mirror.NoSymbol) None + if (implObj == null) None else { - Some((receiver, rmeth)) + val implMethSymbol = implObjSymbol.info.member(macroMirror.newTermName(macroImpl.name.toString)) + if (macroDebug) { + println("implMethSymbol is: " + implMethSymbol.fullNameString) + println("jimplMethSymbol is: " + macroMirror.methodToJava(implMethSymbol)) + } + + if (implMethSymbol == macroMirror.NoSymbol) None + else { + if (macroDebug) println("successfully loaded macro impl as (%s, %s)".format(implObj, implMethSymbol)) + Some((implObj, implMethSymbol)) + } } } + } catch { + case ex: ClassNotFoundException => + macroTrace("implementation class failed to load: ")(ex.toString) + None } - } catch { - case ex: ClassNotFoundException => - trace("implementation class failed to load: ")(ex.toString) - None + } + + val primary = loadMacroImpl(primaryMirror) + primary match { + case Some((implObj, implMethSymbol)) => + def runtime(args: List[Any]) = primaryMirror.invoke(implObj, implMethSymbol)(args: _*).asInstanceOf[Any] + Some(runtime) + case None => + if (settings.XmacroFallbackClasspath.value != "") { + if (macroDebug) println("trying to load macro implementation from the fallback mirror: %s".format(settings.XmacroFallbackClasspath.value)) + val fallback = loadMacroImpl(fallbackMirror) + fallback match { + case Some((implObj, implMethSymbol)) => + def runtime(args: List[Any]) = fallbackMirror.invoke(implObj, implMethSymbol)(args: _*).asInstanceOf[Any] + Some(runtime) + case None => + None + } + } else { + None + } } } - /** Return result of macro expansion. - * Or, if that fails, and the macro overrides a method return - * tree that calls this method instead of the macro. + /** Should become private again once we're done with migrating typetag generation from implicits */ + def macroContext(typer: Typer, prefixTree: Tree, expandeeTree: Tree): MacroContext { val mirror: global.type } = + new { + val mirror: global.type = global + val callsiteTyper: mirror.analyzer.Typer = typer.asInstanceOf[global.analyzer.Typer] + // todo. infer precise typetag for this Expr, namely the PrefixType member of the Context refinement + val prefix = Expr(prefixTree)(TypeTag.Nothing) + val expandee = expandeeTree + } with MacroContext { + override def toString = "MacroContext(%s@%s +%d)".format(expandee.symbol.name, expandee.pos, openMacros.length - 1 /* exclude myself */) + } + + /** Calculate the arguments to pass to a macro implementation when expanding the provided tree. + * + * This includes inferring the exact type and instance of the macro context to pass, and also + * allowing for missing parameter sections in macro implementation (see ``macroImplParamsss'' for more info). + * + * @return list of runtime objects to pass to the implementation obtained by ``macroRuntime'' */ - def macroExpand(tree: Tree, typer: Typer): Option[Any] = { - val trace = scala.tools.nsc.util.trace when settings.Ymacrodebug.value - trace("macroExpand: ")(tree) - - val macroDef = tree.symbol - macroImpl(macroDef) match { - case Some((receiver, rmeth)) => - val argss = List(global) :: macroArgs(tree) - val paramss = macroMeth(macroDef).paramss - trace("paramss: ")(paramss) - val rawArgss = for ((as, ps) <- argss zip paramss) yield { - if (isVarArgsList(ps)) as.take(ps.length - 1) :+ as.drop(ps.length - 1) - else as - } - val rawArgs: Seq[Any] = rawArgss.flatten - trace("rawArgs: ")(rawArgs) - val savedInfolevel = nodePrinters.infolevel + private def macroArgs(typer: Typer, expandee: Tree): Option[List[Any]] = { + var prefixTree: Tree = EmptyTree + var typeArgs = List[Tree]() + val exprArgs = new ListBuffer[List[Expr[_]]] + def collectMacroArgs(tree: Tree): Unit = tree match { + case Apply(fn, args) => + // todo. infer precise typetag for this Expr, namely the declared type of the corresponding macro impl argument + exprArgs.prepend(args map (Expr(_)(TypeTag.Nothing))) + collectMacroArgs(fn) + case TypeApply(fn, args) => + typeArgs = args + collectMacroArgs(fn) + case Select(qual, name) => + prefixTree = qual + case _ => + } + collectMacroArgs(expandee) + val context = macroContext(typer, prefixTree, expandee) + var argss: List[List[Any]] = List(context) :: exprArgs.toList + macroTrace("argss: ")(argss) + + val macroDef = expandee.symbol + val ann = macroDef.getAnnotation(MacroImplAnnotation).getOrElse(throw new Error("assertion failed. %s: %s".format(macroDef, macroDef.annotations))) + val macroImpl = ann.args(0).symbol + var paramss = macroImpl.paramss + val tparams = macroImpl.typeParams + macroTrace("paramss: ")(paramss) + + // we need to take care of all possible combos of nullary/empty-paramlist macro defs vs nullary/empty-arglist invocations + // nullary def + nullary invocation => paramss and argss match, everything is okay + // nullary def + empty-arglist invocation => illegal Scala code, impossible, everything is okay + // empty-paramlist def + nullary invocation => uh-oh, we need to append a List() to argss + // empty-paramlist def + empty-arglist invocation => paramss and argss match, everything is okay + // that's almost it, but we need to account for the fact that paramss might have context bounds that mask the empty last paramlist + val paramss_without_evidences = transformTypeTagEvidenceParams(paramss, (param, tparam) => None) + val isEmptyParamlistDef = paramss_without_evidences.length != 0 && paramss_without_evidences.last.isEmpty + val isEmptyArglistInvocation = argss.length != 0 && argss.last.isEmpty + if (isEmptyParamlistDef && !isEmptyArglistInvocation) { + if (macroDebug) println("isEmptyParamlistDef && !isEmptyArglistInvocation: appending a List() to argss") + argss = argss :+ Nil + } + + // nb! check partial application against paramss without evidences + val numParamLists = paramss_without_evidences.length + val numArgLists = argss.length + if (numParamLists != numArgLists) { + typer.context.error(expandee.pos, "macros cannot be partially applied") + return None + } + + // if paramss have typetag context bounds, add an arglist to argss if necessary and instantiate the corresponding evidences + // consider the following example: + // + // class D[T] { + // class C[U] { + // def foo[V] = macro Impls.foo[T, U, V] + // } + // } + // + // val outer1 = new D[Int] + // val outer2 = new outer1.C[String] + // outer2.foo[Boolean] + // + // then T and U need to be inferred from the lexical scope of the call using ``asSeenFrom'' + // whereas V won't be resolved by asSeenFrom and need to be loaded directly from ``expandee'' which needs to contain a TypeApply node + // also, macro implementation reference may contain a regular type as a type argument, then we pass it verbatim + paramss = transformTypeTagEvidenceParams(paramss, (param, tparam) => Some(tparam)) + if (paramss.lastOption map (params => !params.isEmpty && params.forall(_.isType)) getOrElse false) argss = argss :+ Nil + val evidences = paramss.last takeWhile (_.isType) map (tparam => { + val TypeApply(_, implRefTargs) = ann.args(0) + var implRefTarg = implRefTargs(tparam.paramPos).tpe.typeSymbol + val tpe = if (implRefTarg.isTypeParameterOrSkolem) { + if (implRefTarg.owner == macroDef) { + // [Eugene] doesn't work when macro def is compiled separately from its usages + // then implRefTarg is not a skolem and isn't equal to any of macroDef.typeParams +// val paramPos = implRefTarg.deSkolemize.paramPos + val paramPos = macroDef.typeParams.indexWhere(_.name == implRefTarg.name) + typeArgs(paramPos).tpe + } else + implRefTarg.tpe.asSeenFrom( + if (prefixTree == EmptyTree) macroDef.owner.tpe else prefixTree.tpe, + macroDef.owner) + } else + implRefTarg.tpe + if (macroDebug) println("resolved tparam %s as %s".format(tparam, tpe)) + tpe + }) map (tpe => { + val ttag = TypeTag(tpe) + if (ttag.isGround) ttag.toGround else ttag + }) + argss = argss.dropRight(1) :+ (evidences ++ argss.last) + + assert(argss.length == paramss.length, "argss: %s, paramss: %s".format(argss, paramss)) + val rawArgss = for ((as, ps) <- argss zip paramss) yield { + if (isVarArgsList(ps)) as.take(ps.length - 1) :+ as.drop(ps.length - 1) + else as + } + val rawArgs = rawArgss.flatten + macroTrace("rawArgs: ")(rawArgs) + Some(rawArgs) + } + + /** Keeps track of macros in-flight. + * See more informations in comments to ``openMacros'' in ``scala.reflect.makro.Context''. + */ + var openMacros = List[MacroContext]() + + /** Performs macro expansion: + * 1) Checks whether the expansion needs to be delayed (see ``mustDelayMacroExpansion'') + * 2) Loads macro implementation using ``macroMirror'' + * 3) Synthesizes invocation arguments for the macro implementation + * 4) Checks that the result is a tree bound to this universe + * 5) Typechecks the result against the return type of the macro definition + * + * If -Ymacro-debug is enabled, you will get detailed log of how exactly this function + * performs class loading and method resolution in order to load the macro implementation. + * The log will also include other non-trivial steps of macro expansion. + * + * If -Ymacro-copypaste is enabled along with -Ymacro-debug, you will get macro expansions + * logged in the form that can be copy/pasted verbatim into REPL (useful for debugging!). + * + * @return + * the expansion result if the expansion has been successful, + * the fallback method invocation if the expansion has been unsuccessful, but there is a fallback, + * the expandee unchanged if the expansion has been delayed, + * the expandee fully expanded if the expansion has been delayed before and has been expanded now, + * the expandee with an error marker set if the expansion has been cancelled due malformed arguments or implementation + * the expandee with an error marker set if there has been an error + */ + def macroExpand(typer: Typer, expandee: Tree, pt: Type): Tree = + macroExpand1(typer, expandee) match { + case Success(expanded) => try { - // @xeno.by: InfoLevel.Verbose examines and prints out infos of symbols - // by the means of this'es these symbols can climb up the lexical scope - // when these symbols will be examined by a node printer - // they will enumerate and analyze their children (ask for infos and tpes) - // if one of those children involves macro expansion, things might get nasty - // that's why I'm temporarily turning this behavior off - nodePrinters.infolevel = nodePrinters.InfoLevel.Quiet - val expanded = mirror.invoke(receiver, rmeth)(rawArgs: _*) - expanded match { - case expanded: Tree => - val expectedTpe = tree.tpe - val typed = typer.typed(expanded, EXPRmode, expectedTpe) - Some(typed) - case expanded if expanded.isInstanceOf[Tree] => - typer.context.unit.error(tree.pos, "macro must return a compiler-specific tree; returned value is Tree, but it doesn't belong to this compiler's universe") - None - case expanded => - typer.context.unit.error(tree.pos, "macro must return a compiler-specific tree; returned value is of class: " + expanded.getClass) - None + var expectedTpe = expandee.tpe + + // [Eugene] weird situation. what's the conventional way to deal with it? + val isNullaryInvocation = expandee match { + case TypeApply(Select(_, _), _) => true + case Select(_, _) => true + case _ => false } - } catch { - case ex => - val realex = ReflectionUtils.unwrapThrowable(ex) - val msg = if (settings.Ymacrodebug.value) { - val stacktrace = new java.io.StringWriter() - realex.printStackTrace(new java.io.PrintWriter(stacktrace)) - System.getProperty("line.separator") + stacktrace - } else { - realex.getMessage - } - typer.context.unit.error(tree.pos, "exception during macro expansion: " + msg) - None + if (isNullaryInvocation) expectedTpe match { + case MethodType(Nil, restpe) => + macroTrace("nullary invocation of a method with an empty parameter list. unwrapping expectedTpe from " + expectedTpe + " to:")(restpe) + expectedTpe = restpe + case _ => ; + } + + var typechecked = typer.context.withImplicitsEnabled(typer.typed(expanded, EXPRmode, expectedTpe)) + if (macroDebug) { + println("typechecked1:") + println(typechecked) + println(showRaw(typechecked)) + } + + typechecked = typer.context.withImplicitsEnabled(typer.typed(typechecked, EXPRmode, pt)) + if (macroDebug) { + println("typechecked2:") + println(typechecked) + println(showRaw(typechecked)) + } + + typechecked } finally { - nodePrinters.infolevel = savedInfolevel + openMacros = openMacros.tail } - case None => - def notFound() = { - typer.context.unit.error(tree.pos, "macro implementation not found: " + macroDef.name) - None - } - def fallBackToOverridden(tree: Tree): Option[Tree] = { - tree match { - case Select(qual, name) if (macroDef.isMacro) => - macroDef.allOverriddenSymbols match { - case first :: _ => - Some(Select(qual, name) setPos tree.pos setSymbol first) + case Fallback(fallback) => + typer.context.withImplicitsEnabled(typer.typed(fallback, EXPRmode, pt)) + case Other(result) => + result + } + + private sealed abstract class MacroExpansionResult extends Product with Serializable + private case class Success(expanded: Tree) extends MacroExpansionResult + private case class Fallback(fallback: Tree) extends MacroExpansionResult + private case class Other(result: Tree) extends MacroExpansionResult + private def Delay(expandee: Tree) = Other(expandee) + private def Skip(expanded: Tree) = Other(expanded) + private def Cancel(expandee: Tree) = Other(expandee) + private def Failure(expandee: Tree) = Other(expandee) + private def fail(typer: Typer, expandee: Tree, msg: String = null) = { + if (macroDebug || macroCopypaste) { + var msg1 = if (msg contains "exception during macro expansion") msg.split(EOL).drop(1).headOption.getOrElse("?") else msg + if (macroDebug) msg1 = msg + println("macro expansion has failed: %s".format(msg1)) + } + val pos = if (expandee.pos != NoPosition) expandee.pos else openMacros.find(c => c.expandee.pos != NoPosition).map(_.expandee.pos).getOrElse(NoPosition) + if (msg != null) typer.context.error(pos, msg) + typer.infer.setError(expandee) + Failure(expandee) + } + + /** Does the same as ``macroExpand'', but without typechecking the expansion + * Meant for internal use within the macro infrastructure, don't use it elsewhere. + */ + private def macroExpand1(typer: Typer, expandee: Tree): MacroExpansionResult = { + // if a macro implementation is incompatible or any of the arguments are erroneous + // there is no sense to expand the macro itself => it will only make matters worse + if (expandee.symbol.isErroneous || (expandee exists (_.isErroneous))) { + val reason = if (expandee.symbol.isErroneous) "incompatible macro implementation" else "erroneous arguments" + macroTrace("cancelled macro expansion because of %s: ".format(reason))(expandee) + return Cancel(typer.infer.setError(expandee)) + } + + if (!isDelayed(expandee)) { + if (macroDebug || macroCopypaste) println("typechecking macro expansion %s at %s".format(expandee, expandee.pos)) + + val undetparams = calculateUndetparams(expandee) + if (undetparams.size != 0) { + macroTrace("macro expansion is delayed: ")(expandee) + delayed += expandee -> (typer.context, undetparams) + Delay(expandee) + } else { + val macroDef = expandee.symbol + macroRuntime(macroDef) match { + case Some(runtime) => + val savedInfolevel = nodePrinters.infolevel + try { + // InfoLevel.Verbose examines and prints out infos of symbols + // by the means of this'es these symbols can climb up the lexical scope + // when these symbols will be examined by a node printer + // they will enumerate and analyze their children (ask for infos and tpes) + // if one of those children involves macro expansion, things might get nasty + // that's why I'm temporarily turning this behavior off + nodePrinters.infolevel = nodePrinters.InfoLevel.Quiet + val args = macroArgs(typer, expandee) + args match { + case Some(args) => + // adding stuff to openMacros is easy, but removing it is a nightmare + // it needs to be sprinkled over several different code locations + val (context: MacroContext) :: _ = args + openMacros = context :: openMacros + val expanded: MacroExpansionResult = try { + val prevNumErrors = reporter.ERROR.count + val expanded = runtime(args) + val currNumErrors = reporter.ERROR.count + if (currNumErrors != prevNumErrors) { + fail(typer, expandee) // errors have been reported by the macro itself + } else { + expanded match { + case expanded: Expr[_] => + if (macroDebug || macroCopypaste) { + if (macroDebug) println("original:") + println(expanded.tree) + println(showRaw(expanded.tree)) + } + + freeTerms(expanded.tree) foreach (fte => typer.context.error(expandee.pos, + ("macro expansion contains free term variable %s %s. "+ + "have you forgot to use eval when splicing this variable into a reifee? " + + "if you have troubles tracking free term variables, consider using -Xlog-free-terms").format(fte.name, fte.origin))) + freeTypes(expanded.tree) foreach (fty => typer.context.error(expandee.pos, + ("macro expansion contains free type variable %s %s. "+ + "have you forgot to use c.TypeTag annotation for this type parameter? " + + "if you have troubles tracking free type variables, consider using -Xlog-free-types").format(fty.name, fty.origin))) + + val currNumErrors = reporter.ERROR.count + if (currNumErrors != prevNumErrors) { + fail(typer, expandee) + } else { + // inherit the position from the first position-ful expandee in macro callstack + // this is essential for sane error messages + var tree = expanded.tree + var position = openMacros.find(c => c.expandee.pos != NoPosition).map(_.expandee.pos).getOrElse(NoPosition) + tree = atPos(position.focus)(tree) + + // now macro expansion gets typechecked against the macro definition return type + // however, this happens in macroExpand, not here in macroExpand1 + Success(tree) + } + case expanded if expanded.isInstanceOf[Expr[_]] => + val msg = "macro must return a compiler-specific expr; returned value is Expr, but it doesn't belong to this compiler's universe" + fail(typer, expandee, msg) + case expanded => + val msg = "macro must return a compiler-specific expr; returned value is of class: %s".format(expanded.getClass) + fail(typer, expandee, msg) + } + } + } catch { + case ex: Throwable => + openMacros = openMacros.tail + throw ex + } + if (!expanded.isInstanceOf[Success]) openMacros = openMacros.tail + expanded + case None => + fail(typer, expandee) // error has been reported by macroArgs + } + } catch { + case ex => + // [Eugene] any ideas about how to improve this one? + val realex = ReflectionUtils.unwrapThrowable(ex) + realex match { + case realex: reflect.makro.runtime.AbortMacroException => + if (macroDebug || macroCopypaste) println("macro expansion has failed: %s".format(realex.msg)) + fail(typer, expandee) // error has been reported by abort + case _ => + val message = { + try { + // the most reliable way of obtaining currently executing method + // http://stackoverflow.com/questions/442747/getting-the-name-of-the-current-executing-method + val currentMethodName = new Object(){}.getClass().getEnclosingMethod().getName + val relevancyThreshold = realex.getStackTrace().indexWhere(este => este.getMethodName == currentMethodName) + if (relevancyThreshold == -1) None + else { + var relevantElements = realex.getStackTrace().take(relevancyThreshold + 1) + var framesTillReflectiveInvocationOfMacroImpl = relevantElements.reverse.indexWhere(_.isNativeMethod) + 1 + relevantElements = relevantElements dropRight framesTillReflectiveInvocationOfMacroImpl + + realex.setStackTrace(relevantElements) + val message = new java.io.StringWriter() + realex.printStackTrace(new java.io.PrintWriter(message)) + Some(EOL + message) + } + } catch { + // if the magic above goes boom, just fall back to uninformative, but better than nothing, getMessage + case ex: Throwable => + None + } + } getOrElse realex.getMessage + fail(typer, expandee, "exception during macro expansion: " + message) + } + } finally { + nodePrinters.infolevel = savedInfolevel + } + case None => + def notFound() = { + typer.context.error(expandee.pos, "macro implementation not found: " + macroDef.name + " " + + "(the most common reason for that is that you cannot use macro implementations in the same compilation run that defines them)\n" + + "if you do need to define macro implementations along with the rest of your program, consider two-phase compilation with -Xmacro-fallback-classpath " + + "in the second phase pointing to the output of the first phase") + None + } + def fallBackToOverridden(tree: Tree): Option[Tree] = { + tree match { + case Select(qual, name) if (macroDef.isTermMacro) => + macroDef.allOverriddenSymbols match { + case first :: _ => + Some(Select(qual, name) setPos tree.pos setSymbol first) + case _ => + macroTrace("macro is not overridden: ")(tree) + notFound() + } + case Apply(fn, args) => + fallBackToOverridden(fn) match { + case Some(fn1) => Some(Apply(fn1, args) setPos tree.pos) + case _ => None + } + case TypeApply(fn, args) => + fallBackToOverridden(fn) match { + case Some(fn1) => Some(TypeApply(fn1, args) setPos tree.pos) + case _ => None + } case _ => - trace("macro is not overridden: ")(tree) + macroTrace("unexpected tree in fallback: ")(tree) notFound() } - case Apply(fn, args) => - fallBackToOverridden(fn) match { - case Some(fn1) => Some(Apply(fn1, args) setPos tree.pos) - case _ => None - } - case TypeApply(fn, args) => - fallBackToOverridden(fn) match { - case Some(fn1) => Some(TypeApply(fn1, args) setPos tree.pos) - case _ => None - } - case _ => - trace("unexpected tree in fallback: ")(tree) - notFound() - } - } - fallBackToOverridden(tree) match { - case Some(tree1) => - trace("falling back to ")(tree1) - currentRun.macroExpansionFailed = true - Some(tree1) - case None => - None + } + fallBackToOverridden(expandee) match { + case Some(tree1) => + macroTrace("falling back to ")(tree1) + currentRun.macroExpansionFailed = true + Fallback(tree1) + case None => + fail(typer, expandee) + } } + } + } else { + val undetparams = calculateUndetparams(expandee) + if (undetparams.size != 0) + Delay(expandee) + else + Skip(macroExpandAll(typer, expandee)) } } + + /** Without any restrictions on macro expansion, macro applications will expand at will, + * and when type inference is involved, expansions will end up using yet uninferred type params. + * + * For some macros this might be ok (thanks to TreeTypeSubstituter that replaces + * the occurrences of undetparams with their inferred values), but in general case this won't work. + * E.g. for reification simple substitution is not enough - we actually need to re-reify inferred types. + * + * Luckily, there exists a very simple way to fix the problem: delay macro expansion until everything is inferred. + * Here are the exact rules. Macro application gets delayed if any of its subtrees contain: + * 1) type vars (tpe.isInstanceOf[TypeVar]) // [Eugene] this check is disabled right now, because TypeVars seem to be created from undetparams anyways + * 2) undetparams (sym.isTypeParameter && !sym.isSkolem) + */ + var hasPendingMacroExpansions = false + private val delayed = perRunCaches.newWeakMap[Tree, (Context, collection.mutable.Set[Int])] + private def isDelayed(expandee: Tree) = delayed contains expandee + private def calculateUndetparams(expandee: Tree): collection.mutable.Set[Int] = + delayed.get(expandee).map(_._2).getOrElse { + val calculated = collection.mutable.Set[Int]() + expandee foreach (sub => { + def traverse(sym: Symbol) = if (sym != null && (undetparams contains sym.id)) calculated += sym.id + if (sub.symbol != null) traverse(sub.symbol) + if (sub.tpe != null) sub.tpe foreach (sub => traverse(sub.typeSymbol)) + }) + calculated + } + private val undetparams = perRunCaches.newSet[Int] + def notifyUndetparamsAdded(newUndets: List[Symbol]): Unit = undetparams ++= newUndets map (_.id) + def notifyUndetparamsInferred(undetNoMore: List[Symbol], inferreds: List[Type]): Unit = { + undetparams --= undetNoMore map (_.id) + if (!delayed.isEmpty) + delayed.toList foreach { + case (expandee, (_, undetparams)) if !undetparams.isEmpty => + undetparams --= undetNoMore map (_.id) + if (undetparams.isEmpty) { + hasPendingMacroExpansions = true + macroTrace("macro expansion is pending: ")(expandee) + } + case _ => + // do nothing + } + } + + /** Performs macro expansion on all subtrees of a given tree. + * Innermost macros are expanded first, outermost macros are expanded last. + * See the documentation for ``macroExpand'' for more information. + */ + def macroExpandAll(typer: Typer, expandee: Tree): Tree = + new Transformer { + override def transform(tree: Tree) = super.transform(tree match { + // todo. expansion should work from the inside out + case wannabe if (delayed contains wannabe) && calculateUndetparams(wannabe).isEmpty => + val (context, _) = delayed(wannabe) + delayed -= wannabe + macroExpand(newTyper(context), wannabe, WildcardType) + case _ => + tree + }) + }.transform(expandee) } |