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author | Adriaan Moors <adriaan.moors@epfl.ch> | 2012-03-02 17:33:34 +0100 |
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committer | Adriaan Moors <adriaan.moors@epfl.ch> | 2012-03-09 08:59:13 +0100 |
commit | b9082321219f78a86e80fcea2a71d96ee4beb397 (patch) | |
tree | f17c0b1dfb190cb23dfc5c01a17ece705c865198 /src | |
parent | 9ca7297588538c5f1ee6cd8e535be41dac9031a6 (diff) | |
download | scala-b9082321219f78a86e80fcea2a71d96ee4beb397.tar.gz scala-b9082321219f78a86e80fcea2a71d96ee4beb397.tar.bz2 scala-b9082321219f78a86e80fcea2a71d96ee4beb397.zip |
cleaned up inferConstructorInstance; same behavior
Diffstat (limited to 'src')
-rw-r--r-- | src/compiler/scala/tools/nsc/typechecker/Infer.scala | 91 |
1 files changed, 54 insertions, 37 deletions
diff --git a/src/compiler/scala/tools/nsc/typechecker/Infer.scala b/src/compiler/scala/tools/nsc/typechecker/Infer.scala index c09e535117..310198ec0c 100644 --- a/src/compiler/scala/tools/nsc/typechecker/Infer.scala +++ b/src/compiler/scala/tools/nsc/typechecker/Infer.scala @@ -1051,49 +1051,66 @@ trait Infer { * @param pt the expected result type of the instance */ def inferConstructorInstance(tree: Tree, undetparams: List[Symbol], pt0: Type) { - val pt = widen(pt0) - //println("infer constr inst "+tree+"/"+undetparams+"/"+pt0) - var restpe = tree.tpe.finalResultType - var tvars = undetparams map freshVar + val pt = widen(pt0) + val ptparams = freeTypeParamsOfTerms.collect(pt) + val ctorTp = tree.tpe + val resTp = ctorTp.finalResultType - /** Compute type arguments for undetermined params and substitute them in given tree. + debuglog("infer constr inst "+ tree +"/"+ undetparams +"/ pt= "+ pt +" pt0= "+ pt0 +" resTp: "+ resTp) + + /** Compute type arguments for undetermined params */ - def computeArgs = - try { - val targs = solvedTypes(tvars, undetparams, undetparams map varianceInType(restpe), - true, lubDepth(List(restpe, pt))) -// checkBounds(tree, NoPrefix, NoSymbol, undetparams, targs, "inferred ") -// no checkBounds here. If we enable it, test bug602 fails. - new TreeTypeSubstituter(undetparams, targs).traverse(tree) - } catch ifNoInstance{ msg => - NoConstructorInstanceError(tree, restpe, pt, msg) + def inferFor(pt: Type): Option[List[Type]] = { + val tvars = undetparams map freshVar + val resTpV = resTp.instantiateTypeParams(undetparams, tvars) + + if (resTpV <:< pt) { + try { + // debuglog("TVARS "+ (tvars map (_.constr))) + // look at the argument types of the primary constructor corresponding to the pattern + val variances = undetparams map varianceInType(ctorTp) + val targs = solvedTypes(tvars, undetparams, variances, true, lubDepth(List(resTp, pt))) + // checkBounds(tree, NoPrefix, NoSymbol, undetparams, targs, "inferred ") + // no checkBounds here. If we enable it, test bug602 fails. + // TODO: reinstate checkBounds, return params that fail to meet their bounds to undetparams + Some(targs) + } catch ifNoInstance { msg => + debuglog("NO INST "+ (tvars, tvars map (_.constr))) + NoConstructorInstanceError(tree, resTp, pt, msg) + None + } + } else { + debuglog("not a subtype: "+ resTpV +" </:< "+ pt) + None } - def instError = { - if (settings.debug.value) Console.println("ici " + tree + " " + undetparams + " " + pt) - if (settings.explaintypes.value) explainTypes(restpe.instantiateTypeParams(undetparams, tvars), pt) - ConstrInstantiationError(tree, restpe, pt) } - if (restpe.instantiateTypeParams(undetparams, tvars) <:< pt) { - computeArgs - } else if (isFullyDefined(pt)) { - debuglog("infer constr " + tree + ":" + restpe + ", pt = " + pt) - var ptparams = freeTypeParamsOfTerms.collect(pt) - debuglog("free type params = " + ptparams) - val ptWithWildcards = pt.instantiateTypeParams(ptparams, ptparams map (ptparam => WildcardType)) - tvars = undetparams map freshVar - if (restpe.instantiateTypeParams(undetparams, tvars) <:< ptWithWildcards) { - computeArgs - restpe = skipImplicit(tree.tpe.resultType) - debuglog("new tree = " + tree + ":" + restpe) - val ptvars = ptparams map freshVar - val pt1 = pt.instantiateTypeParams(ptparams, ptvars) - if (isPopulated(restpe, pt1)) { - ptvars foreach instantiateTypeVar - } else { if (settings.debug.value) Console.println("no instance: "); instError } - } else { if (settings.debug.value) Console.println("not a subtype " + restpe.instantiateTypeParams(undetparams, tvars) + " of " + ptWithWildcards); instError } - } else { if (settings.debug.value) Console.println("not fully defined: " + pt); instError } + + def inferForApproxPt = + if (isFullyDefined(pt)) { + inferFor(pt.instantiateTypeParams(ptparams, ptparams map (x => WildcardType))) flatMap { targs => + val ctorTpInst = tree.tpe.instantiateTypeParams(undetparams, targs) + val resTpInst = skipImplicit(ctorTpInst.finalResultType) + val ptvars = ptparams map freshVar + val ptV = pt.instantiateTypeParams(ptparams, ptvars) + + if (isPopulated(resTpInst, ptV)) { + ptvars foreach instantiateTypeVar + debuglog("isPopulated "+ resTpInst +", "+ ptV +" vars= "+ ptvars) + Some(targs) + } else None + } + } else None + + (inferFor(pt) orElse inferForApproxPt) map { targs => + new TreeTypeSubstituter(undetparams, targs).traverse(tree) + } getOrElse { + debugwarn("failed inferConstructorInstance for "+ tree +" : "+ tree.tpe +" under "+ undetparams +" pt = "+ pt +(if(isFullyDefined(pt)) " (fully defined)" else " (not fully defined)")) + // if (settings.explaintypes.value) explainTypes(resTp.instantiateTypeParams(undetparams, tvars), pt) + ConstrInstantiationError(tree, resTp, pt) + } } + def instBounds(tvar: TypeVar): (Type, Type) = { val tparam = tvar.origin.typeSymbol val instType = toOrigin(tvar.constr.inst) |