/* NSC -- new scala compiler
* Copyright 2005 LAMP/EPFL
* @author Martin Odersky
*/
// $Id$
package scala.tools.nsc.typechecker;
import nsc.util.ListBuffer;
import symtab.Flags._;
import scala.tools.util.Position;
/** Methods to create symbols and to enter them into scopes. */
abstract class Typers: Analyzer {
import global._;
import definitions._;
import posAssigner.atPos;
var appcnt = 0;
var idcnt = 0;
var selcnt = 0;
var implcnt = 0;
class TypeCheckPhase(prev: Phase) extends StdPhase(prev) {
def name = "typer";
val global: Typers.this.global.type = Typers.this.global;
def apply(unit: CompilationUnit): unit =
unit.body = newTyper(startContext.make(unit)).transformExpr(unit.body)
}
def newTyper(context: Context): Typer = new Typer(context);
class Typer(context0: Context) {
import context0.unit;
val infer = new Inferencer(context0) {
override def isCoercible(tp: Type, pt: Type): boolean =
context0.reportGeneralErrors && // this condition prevents chains of views
inferView(Position.NOPOS, tp, pt, false) != EmptyTree
}
private def inferView(pos: int, from: Type, to: Type, reportAmbiguous: boolean): Tree = {
if (settings.debug.value) System.out.println("infer view from " + from + " to " + to);//debug
val res = inferImplicit(pos, functionType(List(from), to), true, reportAmbiguous);
res
}
private def inferView(pos: int, from: Type, name: Name, reportAmbiguous: boolean): Tree = {
val to = refinedType(List(WildcardType), NoSymbol);
val psym = (if (name.isTypeName) to.symbol.newAbstractType(pos, name)
else to.symbol.newValue(pos, name)) setInfo WildcardType;
to.decls.enter(psym);
inferView(pos, from, to, reportAmbiguous)
}
import infer._;
private var namerCache: Namer = null;
def namer = {
if (namerCache == null || namerCache.context != context) namerCache = new Namer(context);
namerCache
}
var context = context0;
/** Mode constants
*/
private val NOmode = 0x000;
private val EXPRmode = 0x001; // these 3 modes are mutually exclusive.
private val PATTERNmode = 0x002;
private val TYPEmode = 0x004;
private val INCONSTRmode = 0x008; // orthogonal to above. When set we are
// in the body of a constructor
private val FUNmode = 0x10; // orthogonal to above. When set
// we are looking for a method or constructor
private val POLYmode = 0x020; // orthogonal to above. When set
// expression types can be polymorphic.
private val QUALmode = 0x040; // orthogonal to above. When set
// expressions may be packages and
// Java statics modules.
private val TAPPmode = 0x080; // Set for the function/type constructor part
// of a type application. When set we do not
// decompose PolyTypes.
private val stickyModes: int = EXPRmode | PATTERNmode | TYPEmode;
/** Report a type error.
* @param pos The position where to report the error
* @param ex The exception that caused the error */
def reportTypeError(pos: int, ex: TypeError): unit = {
if (settings.debug.value) ex.printStackTrace();
ex match {
case CyclicReference(sym, info: TypeCompleter) =>
info.tree match {
case ValDef(_, _, tpt, _) if (tpt.tpe == null) =>
error(pos, "recursive " + sym + " needs type")
case DefDef(_, _, _, _, tpt, _) if (tpt.tpe == null) =>
error(pos, "recursive " + sym + " needs result type")
case _ =>
error(pos, ex.getMessage())
}
case _ =>
error(pos, ex.getMessage())
}
}
/** Check that tree is a stable expression.
*/
def checkStable(tree: Tree): Tree =
if (treeInfo.isPureExpr(tree) || tree.tpe.isError) tree;
else errorTree(tree, "stable identifier required, but " + tree + " found.");
/** Check that type of given tree does not contain local or private components
*/
object checkNoEscaping extends TypeMap {
private var owner: Symbol = _;
private var scope: Scope = _;
private var badSymbol: Symbol = _;
/** Check that type `tree' does not refer to private components unless itself is wrapped
* in something private (`owner' tells where the type occurs). */
def privates[T <: Tree](owner: Symbol, tree: T): T = {
check(owner, EmptyScope, tree);
}
/** Check that type `tree' does not refer to entities defined in scope `scope'. */
def locals[T <: Tree](scope: Scope, tree: T): T = check(NoSymbol, scope, tree);
def check[T <: Tree](owner: Symbol, scope: Scope, tree: T): T = {
this.owner = owner;
this.scope = scope;
badSymbol = NoSymbol;
assert(tree.tpe != null, tree);//debug
apply(tree.tpe);
if (badSymbol == NoSymbol) tree
else {
error(tree.pos,
(if (badSymbol.hasFlag(PRIVATE)) "private " else "") + badSymbol +
" escapes its defining scope as part of type " + tree.tpe);
setError(tree)
}
}
override def apply(t: Type): Type = {
def checkNoEscape(sym: Symbol): unit = {
if (sym.hasFlag(PRIVATE)) {
var o = owner;
while (o != NoSymbol && o != sym.owner && !o.isLocal && !o.hasFlag(PRIVATE))
o = o.owner;
if (o == sym.owner) badSymbol = sym
} else if (sym.owner.isTerm) {
val e = scope.lookupEntry(sym.name);
if (e != null && e.sym == sym && e.owner == scope) badSymbol = e.sym
}
}
if (badSymbol == NoSymbol)
t match {
case TypeRef(_, sym, _) => checkNoEscape(sym)
case SingleType(_, sym) => checkNoEscape(sym)
case _ =>
}
mapOver(t)
}
}
def reenterValueParams(vparamss: List[List[ValDef]]): unit =
for (val vparams <- vparamss; val vparam <- vparams) context.scope enter vparam.symbol;
def reenterTypeParams(tparams: List[AbsTypeDef]): List[Symbol] =
for (val tparam <- tparams) yield { context.scope enter tparam.symbol; tparam.symbol }
def attrInfo(attr: Tree): AttrInfo = attr match {
case Apply(Select(New(tpt), nme.CONSTRUCTOR), args) =>
Pair(tpt.tpe, args map {
case Literal(value) =>
value
case arg =>
error(arg.pos, "attribute argument needs to be a constant; found: " + arg);
})
}
private def literalType(value: Any): Type =
if (value.isInstanceOf[unit]) UnitClass.tpe
else if (value.isInstanceOf[boolean]) BooleanClass.tpe
else if (value.isInstanceOf[byte]) ByteClass.tpe
else if (value.isInstanceOf[short]) ShortClass.tpe
else if (value.isInstanceOf[char]) CharClass.tpe
else if (value.isInstanceOf[int]) IntClass.tpe
else if (value.isInstanceOf[long]) LongClass.tpe
else if (value.isInstanceOf[float]) FloatClass.tpe
else if (value.isInstanceOf[double]) DoubleClass.tpe
else if (value.isInstanceOf[String]) StringClass.tpe
else if (value == null) AllRefClass.tpe
else throw new FatalError("unexpected literal value: " + value);
/** Perform the following adaptations of expression, pattern or type `tree' wrt to
* given mode `mode' and given prototype `pt':
* (1) Resolve overloading, unless mode contains FUNmode
* (2) Apply parameterless functions
* (3) Apply polymorphic types to fresh instances of their type parameters and
* store these instances in context.undetparams,
* unless followed by explicit type application.
* (4) Do the following to unapplied methods used as values:
* (4.1) If the method has only implicit parameters pass implicit arguments
* (4.2) otherwise, convert to function by eta-expansion,
* except if the method is a constructor, in which case we issue an error.
* (5) Convert a class type that serves as a constructor in a pattern as follows:
* (5.1) If this type refers to a case class, set tree's type to the unique
* instance of its primary constructor that is a subtype of the expected type.
* (5.2) Otherwise, if this type is a subtype of scala.Seq[A], set trees' type
* to a method type from a repeated parameter sequence type A* to the expected type.
* (6) Convert all other types to TypeTree nodes.
* (7) When in TYPEmode nut not FUNmode, check that types are fully parameterized
* (8) When in both EXPRmode and FUNmode, add apply method calls to values of object type.
* (9) If there are undetermined type variables and not POLYmode, infer expression instance
* Then, if tree's type is not a subtype of expected type, try the following adaptations:
* (10) If the expected type is byte, short or char, and the expression
* is an integer fitting in the range of that type, convert it to that type.
* (11) Widen numeric literals to their expected type, if necessary
* (12) When in mode EXPRmode, convert E to { E; () } if expected type is Scala.unit.
* (13) When in mode EXPRmode, apply a view
* If all this fails, error
*/
// def adapt(tree: Tree, mode: int, pt: Type): Tree = {
private def adapt(tree: Tree, mode: int, pt: Type): Tree = tree.tpe match {
case OverloadedType(pre, alts) if ((mode & FUNmode) == 0) => // (1)
inferExprAlternative(tree, pt);
adapt(tree, mode, pt)
case PolyType(List(), restpe) => // (2)
transform(constfold(tree.setType(restpe)), mode, pt);
case TypeRef(_, sym, List(arg))
if ((mode & EXPRmode) != 0 && sym == ByNameParamClass) => // (2)
adapt(tree setType arg, mode, pt);
case PolyType(tparams, restpe) if ((mode & TAPPmode) == 0) => // (3)
if (tree.symbol != null) {
if (settings.debug.value) System.out.println("adapting " + tree + " " + tree.symbol.tpe + " " + tree.symbol.getClass() + " " + tree.symbol.hasFlag(CASE));//debug
}
val tparams1 = cloneSymbols(tparams);
val tree1 = if (tree.isType) tree
else TypeApply(tree, tparams1 map (tparam =>
TypeTree() setPos tparam.pos setType tparam.tpe)) setPos tree.pos;
context.undetparams = context.undetparams ::: tparams1;
adapt(tree1 setType restpe.substSym(tparams, tparams1), mode, pt)
case mt: ImplicitMethodType if ((mode & (EXPRmode | FUNmode)) == EXPRmode) => // (4.1)
transform(applyImplicitArgs(tree), mode, pt)
case mt: MethodType if ((mode & (EXPRmode | FUNmode)) == EXPRmode &&
isCompatible(tree.tpe, pt)) => // (4.2)
val meth = treeInfo.methSymbol(tree);
if (meth.isConstructor) errorTree(tree, "missing arguments for " + meth)
else transform(etaExpand(tree), mode, pt)
case _ =>
if (tree.isType) {
val clazz = tree.tpe.symbol;
if ((mode & PATTERNmode) != 0) { // (5)
if (tree.tpe.isInstanceOf[MethodType]) {
tree // everything done already
} else {
clazz.initialize;
if (clazz.hasFlag(CASE)) { // (5.1)
val tree1 = TypeTree() setPos tree.pos
setType
clazz.primaryConstructor.tpe.asSeenFrom(tree.tpe.prefix, clazz.owner);
// tree.tpe.prefix.memberType(clazz.primaryConstructor); //!!!
inferConstructorInstance(tree1, clazz.unsafeTypeParams, pt);
tree1
} else if (clazz.isSubClass(SeqClass)) { // (5.2)
pt.baseType(clazz).baseType(SeqClass) match {
case TypeRef(pre, seqClass, args) =>
tree.setType(MethodType(List(typeRef(pre, RepeatedParamClass, args)), pt))
case NoType =>
errorTree(tree, "expected pattern type " + pt +
" does not conform to sequence " + clazz)
}
} else {
System.out.println("bad: " + clazz + ":" + tree.tpe + " " + flagsToString(clazz.flags) + clazz.hasFlag(CASE));//debug
errorTree(tree, clazz.toString() + " is neither a case class nor a sequence class")
}
}
} else if ((mode & FUNmode) != 0) {
tree
} else if (tree.symbol != null && !tree.symbol.unsafeTypeParams.isEmpty) { // (7)
errorTree(tree, "" + clazz + " takes type parameters");
} else tree match { // (6)
case TypeTree() => tree
case _ => TypeTree() setPos tree.pos setType tree.tpe
}
} else if ((mode & (EXPRmode | FUNmode)) == (EXPRmode | FUNmode) &&
((mode & TAPPmode) == 0 || tree.tpe.typeParams.isEmpty) &&
tree.tpe.member(nme.apply).filter(m => m.tpe.paramSectionCount > 0)
!= NoSymbol) { // (8)
transform(Select(tree, nme.apply), mode, pt)
} else if (!context.undetparams.isEmpty & (mode & POLYmode) == 0) { // (9)
val tparams = context.undetparams;
context.undetparams = List();
inferExprInstance(tree, tparams, pt);
tree
} else if (tree.tpe <:< pt) {
tree
} else {
val tree1 = constfold(tree, pt); // (10) (11)
if (tree1 != tree) transform(tree1, mode, pt);
else {
if ((mode & (EXPRmode | FUNmode)) == EXPRmode) {
assert(pt != null);
assert(tree1.tpe != null, tree1);
if (pt.symbol == UnitClass && tree1.tpe <:< AnyClass.tpe) // (12)
return transform(Block(List(tree), Literal(())), mode, pt)
else if (context.reportGeneralErrors) { // (13); the condition prevents chains of views
val coercion = inferView(tree.pos, tree.tpe, pt, true);
if (coercion != EmptyTree)
return transform(Apply(coercion, List(tree)) setPos tree.pos, mode, pt);
}
}
typeErrorTree(tree, tree.tpe, pt)
}
}
}
// System.out.println("adapt " + tree + ":" + tree.tpe + ", mode = " + mode + ", pt = " + pt);
// adapt(tree, mode, pt)
// }
private def completeSuperType(supertpt: Tree, tparams: List[Symbol], vparamss: List[List[ValDef]], superargs: List[Tree]): Type = {
tparams foreach context.scope.enter;
namer.enterValueParams(context.owner, vparamss);
val newTree = New(supertpt) setType
PolyType(tparams, appliedType(supertpt.tpe, tparams map (.tpe)));
val tree = transformExpr(atPos(supertpt.pos)(Apply(Select(newTree, nme.CONSTRUCTOR), superargs)));
if (settings.debug.value) System.out.println("superconstr " + tree + " co = " + context.owner);//debug
tree.tpe
}
def parentTypes(templ: Template): List[Tree] = {
var supertpt = transform(templ.parents.head, TYPEmode | FUNmode, WildcardType);
var mixins = templ.parents.tail map transformType;
// If first parent is trait, make it first mixin and add its superclass as first parent
if (supertpt.tpe.symbol != null && supertpt.tpe.symbol.initialize.isTrait) {
mixins = supertpt :: mixins;
supertpt = gen.TypeTree(supertpt.tpe.parents(0)) setPos supertpt.pos;
}
if (supertpt.symbol != null) {
val tparams = supertpt.symbol.typeParams;
if (!tparams.isEmpty) {
val constr @ DefDef(_, _, _, vparamss, _, Apply(_, superargs)) =
treeInfo.firstConstructor(templ.body);
val outercontext = context.outer.outer;
supertpt = gen.TypeTree(
newTyper(context.outer.outer.makeNewScope(constr, context.outer.outer.owner))
.completeSuperType(
supertpt,
tparams,
vparamss map (.map(.duplicate.asInstanceOf[ValDef])),
superargs map (.duplicate))) setPos supertpt.pos;
}
}
List.mapConserve(supertpt :: mixins)(tpt => checkNoEscaping.privates(context.owner, tpt))
}
/** Check that
* - all parents are class types,
* - first parent cluss is not a trait; following classes are traits,
* - final classes are not inherited,
* - sealed classes are only inherited by classes which are
* nested within definition of base class, or that occur within same
* statement sequence,
* - self-type of current class is a subtype of self-type of each parent class.
* - no two parents define same symbol.
*/
def validateParentClasses(parents: List[Tree], selfType: Type): unit = {
var c = context;
do { c = c.outer } while (c.owner == context.owner);
val defscope = c.scope;
def validateParentClass(parent: Tree, isFirst: boolean): unit =
if (!parent.tpe.isError) {
val psym = parent.tpe.symbol.initialize;
if (!psym.isClass)
error(parent.pos, "class type expected");
else if (!isFirst && !psym.isTrait)
error(parent.pos, "" + psym + " is not a trait; cannot be used as mixin");
else if (psym.hasFlag(FINAL))
error(parent.pos, "illegal inheritance from final class");
else if (psym.isSealed) {
// are we in same scope as base type definition?
val e = defscope.lookupEntry(psym.name);
if (!(e.sym == psym && e.owner == defscope)) {
// we are not within same statement sequence
var c = context;
while (c != NoContext && c.owner != psym) c = c.outer.enclClass;
if (c == NoContext) error(parent.pos, "illegal inheritance from sealed class")
}
}
if (!(selfType <:< parent.tpe.typeOfThis)) {
System.out.println(context.owner);//debug
System.out.println(context.owner.thisSym);//debug
error(parent.pos, "illegal inheritance;\n self-type " +
selfType + " does not conform to " + parent +
"'s selftype " + parent.tpe.typeOfThis);
if (settings.explaintypes.value) explainTypes(selfType, parent.tpe.typeOfThis);
}
if (parents exists (p => p != parent && p.tpe.symbol == psym && !psym.isError))
error(parent.pos, "" + psym + " is inherited twice")
}
if (!parents.isEmpty) {
validateParentClass(parents.head, true);
for (val p <- parents.tail) validateParentClass(p, false);
}
}
def transformClassDef(cdef: ClassDef): Tree = {
val clazz = cdef.symbol;
reenterTypeParams(cdef.tparams);
val tparams1 = List.mapConserve(cdef.tparams)(transformAbsTypeDef);
val tpt1 = checkNoEscaping.privates(clazz.thisSym, transformType(cdef.tpt));
val impl1 = newTyper(context.make(cdef.impl, clazz, new Scope()))
.transformTemplate(cdef.impl);
copy.ClassDef(cdef, cdef.mods, cdef.name, tparams1, tpt1, impl1) setType NoType
}
def transformModuleDef(mdef: ModuleDef): Tree = {
val clazz = mdef.symbol.moduleClass;
val impl1 = newTyper(context.make(mdef.impl, clazz, new Scope()))
.transformTemplate(mdef.impl);
copy.ModuleDef(mdef, mdef.mods, mdef.name, impl1) setType NoType
}
def addGetterSetter(stat: Tree): List[Tree] = stat match {
case vd @ ValDef(mods, _, _, _) if (mods & PRIVATE) == 0 =>
def setter: DefDef = {
val sym = vd.symbol;
val setter = sym.owner.info.decls.lookup(nme.SETTER_NAME(sym.name)).suchThat(.hasFlag(ACCESSOR));
atPos(vd.pos)(gen.DefDef(
setter, vparamss => gen.Assign(gen.mkRef(vparamss.head.head), gen.mkRef(sym))));
}
def getter: DefDef = {
val sym = vd.symbol;
val getter = sym.owner.info.decls.lookup(sym.name).suchThat(.hasFlag(ACCESSOR));
val result = atPos(vd.pos)(gen.DefDef(getter, vparamss => gen.mkRef(sym)));
checkNoEscaping.privates(result.symbol, result.tpt);
result
}
if ((mods & MUTABLE) != 0) List(stat, getter, setter) else List(stat, getter)
case _ =>
List(stat)
}
def transformTemplate(templ: Template): Template = {
templ setSymbol context.owner.newLocalDummy(templ.pos);
val parents1 = parentTypes(templ);
val selfType =
if (context.owner.isAnonymousClass)
refinedType(context.owner.info.parents, context.owner.owner)
else context.owner.typeOfThis;
validateParentClasses(parents1, selfType);
val body1 = templ.body flatMap addGetterSetter;
val body2 = transformStats(body1, templ.symbol);
copy.Template(templ, parents1, body2) setType context.owner.tpe
}
def transformValDef(vdef: ValDef): ValDef = {
val sym = vdef.symbol;
var tpt1 = checkNoEscaping.privates(sym, transformType(vdef.tpt));
val rhs1 =
if (vdef.rhs.isEmpty) vdef.rhs
else newTyper(context.make(vdef, sym)).transform(vdef.rhs, EXPRmode, tpt1.tpe.deconst);
copy.ValDef(vdef, vdef.mods, vdef.name, tpt1, rhs1) setType NoType
}
def transformDefDef(ddef: DefDef): DefDef = {
val meth = ddef.symbol;
reenterTypeParams(ddef.tparams);
reenterValueParams(ddef.vparamss);
val tparams1 = List.mapConserve(ddef.tparams)(transformAbsTypeDef);
val vparamss1 = List.mapConserve(ddef.vparamss)(vparams1 =>
List.mapConserve(vparams1)(transformValDef));
var tpt1 = checkNoEscaping.privates(meth, transformType(ddef.tpt));
val rhs1 =
if (ddef.name == nme.CONSTRUCTOR) {
if (!meth.hasFlag(SYNTHETIC) &&
!(meth.owner.isClass ||
meth.owner.isModuleClass ||
meth.owner.isAnonymousClass ||
meth.owner.isRefinementClass))
error(ddef.pos, "constructor definition not allowed here " + meth.owner);//debug
context.enclClass.owner.setFlag(INCONSTRUCTOR);
val result = transform(ddef.rhs, EXPRmode | INCONSTRmode, UnitClass.tpe);
context.enclClass.owner.resetFlag(INCONSTRUCTOR);
result
} else {
transform(ddef.rhs, EXPRmode, tpt1.tpe);
}
copy.DefDef(ddef, ddef.mods, ddef.name, tparams1, vparamss1, tpt1, rhs1) setType NoType
}
def transformAbsTypeDef(tdef: AbsTypeDef): AbsTypeDef = {
val lo1 = checkNoEscaping.privates(tdef.symbol, transformType(tdef.lo));
val hi1 = checkNoEscaping.privates(tdef.symbol, transformType(tdef.hi));
copy.AbsTypeDef(tdef, tdef.mods, tdef.name, lo1, hi1) setType NoType
}
def transformAliasTypeDef(tdef: AliasTypeDef): AliasTypeDef = {
reenterTypeParams(tdef.tparams);
val tparams1 = List.mapConserve(tdef.tparams)(transformAbsTypeDef);
val rhs1 = checkNoEscaping.privates(tdef.symbol, transformType(tdef.rhs));
copy.AliasTypeDef(tdef, tdef.mods, tdef.name, tparams1, rhs1) setType NoType
}
def transformLabelDef(ldef: LabelDef): LabelDef = {
val lsym = namer.enterInScope(
context.owner.newLabel(ldef.pos, ldef.name) setInfo MethodType(List(), UnitClass.tpe));
val rhs1 = transform(ldef.rhs, EXPRmode, UnitClass.tpe);
copy.LabelDef(ldef, ldef.name, ldef.params, rhs1) setType UnitClass.tpe
}
def transformBlock(block: Block, mode: int, pt: Type): Block = {
namer.enterSyms(block.stats);
val stats1 =
if ((mode & INCONSTRmode) != 0) {
val constrCall = transform(block.stats.head, mode, WildcardType);
context.enclClass.owner.resetFlag(INCONSTRUCTOR);
constrCall :: transformStats(block.stats.tail, context.owner);
} else {
transformStats(block.stats, context.owner)
}
val expr1 = transform(block.expr, mode & ~(FUNmode | QUALmode), pt);
val block1 = copy.Block(block, stats1, expr1) setType expr1.tpe.deconst;
if (block1.tpe.symbol.isAnonymousClass)
block1 setType refinedType(block1.tpe.parents, block1.tpe.symbol.owner);
if (isFullyDefined(pt)) block1 else checkNoEscaping.locals(context.scope, block1)
}
def transformCase(cdef: CaseDef, pattpe: Type, pt: Type): CaseDef = {
val pat1: Tree = transform(cdef.pat, PATTERNmode, pattpe);
val guard1: Tree = if (cdef.guard == EmptyTree) EmptyTree
else transform(cdef.guard, EXPRmode, BooleanClass.tpe);
val body1: Tree = transform(cdef.body, EXPRmode, pt);
copy.CaseDef(cdef, pat1, guard1, body1) setType body1.tpe
}
def transformFunction(fun: Function, mode: int, pt: Type): Function = {
val Triple(clazz, argpts, respt) = pt match {
case TypeRef(_, sym, argtps)
if (fun.vparams.length <= MaxFunctionArity && sym == FunctionClass(fun.vparams.length) ||
sym == PartialFunctionClass && fun.vparams.length == 1 && fun.body.isInstanceOf[Match]) =>
Triple(sym, argtps.init, argtps.last)
case _ =>
Triple(FunctionClass(fun.vparams.length), fun.vparams map (x => NoType), WildcardType)
}
val vparamSyms = List.map2(fun.vparams, argpts) { (vparam, argpt) =>
vparam match {
case ValDef(_, _, tpt, _) =>
if (tpt.isEmpty)
tpt.tpe =
if (argpt == NoType) { error(vparam.pos, "missing parameter type"); ErrorType }
else argpt
}
namer.enterSym(vparam);
vparam.symbol
}
val vparams1 = List.mapConserve(fun.vparams)(transformValDef);
val body1 = transform(fun.body, EXPRmode, respt);
copy.Function(fun, vparams1, body1)
setType typeRef(clazz.tpe.prefix, clazz, (vparamSyms map (.tpe)) ::: List(body1.tpe))
}
def transformRefinement(stats: List[Tree]): List[Tree] = {
namer.enterSyms(stats);
for (val stat <- stats) stat.symbol setFlag OVERRIDE;
transformStats(stats, NoSymbol);
}
def transformStats(stats: List[Tree], exprOwner: Symbol): List[Tree] =
List.mapConserve(stats) { stat =>
if (context.owner.isRefinementClass && !treeInfo.isDeclaration(stat))
errorTree(stat, "only declarations allowed here");
stat match {
case imp @ Import(_, _) =>
context = context.makeNewImport(imp);
EmptyTree
case _ =>
(if (!stat.isDef && exprOwner != context.owner)
newTyper(context.make(stat, exprOwner)) else this).transformExpr(stat)
}
}
private def transform1(tree: Tree, mode: int, pt: Type): Tree = {
def funmode = mode & stickyModes | FUNmode | POLYmode;
def transformCases(cases: List[CaseDef], pattp: Type): List[CaseDef] = {
List.mapConserve(cases)(cdef =>
newTyper(context.makeNewScope(tree, context.owner)).transformCase(cdef, pattp, pt))
}
def transformTypeApply(fun: Tree, args: List[Tree]): Tree = fun.tpe match {
case OverloadedType(pre, alts) =>
inferPolyAlternative(fun, args.length);
transformTypeApply(fun, args)
case PolyType(tparams, restpe) if (tparams.length != 0) =>
if (tparams.length == args.length) {
val targs = args map (.tpe);
checkBounds(tree.pos, tparams, targs, "");
if (settings.debug.value) System.out.println("type app " + tparams + " => " + targs + " = " + restpe.subst(tparams, targs));//debug
copy.TypeApply(tree, fun, args) setType restpe.subst(tparams, targs);
} else {
errorTree(tree, "wrong number of type parameters for " + treeSymTypeMsg(fun))
}
case ErrorType =>
setError(tree)
case _ =>
System.out.println(fun.toString() + " " + args);//debug
errorTree(tree, treeSymTypeMsg(fun) + " does not take type parameters.");
}
def transformApply(fun: Tree, args: List[Tree]): Tree = fun.tpe match {
case OverloadedType(pre, alts) =>
val args1 = List.mapConserve(args)(arg =>
transform(arg, mode & stickyModes, WildcardType));
inferMethodAlternative(fun, context.undetparams, args1 map (.tpe.deconst), pt);
transformApply(adapt(fun, funmode, WildcardType), args1);
case MethodType(formals0, restpe) =>
val formals = formalTypes(formals0, args.length);
if (formals.length != args.length) {
System.out.println("" + formals.length + " " + args.length);
errorTree(tree, "wrong number of arguments for " + treeSymTypeMsg(fun))
} else {
val tparams = context.undetparams;
context.undetparams = List();
if (tparams.isEmpty) {
val args1 = List.map2(args, formals) ((arg, formal) =>
transform(arg, mode & stickyModes, formal));
def ifPatternSkipFormals(tp: Type) = tp match {
case MethodType(_, rtp) if ((mode & PATTERNmode) != 0) => rtp
case _ => tp
}
val tree1 = copy.Apply(tree, fun, args1).setType(ifPatternSkipFormals(restpe));
val tree2 = constfold(tree1);
if (tree1 == tree2) tree2 else transform(tree2, mode, pt)
} else {
assert((mode & PATTERNmode) == 0); // this case cannot arise for patterns
val lenientTargs = protoTypeArgs(tparams, formals, restpe, pt);
val strictTargs = List.map2(lenientTargs, tparams)((targ, tparam) =>
if (targ == WildcardType) tparam.tpe else targ);
def transformArg(tree: Tree, formal: Type): Tree = {
val lenientPt = formal.subst(tparams, lenientTargs);
val tree1 = transform(tree, mode & stickyModes | POLYmode, lenientPt);
val argtparams = context.undetparams;
context.undetparams = List();
if (!argtparams.isEmpty) {
val strictPt = formal.subst(tparams, strictTargs);
inferArgumentInstance(tree1, argtparams, strictPt, lenientPt);
}
tree1
}
val args1 = List.map2(args, formals)(transformArg);
if (args1 exists (.tpe.isError)) setError(tree)
else {
if (settings.debug.value) System.out.println("infer method inst " + fun + ", tparams = " + tparams + ", args = " + args1.map(.tpe) + ", pt = " + pt + ", lobounds = " + tparams.map(.tpe.bounds.lo));//debug
val undetparams = inferMethodInstance(fun, tparams, args1, pt);
val result = transformApply(fun, args1);
context.undetparams = undetparams;
result
}
}
}
case ErrorType =>
setError(tree)
}
/** The qualifying class of a this or super with prefix `qual' */
def qualifyingClass(qual: Name): Symbol = {
if (qual == nme.EMPTY.toTypeName) {
val clazz = context.enclClass.owner;
if (!clazz.isPackageClass) clazz
else {
error(tree.pos, "" + tree + " can be used only in a class, object, or template");
NoSymbol
}
} else {
var c = context.enclClass;
while (c != NoContext && c.owner.name != qual) c = c.outer.enclClass;
if (c != NoContext) c.owner
else {
error(tree.pos, "" + qual + " is not an enclosing class");
NoSymbol
}
}
}
/** Attribute a selection where `tree' is `qual.name'.
* `qual' is already attributed.
*/
def transformSelect(qual: Tree, name: Name): Tree = {
val sym = qual.tpe.member(name);
if (sym == NoSymbol && qual.isTerm && (qual.symbol == null || qual.symbol.isValue)) {
val coercion = inferView(qual.pos, qual.tpe, name, true);
if (coercion != EmptyTree)
return transform(
copy.Select(tree, Apply(coercion, List(qual)) setPos qual.pos, name), mode, pt)
}
if (sym.info == NoType) {
System.out.println(qual);
System.out.println(qual.tpe.members);//debug
System.out.println(qual.tpe.member(name));//debug
errorTree(tree, decode(name) + " is not a member of " + qual.tpe.widen)
} else {
val tree1 = tree match {
case Select(_, _) => copy.Select(tree, qual, name)
case SelectFromTypeTree(_, _) => copy.SelectFromTypeTree(tree, qual, name);
}
stabilize(checkAccessible(tree1, sym, qual.tpe, qual), qual.tpe)
}
}
/** Attribute an identifier consisting of a simple name or an outer reference.
* @param tree The tree representing the identifier.
* @param name The name of the identifier.
* Transformations: (1) Prefix class members with this.
* (2) Change imported symbols to selections
*/
def transformIdent(name: Name): Tree = {
def ambiguousError(msg: String) =
error(tree.pos, "reference to " + name + " is ambiguous;\n" + msg);
var defSym: Symbol = NoSymbol; // the directly found symbol
var defEntry: ScopeEntry = null; // the scope entry of defSym, if defined in a local scope
var pre: Type = NoPrefix; // the prefix type of defSym, if a class member
var cx = context;
while (defSym == NoSymbol && cx != NoContext) {
pre = cx.enclClass.owner.thisType;
defEntry = cx.scope.lookupEntry(name);
if (defEntry != null)
defSym = defEntry.sym
else {
cx = cx.enclClass;
defSym = pre.member(name) filter (sym => context.isAccessible(sym, pre, false));
if (defSym == NoSymbol) cx = cx.outer;
}
}
val symDepth = if (defEntry == null) cx.depth
else cx.depth - (cx.scope.nestingLevel - defEntry.owner.nestingLevel);
var impSym: Symbol = NoSymbol; // the imported symbol
var imports = context.imports; // impSym != NoSymbol => it is imported from imports.head
while (impSym == NoSymbol && !imports.isEmpty && imports.head.depth > symDepth) {
impSym = imports.head.importedSymbol(name);
if (impSym == NoSymbol) imports = imports.tail;
}
// detect ambiguous definition/import,
// update `defSym' to be the final resolved symbol,
// update `pre' to be `sym's prefix type in case it is an imported member,
// and compute value of:
var qual: Tree = EmptyTree; // the qualififier tree if transformed tree is a select
// imported symbols take precedence over external package-owned symbols (hack?)
if (defSym.tpe != NoType && impSym.tpe != NoType && defSym.isExternal && defSym.owner.isPackageClass)
defSym = NoSymbol;
if (defSym.tpe != NoType) {
if (impSym.tpe != NoType)
ambiguousError(
"it is both defined in " + defSym.owner +
" and imported subsequently by \n" + imports.head);
else if (defSym.owner.isClass && !defSym.owner.isPackageClass && !defSym.isTypeParameter)
qual = atPos(tree.pos)(gen.mkQualifier(pre));
else
pre = NoPrefix;
} else {
if (impSym.tpe != NoType) {
var impSym1 = NoSymbol;
var imports1 = imports.tail;
def ambiguousImportError = ambiguousError(
"it is imported twice in the same scope by\n" + imports.head + "\nand " + imports1.head);
while (!imports1.isEmpty && imports1.head.depth == imports.head.depth) {
var impSym1 = imports1.head.importedSymbol(name);
if (impSym1 != NoSymbol) {
if (imports1.head.isExplicitImport(name)) {
if (imports.head.isExplicitImport(name)) ambiguousImportError;
impSym = impSym1;
imports = imports1;
} else if (!imports.head.isExplicitImport(name)) ambiguousImportError
}
imports1 = imports1.tail;
}
defSym = impSym;
qual = imports.head.qual;
pre = qual.tpe;
} else {
System.out.println(context);//debug
System.out.println(context.imports);//debug
error(tree.pos, "not found: " + decode(name));
defSym = context.owner.newErrorSymbol(name);
}
}
val tree1 = if (qual == EmptyTree) tree else Select(qual, name) setPos tree.pos;
stabilize(checkAccessible(tree1, defSym, pre, qual), pre);
}
/** Post-process an identifier or selection node, performing the following:
* (1) Turn trees of constant type into literals
* (2) Check that non-function pattern expressions are stable
* (3) Check that packages and static modules are not used as values
* (4) Turn tree type into stable type if possible and required by context. */
def stabilize(tree: Tree, pre: Type): Tree = tree.tpe match {
case ConstantType(base, value) => // (1)
Literal(value) setPos tree.pos setType tree.tpe
case PolyType(List(), restp @ ConstantType(base, value)) => // (1)
Literal(value) setPos tree.pos setType restp
case _ =>
if (tree.symbol.hasFlag(OVERLOADED) && (mode & FUNmode) == 0) {
inferExprAlternative(tree, pt)
}
if ((mode & (PATTERNmode | FUNmode)) == PATTERNmode && tree.isTerm) // (2)
checkStable(tree)
else if ((mode & (EXPRmode | QUALmode)) == EXPRmode && !tree.symbol.isValue) // (3)
errorTree(tree, tree.symbol.toString() + " is not a value");
else if (tree.symbol.isStable && pre.isStable && tree.tpe.symbol != ByNameParamClass &&
(pt.isStable || (mode & QUALmode) != 0 || tree.symbol.isModule)) // (4)
tree.setType(singleType(pre, tree.symbol))
else
tree
}
// begin transform1
val sym: Symbol = tree.symbol;
if (sym != null) sym.initialize;
//if (settings.debug.value && tree.isDef) global.log("transforming definition of " + sym);//DEBUG
tree match {
case PackageDef(name, stats) =>
val stats1 = newTyper(context.make(tree, sym.moduleClass, sym.info.decls))
.transformStats(stats, NoSymbol);
copy.PackageDef(tree, name, stats1) setType NoType
case cdef @ ClassDef(_, _, _, _, _) =>
newTyper(context.makeNewScope(tree, sym)).transformClassDef(cdef)
case mdef @ ModuleDef(_, _, _) =>
transformModuleDef(mdef)
case vdef @ ValDef(_, _, _, _) =>
transformValDef(vdef)
case ddef @ DefDef(_, _, _, _, _, _) =>
newTyper(context.makeNewScope(tree, sym)).transformDefDef(ddef)
case tdef @ AbsTypeDef(_, _, _, _) =>
transformAbsTypeDef(tdef)
case tdef @ AliasTypeDef(_, _, _, _) =>
newTyper(context.makeNewScope(tree, sym)).transformAliasTypeDef(tdef)
case ldef @ LabelDef(_, List(), _) =>
newTyper(context.makeNewScope(tree, context.owner)).transformLabelDef(ldef)
case Attributed(attr, defn) =>
val attr1 = transform(attr, EXPRmode, AttributeClass.tpe);
val defn1 = transform(defn, mode, pt);
val existing = attributes.get(defn1.symbol) match {
case None => List()
case Some(attrs) => attrs
}
attributes(defn1.symbol) = attrInfo(attr1) :: existing;
defn1
case DocDef(comment, defn) =>
transform(defn, mode, pt);
case block @ Block(_, _) =>
newTyper(context.makeNewScope(tree, context.owner))
.transformBlock(block, mode, pt)
case Sequence(elems) =>
val elems1 = List.mapConserve(elems)(elem => transform(elem, mode, pt));
copy.Sequence(tree, elems1) setType pt
case Alternative(alts) =>
val alts1 = List.mapConserve(alts)(alt => transform(alt, mode, pt));
copy.Alternative(tree, alts1) setType pt
case Bind(name, body) =>
val body1 = transform(body, mode, pt);
val vble = context.owner.newValue(tree.pos, name).setInfo(
if (treeInfo.isSequenceValued(body)) seqType(pt) else body1.tpe);
//todo: check whether we can always use body1.tpe
namer.enterInScope(vble);
copy.Bind(tree, name, body1) setSymbol vble setType pt
case fun @ Function(_, _) =>
newTyper(context.makeNewScope(tree, context.owner))
.transformFunction(fun, mode, pt)
case Assign(lhs, rhs) =>
def isGetter(sym: Symbol) = sym.info match {
case PolyType(List(), _) => sym.owner.isClass && !sym.isStable
case _ => false
}
val lhs1 = transformExpr(lhs);
val varsym = lhs1.symbol;
if (varsym != null && isGetter(varsym)) {
lhs1 match {
case Select(qual, name) =>
transform(
Apply(
Select(qual, nme.SETTER_NAME(name)) setPos lhs.pos,
List(rhs)), mode, pt) setPos tree.pos
}
} else if (varsym != null && varsym.isVariable) {
val rhs1 = transform(rhs, EXPRmode, lhs1.tpe);
copy.Assign(tree, lhs1, rhs1) setType UnitClass.tpe;
} else {
System.out.println("" + lhs1 + " " + varsym + " " + flagsToString(varsym.flags));//debug
if (!lhs1.tpe.isError) error(tree.pos, "assignment to non-variable ");
setError(tree)
}
case If(cond, thenp, elsep) =>
val cond1 = transform(cond, EXPRmode, BooleanClass.tpe);
if (elsep.isEmpty) {
val thenp1 = transform(thenp, EXPRmode, UnitClass.tpe);
copy.If(tree, cond1, thenp1, elsep) setType UnitClass.tpe
} else {
val thenp1 = transform(thenp, EXPRmode, pt);
val elsep1 = transform(elsep, EXPRmode, pt);
copy.If(tree, cond1, thenp1, elsep1) setType lub(List(thenp1.tpe, elsep1.tpe));
}
case Match(selector, cases) =>
val selector1 = transformExpr(selector);
val cases1 = transformCases(cases, selector1.tpe);
copy.Match(tree, selector1, cases1) setType lub(cases1 map (.tpe))
case Return(expr) =>
val enclFun = context.owner.enclMethod;
if (!enclFun.isMethod || enclFun.isConstructor)
errorTree(tree, "return outside method definition")
else if (!context.owner.hasFlag(INITIALIZED))
errorTree(tree, "method " + context.owner + " has return statement; needs result type")
else {
val expr1: Tree = transform(expr, EXPRmode, enclFun.tpe.resultType);
copy.Return(tree, expr1) setSymbol enclFun setType AllClass.tpe;
}
case Try(block, catches, finalizer) =>
val block1 = transform(block, EXPRmode, pt);
val catches1 = transformCases(catches, ThrowableClass.tpe);
val finalizer1 = if (finalizer.isEmpty) finalizer
else transform(finalizer, EXPRmode, UnitClass.tpe);
copy.Try(tree, block1, catches1, finalizer1)
setType lub(block1.tpe :: (catches1 map (.tpe)))
case Throw(expr) =>
val expr1 = transform(expr, EXPRmode, ThrowableClass.tpe);
copy.Throw(tree, expr1) setType AllClass.tpe
case New(tpt: Tree) =>
var tpt1 = transform(tpt, TYPEmode | FUNmode, WildcardType);
if (tpt1.symbol != null && !tpt1.symbol.typeParams.isEmpty) {
context.undetparams = cloneSymbols(tpt1.symbol.unsafeTypeParams);
tpt1 = TypeTree()
setPos tpt1.pos
setType appliedType(tpt1.tpe, context.undetparams map (.tpe));
}
copy.New(tree, tpt1).setType(tpt1.tpe)
case Typed(expr, tpt @ Ident(name)) if (name == nme.WILDCARD_STAR.toTypeName) =>
val expr1 = transform(expr, mode & stickyModes, seqType(pt));
expr1.tpe.baseType(SeqClass) match {
case TypeRef(_, _, List(elemtp)) =>
copy.Typed(tree, expr1, tpt setType elemtp) setType elemtp
case _ =>
setError(tree)
}
case Typed(expr, tpt) =>
val tpt1 = transformType(tpt);
val expr1 = transform(expr, mode & stickyModes, tpt1.tpe);
copy.Typed(tree, expr1, tpt1) setType tpt1.tpe
case TypeApply(fun, args) =>
val args1 = List.mapConserve(args)(transformType);
// do args first in order to maintain conext.undetparams on the function side.
transformTypeApply(transform(fun, funmode | TAPPmode, WildcardType), args1)
case Apply(fun, args) =>
val funpt = if ((mode & PATTERNmode) != 0) pt else WildcardType;
var fun1 = transform(fun, funmode, funpt);
// if function is overloaded, filter all alternatives that match
// number of arguments and expected result type.
if (settings.debug.value) System.out.println("trans app " + fun1 + ":" + fun1.symbol + ":" + fun1.tpe + " " + args);//debug
if (fun1.hasSymbol && fun1.symbol.hasFlag(OVERLOADED)) {
val argtypes = args map (arg => AllClass.tpe);
val pre = fun1.symbol.tpe.prefix;
val sym = fun1.symbol filter (alt =>
isApplicable(context.undetparams, pre.memberType(alt), argtypes, pt));
if (sym != NoSymbol)
fun1 = adapt(fun1 setSymbol sym setType pre.memberType(sym), funmode, WildcardType)
}
appcnt = appcnt + 1;
transformApply(fun1, args)
case Super(qual, mix) =>
val clazz = qualifyingClass(qual);
if (clazz == NoSymbol) setError(tree)
else {
val owntype =
if (mix == nme.EMPTY.toTypeName) intersectionType(clazz.info.parents)
else {
val ps = clazz.info.parents dropWhile (p => p.symbol.name != mix);
if (ps.isEmpty) {
System.out.println(clazz.info.parents map (.symbol.name));//debug
error(tree.pos, "" + mix + " does not name a base class of " + clazz);
ErrorType
} else ps.head
}
tree setSymbol clazz setType owntype
}
case This(qual) =>
val clazz = qualifyingClass(qual);
if (clazz == NoSymbol) setError(tree)
else {
val owntype = if (pt.isStable || (mode & QUALmode) != 0) clazz.thisType
else clazz.typeOfThis;
tree setSymbol clazz setType owntype
}
case Select(qual @ Super(_, _), nme.CONSTRUCTOR) =>
val qual1 = transform(qual, EXPRmode | QUALmode | POLYmode, WildcardType);
// the qualifier type of a supercall constructor is its first parent class
qual1.tpe match {
case RefinedType(parents, _) => qual1.tpe = parents.head;
case _ =>
}
transformSelect(qual1, nme.CONSTRUCTOR);
case Select(qual, name) =>
selcnt = selcnt + 1;
assert (name != nme.CONSTRUCTOR || !qual.isInstanceOf[Super], tree);//debug
var qual1 = transform(qual, EXPRmode | QUALmode | POLYmode, WildcardType);
if (name.isTypeName) qual1 = checkStable(qual1);
transformSelect(qual1, name);
case Ident(name) =>
idcnt = idcnt + 1;
if (name == nme.WILDCARD && (mode & (PATTERNmode | FUNmode)) == PATTERNmode)
tree setType pt
else
transformIdent(name);
case Literal(value) =>
tree setType ConstantType(literalType(value), value)
case SingletonTypeTree(ref) =>
val ref1 = checkStable(transform(ref, EXPRmode | QUALmode, AnyRefClass.tpe));
tree setType ref1.tpe.resultType;
case SelectFromTypeTree(qual, selector) =>
tree setType transformSelect(transformType(qual), selector).tpe
case CompoundTypeTree(templ: Template) =>
tree setType {
val parents1 = List.mapConserve(templ.parents)(transformType);
if (parents1 exists (.tpe.isError)) ErrorType
else {
val decls = new Scope();
val self = refinedType(parents1 map (.tpe), context.enclClass.owner, decls);
newTyper(context.make(tree, self.symbol, new Scope())).transformRefinement(templ.body);
self
}
}
case AppliedTypeTree(tpt, args) =>
val tpt1 = transform(tpt, mode | FUNmode | TAPPmode, WildcardType);
val tparams = tpt1.tpe.symbol.typeParams;
val args1 = List.mapConserve(args)(transformType);
if (tpt1.tpe.isError)
setError(tree)
else if (tparams.length == args1.length)
tree setType appliedType(tpt1.tpe, args1 map (.tpe))
else if (tparams.length == 0)
errorTree(tree, "" + tpt1.tpe + " does not take type parameters")
else
errorTree(tree, "wrong number of type arguments for " + tpt1.tpe)
}
}
def transform(tree: Tree, mode: int, pt: Type): Tree =
try {
if (settings.debug.value) assert(pt != null, tree);//debug
if (settings.debug.value) System.out.println("transforming " + tree);//debug
val tree1 = if (tree.tpe != null) tree else transform1(tree, mode, pt);
if (tree1.isEmpty) tree1 else adapt(tree1, mode, pt)
} catch {
case ex: TypeError =>
reportTypeError(tree.pos, ex);
setError(tree)
case ex: Throwable =>
if (true || settings.debug.value)//!!!
System.out.println("exception when tranforming " + tree + ", pt = " + pt);
throw(ex)
}
def transformExpr(tree: Tree): Tree = transform(tree, EXPRmode, WildcardType);
def transformQualExpr(tree: Tree): Tree = transform(tree, EXPRmode | QUALmode, WildcardType);
def transformType(tree: Tree) = transform(tree, TYPEmode, WildcardType);
/* -- Views --------------------------------------------------------------- */
private def transformImplicit(pos: int, info: ImplicitInfo, pt: Type): Tree =
if (isCompatible(info.tpe, pt)) {
implcnt = implcnt + 1;
var tree: Tree = EmptyTree;
try {
tree = transform1(Ident(info.name) setPos pos, EXPRmode, pt);
if (settings.debug.value) System.out.println("transformed implicit " + tree + ":" + tree.tpe + ", pt = " + pt);//debug
if (settings.debug.value) assert(isCompatible(tree.tpe, pt), "bad impl " + info.tpe + " " + tree.tpe + " " + pt);//debug
val tree1 = adapt(tree, EXPRmode, pt);
if (settings.debug.value) System.out.println("adapted implicit " + tree.symbol + ":" + info.sym);//debug
if (info.sym == tree.symbol) tree1 else EmptyTree
} catch {
case ex: TypeError =>
if (settings.debug.value)
System.out.println(tree.toString() + " is not a valid implicit value because:\n" + ex.getMessage());
EmptyTree
}
} else EmptyTree;
private def inferImplicit(pos: int, pt: Type, isView: boolean, reportAmbiguous: boolean): Tree = {
def isBetter(sym1: Symbol, tpe1: Type, sym2: Symbol, tpe2: Type): boolean =
(sym1.owner != sym2.owner) && (sym1.owner isSubClass sym2.owner) && (tpe1 matches tpe2);
val tc = newTyper(context.makeImplicit(reportAmbiguous));
var iss = context.implicitss;
var tree: Tree = EmptyTree;
while (tree == EmptyTree && !iss.isEmpty) {
var is = iss.head;
if (settings.debug.value) System.out.println("testing " + is.head.sym + ":" + is.head.tpe);//debug
iss = iss.tail;
while (!is.isEmpty) {
tree = tc.transformImplicit(pos, is.head, pt);
val is0 = is;
is = is.tail;
if (tree != EmptyTree) {
while (!is.isEmpty) {
val tree1 = tc.transformImplicit(pos, is.head, pt);
if (tree1 != EmptyTree) {
if (isBetter(is.head.sym, tree1.tpe, is0.head.sym, tree.tpe))
tree = tree1
else if (!isBetter(is0.head.sym, tree.tpe, is.head.sym, tree1.tpe))
error(
pos,
"ambiguous implicit value:\n" +
" both " + is0.head.sym + is0.head.sym.locationString + " of type " + tree.tpe +
"\n and" + is.head.sym + is.head.sym.locationString + " of type " + tree1.tpe +
(if (isView)
"\n are possible conversion functions from " +
pt.typeArgs(0) + " to " + pt.typeArgs(1)
else
"\n match expected type " + pt));
}
is = is.tail
}
}
}
}
tree
}
def applyImplicitArgs(tree: Tree): Tree = tree.tpe match {
case MethodType(formals, _) =>
def implicitArg(pt: Type) = {
val arg = inferImplicit(tree.pos, pt, false, true);
if (arg != EmptyTree) arg
else errorTree(tree, "no implicit argument matching parameter type " + pt + " was found.")
}
Apply(tree, formals map implicitArg) setPos tree.pos
}
}
}