package dotty.tools
package dotc
package typer
import core._
import ast._
import Trees._
import Constants._
import StdNames._
import Scopes._
import Denotations._
import Inferencing._
import Contexts._
import Symbols._
import Types._
import SymDenotations._
import Annotations._
import Names._
import NameOps._
import Flags._
import Decorators._
import ErrorReporting._
import Inferencing.{FunProto, PolyProto, Compatibility, normalize}
import EtaExpansion.etaExpand
import util.Positions._
import util.common._
import util.SourcePosition
import collection.mutable
import annotation.tailrec
import Implicits._
import util.Stats.track
import language.implicitConversions
trait TyperContextOps { ctx: Context => }
object Typer {
/** The precedence of bindings which determines which of several bindings will be
* accessed by an Ident.
*/
object BindingPrec {
val definition = 4
val namedImport = 3
val wildImport = 2
val packageClause = 1
val nothingBound = 0
def isImportPrec(prec: Int) = prec == namedImport || prec == wildImport
}
}
class Typer extends Namer with Applications with Implicits {
import Typer._
import tpd.{cpy => _, _}
import untpd.cpy
/** A temporary data item valid for a single typed ident:
* The set of all root import symbols that have been
* encountered as a qualifier of an import so far.
* Note: It would be more proper to move importedFromRoot into typedIdent.
* We should check that this has no performance degradation, however.
*/
private var importedFromRoot: Set[Symbol] = Set()
/** A denotation exists really if it exists and does not point to a stale symbol. */
def reallyExists(denot: Denotation)(implicit ctx: Context): Boolean =
denot.exists && {
val sym = denot.symbol
(sym eq NoSymbol) || !sym.isAbsent
}
/** The type of a selection with `name` of a tree with type `site`.
*/
def selectionType(site: Type, name: Name, pos: Position)(implicit ctx: Context): Type = {
val refDenot = site.member(name)
if (reallyExists(refDenot)) site.select(name, refDenot)
else {
if (!site.isErroneous)
ctx.error(
if (name == nme.CONSTRUCTOR) i"$site does not have a constructor"
else i"$name is not a member of $site", pos)
ErrorType
}
}
/** The selection type, which is additionally checked for accessibility.
*/
def checkedSelectionType(qual1: Tree, tree: untpd.RefTree)(implicit ctx: Context): Type = {
val ownType = selectionType(qual1.tpe.widenIfUnstable, tree.name, tree.pos)
checkAccessible(ownType, qual1.isInstanceOf[Super], tree.pos)
}
/** Check that Java statics and packages can only be used in selections.
*/
def checkValue(tpe: Type, proto: Type, pos: Position)(implicit ctx: Context): Unit =
if (!proto.isInstanceOf[SelectionProto]) {
val sym = tpe.termSymbol
if ((sym is Package) || (sym is JavaModule)) ctx.error(i"$sym is not a value", pos)
}
/** If `tpe` is a named type, check that its denotation is accessible in the
* current context. Return the type with those alternatives as denotations
* which are accessible.
*/
def checkAccessible(tpe: Type, superAccess: Boolean, pos: Position)(implicit ctx: Context): Type = tpe match {
case tpe: NamedType =>
val pre = tpe.prefix
val name = tpe.name
val d = tpe.denot.accessibleFrom(pre, superAccess)
if (!d.exists) {
val d2 = pre.nonPrivateMember(name)
if (reallyExists(d2))
checkAccessible(pre.select(name, d2), superAccess, pos)
else {
val alts = tpe.denot.alternatives.map(_.symbol).filter(_.exists)
val where = pre.typeSymbol
val what = alts match {
case Nil =>
name.toString
case sym :: Nil =>
if (sym.owner == where) sym.show else sym.showLocated
case _ =>
i"none of the overloaded alternatives named $name"
}
val whyNot = new StringBuffer
val addendum =
alts foreach (_.isAccessibleFrom(pre, superAccess, whyNot))
if (!tpe.isError)
ctx.error(i"$what cannot be accessed from $pre.$whyNot", pos)
ErrorType
}
}
else if (d.symbol is TypeParamAccessor) // always dereference type param accessors
checkAccessible(d.info.bounds.hi, superAccess, pos)
else
tpe withDenot d
case _ =>
tpe
}
/** The qualifying class of a this or super with prefix `qual` (which might be empty).
* @param packageOk The qualifier may refer to a package.
*/
def qualifyingClass(tree: untpd.Tree, qual: Name, packageOK: Boolean)(implicit ctx: Context): Symbol =
ctx.owner.enclosingClass.ownersIterator.find(o => qual.isEmpty || o.isClass && o.name == qual) match {
case Some(c) if packageOK || !(c is Package) =>
c
case _ =>
ctx.error(
if (qual.isEmpty) tree.show + " can be used only in a class, object, or template"
else qual.show + " is not an enclosing class", tree.pos)
NoSymbol
}
/** Attribute an identifier consisting of a simple name or wildcard
*
* @param tree The tree representing the identifier.
* Transformations: (1) Prefix class members with this.
* (2) Change imported symbols to selections.
* (3) Change pattern Idents id (but not wildcards) to id @ _
*/
def typedIdent(tree: untpd.Ident, pt: Type)(implicit ctx: Context): Tree = track("typedIdent") {
val name = tree.name
/** Method is necessary because error messages need to bind to
* to typedIdent's context which is lost in nested calls to findRef
*/
def error(msg: => String, pos: Position) = ctx.error(msg, pos)
/** Is this import a root import that has been shadowed by an explicit
* import in the same program?
*/
def isDisabled(imp: ImportInfo, site: Type): Boolean = {
val qualSym = site.termSymbol
if (defn.RootImports contains qualSym) {
if (imp.isRootImport && (importedFromRoot contains qualSym)) return true
importedFromRoot += qualSym
}
false
}
/** Does this identifier appear as a constructor of a pattern? */
def isPatternConstr =
if (ctx.mode.isExpr && (ctx.outer.mode is Mode.Pattern))
ctx.outer.tree match {
case Apply(`tree`, _) => true
case _ => false
}
else false
/** A symbol qualifies if it really exists. In addition,
* if we are in a constructor of a pattern, we ignore all definitions
* which are methods and not accessors (note: if we don't do that
* case x :: xs in class List would return the :: method).
*/
def qualifies(denot: Denotation): Boolean =
reallyExists(denot) && !(
pt.isInstanceOf[UnapplySelectionProto] &&
(denot.symbol is (Method, butNot = Accessor)))
/** Find the denotation of enclosing `name` in given context `ctx`.
* @param previous A denotation that was found in a more deeply nested scope,
* or else `NoDenotation` if nothing was found yet.
* @param prevPrec The binding precedence of the previous denotation,
* or else `nothingBound` if nothing was found yet.
* @param prevCtx The context of the previous denotation,
* or else `NoContext` if nothing was found yet.
*/
def findRef(previous: Type, prevPrec: Int, prevCtx: Context)(implicit ctx: Context): Type = {
import BindingPrec._
/** A string which explains how something was bound; Depending on `prec` this is either
* imported by <tree>
* or defined in <symbol>
*/
def bindingString(prec: Int, whereFound: Context, qualifier: String = "") =
if (prec == wildImport || prec == namedImport) i"imported$qualifier by ${whereFound.importInfo}"
else i"defined$qualifier in ${whereFound.owner}"
/** Check that any previously found result from an inner context
* does properly shadow the new one from an outer context.
*/
def checkNewOrShadowed(found: Type, newPrec: Int): Type =
if (!previous.exists || (previous == found)) found
else if (newPrec == definition && (prevCtx.scope eq ctx.scope)) {
// special case: definitions beat imports if both are in contexts with same scope
found
}
else {
if (!previous.isError && !found.isError) {
error(
i"""reference to $name is ambiguous;
|it is both ${bindingString(newPrec, ctx, "")}
|and ${bindingString(prevPrec, prevCtx, " subsequently")}""".stripMargin,
tree.pos)
}
previous
}
/** The type representing a named import with enclosing name when imported
* from given `site` and `selectors`.
*/
def namedImportRef(site: Type, selectors: List[untpd.Tree]): Type = {
def checkUnambiguous(found: Type) = {
val other = namedImportRef(site, selectors.tail)
if (other.exists && found.exists && (found != other))
error(i"reference to $name is ambiguous; it is imported twice in ${ctx.tree}",
tree.pos)
found
}
val Name = name.toTermName
selectors match {
case Pair(Ident(from), Ident(Name)) :: rest =>
checkUnambiguous(selectionType(site, name, tree.pos))
case Ident(Name) :: rest =>
checkUnambiguous(selectionType(site, name, tree.pos))
case _ :: rest =>
namedImportRef(site, rest)
case nil =>
NoType
}
}
/** The type representing a wildcard import with enclosing name when imported
* from given import info
*/
def wildImportRef(imp: ImportInfo): Type = {
if (imp.isWildcardImport && !(imp.excluded contains name.toTermName)) {
val pre = imp.site
if (!isDisabled(imp, pre)) {
val denot = pre.member(name)
if (reallyExists(denot)) return pre.select(name, denot)
}
}
NoType
}
/** Is (some alternative of) the given predenotation `denot`
* defined in current compilation unit?
*/
def isDefinedInCurrentUnit(denot: Denotation): Boolean = denot match {
case MultiDenotation(d1, d2) => isDefinedInCurrentUnit(d1) || isDefinedInCurrentUnit(d2)
case denot: SingleDenotation => denot.symbol.sourceFile == ctx.source
}
/** Is `denot` the denotation of a self symbol? */
def isSelfDenot(denot: Denotation) = denot match {
case denot: SymDenotation => denot is SelfName
case _ => false
}
// begin findRef
if (ctx.scope == null) previous
else {
val outer = ctx.outer
if ((ctx.scope ne outer.scope) || (ctx.owner ne outer.owner)) {
val defDenot = ctx.denotNamed(name)
if (qualifies(defDenot)) {
val curOwner = ctx.owner
val found =
if (isSelfDenot(defDenot)) curOwner.thisType
else curOwner.thisType.select(name, defDenot)
if (!(curOwner is Package) || (defDenot.symbol is Package) || isDefinedInCurrentUnit(defDenot))
return checkNewOrShadowed(found, definition) // no need to go further out, we found highest prec entry
else if (prevPrec < packageClause)
return findRef(found, packageClause, ctx)(outer)
}
}
val curImport = ctx.importInfo
if (curImport != null && curImport.isRootImport && previous.exists) return previous
if (prevPrec < namedImport && (curImport ne outer.importInfo)) {
val namedImp = namedImportRef(curImport.site, curImport.selectors)
if (namedImp.exists)
return findRef(checkNewOrShadowed(namedImp, namedImport), namedImport, ctx)(outer)
if (prevPrec < wildImport) {
val wildImp = wildImportRef(curImport)
if (wildImp.exists)
return findRef(checkNewOrShadowed(wildImp, wildImport), wildImport, ctx)(outer)
}
}
findRef(previous, prevPrec, prevCtx)(outer)
}
}
// begin typedIdent
def kind = if (name.isTermName) "" else "type "
println(s"typed ident $kind$name in ${ctx.owner}") // !!! DEBUG
if (ctx.mode is Mode.Pattern) {
if (name == nme.WILDCARD)
return tree.withType(pt)
if (isVarPattern(tree))
return typed(untpd.Bind(name, untpd.Ident(nme.WILDCARD)).withPos(tree.pos), pt)
}
val saved = importedFromRoot
importedFromRoot = Set.empty
val rawType =
try findRef(NoType, BindingPrec.nothingBound, NoContext)
finally importedFromRoot = saved
checkValue(rawType, pt, tree.pos)
val ownType =
if (rawType.exists)
checkAccessible(rawType, superAccess = false, tree.pos)
else {
error(i"not found: $kind$name", tree.pos)
ErrorType
}
tree.withType(ownType.underlyingIfRepeated)
}
def typedSelect(tree: untpd.Select, pt: Type)(implicit ctx: Context): Tree = track("typedSelect") {
val qual1 = typedExpr(tree.qualifier, selectionProto(tree.name, pt))
val ownType = checkedSelectionType(qual1, tree)
checkValue(ownType, pt, tree.pos)
cpy.Select(tree, qual1, tree.name).withType(ownType)
}
def typedThis(tree: untpd.This)(implicit ctx: Context): Tree = track("typedThis") {
val cls = qualifyingClass(tree, tree.qual, packageOK = false)
tree.withType(cls.thisType)
}
def typedSuper(tree: untpd.Super, pt: Type)(implicit ctx: Context): Tree = track("typedSuper") {
val mix = tree.mix
val qual1 = typed(tree.qual)
val cls = qual1.tpe.widen.typeSymbol
def findMixinSuper(site: Type): Type = site.parents filter (_.name == mix) match {
case p :: Nil =>
p
case Nil =>
errorType(i"$mix does not name a parent class of $cls", tree.pos)
case p :: q :: _ =>
errorType(s"ambiguous parent class qualifier", tree.pos)
}
val owntype =
if (!mix.isEmpty) findMixinSuper(cls.info)
else pt match {
case pt: SelectionProto if pt.name == nme.CONSTRUCTOR => cls.info.firstParent
case _ => cls.info.parents.reduceLeft((x: Type, y: Type) => AndType(x, y))
}
cpy.Super(tree, qual1, mix).withType(SuperType(cls.thisType, owntype))
}
def typedLiteral(tree: untpd.Literal)(implicit ctx: Context) = track("typedLiteral") {
tree.withType {
tree.const.tag match {
case UnitTag => defn.UnitType
case NullTag => defn.NullType
case _ => ConstantType(tree.const)
}
}
}
def typedNew(tree: untpd.New, pt: Type)(implicit ctx: Context) = track("typedNew") {
tree.tpt match {
case templ: untpd.Template =>
import untpd._
val x = tpnme.ANON_CLASS
val clsDef = TypeDef(Modifiers(Final), x, templ)
typed(cpy.Block(tree, clsDef :: Nil, New(Ident(x), Nil)), pt)
case _ =>
val tpt1 = typedType(tree.tpt)
val clsref = checkClassTypeWithStablePrefix(tpt1.tpe, tpt1.pos)
// todo in a later phase: checkInstantiatable(cls, tpt1.pos)
cpy.New(tree, tpt1).withType(tpt1.tpe)
}
}
def typedPair(tree: untpd.Pair, pt: Type)(implicit ctx: Context) = track("typedPair") {
val (leftProto, rightProto) = pt.typeArgs match {
case l :: r :: Nil if pt isRef defn.PairClass => (l, r)
case _ => (WildcardType, WildcardType)
}
val left1 = typed(tree.left, leftProto)
val right1 = typed(tree.right, rightProto)
cpy.Pair(tree, left1, right1).withType(defn.PairType.appliedTo(left1.tpe :: right1.tpe :: Nil))
}
def typedTyped(tree: untpd.Typed, pt: Type)(implicit ctx: Context): Tree = track("typedTyped") {
def regularTyped(isWildcard: Boolean) = {
val tpt1 = typedType(tree.tpt)
val expr1 =
if (isWildcard) tree.expr withType tpt1.tpe
else typedExpr(tree.expr, tpt1.tpe)
cpy.Typed(tree, expr1, tpt1).withType(tpt1.tpe)
}
tree.expr match {
case id: untpd.Ident if (ctx.mode is Mode.Pattern) && isVarPattern(id) =>
if (id.name == nme.WILDCARD) regularTyped(isWildcard = true)
else {
import untpd._
typed(Bind(id.name, Typed(Ident(nme.WILDCARD), tree.tpt)).withPos(id.pos))
}
case _ =>
if (untpd.isWildcardStarArg(tree))
seqToRepeated(typedExpr(tree.expr, defn.SeqType))
else
regularTyped(isWildcard = false)
}
}
def typedNamedArg(tree: untpd.NamedArg, pt: Type)(implicit ctx: Context) = track("typedNamedArg") {
val arg1 = typed(tree.arg, pt)
cpy.NamedArg(tree, tree.name, arg1).withType(arg1.tpe)
}
def typedAssign(tree: untpd.Assign, pt: Type)(implicit ctx: Context) = track("typedAssign") {
tree.lhs match {
case lhs @ Apply(fn, args) =>
typed(cpy.Apply(lhs, untpd.Select(fn, nme.update), args :+ tree.rhs), pt)
case untpd.TypedSplice(Apply(Select(fn, app), args)) if app == nme.apply =>
typed(cpy.Apply(fn,
untpd.Select(untpd.TypedSplice(fn), nme.update),
(args map untpd.TypedSplice) :+ tree.rhs), pt)
case lhs =>
val lhs1 = typed(lhs)
def reassignmentToVal =
errorTree(cpy.Assign(tree, lhs1, typed(tree.rhs, lhs1.tpe.widen)),
"reassignment to val")
lhs1.tpe match {
case ref: TermRef if ref.symbol is (Mutable, butNot = Accessor) =>
cpy.Assign(tree, lhs1, typed(tree.rhs, ref.info)).withType(defn.UnitType)
case ref: TermRef if ref.info.isParameterless =>
val pre = ref.prefix
val setterName = ref.name.setterName
val setter = pre.member(setterName)
lhs1 match {
case lhs1: RefTree if setter.exists =>
val setterTypeRaw = pre select (setterName, setter)
val setterType = checkAccessible(setterTypeRaw, isSuperSelection(lhs1), tree.pos)
val lhs2 = lhs1.withName(setterName).withType(setterType)
typed(cpy.Apply(tree, untpd.TypedSplice(lhs2), tree.rhs :: Nil))
case _ =>
reassignmentToVal
}
case _ =>
reassignmentToVal
}
}
}
def typedBlock(tree: untpd.Block, pt: Type)(implicit ctx: Context) = track("typedBlock") {
val exprCtx = index(tree.stats)
val stats1 = typedStats(tree.stats, ctx.owner)
val expr1 = typedExpr(tree.expr, pt)(exprCtx)
val result = cpy.Block(tree, stats1, expr1).withType(blockType(stats1, expr1.tpe))
val leaks = CheckTrees.escapingRefs(result)
if (leaks.isEmpty) result
else if (isFullyDefined(pt, ForceDegree.all)) {
val expr2 = typed(untpd.Typed(untpd.TypedSplice(expr1), untpd.TypeTree(pt)))
untpd.Block(stats1, expr2) withType expr2.tpe
} else
errorTree(result,
i"local definition of ${leaks.head.name} escapes as part of block's type ${result.tpe}"/*; full type: ${result.tpe.toString}"*/)
}
def typedIf(tree: untpd.If, pt: Type)(implicit ctx: Context) = track("typedIf") {
val cond1 = typed(tree.cond, defn.BooleanType)
val thenp1 = typed(tree.thenp, pt)
val elsep1 = typed(tree.elsep orElse untpd.unitLiteral withPos tree.pos, pt)
cpy.If(tree, cond1, thenp1, elsep1).withType(thenp1.tpe | elsep1.tpe)
}
def typedFunction(tree: untpd.Function, pt: Type)(implicit ctx: Context) = track("typedFunction") {
val untpd.Function(args, body) = tree
if (ctx.mode is Mode.Type)
typed(cpy.AppliedTypeTree(tree,
untpd.TypeTree(defn.FunctionClass(args.length).typeRef), args :+ body), pt)
else {
val params = args.asInstanceOf[List[untpd.ValDef]]
val protoFormals: List[Type] = pt match {
case _ if pt isRef defn.FunctionClass(params.length) =>
pt.typeArgs take params.length
case SAMType(meth) =>
val MethodType(_, paramTypes) = meth.info
paramTypes
case _ =>
params map alwaysWildcardType
}
def refersTo(arg: untpd.Tree, param: untpd.ValDef): Boolean = arg match {
case Ident(name) => name == param.name
case _ => false
}
/** The funcion body to be returned in the closure. Can become a TypedSplice
* of a typed expression if this is necessary to infer a parameter type.
*/
var fnBody = tree.body
/** If function is of the form
* (x1, ..., xN) => f(x1, ..., XN)
* the type of `f`, otherwise NoType. (updates `fnBody` as a side effect).
*/
def calleeType: Type = fnBody match {
case Apply(expr, args) if (args corresponds params)(refersTo) =>
expr match {
case untpd.TypedSplice(expr1) =>
expr1.tpe
case _ =>
val protoArgs = args map (_ withType WildcardType)
val callProto = FunProto(protoArgs, WildcardType, this)
val expr1 = typedExpr(expr, callProto)
fnBody = cpy.Apply(fnBody, untpd.TypedSplice(expr1), args)
expr1.tpe
}
case _ =>
NoType
}
/** Two attempts: First, if expected type is fully defined pick this one.
* Second, if function is of the form
* (x1, ..., xN) => f(x1, ..., XN)
* and f has a method type MT, pick the corresponding parameter type in MT,
* if this one is fully defined.
* If both attempts fail, issue a "missing parameter type" error.
*/
def inferredParamType(param: untpd.ValDef, formal: Type): Type = {
if (isFullyDefined(formal, ForceDegree.noBottom)) return formal
calleeType.widen match {
case mtpe: MethodType =>
val pos = params indexWhere (_.name == param.name)
if (pos < mtpe.paramTypes.length) {
val ptype = mtpe.paramTypes(pos)
if (isFullyDefined(ptype, ForceDegree.none)) return ptype
}
case _ =>
}
val ofFun =
if (nme.syntheticParamNames(args.length + 1) contains param.name)
s" of expanded function ${tree.show}"
else
""
errorType(s"missing parameter type for parameter ${param.name}$ofFun, expected = ${pt.show}", param.pos)
}
val inferredParams: List[untpd.ValDef] =
for ((param, formal) <- params zip protoFormals) yield
if (!param.tpt.isEmpty) param
else {
val paramTpt = untpd.TypeTree(inferredParamType(param, formal))
cpy.ValDef(param, param.mods, param.name, paramTpt, param.rhs)
}
typed(desugar.makeClosure(inferredParams, fnBody), pt)
}
}
def typedClosure(tree: untpd.Closure, pt: Type)(implicit ctx: Context) = track("typedClosure") {
val env1 = tree.env mapconserve (typed(_))
val meth1 = typedUnadapted(tree.meth)
val (ownType, target) = meth1.tpe.widen match {
case mt: MethodType =>
pt match {
case SAMType(meth) if !defn.isFunctionType(pt) && mt <:< meth.info =>
if (!isFullyDefined(pt, ForceDegree.all))
ctx.error(i"result type of closure is an underspecified SAM type $pt", tree.pos)
(pt, TypeTree(pt))
case _ =>
if (!mt.isDependent) (mt.toFunctionType, EmptyTree)
else throw new Error(s"internal error: cannot turn dependent method type $mt into closure, position = ${tree.pos}") // !!! DEBUG. Eventually, convert to an error?
}
case tp =>
throw new Error(i"internal error: closing over non-method $tp, pos = ${tree.pos}")
}
cpy.Closure(tree, env1, meth1, target).withType(ownType)
}
def typedMatch(tree: untpd.Match, pt: Type)(implicit ctx: Context) = track("typedMatch") {
tree.selector match {
case EmptyTree =>
typed(desugar.makeCaseLambda(tree.cases) withPos tree.pos, pt)
case _ =>
val sel1 = typedExpr(tree.selector)
val selType = fullyDefinedType(sel1.tpe, "pattern selector", tree.pos)
/** gadtSyms = "all type parameters of enclosing methods that appear
* non-variantly in the selector type" todo: should typevars
* which appear with variances +1 and -1 (in different
* places) be considered as well?
*/
val gadtSyms: Set[Symbol] = {
val accu = new TypeAccumulator[Set[Symbol]] {
def apply(tsyms: Set[Symbol], t: Type): Set[Symbol] = {
val tsyms1 = t match {
case tr: TypeRef if (tr.symbol is TypeParam) && tr.symbol.owner.isTerm && variance == 0 =>
tsyms + tr.symbol
case _ =>
tsyms
}
foldOver(tsyms1, t)
}
}
accu(Set.empty, selType)
}
def typedCase(tree: untpd.CaseDef): CaseDef = track("typedCase") {
def caseRest(pat: Tree)(implicit ctx: Context) = {
gadtSyms foreach (_.resetGADTFlexType)
foreachSubTreeOf(pat) {
case b: Bind =>
if (ctx.scope.lookup(b.name) == NoSymbol) ctx.enter(b.symbol)
else ctx.error(i"duplicate pattern variable: ${b.name}", b.pos)
case _ =>
}
val guard1 = typedExpr(tree.guard, defn.BooleanType)
val body1 = typedExpr(tree.body, pt)
cpy.CaseDef(tree, pat, guard1, body1) withType body1.tpe
}
val doCase: () => CaseDef =
() => caseRest(typedPattern(tree.pat, selType))(ctx.fresh.withNewScope)
(doCase /: gadtSyms)((op, tsym) => tsym.withGADTFlexType(op))()
}
val cases1 = tree.cases mapconserve typedCase
cpy.Match(tree, sel1, cases1).withType(ctx.typeComparer.lub(cases1.tpes))
}
}
def typedReturn(tree: untpd.Return)(implicit ctx: Context): Return = track("typedReturn") {
def enclMethInfo(cx: Context): (Tree, Type) = {
val owner = cx.owner
if (cx == NoContext || owner.isType) {
ctx.error("return outside method definition", tree.pos)
(EmptyTree, WildcardType)
}
else if (owner.isSourceMethod)
if (owner.isCompleted) {
val from = Ident(TermRef(NoPrefix, owner.asTerm))
val proto = if (owner.isConstructor) defn.UnitType else owner.info.finalResultType
(from, proto)
}
else (EmptyTree, errorType(i"$owner has return statement; needs result type", tree.pos))
else enclMethInfo(cx.outer)
}
val (from, proto) = enclMethInfo(ctx)
val expr1 = typedExpr(tree.expr orElse untpd.unitLiteral, proto)
cpy.Return(tree, expr1, from) withType defn.NothingType
}
def typedTry(tree: untpd.Try, pt: Type)(implicit ctx: Context): Try = track("typedTry") {
val expr1 = typed(tree.expr, pt)
val handler1 = typed(tree.handler, defn.FunctionType(defn.ThrowableType :: Nil, pt))
val finalizer1 = typed(tree.finalizer, defn.UnitType)
val handlerTypeArgs = handler1.tpe.baseTypeArgs(defn.FunctionClass(1))
val ownType = if (handlerTypeArgs.nonEmpty) expr1.tpe | handlerTypeArgs(1) else expr1.tpe
cpy.Try(tree, expr1, handler1, finalizer1) withType ownType
}
def typedThrow(tree: untpd.Throw)(implicit ctx: Context): Throw = track("typedThrow") {
val expr1 = typed(tree.expr, defn.ThrowableType)
cpy.Throw(tree, expr1) withType defn.NothingType
}
def typedSeqLiteral(tree: untpd.SeqLiteral, pt: Type)(implicit ctx: Context): SeqLiteral = track("typedSeqLiteral") {
val proto1 = pt.elemType orElse WildcardType
val elems1 = tree.elems mapconserve (typed(_, proto1))
cpy.SeqLiteral(tree, elems1) withType defn.SeqType.appliedTo(ctx.typeComparer.lub(elems1.tpes))
}
def typedTypeTree(tree: untpd.TypeTree, pt: Type)(implicit ctx: Context): TypeTree = track("typedTypeTree") {
val original1 = typed(tree.original)
val ownType =
if (original1.isEmpty) { assert(isFullyDefined(pt, ForceDegree.none)); pt }
else original1.tpe
cpy.TypeTree(tree, original1) withType ownType
}
def typedSingletonTypeTree(tree: untpd.SingletonTypeTree)(implicit ctx: Context): SingletonTypeTree = track("typedSingletonTypeTree") {
val ref1 = typedExpr(tree.ref)
checkStable(ref1.tpe, tree.pos)
cpy.SingletonTypeTree(tree, ref1) withType ref1.tpe
}
def typedSelectFromTypeTree(tree: untpd.SelectFromTypeTree, pt: Type)(implicit ctx: Context): SelectFromTypeTree = track("typedSelectFromTypeTree") {
val qual1 = typedType(tree.qualifier, selectionProto(tree.name, pt))
cpy.SelectFromTypeTree(tree, qual1, tree.name).withType(checkedSelectionType(qual1, tree))
}
def typedAndTypeTree(tree: untpd.AndTypeTree)(implicit ctx: Context): AndTypeTree = track("typedAndTypeTree") {
val left1 = typed(tree.left)
val right1 = typed(tree.right)
cpy.AndTypeTree(tree, left1, right1) withType left1.tpe & right1.tpe
}
def typedOrTypeTree(tree: untpd.OrTypeTree)(implicit ctx: Context): OrTypeTree = track("typedOrTypeTree") {
val left1 = typed(tree.left)
val right1 = typed(tree.right)
cpy.OrTypeTree(tree, left1, right1) withType left1.tpe | right1.tpe
}
def typedRefinedTypeTree(tree: untpd.RefinedTypeTree)(implicit ctx: Context): RefinedTypeTree = track("typedRefinedTypeTree") {
val tpt1 = typedAheadType(tree.tpt)
val refineClsDef = desugar.refinedTypeToClass(tree)
val refineCls = createSymbol(refineClsDef).asClass
val TypeDef(_, _, Template(_, _, _, refinements1)) = typed(refineClsDef)
assert(tree.refinements.length == refinements1.length, s"${tree.refinements} != $refinements1")
def addRefinement(parent: Type, refinement: Tree): Type = {
println(s"adding refinement $refinement")
foreachSubTreeOf(refinement) {
case tree: RefTree =>
if (tree.symbol.owner == refineCls && tree.pos.start <= tree.symbol.pos.end)
ctx.error("illegal forward reference in refinement", tree.pos)
case _ =>
}
val rsym = refinement.symbol
val rinfo = if (rsym is Accessor) rsym.info.resultType else rsym.info
RefinedType(parent, rsym.name, rt => rinfo.substThis(refineCls, RefinedThis(rt)))
// todo later: check that refinement is within bounds
}
val res = cpy.RefinedTypeTree(tree, tpt1, refinements1) withType
(tpt1.tpe /: refinements1)(addRefinement)
// println(s"typed refinement: ${res.tpe.show}")
res
}
def typedAppliedTypeTree(tree: untpd.AppliedTypeTree)(implicit ctx: Context): AppliedTypeTree = track("typedAppliedTypeTree") {
val tpt1 = typed(tree.tpt)
val args1 = tree.args mapconserve (typed(_))
val tparams = tpt1.tpe.typeParams
if (args1.length != tparams.length)
ctx.error(i"wrong number of type arguments for ${tpt1.tpe}, should be ${tparams.length}")
// todo in later phase: check arguments conform to parameter bounds
cpy.AppliedTypeTree(tree, tpt1, args1) withType tpt1.tpe.appliedTo(args1.tpes)
}
def typedByNameTypeTree(tree: untpd.ByNameTypeTree)(implicit ctx: Context): ByNameTypeTree = track("typedByNameTypeTree") {
val result1 = typed(tree.result)
cpy.ByNameTypeTree(tree, result1) withType ExprType(result1.tpe)
}
def typedTypeBoundsTree(tree: untpd.TypeBoundsTree)(implicit ctx: Context): TypeBoundsTree = track("typedTypeBoundsTree") {
val TypeBoundsTree(lo, hi) = desugar.typeBoundsTree(tree)
val lo1 = typed(lo)
val hi1 = typed(hi)
if (!(lo1.tpe <:< hi1.tpe))
ctx.error(i"lower bound ${lo1.tpe} does not conform to upper bound ${hi1.tpe}", tree.pos)
cpy.TypeBoundsTree(tree, lo1, hi1) withType TypeBounds(lo1.tpe, hi1.tpe)
}
def typedBind(tree: untpd.Bind, pt: Type)(implicit ctx: Context): Bind = track("typedBind") {
val body1 = typed(tree.body, pt)
// println(i"typed bind $tree pt = $pt bodytpe = ${body1.tpe}")
val sym = ctx.newSymbol(ctx.owner, tree.name.asTermName, EmptyFlags, body1.tpe, coord = tree.pos)
cpy.Bind(tree, tree.name, body1) withType TermRef(NoPrefix, sym)
}
def typedAlternative(tree: untpd.Alternative, pt: Type)(implicit ctx: Context): Alternative = track("typedAlternative") {
val trees1 = tree.trees mapconserve (typed(_, pt))
cpy.Alternative(tree, trees1) withType ctx.typeComparer.lub(trees1.tpes)
}
def typedModifiers(mods: untpd.Modifiers)(implicit ctx: Context): Modifiers = track("typedModifiers") {
val annotations1 = mods.annotations mapconserve typedAnnotation
if (annotations1 eq mods.annotations) mods.asInstanceOf[Modifiers]
else Modifiers(mods.flags, mods.privateWithin, annotations1)
}
def typedAnnotation(annot: untpd.Tree)(implicit ctx: Context): Tree = track("typedAnnotation") {
typed(annot, defn.AnnotationClass.typeRef)
}
def typedValDef(vdef: untpd.ValDef, sym: Symbol)(implicit ctx: Context) = track("typedValDef") {
val ValDef(mods, name, tpt, rhs) = vdef
val mods1 = typedModifiers(mods)
val tpt1 = typedType(tpt)
val rhs1 = rhs match {
case Ident(nme.WILDCARD) => rhs withType tpt1.tpe
case _ => typedExpr(rhs, tpt1.tpe)
}
val refType = if (sym.exists) sym.valRef else NoType
cpy.ValDef(vdef, mods1, name, tpt1, rhs1).withType(refType)
}
def typedDefDef(ddef: untpd.DefDef, sym: Symbol)(implicit ctx: Context) = track("typedDefDef") {
val DefDef(mods, name, tparams, vparamss, tpt, rhs) = ddef
val mods1 = typedModifiers(mods)
val tparams1 = tparams mapconserve (typed(_).asInstanceOf[TypeDef])
val vparamss1 = vparamss nestedMapconserve (typed(_).asInstanceOf[ValDef])
val tpt1 = typedType(tpt)
val rhs1 = typedExpr(rhs, tpt1.tpe)
cpy.DefDef(ddef, mods1, name, tparams1, vparamss1, tpt1, rhs1).withType(sym.termRefWithSig)
//todo: make sure dependent method types do not depend on implicits or by-name params
}
def typedTypeDef(tdef: untpd.TypeDef, sym: Symbol)(implicit ctx: Context): TypeDef = track("typedTypeDef") {
val TypeDef(mods, name, rhs) = tdef
val mods1 = typedModifiers(mods)
val _ = typedType(rhs) // unused, typecheck only to remove from typedTree
cpy.TypeDef(tdef, mods1, name, TypeTree(sym.info)).withType(sym.typeRef)
}
def typedClassDef(cdef: untpd.TypeDef, cls: ClassSymbol)(implicit ctx: Context) = track("typedClassDef") {
val TypeDef(mods, name, impl @ Template(constr, parents, self, body)) = cdef
val mods1 = typedModifiers(mods)
val constr1 = typed(constr).asInstanceOf[DefDef]
val parents1 = parents mapconserve (typed(_))
val self1 = typed(self).asInstanceOf[ValDef]
val localDummy = ctx.newLocalDummy(cls, impl.pos)
val body1 = typedStats(body, localDummy)(inClassContext(self1.symbol))
checkNoDoubleDefs(cls)
val impl1 = cpy.Template(impl, constr1, parents1, self1, body1)
.withType(localDummy.termRef)
cpy.TypeDef(cdef, mods1, name, impl1).withType(cls.typeRef)
// todo later: check that
// 1. If class is non-abstract, it is instantiatable:
// - self type is s supertype of own type
// - all type members have consistent bounds
// 2. all private type members have consistent bounds
// 3. Types do not override classes.
// 4. Polymorphic type defs override nothing.
}
def typedImport(imp: untpd.Import, sym: Symbol)(implicit ctx: Context): Import = track("typedImport") {
val expr1 = typedExpr(imp.expr, AnySelectionProto)
checkStable(expr1.tpe, imp.expr.pos)
cpy.Import(imp, expr1, imp.selectors).withType(sym.termRef)
}
def typedAnnotated(tree: untpd.Annotated, pt: Type)(implicit ctx: Context): Tree = track("typedAnnotated") {
val annot1 = typed(tree.annot, defn.AnnotationClass.typeRef)
val arg1 = typed(tree.arg, pt)
val underlyingType = if (arg1.isTerm) arg1.tpe.widen else arg1.tpe
val ownType = AnnotatedType(Annotation(annot1), underlyingType)
if (ctx.mode is Mode.Type)
cpy.Annotated(tree, annot1, arg1) withType ownType
else
cpy.Typed(tree, arg1, TypeTree(ownType)) withType ownType
}
def typedAsFunction(tree: untpd.Tree, pt: Type)(implicit ctx: Context): Tree =
typed(tree, if (defn.isFunctionType(pt)) pt else AnyFunctionProto)
def typedPackageDef(tree: untpd.PackageDef)(implicit ctx: Context): Tree = track("typedPackageDef") {
val pid1 = typedExpr(tree.pid, AnySelectionProto)
val pkg = pid1.symbol
val packageContext =
if (pkg is Package) ctx.fresh.withOwner(pkg.moduleClass).withTree(tree)
else {
ctx.error(i"$pkg is not a packge", tree.pos)
ctx
}
val stats1 = typedStats(tree.stats, NoSymbol)(packageContext)
cpy.PackageDef(tree, pid1.asInstanceOf[RefTree], stats1) withType pkg.valRef
}
def typedUnadapted(initTree: untpd.Tree, pt: Type = WildcardType)(implicit ctx: Context): Tree = {
val xtree = expanded(initTree)
typedTree remove xtree match {
case Some(ttree) => ttree
case none =>
val sym = symOfTree.getOrElse(xtree, NoSymbol)
sym.ensureCompleted()
symOfTree.remove(xtree)
def localContext = ctx.fresh.withOwner(sym).withTree(xtree)
def typedNamed(tree: untpd.NameTree): Tree = tree match {
case tree: untpd.Ident => typedIdent(tree, pt)
case tree: untpd.Select => typedSelect(tree, pt)
case tree: untpd.SelectFromTypeTree => typedSelectFromTypeTree(tree, pt)
case tree: untpd.Bind => typedBind(tree, pt)
case tree: untpd.ValDef =>
if (tree.isEmpty) tpd.EmptyValDef
else typedValDef(tree, sym)(localContext.withNewScope)
case tree: untpd.DefDef =>
val typer1 = nestedTyper.remove(sym).get
typer1.typedDefDef(tree, sym)(localContext.withTyper(typer1))
case tree: untpd.TypeDef =>
if (tree.isClassDef) typedClassDef(tree, sym.asClass)(localContext)
else typedTypeDef(tree, sym)(localContext.withNewScope)
case _ => typedUnadapted(desugar(tree), pt)
}
def typedUnnamed(tree: untpd.Tree): Tree = tree match {
case tree: untpd.Apply =>
if (ctx.mode is Mode.Pattern) typedUnApply(tree, pt) else typedApply(tree, pt)
case tree: untpd.This => typedThis(tree)
case tree: untpd.Literal => typedLiteral(tree)
case tree: untpd.New => typedNew(tree, pt)
case tree: untpd.Pair => typedPair(tree, pt)
case tree: untpd.Typed => typedTyped(tree, pt)
case tree: untpd.NamedArg => typedNamedArg(tree, pt)
case tree: untpd.Assign => typedAssign(tree, pt)
case tree: untpd.Block => typedBlock(desugar.block(tree), pt)(ctx.fresh.withNewScope)
case tree: untpd.If => typedIf(tree, pt)
case tree: untpd.Function => typedFunction(tree, pt)
case tree: untpd.Closure => typedClosure(tree, pt)
case tree: untpd.Match => typedMatch(tree, pt)
case tree: untpd.Return => typedReturn(tree)
case tree: untpd.Try => typedTry(tree, pt)
case tree: untpd.Throw => typedThrow(tree)
case tree: untpd.TypeApply => typedTypeApply(tree, pt)
case tree: untpd.Super => typedSuper(tree, pt)
case tree: untpd.SeqLiteral => typedSeqLiteral(tree, pt)
case tree: untpd.TypeTree => typedTypeTree(tree, pt)
case tree: untpd.SingletonTypeTree => typedSingletonTypeTree(tree)
case tree: untpd.AndTypeTree => typedAndTypeTree(tree)
case tree: untpd.OrTypeTree => typedOrTypeTree(tree)
case tree: untpd.RefinedTypeTree => typedRefinedTypeTree(tree)
case tree: untpd.AppliedTypeTree => typedAppliedTypeTree(tree)
case tree: untpd.ByNameTypeTree => typedByNameTypeTree(tree)
case tree: untpd.TypeBoundsTree => typedTypeBoundsTree(tree)
case tree: untpd.Alternative => typedAlternative(tree, pt)
case tree: untpd.Import => typedImport(tree, sym)
case tree: untpd.PackageDef => typedPackageDef(tree)
case tree: untpd.Annotated => typedAnnotated(tree, pt)
case tree: untpd.TypedSplice => tree.tree
case untpd.PostfixOp(tree, nme.WILDCARD) => typedAsFunction(tree, pt)
case untpd.EmptyTree => tpd.EmptyTree
case _ => typedUnadapted(desugar(tree), pt)
}
xtree match {
case xtree: untpd.NameTree => typedNamed(xtree withName xtree.name.encode)
case xtree => typedUnnamed(xtree)
}
}
}
def typed(tree: untpd.Tree, pt: Type = WildcardType)(implicit ctx: Context): Tree = ctx.traceIndented (s"typing ${tree.show}", show = true) {
if (!tree.isEmpty && ctx.typerState.isGlobalCommittable) assert(tree.pos.exists, tree)
try adapt(typedUnadapted(tree, pt), pt)
catch {
case ex: CyclicReference => errorTree(tree, cyclicErrorMsg(ex))
case ex: FatalTypeError => errorTree(tree, ex.getMessage)
}
}
def typedTrees(trees: List[untpd.Tree])(implicit ctx: Context): List[Tree] =
trees mapconserve (typed(_))
def typedStats(stats: List[untpd.Tree], exprOwner: Symbol)(implicit ctx: Context): List[tpd.Tree] = {
val buf = new mutable.ListBuffer[Tree]
@tailrec def traverse(stats: List[untpd.Tree])(implicit ctx: Context): List[Tree] = stats match {
case (imp: untpd.Import) :: rest =>
val imp1 = typed(imp)
buf += imp1
traverse(rest)(importContext(imp1.symbol, imp.selectors))
case (mdef: untpd.DefTree) :: rest =>
expandedTree remove mdef match {
case Some(xtree) =>
traverse(xtree :: rest)
case none =>
buf += typed(mdef)
traverse(rest)
}
case Thicket(stats) :: rest =>
traverse(stats ++ rest)
case stat :: rest =>
val nestedCtx = if (exprOwner == ctx.owner) ctx else ctx.fresh.withOwner(exprOwner)
buf += typed(stat)(nestedCtx)
traverse(rest)
case nil =>
buf.toList
}
traverse(stats)
}
def typedExpr(tree: untpd.Tree, pt: Type = WildcardType)(implicit ctx: Context): Tree =
typed(tree, pt)(ctx retractMode Mode.PatternOrType)
def typedType(tree: untpd.Tree, pt: Type = WildcardType)(implicit ctx: Context): Tree = // todo: retract mode between Type and Pattern?
typed(tree, pt)(ctx addMode Mode.Type)
def typedPattern(tree: untpd.Tree, pt: Type = WildcardType)(implicit ctx: Context): Tree =
typed(tree, pt)(ctx addMode Mode.Pattern)
def tryEither[T](op: Context => T)(fallBack: (T, TyperState) => T)(implicit ctx: Context) = {
val nestedCtx = ctx.fresh.withNewTyperState
val result = op(nestedCtx)
if (nestedCtx.reporter.hasErrors)
fallBack(result, nestedCtx.typerState)
else {
nestedCtx.typerState.commit()
result
}
}
def tryInsertApply(tree: Tree, pt: Type)(fallBack: (Tree, TyperState) => Tree)(implicit ctx: Context): Tree =
tryEither {
implicit ctx =>
val sel = typedSelect(untpd.Select(untpd.TypedSplice(tree), nme.apply), pt)
if (sel.tpe.isError) sel else adapt(sel, pt)
} {
fallBack
}
def adapt(tree: Tree, pt: Type)(implicit ctx: Context) = track("adapt") {
ctx.traceIndented(i"adapting $tree of type ${tree.tpe} to $pt", show = true) {
interpolateUndetVars(tree)
tree overwriteType tree.tpe.simplified
adaptInterpolated(tree, pt)
}
}
/** (-1) For expressions with annotated types, let AnnotationCheckers decide what to do
* (0) Convert expressions with constant types to literals (unless in interactive/scaladoc mode)
*/
/** Perform the following adaptations of expression, pattern or type `tree` wrt to
* given prototype `pt`:
* (1) Resolve overloading
* (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, if `pt` is a function type and method is not a constructor,
* convert to function by eta-expansion,
* (4.3) otherwise, if the method is nullary with a result type compatible to `pt`
* and it is not a constructor, apply it to ()
* otherwise issue an error
* (5) Convert constructors in a pattern as follows:
* (5.1) If constructor refers to a case class factory, set tree's type to the unique
* instance of its primary constructor that is a subtype of the expected type.
* (5.2) If constructor refers to an extractor, convert to application of
* unapply or unapplySeq method.
*
* (6) Convert all other types to TypeTree nodes.
* (7) When in TYPEmode but not FUNmode or HKmode, check that types are fully parameterized
* (7.1) In HKmode, higher-kinded types are allowed, but they must have the expected kind-arity
* (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 AnnotationChecker conversion if expected type is annotated.
* (14) When in mode EXPRmode, apply a view
* If all this fails, error
*/
def adaptInterpolated(tree: Tree, pt: Type)(implicit ctx: Context): Tree = {
assert(pt.exists)
def methodStr = err.refStr(methPart(tree).tpe)
def adaptOverloaded(ref: TermRef) = {
val altDenots = ref.denot.alternatives
println(i"adapt overloaded $ref with alternatives ${altDenots map (_.info)}%, %")
val alts = altDenots map (alt =>
TermRef.withSig(ref.prefix, ref.name, alt.info.signature, alt))
def expectedStr = err.expectedTypeStr(pt)
resolveOverloaded(alts, pt)(ctx.fresh.withExploreTyperState) match {
case alt :: Nil =>
adapt(tree.withType(alt), pt)
case Nil =>
def noMatches =
errorTree(tree,
i"""none of the ${err.overloadedAltsStr(altDenots)}
|match $expectedStr""".stripMargin)
def hasEmptyParams(denot: SingleDenotation) = denot.info.paramTypess == ListOfNil
pt match {
case pt: FunProto =>
tryInsertApply(tree, pt)((_, _) => noMatches)
case _ =>
if (altDenots exists (_.info.paramTypess == ListOfNil))
typed(untpd.Apply(untpd.TypedSplice(tree), Nil), pt)
else
noMatches
}
case alts =>
def all = if (altDenots.length == 2) "both" else "all"
errorTree(tree,
i"""Ambiguous overload. The ${err.overloadedAltsStr(altDenots)}
|$all match $expectedStr""".stripMargin)
}
}
def adaptToArgs(wtp: Type, pt: FunProto) = wtp match {
case _: MethodType | _: PolyType => tree
case _ => tryInsertApply(tree, pt) {
val more = tree match {
case Apply(_, _) => " more"
case _ => ""
}
(_, _) => errorTree(tree, i"$methodStr does not take$more parameters")
}
}
def adaptNoArgs(wtp: Type): Tree = wtp match {
case wtp: ExprType =>
adaptInterpolated(tree.withType(wtp.resultType), pt)
case wtp: ImplicitMethodType =>
def implicitArgError(msg: => String): Tree = {
ctx.error(msg, tree.pos.endPos)
EmptyTree
}
val args = (wtp.paramNames, wtp.paramTypes).zipped map { (pname, formal) =>
def where = i"parameter $pname of $methodStr"
inferImplicit(formal, EmptyTree, tree.pos.endPos) match {
case SearchSuccess(arg, _, _) =>
arg
case ambi: AmbiguousImplicits =>
implicitArgError(s"ambiguous implicits: ${ambi.explanation} of $where")
case failure: SearchFailure =>
implicitArgError(i"no implicit argument of type $formal found for $where" + failure.postscript)
}
}
adapt(tpd.Apply(tree, args), pt)
case wtp: MethodType if !pt.isInstanceOf[SingletonType] =>
val arity =
if (defn.isFunctionType(pt)) defn.functionArity(pt)
else if (pt eq AnyFunctionProto) wtp.paramTypes.length
else -1
if (arity >= 0 && !tree.symbol.isConstructor)
typed(etaExpand(tree, wtp.paramNames take arity), pt)
else if (wtp.paramTypes.isEmpty)
adaptInterpolated(tpd.Apply(tree, Nil), pt)
else
errorTree(tree,
i"""missing arguments for $methodStr
|follow this method with `_' if you want to treat it as a partially applied function""".stripMargin)
case _ =>
if (tree.tpe <:< pt) tree
else if (ctx.mode is Mode.Pattern) tree // no subtype check for pattern
else {
println(s"adapt to subtype ${tree.tpe} !<:< $pt") // !!!DEBUG
// println(TypeComparer.explained(implicit ctx => tree.tpe <:< pt)) // !!!DEBUG
adaptToSubType(wtp)
}
}
def adaptToSubType(wtp: Type): Tree = {
// try converting a constant to the target type
val folded = ConstFold(tree, pt)
if (folded ne EmptyTree) return folded
// drop type if prototype is Unit
if (pt isRef defn.UnitClass)
return tpd.Block(tree :: Nil, Literal(Constant(())))
// convert function literal to SAM closure
tree match {
case Closure(Nil, id @ Ident(nme.ANON_FUN), _)
if defn.isFunctionType(wtp) && !defn.isFunctionType(pt) =>
pt match {
case SAMType(meth)
if wtp <:< meth.info.toFunctionType && isFullyDefined(pt, ForceDegree.noBottom) =>
return cpy.Closure(tree, Nil, id, TypeTree(pt)).withType(pt)
case _ =>
}
case _ =>
}
// try an implicit conversion
inferView(tree, pt) match {
case SearchSuccess(inferred, _, _) =>
adapt(inferred, pt)
case failure: SearchFailure =>
if (pt.isInstanceOf[ProtoType]) tree
else err.typeMismatch(tree, pt, failure)
}
}
tree match {
case _: MemberDef | _: PackageDef | _: Import | _: WithoutTypeOrPos[_] => tree
case _ => tree.tpe.widen match {
case ErrorType =>
tree
case ref: TermRef =>
adaptOverloaded(ref)
case poly: PolyType =>
if (pt.isInstanceOf[PolyProto]) tree
else {
val (_, tvars) = constrained(poly, tree)
adaptInterpolated(tree appliedToTypes tvars, pt)
}
case wtp =>
pt match {
case pt: FunProto =>
adaptToArgs(wtp, pt)
case pt: PolyProto =>
tryInsertApply(tree, pt) {
(_, _) => tree // error will be reported in typedTypeApply
}
case _ =>
if (ctx.mode is Mode.Type)
if (tree.tpe <:< pt) tree
else err.typeMismatch(tree, pt)
else adaptNoArgs(wtp)
}
}
}
}
}