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|
package dotty.tools
package dotc
package typer
import core._
import ast._
import Trees._
import Constants._
import StdNames._
import Scopes._
import Denotations._
import ProtoTypes._
import Contexts._
import Symbols._
import Types._
import SymDenotations._
import Annotations._
import Names._
import NameOps._
import Applications._
import Flags._
import Decorators._
import ErrorReporting._
import Checking._
import Inferencing._
import EtaExpansion.etaExpand
import dotty.tools.dotc.transform.Erasure.Boxing
import util.Positions._
import util.common._
import util.SourcePosition
import collection.mutable
import annotation.tailrec
import Implicits._
import util.Stats.{track, record}
import config.Printers._
import rewrite.Rewrites.patch
import NavigateAST._
import transform.SymUtils._
import language.implicitConversions
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
}
/** Assert tree has a position, unless it is empty or a typed splice */
def assertPositioned(tree: untpd.Tree)(implicit ctx: Context) =
if (!tree.isEmpty && !tree.isInstanceOf[untpd.TypedSplice] && ctx.typerState.isGlobalCommittable)
assert(tree.pos.exists, s"position not set for $tree # ${tree.uniqueId}")
}
class Typer extends Namer with TypeAssigner with Applications with Implicits with Checking {
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()
def newLikeThis: Typer = new Typer
/** 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 refctx = ctx
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 = {
if (imp.isRootImport && (importedFromRoot contains site.termSymbol)) return true
if (imp.hiddenRoot.exists) importedFromRoot += imp.hiddenRoot
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) d"imported$qualifier by ${whereFound.importInfo}"
else d"defined$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 || ctx.typeComparer.isSameRef(previous, found)) found
else if ((prevCtx.scope eq ctx.scope) &&
(newPrec == definition ||
newPrec == namedImport && prevPrec == wildImport)) {
// special cases: definitions beat imports, and named imports beat
// wildcard imports, provided both are in contexts with same scope
found
}
else {
if (!previous.isError && !found.isError) {
error(
d"""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(d"reference to $name is ambiguous; it is imported twice in ${ctx.tree}",
tree.pos)
found
}
val Name = name.toTermName.decode
selectors match {
case Pair(Ident(from), Ident(Name)) :: rest =>
val selName = if (name.isTypeName) from.toTypeName else from
// Pass refctx so that any errors are reported in the context of the
// reference instead of the context of the import.
checkUnambiguous(selectionType(site, selName, tree.pos)(refctx))
case Ident(Name) :: rest =>
checkUnambiguous(selectionType(site, name, tree.pos)(refctx))
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) {
val pre = imp.site
if (!isDisabled(imp, pre) && !(imp.excluded contains name.toTermName) && name != nme.CONSTRUCTOR) {
val denot = pre.member(name).accessibleFrom(pre)(refctx)
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.file
}
/** 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.enclosingClass.thisType
else curOwner.thisType.select(name, defDenot)
if (!(curOwner is Package) || isDefinedInCurrentUnit(defDenot))
return checkNewOrShadowed(found, definition) // no need to go further out, we found highest prec entry
else if (defDenot.symbol is Package)
return checkNewOrShadowed(previous orElse found, packageClause)
else if (prevPrec < packageClause)
return findRef(found, packageClause, ctx)(outer)
}
}
val curImport = ctx.importInfo
if (ctx.owner.is(Package) && curImport != null && curImport.isRootImport && previous.exists)
return previous // no more conflicts possible in this case
// would import of kind `prec` be not shadowed by a nested higher-precedence definition?
def isPossibleImport(prec: Int) =
prevPrec < prec || prevPrec == prec && (prevCtx.scope eq ctx.scope)
if (isPossibleImport(namedImport) && (curImport ne outer.importInfo) && !curImport.sym.isCompleting) {
val namedImp = namedImportRef(curImport.site, curImport.selectors)
if (namedImp.exists)
return findRef(checkNewOrShadowed(namedImp, namedImport), namedImport, ctx)(outer)
if (isPossibleImport(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 "
typr.println(s"typed ident $kind$name in ${ctx.owner}")
if (ctx.mode is Mode.Pattern) {
if (name == nme.WILDCARD)
return tree.withType(pt)
if (isVarPattern(tree) && name.isTermName)
return typed(desugar.patternVar(tree), pt)
}
val saved = importedFromRoot
importedFromRoot = Set.empty
val rawType =
try findRef(NoType, BindingPrec.nothingBound, NoContext)
finally importedFromRoot = saved
val ownType =
if (rawType.exists)
ensureAccessible(rawType, superAccess = false, tree.pos)
else {
error(d"not found: $kind$name", tree.pos)
ErrorType
}
val tree1 = ownType match {
case ownType: NamedType if !prefixIsElidable(ownType) =>
ref(ownType).withPos(tree.pos)
case _ =>
tree.withType(ownType)
}
checkValue(tree1, pt)
}
private def typedSelect(tree: untpd.Select, pt: Type, qual: Tree)(implicit ctx: Context): Select =
healNonvariant(
checkValue(assignType(cpy.Select(tree)(qual, tree.name), qual), pt),
pt)
/** Let `tree = p.n` where `p: T`. If tree's type is an unsafe instantiation
* (see TypeOps#asSeenFrom for how this can happen), rewrite the prefix `p`
* to `(p: <unknown skolem of type T>)` and try again with the new (stable)
* prefix. If the result has another unsafe instantiation, raise an error.
*/
private def healNonvariant[T <: Tree](tree: T, pt: Type)(implicit ctx: Context): T =
if (ctx.unsafeNonvariant == ctx.runId && tree.tpe.widen.hasUnsafeNonvariant)
tree match {
case tree @ Select(qual, _) if !qual.tpe.isStable =>
val alt = typedSelect(tree, pt, Typed(qual, TypeTree(SkolemType(qual.tpe.widen))))
typr.println(d"healed type: ${tree.tpe} --> $alt")
alt.asInstanceOf[T]
case _ =>
ctx.error(d"unsafe instantiation of type ${tree.tpe}", tree.pos)
tree
}
else tree
def typedSelect(tree: untpd.Select, pt: Type)(implicit ctx: Context): Tree = track("typedSelect") {
def asSelect(implicit ctx: Context): Tree = {
val qual1 = typedExpr(tree.qualifier, selectionProto(tree.name, pt, this))
if (tree.name.isTypeName) checkStable(qual1.tpe, qual1.pos)
typedSelect(tree, pt, qual1)
}
def asJavaSelectFromTypeTree(implicit ctx: Context): Tree = {
// Translate names in Select/Ident nodes to type names.
def convertToTypeName(tree: untpd.Tree): Option[untpd.Tree] = tree match {
case Select(qual, name) => Some(untpd.Select(qual, name.toTypeName))
case Ident(name) => Some(untpd.Ident(name.toTypeName))
case _ => None
}
// Try to convert Select(qual, name) to a SelectFromTypeTree.
def convertToSelectFromType(qual: untpd.Tree, origName: Name): Option[untpd.SelectFromTypeTree] =
convertToTypeName(qual) match {
case Some(qual1) => Some(untpd.SelectFromTypeTree(qual1 withPos qual.pos, origName.toTypeName))
case _ => None
}
convertToSelectFromType(tree.qualifier, tree.name) match {
case Some(sftt) => typedSelectFromTypeTree(sftt, pt)
case _ => ctx.error(d"Could not convert $tree to a SelectFromTypeTree"); EmptyTree
}
}
if (ctx.compilationUnit.isJava && tree.name.isTypeName) {
// SI-3120 Java uses the same syntax, A.B, to express selection from the
// value A and from the type A. We have to try both.
tryEither(tryCtx => asSelect(tryCtx))((_, _) => asJavaSelectFromTypeTree(ctx))
} else asSelect(ctx)
}
def typedSelectFromTypeTree(tree: untpd.SelectFromTypeTree, pt: Type)(implicit ctx: Context): Tree = track("typedSelectFromTypeTree") {
val qual1 = typedType(tree.qualifier, selectionProto(tree.name, pt, this))
assignType(cpy.SelectFromTypeTree(tree)(qual1, tree.name), qual1)
}
def typedThis(tree: untpd.This)(implicit ctx: Context): Tree = track("typedThis") {
assignType(tree)
}
def typedSuper(tree: untpd.Super, pt: Type)(implicit ctx: Context): Tree = track("typedSuper") {
val qual1 = typed(tree.qual)
val inConstrCall = pt match {
case pt: SelectionProto if pt.name == nme.CONSTRUCTOR => true
case _ => false
}
pt match {
case pt: SelectionProto if pt.name.isTypeName =>
qual1 // don't do super references for types; they are meaningless anyway
case _ =>
assignType(cpy.Super(tree)(qual1, tree.mix), qual1, inConstrCall)
}
}
def typedLiteral(tree: untpd.Literal)(implicit ctx: Context) = track("typedLiteral") {
assignType(tree)
}
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(x, templ).withFlags(Final)
typed(cpy.Block(tree)(clsDef :: Nil, New(Ident(x), Nil)), pt)
case _ =>
var tpt1 = typedType(tree.tpt)
tpt1.tpe.dealias match {
case TypeApplications.EtaExpansion(tycon) => tpt1 = tpt1.withType(tycon)
case _ =>
}
checkClassType(tpt1.tpe, tpt1.pos, traitReq = false, stablePrefixReq = true)
assignType(cpy.New(tree)(tpt1), tpt1)
// todo in a later phase: checkInstantiatable(cls, tpt1.pos)
}
}
def typedPair(tree: untpd.Pair, pt: Type)(implicit ctx: Context) = track("typedPair") {
val (leftProto, rightProto) = pt.argTypesLo 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)
assignType(cpy.Pair(tree)(left1, right1), left1, right1)
}
def typedTyped(tree: untpd.Typed, pt: Type)(implicit ctx: Context): Tree = track("typedTyped") {
/* Handles three cases:
* @param ifPat how to handle a pattern (_: T)
* @param ifExpr how to handle an expression (e: T)
* @param wildName what name `w` to use in the rewriting of
* (x: T) to (x @ (w: T)). This is either `_` or `_*`.
*/
def cases(ifPat: => Tree, ifExpr: => Tree, wildName: TermName) = tree.expr match {
case id: untpd.Ident if (ctx.mode is Mode.Pattern) && isVarPattern(id) =>
if (id.name == nme.WILDCARD || id.name == nme.WILDCARD_STAR) ifPat
else {
import untpd._
typed(Bind(id.name, Typed(Ident(wildName), tree.tpt)).withPos(id.pos), pt)
}
case _ => ifExpr
}
def ascription(tpt: Tree, isWildcard: Boolean) = {
val expr1 =
if (isWildcard) tree.expr.withType(tpt.tpe)
else typed(tree.expr, tpt.tpe.widenSkolem)
assignType(cpy.Typed(tree)(expr1, tpt), tpt)
}
if (untpd.isWildcardStarArg(tree))
cases(
ifPat = ascription(TypeTree(defn.SeqType.appliedTo(pt :: Nil)), isWildcard = true),
ifExpr = seqToRepeated(typedExpr(tree.expr, defn.SeqType)),
wildName = nme.WILDCARD_STAR)
else {
def typedTpt = checkSimpleKinded(typedType(tree.tpt))
def handlePattern: Tree = {
val tpt1 = typedTpt
// special case for an abstract type that comes with a class tag
tpt1.tpe.dealias match {
case tref: TypeRef if !tref.symbol.isClass && !ctx.isAfterTyper =>
inferImplicit(defn.ClassTagType.appliedTo(tref),
EmptyTree, tpt1.pos)(ctx.retractMode(Mode.Pattern)) match {
case SearchSuccess(arg, _, _) =>
return typed(untpd.Apply(untpd.TypedSplice(arg), tree.expr), pt)
case _ =>
}
case _ =>
}
ascription(tpt1, isWildcard = true)
}
cases(
ifPat = handlePattern,
ifExpr = ascription(typedTpt, isWildcard = false),
wildName = nme.WILDCARD)
}
}
def typedNamedArg(tree: untpd.NamedArg, pt: Type)(implicit ctx: Context) = track("typedNamedArg") {
val arg1 = typed(tree.arg, pt)
assignType(cpy.NamedArg(tree)(tree.name, arg1), arg1)
}
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(MaybePoly(Select(fn, app), targs), args)) if app == nme.apply =>
val rawUpdate: untpd.Tree = untpd.Select(untpd.TypedSplice(fn), nme.update)
val wrappedUpdate =
if (targs.isEmpty) rawUpdate
else untpd.TypeApply(rawUpdate, targs map untpd.TypedSplice)
val appliedUpdate = cpy.Apply(fn)(wrappedUpdate, (args map untpd.TypedSplice) :+ tree.rhs)
typed(appliedUpdate, pt)
case lhs =>
val lhsCore = typedUnadapted(lhs)
def lhs1 = typed(untpd.TypedSplice(lhsCore))
def canAssign(sym: Symbol) = // allow assignments from the primary constructor to class fields
sym.is(Mutable, butNot = Accessor) ||
ctx.owner.isPrimaryConstructor && !sym.is(Method) && sym.owner == ctx.owner.owner ||
ctx.owner.name.isTraitSetterName
lhsCore.tpe match {
case ref: TermRef if canAssign(ref.symbol) =>
assignType(cpy.Assign(tree)(lhs1, typed(tree.rhs, ref.info)))
case _ =>
def reassignmentToVal =
errorTree(cpy.Assign(tree)(lhsCore, typed(tree.rhs, lhs1.tpe.widen)),
"reassignment to val")
lhsCore.tpe match {
case ref: TermRef => // todo: further conditions to impose on getter?
val pre = ref.prefix
val setterName = ref.name.setterName
val setter = pre.member(setterName)
lhsCore match {
case lhsCore: RefTree if setter.exists =>
val setterTypeRaw = pre.select(setterName, setter)
val setterType = ensureAccessible(setterTypeRaw, isSuperSelection(lhsCore), tree.pos)
val lhs2 = healNonvariant(
untpd.rename(lhsCore, setterName).withType(setterType), WildcardType)
typedUnadapted(cpy.Apply(tree)(untpd.TypedSplice(lhs2), tree.rhs :: Nil))
case _ =>
reassignmentToVal
}
case tpe =>
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)
ensureNoLocalRefs(
assignType(cpy.Block(tree)(stats1, expr1), stats1, expr1), pt, localSyms(stats1))
}
def escapingRefs(block: Tree, localSyms: => List[Symbol])(implicit ctx: Context): collection.Set[NamedType] = {
var hoisted: Set[Symbol] = Set()
lazy val locals = localSyms.toSet
def leakingTypes(tp: Type): collection.Set[NamedType] =
tp namedPartsWith (tp => locals.contains(tp.symbol))
def typeLeaks(tp: Type): Boolean = leakingTypes(tp).nonEmpty
def classLeaks(sym: ClassSymbol): Boolean =
(ctx.owner is Method) || // can't hoist classes out of method bodies
(sym.info.parents exists typeLeaks) ||
(sym.info.decls.toList exists (t => typeLeaks(t.info)))
leakingTypes(block.tpe)
}
/** Check that expression's type can be expressed without references to locally defined
* symbols. The following two remedies are tried before giving up:
* 1. If the expected type of the expression is fully defined, pick it as the
* type of the result expressed by adding a type ascription.
* 2. If (1) fails, force all type variables so that the block's type is
* fully defined and try again.
*/
protected def ensureNoLocalRefs(tree: Tree, pt: Type, localSyms: => List[Symbol], forcedDefined: Boolean = false)(implicit ctx: Context): Tree = {
def ascribeType(tree: Tree, pt: Type): Tree = tree match {
case block @ Block(stats, expr) =>
val expr1 = ascribeType(expr, pt)
cpy.Block(block)(stats, expr1) withType expr1.tpe // no assignType here because avoid is redundant
case _ =>
Typed(tree, TypeTree(pt.simplified))
}
val leaks = escapingRefs(tree, localSyms)
if (leaks.isEmpty) tree
else if (isFullyDefined(pt, ForceDegree.none)) ascribeType(tree, pt)
else if (!forcedDefined) {
fullyDefinedType(tree.tpe, "block", tree.pos)
val tree1 = ascribeType(tree, avoid(tree.tpe, localSyms))
ensureNoLocalRefs(tree1, pt, localSyms, forcedDefined = true)
} else
errorTree(tree,
d"local definition of ${leaks.head.name} escapes as part of expression's type ${tree.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)
val thenp2 :: elsep2 :: Nil = harmonize(thenp1 :: elsep1 :: Nil)
assignType(cpy.If(tree)(cond1, thenp2, elsep2), thenp2, elsep2)
}
private def decomposeProtoFunction(pt: Type, defaultArity: Int)(implicit ctx: Context): (List[Type], Type) = pt match {
case _ if defn.isFunctionType(pt) =>
(pt.dealias.argInfos.init, pt.dealias.argInfos.last)
case SAMType(meth) =>
val mt @ MethodType(_, paramTypes) = meth.info
(paramTypes, mt.resultType)
case _ =>
(List.range(0, defaultArity) map alwaysWildcardType, WildcardType)
}
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, protoResult) = decomposeProtoFunction(pt, params.length)
def refersTo(arg: untpd.Tree, param: untpd.ValDef): Boolean = arg match {
case Ident(name) => name == param.name
case _ => false
}
/** The function 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.noBottom)) return ptype
}
case _ =>
}
val ofFun =
if (nme.syntheticParamNames(args.length + 1) contains param.name)
i" of expanded function $tree"
else
""
errorType(i"missing parameter type for parameter ${param.name}$ofFun, expected = $pt", param.pos)
}
def protoFormal(i: Int): Type =
if (protoFormals.length == params.length) protoFormals(i)
else errorType(i"wrong number of parameters, expected: ${protoFormals.length}", tree.pos)
/** Is `formal` a product type which is elementwise compatible with `params`? */
def ptIsCorrectProduct(formal: Type) = {
val pclass = defn.ProductNType(params.length).symbol
isFullyDefined(formal, ForceDegree.noBottom) &&
formal.derivesFrom(pclass) &&
formal.baseArgTypes(pclass).corresponds(params) {
(argType, param) =>
param.tpt.isEmpty || argType <:< typedAheadType(param.tpt).tpe
}
}
val desugared =
if (protoFormals.length == 1 && params.length != 1 && ptIsCorrectProduct(protoFormals.head)) {
desugar.makeTupledFunction(params, fnBody)
}
else {
val inferredParams: List[untpd.ValDef] =
for ((param, i) <- params.zipWithIndex) yield
if (!param.tpt.isEmpty) param
else cpy.ValDef(param)(
tpt = untpd.TypeTree(
inferredParamType(param, protoFormal(i)).underlyingIfRepeated(isJava = false)))
// Define result type of closure as the expected type, thereby pushing
// down any implicit searches. We do this even if the expected type is not fully
// defined, which is a bit of a hack. But it's needed to make the following work
// (see typers.scala and printers/PlainPrinter.scala for examples).
//
// def double(x: Char): String = s"$x$x"
// "abc" flatMap double
//
val resultTpt = protoResult match {
case WildcardType(_) => untpd.TypeTree()
case _ => untpd.TypeTree(protoResult)
}
desugar.makeClosure(inferredParams, fnBody, resultTpt)
}
typed(desugared, pt)
}
}
def typedClosure(tree: untpd.Closure, pt: Type)(implicit ctx: Context): Tree = track("typedClosure") {
val env1 = tree.env mapconserve (typed(_))
val meth1 = typedUnadapted(tree.meth)
val target =
if (tree.tpt.isEmpty)
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(d"result type of closure is an underspecified SAM type $pt", tree.pos)
TypeTree(pt)
case _ =>
if (!mt.isDependent) EmptyTree
else throw new Error(i"internal error: cannot turn dependent method type $mt into closure, position = ${tree.pos}, raw type = ${mt.toString}") // !!! DEBUG. Eventually, convert to an error?
}
case tp =>
throw new Error(i"internal error: closing over non-method $tp, pos = ${tree.pos}")
}
else typed(tree.tpt)
//println(i"typing closure $tree : ${meth1.tpe.widen}")
assignType(cpy.Closure(tree)(env1, meth1, target), meth1, target)
}
def typedMatch(tree: untpd.Match, pt: Type)(implicit ctx: Context) = track("typedMatch") {
tree.selector match {
case EmptyTree =>
val (protoFormals, _) = decomposeProtoFunction(pt, 1)
typed(desugar.makeCaseLambda(tree.cases, protoFormals.length) withPos tree.pos, pt)
case _ =>
val sel1 = typedExpr(tree.selector)
val selType = widenForMatchSelector(
fullyDefinedType(sel1.tpe, "pattern selector", tree.pos))
val cases1 = typedCases(tree.cases, selType, pt)
val cases2 = harmonize(cases1).asInstanceOf[List[CaseDef]]
assignType(cpy.Match(tree)(sel1, cases2), cases2)
}
}
def typedCases(cases: List[untpd.CaseDef], selType: Type, pt: Type)(implicit ctx: Context) = {
/** 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] = ctx.traceIndented(i"GADT syms of $selType", gadts) {
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)
}
cases mapconserve (typedCase(_, pt, selType, gadtSyms))
}
/** Type a case. Overridden in ReTyper, that's why it's separate from
* typedCases.
*/
def typedCase(tree: untpd.CaseDef, pt: Type, selType: Type, gadtSyms: Set[Symbol])(implicit ctx: Context): CaseDef = track("typedCase") {
val originalCtx = ctx
def caseRest(pat: Tree)(implicit ctx: Context) = {
pat foreachSubTree {
case b: Bind =>
if (ctx.scope.lookup(b.name) == NoSymbol) ctx.enter(b.symbol)
else ctx.error(d"duplicate pattern variable: ${b.name}", b.pos)
case _ =>
}
val guard1 = typedExpr(tree.guard, defn.BooleanType)
val body1 = ensureNoLocalRefs(typedExpr(tree.body, pt), pt, ctx.scope.toList)
.ensureConforms(pt)(originalCtx) // insert a cast if body does not conform to expected type if we disregard gadt bounds
assignType(cpy.CaseDef(tree)(pat, guard1, body1), body1)
}
val gadtCtx =
if (gadtSyms.isEmpty) ctx
else {
val c = ctx.fresh.setFreshGADTBounds
for (sym <- gadtSyms)
if (!c.gadt.bounds.contains(sym))
c.gadt.setBounds(sym, TypeBounds.empty)
c
}
val pat1 = typedPattern(tree.pat, selType)(gadtCtx)
caseRest(pat1)(gadtCtx.fresh.setNewScope)
}
def typedReturn(tree: untpd.Return)(implicit ctx: Context): Return = track("typedReturn") {
def returnProto(owner: Symbol, locals: Scope): Type =
if (owner.isConstructor) defn.UnitType
else owner.info match {
case info: PolyType =>
val tparams = locals.toList.takeWhile(_ is TypeParam)
assert(info.paramNames.length == tparams.length,
i"return mismatch from $owner, tparams = $tparams, locals = ${locals.toList}%, %")
info.instantiate(tparams.map(_.typeRef)).finalResultType
case info =>
info.finalResultType
}
def enclMethInfo(cx: Context): (Tree, Type) = {
val owner = cx.owner
if (cx == NoContext || owner.isType) {
ctx.error("return outside method definition", tree.pos)
(EmptyTree, WildcardType)
}
else if (owner != cx.outer.owner && owner.isRealMethod) {
if (owner.isCompleted) {
val from = Ident(TermRef(NoPrefix, owner.asTerm))
val proto = returnProto(owner, cx.scope)
(from, proto)
}
else (EmptyTree, errorType(d"$owner has return statement; needs result type", tree.pos))
}
else enclMethInfo(cx.outer)
}
val (from, proto) =
if (tree.from.isEmpty) enclMethInfo(ctx)
else {
val from = tree.from.asInstanceOf[tpd.Tree]
val proto =
if (ctx.erasedTypes) from.symbol.info.finalResultType
else WildcardType // We cannot reliably detect the internal type view of polymorphic or dependent methods
// because we do not know the internal type params and method params.
// Hence no adaptation is possible, and we assume WildcardType as prototype.
(from, proto)
}
val expr1 = typedExpr(tree.expr orElse untpd.unitLiteral.withPos(tree.pos), proto)
assignType(cpy.Return(tree)(expr1, from))
}
def typedTry(tree: untpd.Try, pt: Type)(implicit ctx: Context): Try = track("typedTry") {
val expr1 = typed(tree.expr, pt)
val cases1 = typedCases(tree.cases, defn.ThrowableType, pt)
val finalizer1 = typed(tree.finalizer, defn.UnitType)
val expr2 :: cases2x = harmonize(expr1 :: cases1)
val cases2 = cases2x.asInstanceOf[List[CaseDef]]
assignType(cpy.Try(tree)(expr2, cases2, finalizer1), expr2, cases2)
}
def typedThrow(tree: untpd.Throw)(implicit ctx: Context): Tree = track("typedThrow") {
val expr1 = typed(tree.expr, defn.ThrowableType)
Throw(expr1).withPos(tree.pos)
}
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))
val proto2 = // the computed type of the `elemtpt` field
if (!tree.elemtpt.isEmpty) WildcardType
else if (isFullyDefined(proto1, ForceDegree.none)) proto1
else if (tree.elems.isEmpty && tree.isInstanceOf[Trees.JavaSeqLiteral[_]])
defn.ObjectType // generic empty Java varargs are of type Object[]
else ctx.typeComparer.lub(elems1.tpes)
val elemtpt1 = typed(tree.elemtpt, proto2)
assignType(cpy.SeqLiteral(tree)(elems1, elemtpt1), elems1, elemtpt1)
}
def typedTypeTree(tree: untpd.TypeTree, pt: Type)(implicit ctx: Context): TypeTree = track("typedTypeTree") {
if (tree.original.isEmpty)
tree match {
case tree: untpd.DerivedTypeTree =>
tree.ensureCompletions
try
TypeTree(tree.derivedType(tree.attachment(untpd.OriginalSymbol))) withPos tree.pos
// btw, no need to remove the attachment. The typed
// tree is different from the untyped one, so the
// untyped tree is no longer accessed after all
// accesses with typedTypeTree are done.
catch {
case ex: NoSuchElementException =>
println(s"missing OriginalSymbol for ${ctx.owner.ownersIterator.toList}")
throw ex
}
case _ =>
assert(isFullyDefined(pt, ForceDegree.none))
tree.withType(pt)
}
else {
val original1 = typed(tree.original)
cpy.TypeTree(tree)(original1).withType(original1.tpe)
}
}
def typedSingletonTypeTree(tree: untpd.SingletonTypeTree)(implicit ctx: Context): SingletonTypeTree = track("typedSingletonTypeTree") {
val ref1 = typedExpr(tree.ref)
checkStable(ref1.tpe, tree.pos)
assignType(cpy.SingletonTypeTree(tree)(ref1), ref1)
}
def typedAndTypeTree(tree: untpd.AndTypeTree)(implicit ctx: Context): AndTypeTree = track("typedAndTypeTree") {
val left1 = typed(tree.left)
val right1 = typed(tree.right)
assignType(cpy.AndTypeTree(tree)(left1, right1), left1, right1)
}
def typedOrTypeTree(tree: untpd.OrTypeTree)(implicit ctx: Context): OrTypeTree = track("typedOrTypeTree") {
val left1 = typed(tree.left)
val right1 = typed(tree.right)
assignType(cpy.OrTypeTree(tree)(left1, right1), left1, right1)
}
def typedRefinedTypeTree(tree: untpd.RefinedTypeTree)(implicit ctx: Context): RefinedTypeTree = track("typedRefinedTypeTree") {
val tpt1 = if (tree.tpt.isEmpty) TypeTree(defn.ObjectType) else typedAheadType(tree.tpt)
val refineClsDef = desugar.refinedTypeToClass(tpt1, tree.refinements)
val refineCls = createSymbol(refineClsDef).asClass
val TypeDef(_, impl: Template) = typed(refineClsDef)
val refinements1 = impl.body
val seen = mutable.Set[Symbol]()
assert(tree.refinements.length == refinements1.length, s"${tree.refinements} != $refinements1")
def addRefinement(parent: Type, refinement: Tree): Type = {
typr.println(s"adding refinement $refinement")
checkRefinementNonCyclic(refinement, refineCls, seen)
val rsym = refinement.symbol
if ((rsym.is(Method) || rsym.isType) && rsym.allOverriddenSymbols.isEmpty)
ctx.error(i"refinement $rsym without matching type in parent $parent", refinement.pos)
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)
typr.println(i"typed refinement: ${res.tpe}")
res
}
def typedAppliedTypeTree(tree: untpd.AppliedTypeTree)(implicit ctx: Context): Tree = track("typedAppliedTypeTree") {
val tpt1 = typed(tree.tpt)(ctx retractMode Mode.Pattern)
val tparams = tpt1.tpe.typeParams
if (tparams.isEmpty) {
ctx.error(d"${tpt1.tpe} does not take type parameters", tree.pos)
tpt1
}
else {
var args = tree.args
val args1 =
if (hasNamedArg(args)) typedNamedArgs(args)
else {
if (args.length != tparams.length) {
ctx.error(d"wrong number of type arguments for ${tpt1.tpe}, should be ${tparams.length}", tree.pos)
args = args.take(tparams.length)
}
def typedArg(arg: untpd.Tree, tparam: Symbol) = {
val (desugaredArg, argPt) =
if (ctx.mode is Mode.Pattern)
(if (isVarPattern(arg)) desugar.patternVar(arg) else arg, tparam.info)
else
(arg, WildcardType)
val arg1 = typed(desugaredArg, argPt)
adaptTypeArg(arg1, tparam.info)
}
args.zipWithConserve(tparams)(typedArg(_, _)).asInstanceOf[List[Tree]]
}
// check that arguments conform to bounds is done in phase PostTyper
assignType(cpy.AppliedTypeTree(tree)(tpt1, args1), tpt1, args1)
}
}
def typedByNameTypeTree(tree: untpd.ByNameTypeTree)(implicit ctx: Context): ByNameTypeTree = track("typedByNameTypeTree") {
val result1 = typed(tree.result)
assignType(cpy.ByNameTypeTree(tree)(result1), result1)
}
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)
assignType(cpy.TypeBoundsTree(tree)(lo1, hi1), lo1, hi1)
}
def typedBind(tree: untpd.Bind, pt: Type)(implicit ctx: Context): Tree = track("typedBind") {
val pt1 = fullyDefinedType(pt, "pattern variable", tree.pos)
val body1 = typed(tree.body, pt1)
typr.println(i"typed bind $tree pt = $pt1 bodytpe = ${body1.tpe}")
body1 match {
case UnApply(fn, Nil, arg :: Nil) if tree.body.isInstanceOf[untpd.Typed] =>
// A typed pattern `x @ (_: T)` with an implicit `ctag: ClassTag[T]`
// was rewritten to `x @ ctag(_)`.
// Rewrite further to `ctag(x @ _)`
assert(fn.symbol.owner == defn.ClassTagClass)
tpd.cpy.UnApply(body1)(fn, Nil,
typed(untpd.Bind(tree.name, arg).withPos(tree.pos), arg.tpe) :: Nil)
case _ =>
val flags = if (tree.isType) BindDefinedType else EmptyFlags
val sym = ctx.newSymbol(ctx.owner, tree.name, flags, body1.tpe, coord = tree.pos)
assignType(cpy.Bind(tree)(tree.name, body1), sym)
}
}
def typedAlternative(tree: untpd.Alternative, pt: Type)(implicit ctx: Context): Alternative = track("typedAlternative") {
val trees1 = tree.trees mapconserve (typed(_, pt))
assignType(cpy.Alternative(tree)(trees1), trees1)
}
def completeAnnotations(mdef: untpd.MemberDef, sym: Symbol)(implicit ctx: Context): Unit = {
// necessary to force annotation trees to be computed.
sym.annotations.foreach(_.tree)
// necessary in order to mark the typed ahead annotations as definitely typed:
untpd.modsDeco(mdef).mods.annotations.foreach(typedAnnotation)
}
def typedAnnotation(annot: untpd.Tree)(implicit ctx: Context): Tree = track("typedAnnotation") {
typed(annot, defn.AnnotationType)
}
def typedValDef(vdef: untpd.ValDef, sym: Symbol)(implicit ctx: Context) = track("typedValDef") {
val ValDef(name, tpt, _) = vdef
completeAnnotations(vdef, sym)
val tpt1 = checkSimpleKinded(typedType(tpt))
val rhs1 = vdef.rhs match {
case rhs @ Ident(nme.WILDCARD) => rhs withType tpt1.tpe
case rhs => typedExpr(rhs, tpt1.tpe)
}
val vdef1 = assignType(cpy.ValDef(vdef)(name, tpt1, rhs1), sym)
patchIfLazy(vdef1)
vdef1
}
/** Add a @volitile to lazy vals when rewriting from Scala2 */
private def patchIfLazy(vdef: ValDef)(implicit ctx: Context): Unit = {
val sym = vdef.symbol
if (sym.is(Lazy, butNot = Deferred | Module | Synthetic) && !sym.isVolatile &&
ctx.scala2Mode && ctx.settings.rewrite.value.isDefined &&
!ctx.isAfterTyper)
patch(Position(toUntyped(vdef).envelope.start), "@volatile ")
}
def typedDefDef(ddef: untpd.DefDef, sym: Symbol)(implicit ctx: Context) = track("typedDefDef") {
val DefDef(name, tparams, vparamss, tpt, _) = ddef
completeAnnotations(ddef, sym)
val tparams1 = tparams mapconserve (typed(_).asInstanceOf[TypeDef])
// for secondary constructors we need to use that their type parameters
// are aliases of the class type parameters. See pos/i941.scala
if (sym.isConstructor && !sym.isPrimaryConstructor)
(sym.owner.typeParams, tparams1).zipped.foreach {(tparam, tdef) =>
tdef.symbol.info = TypeAlias(tparam.typeRef)
}
val vparamss1 = vparamss nestedMapconserve (typed(_).asInstanceOf[ValDef])
if (sym is Implicit) checkImplicitParamsNotSingletons(vparamss1)
val tpt1 = checkSimpleKinded(typedType(tpt))
val rhs1 = typedExpr(ddef.rhs, tpt1.tpe)
assignType(cpy.DefDef(ddef)(name, tparams1, vparamss1, tpt1, rhs1), sym)
//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): Tree = track("typedTypeDef") {
val TypeDef(name, rhs) = tdef
checkLowerNotHK(sym, tdef.tparams.map(symbolOfTree), tdef.pos)
completeAnnotations(tdef, sym)
assignType(cpy.TypeDef(tdef)(name, typedType(rhs), Nil), sym)
}
def typedClassDef(cdef: untpd.TypeDef, cls: ClassSymbol)(implicit ctx: Context) = track("typedClassDef") {
val TypeDef(name, impl @ Template(constr, parents, self, _)) = cdef
val superCtx = ctx.superCallContext
def typedParent(tree: untpd.Tree): Tree =
if (tree.isType) typedType(tree)(superCtx)
else {
val result = typedExpr(tree)(superCtx)
checkParentCall(result, cls)
result
}
completeAnnotations(cdef, cls)
val constr1 = typed(constr).asInstanceOf[DefDef]
val parentsWithClass = ensureFirstIsClass(parents mapconserve typedParent, cdef.pos.toSynthetic)
val parents1 = ensureConstrCall(cls, parentsWithClass)(superCtx)
val self1 = typed(self)(ctx.outer).asInstanceOf[ValDef] // outer context where class members are not visible
val dummy = localDummy(cls, impl)
val body1 = typedStats(impl.body, dummy)(inClassContext(self1.symbol))
checkNoDoubleDefs(cls)
val impl1 = cpy.Template(impl)(constr1, parents1, self1, body1)
.withType(dummy.nonMemberTermRef)
checkVariance(impl1)
if (!cls.is(AbstractOrTrait) && !ctx.isAfterTyper) checkRealizableBounds(cls.typeRef, cdef.pos)
assignType(cpy.TypeDef(cdef)(name, impl1, Nil), cls)
// 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.
}
/** Ensure that the first type in a list of parent types Ps points to a non-trait class.
* If that's not already the case, add one. The added class type CT is determined as follows.
* First, let C be the unique class such that
* - there is a parent P_i such that P_i derives from C, and
* - for every class D: If some parent P_j, j <= i derives from D, then C derives from D.
* Then, let CT be the smallest type which
* - has C as its class symbol, and
* - for all parents P_i: If P_i derives from C then P_i <:< CT.
*/
def ensureFirstIsClass(parents: List[Type])(implicit ctx: Context): List[Type] = {
def realClassParent(cls: Symbol): ClassSymbol =
if (!cls.isClass) defn.ObjectClass
else if (!(cls is Trait)) cls.asClass
else cls.asClass.classParents match {
case parentRef :: _ => realClassParent(parentRef.symbol)
case nil => defn.ObjectClass
}
def improve(candidate: ClassSymbol, parent: Type): ClassSymbol = {
val pcls = realClassParent(parent.classSymbol)
if (pcls derivesFrom candidate) pcls else candidate
}
parents match {
case p :: _ if p.classSymbol.isRealClass => parents
case _ =>
val pcls = (defn.ObjectClass /: parents)(improve)
typr.println(i"ensure first is class $parents%, % --> ${parents map (_ baseTypeWithArgs pcls)}%, %")
val ptype = ctx.typeComparer.glb(
defn.ObjectType :: (parents map (_ baseTypeWithArgs pcls)))
ptype :: parents
}
}
/** Ensure that first parent tree refers to a real class. */
def ensureFirstIsClass(parents: List[Tree], pos: Position)(implicit ctx: Context): List[Tree] = parents match {
case p :: ps if p.tpe.classSymbol.isRealClass => parents
case _ =>
// add synthetic class type
val first :: _ = ensureFirstIsClass(parents.tpes)
TypeTree(checkFeasible(first, pos, d"\n in inferred parent $first")).withPos(pos) :: parents
}
/** If this is a real class, make sure its first parent is a
* constructor call. Cannot simply use a type. Overridden in ReTyper.
*/
def ensureConstrCall(cls: ClassSymbol, parents: List[Tree])(implicit ctx: Context): List[Tree] = {
val firstParent :: otherParents = parents
if (firstParent.isType && !(cls is Trait) && !cls.is(JavaDefined))
typed(untpd.New(untpd.TypedSplice(firstParent), Nil)) :: otherParents
else parents
}
/** Overridden in retyper */
def checkVariance(tree: Tree)(implicit ctx: Context) = VarianceChecker.check(tree)
def localDummy(cls: ClassSymbol, impl: untpd.Template)(implicit ctx: Context): Symbol =
ctx.newLocalDummy(cls, impl.pos)
def typedImport(imp: untpd.Import, sym: Symbol)(implicit ctx: Context): Import = track("typedImport") {
val expr1 = typedExpr(imp.expr, AnySelectionProto)
checkStable(expr1.tpe, imp.expr.pos)
if (!ctx.isAfterTyper) checkRealizable(expr1.tpe, imp.expr.pos)
assignType(cpy.Import(imp)(expr1, imp.selectors), sym)
}
def typedPackageDef(tree: untpd.PackageDef)(implicit ctx: Context): Tree = track("typedPackageDef") {
val pid1 = typedExpr(tree.pid, AnySelectionProto)
val pkg = pid1.symbol
val packageContext =
if (pkg is Package) ctx.fresh.setOwner(pkg.moduleClass).setTree(tree)
else {
ctx.error(d"$pkg is already defined, cannot be a package", tree.pos)
ctx
}
val stats1 = typedStats(tree.stats, pkg.moduleClass)(packageContext)
cpy.PackageDef(tree)(pid1.asInstanceOf[RefTree], stats1) withType pkg.valRef
}
def typedAnnotated(tree: untpd.Annotated, pt: Type)(implicit ctx: Context): Tree = track("typedAnnotated") {
val annot1 = typedExpr(tree.annot, defn.AnnotationType)
val arg1 = typed(tree.arg, pt)
if (ctx.mode is Mode.Type)
assignType(cpy.Annotated(tree)(annot1, arg1), annot1, arg1)
else {
val tpt = TypeTree(AnnotatedType(arg1.tpe.widen, Annotation(annot1)))
assignType(cpy.Typed(tree)(arg1, tpt), tpt)
}
}
def typedAsFunction(tree: untpd.PostfixOp, pt: Type)(implicit ctx: Context): Tree = {
val untpd.PostfixOp(qual, nme.WILDCARD) = tree
val pt1 = if (defn.isFunctionType(pt)) pt else AnyFunctionProto
var res = typed(qual, pt1)
if (pt1.eq(AnyFunctionProto) && !defn.isFunctionClass(res.tpe.classSymbol)) {
def msg = i"not a function: ${res.tpe}; cannot be followed by `_'"
if (ctx.scala2Mode) {
// Under -rewrite, patch `x _` to `(() => x)`
ctx.migrationWarning(msg, tree.pos)
patch(Position(tree.pos.start), "(() => ")
patch(Position(qual.pos.end, tree.pos.end), ")")
res = typed(untpd.Function(Nil, untpd.TypedSplice(res)))
}
else ctx.error(msg, tree.pos)
}
res
}
/** Retrieve symbol attached to given tree */
protected def retrieveSym(tree: untpd.Tree)(implicit ctx: Context) = tree.removeAttachment(SymOfTree) match {
case Some(sym) =>
sym.ensureCompleted()
sym
case none =>
NoSymbol
}
/** A fresh local context with given tree and owner.
* Owner might not exist (can happen for self valdefs), in which case
* no owner is set in result context
*/
protected def localContext(tree: untpd.Tree, owner: Symbol)(implicit ctx: Context): FreshContext = {
val freshCtx = ctx.fresh.setTree(tree)
if (owner.exists) freshCtx.setOwner(owner) else freshCtx
}
protected def localTyper(sym: Symbol): Typer = nestedTyper.remove(sym).get
def typedUnadapted(initTree: untpd.Tree, pt: Type = WildcardType)(implicit ctx: Context): Tree = {
record("typedUnadapted")
val xtree = expanded(initTree)
xtree.removeAttachment(TypedAhead) match {
case Some(ttree) => ttree
case none =>
def typedNamed(tree: untpd.NameTree, pt: Type)(implicit ctx: Context): Tree = {
val sym = retrieveSym(xtree)
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(tree, sym).setNewScope)
case tree: untpd.DefDef =>
val typer1 = localTyper(sym)
typer1.typedDefDef(tree, sym)(localContext(tree, sym).setTyper(typer1))
case tree: untpd.TypeDef =>
if (tree.isClassDef)
typedClassDef(tree, sym.asClass)(localContext(tree, sym).setMode(ctx.mode &~ Mode.InSuperCall))
else
typedTypeDef(tree, sym)(localContext(tree, sym).setNewScope)
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.setNewScope)
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.PackageDef => typedPackageDef(tree)
case tree: untpd.Annotated => typedAnnotated(tree, pt)
case tree: untpd.TypedSplice => tree.tree
case tree: untpd.UnApply => typedUnApply(tree, pt)
case tree @ untpd.PostfixOp(qual, nme.WILDCARD) => typedAsFunction(tree, pt)
case untpd.EmptyTree => tpd.EmptyTree
case _ => typedUnadapted(desugar(tree), pt)
}
xtree match {
case xtree: untpd.NameTree => typedNamed(encodeName(xtree), pt)
case xtree: untpd.Import => typedImport(xtree, retrieveSym(xtree))
case xtree => typedUnnamed(xtree)
}
}
}
protected def encodeName(tree: untpd.NameTree)(implicit ctx: Context): untpd.NameTree =
untpd.rename(tree, tree.name.encode)
def typed(tree: untpd.Tree, pt: Type = WildcardType)(implicit ctx: Context): Tree = /*>|>*/ ctx.traceIndented (i"typing $tree", typr, show = true) /*<|<*/ {
assertPositioned(tree)
try adapt(typedUnadapted(tree, pt), pt, tree)
catch {
case ex: CyclicReference => errorTree(tree, cyclicErrorMsg(ex))
case ex: TypeError => 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 =>
mdef.removeAttachment(ExpandedTree) match {
case Some(xtree) =>
traverse(xtree :: rest)
case none =>
buf += typed(mdef)
traverse(rest)
}
case Thicket(stats) :: rest =>
traverse(stats ++ rest)
case stat :: rest =>
buf += typed(stat)(ctx.exprContext(stat, exprOwner))
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, selType: Type = WildcardType)(implicit ctx: Context): Tree =
typed(tree, selType)(ctx addMode Mode.Pattern)
def tryEither[T](op: Context => T)(fallBack: (T, TyperState) => T)(implicit ctx: Context) = {
val nestedCtx = ctx.fresh.setNewTyperState
val result = op(nestedCtx)
if (nestedCtx.reporter.hasErrors)
fallBack(result, nestedCtx.typerState)
else {
nestedCtx.typerState.commit()
result
}
}
/** Add apply node or implicit conversions. Two strategies are tried, and the first
* that is successful is picked. If neither of the strategies are successful, continues with
* `fallBack`.
*
* 1st strategy: Try to insert `.apply` so that the result conforms to prototype `pt`.
* 2nd strategy: If tree is a select `qual.name`, try to insert an implicit conversion
* around the qualifier part `qual` so that the result conforms to the expected type
* with wildcard result type.
*/
def tryInsertApplyOrImplicit(tree: Tree, pt: ProtoType)(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)
} { (failedTree, failedState) =>
val tree1 = tryInsertImplicitOnQualifier(tree, pt)
if (tree1 eq tree) fallBack(failedTree, failedState)
else adapt(tree1, pt)
}
/** If this tree is a select node `qual.name`, try to insert an implicit conversion
* `c` around `qual` so that `c(qual).name` conforms to `pt`. If that fails
* return `tree` itself.
*/
def tryInsertImplicitOnQualifier(tree: Tree, pt: Type)(implicit ctx: Context): Tree = ctx.traceIndented(i"try insert impl on qualifier $tree $pt") {
tree match {
case Select(qual, name) =>
val qualProto = SelectionProto(name, pt, NoViewsAllowed)
tryEither { implicit ctx =>
val qual1 = adaptInterpolated(qual, qualProto, EmptyTree)
if ((qual eq qual1) || ctx.reporter.hasErrors) tree
else typedSelect(cpy.Select(tree)(untpd.TypedSplice(qual1), name), pt)
} { (_, _) => tree
}
case _ => tree
}
}
def adapt(tree: Tree, pt: Type, original: untpd.Tree = untpd.EmptyTree)(implicit ctx: Context) = /*>|>*/ track("adapt") /*<|<*/ {
/*>|>*/ ctx.traceIndented(i"adapting $tree of type ${tree.tpe} to $pt", typr, show = true) /*<|<*/ {
if (tree.isDef) interpolateUndetVars(tree, tree.symbol)
else if (!tree.tpe.widen.isInstanceOf[MethodOrPoly]) interpolateUndetVars(tree, NoSymbol)
tree.overwriteType(tree.tpe.simplified)
adaptInterpolated(tree, pt, original)
}
}
/** (-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, original: untpd.Tree)(implicit ctx: Context): Tree = {
assert(pt.exists)
def methodStr = err.refStr(methPart(tree).tpe)
def missingArgs = errorTree(tree,
d"""missing arguments for $methodStr
|follow this method with `_' if you want to treat it as a partially applied function""".stripMargin)
def adaptOverloaded(ref: TermRef) = {
val altDenots = ref.denot.alternatives
typr.println(i"adapt overloaded $ref with alternatives ${altDenots map (_.info)}%, %")
val alts = altDenots map (alt =>
TermRef.withSigAndDenot(ref.prefix, ref.name, alt.info.signature, alt))
def expectedStr = err.expectedTypeStr(pt)
resolveOverloaded(alts, pt) match {
case alt :: Nil =>
adapt(tree.withType(alt), pt, original)
case Nil =>
def noMatches =
errorTree(tree,
d"""none of the ${err.overloadedAltsStr(altDenots)}
|match $expectedStr""".stripMargin)
def hasEmptyParams(denot: SingleDenotation) = denot.info.paramTypess == ListOfNil
pt match {
case pt: FunProto =>
tryInsertApplyOrImplicit(tree, pt)((_, _) => noMatches)
case _ =>
if (altDenots exists (_.info.paramTypess == ListOfNil))
typed(untpd.Apply(untpd.TypedSplice(tree), Nil), pt)
else
noMatches
}
case alts =>
val remainingDenots = alts map (_.denot.asInstanceOf[SingleDenotation])
def all = if (remainingDenots.length == 2) "both" else "all"
errorTree(tree,
d"""Ambiguous overload. The ${err.overloadedAltsStr(remainingDenots)}
|$all match $expectedStr""".stripMargin)
}
}
def adaptToArgs(wtp: Type, pt: FunProto): Tree = wtp match {
case _: MethodType | _: PolyType =>
def isUnary = wtp.firstParamTypes match {
case ptype :: Nil => !ptype.isRepeatedParam
case _ => false
}
if (pt.args.lengthCompare(1) > 0 && isUnary && ctx.canAutoTuple)
adaptToArgs(wtp, pt.tupled)
else
tree
case _ => tryInsertApplyOrImplicit(tree, pt) {
val more = tree match {
case Apply(_, _) => " more"
case _ => ""
}
(_, _) => errorTree(tree, d"$methodStr does not take$more parameters")
}
}
/** If `tp` is a TypeVar which is fully constrained (i.e. its upper bound `hi` conforms
* to its lower bound `lo`), replace `tp` by `hi`. This is necessary to
* keep the right constraints for some implicit search problems. The paradigmatic case
* is `implicitNums.scala`. Without the healing done in `followAlias`, we cannot infer
* implicitly[_3], where _2 is the typelevel number 3. The problem here is that if a
* prototype is, say, Succ[Succ[Zero]], we can infer that it's argument type is Succ[Zero].
* But if the prototype is N? >: Succ[Succ[Zero]] <: Succ[Succ[Zero]], the same
* decomposition does not work - we'd get a N?#M where M is the element type name of Succ
* instead.
*/
def followAlias(tp: Type)(implicit ctx: Context): Type = {
val constraint = ctx.typerState.constraint
def inst(tp: Type): Type = tp match {
case TypeBounds(lo, hi)
if (lo eq hi) || (hi <:< lo)(ctx.fresh.setExploreTyperState) =>
inst(lo)
case tp: PolyParam =>
constraint.typeVarOfParam(tp).orElse(tp)
case _ => tp
}
tp match {
case tp: TypeVar if constraint.contains(tp) => inst(constraint.entry(tp.origin))
case _ => tp
}
}
def adaptNoArgs(wtp: Type): Tree = wtp match {
case wtp: ExprType =>
adaptInterpolated(tree.withType(wtp.resultType), pt, original)
case wtp: ImplicitMethodType if constrainResult(wtp, followAlias(pt)) =>
val tvarsToInstantiate = tvarsInParams(tree)
wtp.paramTypes.foreach(instantiateSelected(_, tvarsToInstantiate))
val constr = ctx.typerState.constraint
def addImplicitArgs = {
val errors = new mutable.ListBuffer[() => String]
def implicitArgError(msg: => String) = {
errors += (() => msg)
EmptyTree
}
def issueErrors() = {
for (err <- errors) ctx.error(err(), tree.pos.endPos)
tree
}
val args = (wtp.paramNames, wtp.paramTypes).zipped map { (pname, formal) =>
def where = d"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 =>
val arg = synthesizedClassTag(formal)
if (!arg.isEmpty) arg
else implicitArgError(d"no implicit argument of type $formal found for $where" + failure.postscript)
}
}
if (errors.nonEmpty) {
// If there are several arguments, some arguments might already
// have influenced the context, binding variables, but later ones
// might fail. In that case the constraint needs to be reset.
ctx.typerState.constraint = constr
// If method has default params, fall back to regular application
// where all inferred implicits are passed as named args.
if (tree.symbol.hasDefaultParams) {
val namedArgs = (wtp.paramNames, args).zipped.flatMap { (pname, arg) =>
arg match {
case EmptyTree => Nil
case _ => untpd.NamedArg(pname, untpd.TypedSplice(arg)) :: Nil
}
}
tryEither { implicit ctx =>
typed(untpd.Apply(untpd.TypedSplice(tree), namedArgs), pt)
} { (_, _) =>
issueErrors()
}
} else issueErrors()
}
else adapt(tpd.Apply(tree, args), pt)
}
if ((pt eq WildcardType) || original.isEmpty) addImplicitArgs
else
ctx.typerState.tryWithFallback(addImplicitArgs) {
adapt(typed(original, WildcardType), pt, EmptyTree)
}
case wtp: MethodType if !pt.isInstanceOf[SingletonType] =>
val arity =
if (defn.isFunctionType(pt))
if (!isFullyDefined(pt, ForceDegree.none) && isFullyDefined(wtp, ForceDegree.none))
// if method type is fully defined, but expected type is not,
// prioritize method parameter types as parameter types of the eta-expanded closure
0
else defn.functionArity(pt)
else if (pt eq AnyFunctionProto) wtp.paramTypes.length
else -1
if (arity >= 0 && !tree.symbol.isConstructor)
typed(etaExpand(tree, wtp, arity), pt)
else if (wtp.paramTypes.isEmpty)
adaptInterpolated(tpd.Apply(tree, Nil), pt, EmptyTree)
else if (wtp.isImplicit)
err.typeMismatch(tree, pt)
else
missingArgs
case _ =>
if (tree.tpe <:< pt) tree
else if (ctx.mode is Mode.Pattern) tree // no subtype check for pattern
else if (wtp.isInstanceOf[MethodType]) missingArgs
else {
typr.println(i"adapt to subtype ${tree.tpe} !<:< $pt")
//typr.println(TypeComparer.explained(implicit ctx => tree.tpe <:< pt))
adaptToSubType(wtp)
}
}
/** If `formal` is of the form ClassTag[T], where `T` is a class type,
* synthesize a class tag for `T`.
*/
def synthesizedClassTag(formal: Type): Tree = {
if (formal.isRef(defn.ClassTagClass))
formal.argTypes match {
case arg :: Nil =>
val tp = fullyDefinedType(arg, "ClassTag argument", tree.pos)
tp.underlyingClassRef(refinementOK = false) match {
case tref: TypeRef =>
return ref(defn.ClassTagModule)
.select(nme.apply)
.appliedToType(tp)
.appliedTo(clsOf(tref))
.withPos(tree.pos.endPos)
case _ =>
}
case _ =>
}
EmptyTree
}
/** Adapt an expression of constant type to a different constant type `tpe`. */
def adaptConstant(tree: Tree, tpe: ConstantType): Tree = {
def lit = Literal(tpe.value).withPos(tree.pos)
tree match {
case Literal(c) => lit
case tree @ Block(stats, expr) => tpd.cpy.Block(tree)(stats, adaptConstant(expr, tpe))
case tree =>
if (isIdempotentExpr(tree)) lit // See discussion in phase Literalize why we demand isIdempotentExpr
else Block(tree :: Nil, lit)
}
}
def adaptToSubType(wtp: Type): Tree = {
// try converting a constant to the target type
val folded = ConstFold(tree, pt)
if (folded ne tree) return adaptConstant(folded, folded.tpe.asInstanceOf[ConstantType])
// 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() =>
// was ... && isFullyDefined(pt, ForceDegree.noBottom)
// but this prevents case blocks from implementing polymorphic partial functions,
// since we do not know the result parameter a priori. Have to wait until the
// body is typechecked.
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] && !failure.isInstanceOf[AmbiguousImplicits]) 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 {
var typeArgs = tree match {
case Select(New(tpt), nme.CONSTRUCTOR) => tpt.tpe.dealias.argTypesLo
case _ => Nil
}
if (typeArgs.isEmpty) typeArgs = constrained(poly, tree)._2
convertNewArray(
adaptInterpolated(tree.appliedToTypes(typeArgs), pt, original))
}
case wtp =>
pt match {
case pt: FunProto =>
adaptToArgs(wtp, pt)
case pt: PolyProto =>
tryInsertApplyOrImplicit(tree, pt) {
(_, _) => tree // error will be reported in typedTypeApply
}
case _ =>
if (ctx.mode is Mode.Type)
if ((ctx.mode is Mode.Pattern) || tree.tpe <:< pt) tree
else err.typeMismatch(tree, pt)
else adaptNoArgs(wtp)
}
}
}
}
}
|