/* NSC -- new Scala compiler
* Copyright 2005-2006 LAMP/EPFL
* @author Martin Odersky
*/
// $Id$
package scala.tools.nsc.typechecker
import symtab.Flags._
import scala.tools.nsc.util.Position
/** This trait ...
*
* @author Martin Odersky
* @version 1.0
*/
trait Contexts requires Analyzer {
import global._
val NoContext = new Context {
override def implicitss: List[List[ImplicitInfo]] = List()
outer = this;
}
NoContext.enclClass = NoContext
NoContext.enclMethod = NoContext
private val startContext = {
NoContext.make(
global.Template(List(), List()) setSymbol global.NoSymbol setType global.NoType,
global.definitions.RootClass,
global.definitions.RootClass.info.decls)
}
def rootContext(unit: CompilationUnit): Context =
rootContext(unit, EmptyTree, false)
def rootContext(unit: CompilationUnit, tree: Tree, erasedTypes: boolean): Context = {
import definitions._
var sc = startContext
def addImport(pkg: Symbol): unit = {
assert(pkg ne null)
val qual = gen.mkAttributedStableRef(pkg)
sc = sc.makeNewImport(
Import(qual, List((nme.WILDCARD, null)))
.setSymbol(NoSymbol.newImport(NoPos).setFlag(SYNTHETIC).setInfo(ImportType(qual)))
.setType(NoType))
sc.depth = sc.depth + 1
}
if (!settings.noimports.value) {
assert(isDefinitionsInitialized)
addImport(JavaLangPackage)
assert(ScalaPackage ne null, "Scala package is null")
addImport(ScalaPackage)
if (!(settings.nopredefs.value || treeInfo.containsLeadingPredefImport(List(unit.body))))
addImport(PredefModule)
}
val c = sc.make(unit, tree, sc.owner, sc.scope, sc.imports)
c.reportAmbiguousErrors = !erasedTypes
c.reportGeneralErrors = !erasedTypes
c.implicitsEnabled = !erasedTypes
c
}
def resetContexts: unit = {
var sc = startContext
while (sc != NoContext) {
sc.tree match {
case Import(qual, _) => qual.tpe = singleType(qual.symbol.owner.thisType, qual.symbol)
case _ =>
}
sc = sc.outer
}
}
class Context {
var unit: CompilationUnit = _
var tree: Tree = _ // Tree associated with this context
var owner: Symbol = NoSymbol// The current owner
var scope: Scope = _ // The current scope
var outer: Context = _ // The next outer context
var enclClass: Context = _ // The next outer context whose tree is a
// template or package definition
var enclMethod: Context = _ // The next outer context whose tree is a method
var variance: int = _ // Variance relative to enclosing class
private var _undetparams: List[Symbol] = List() // Undetermined type parameters,
// not inherited to child contexts
var depth: int = 0
var imports: List[ImportInfo] = List()
var prefix: Type = NoPrefix
var inConstructorSuffix = false // are we in a secondary constructor
// after the this constructor call?
var returnsSeen = false // for method context: were returns encountered?
var reportAmbiguousErrors = false
var reportGeneralErrors = false
var implicitsEnabled = false
var checking = false
var retyping = false
var savedTypeBounds: List[(Symbol, Type)] = List()
override def equals(that : Any) = that match {
case that if (super.equals(that)) => true
case NoContext => false
case that : Context =>
val a0 = if (tree eq null) tree == that.tree else tree equalsStructure that.tree;
val a1 = owner == that.owner;
val a2 = scope == that.scope;
val a3 = outer == that.outer;
val a4 = {
if (enclClass eq this) {
that.enclClass eq that;
} else enclClass == that.enclClass;
}
val a5 = {
if (enclMethod eq this)
that.enclMethod eq that;
else enclMethod == that.enclMethod;
}
val a6 = variance == that.variance;
val a7 = _undetparams == that._undetparams;
val a8 = depth == that.depth;
val a9 = if (imports.length != that.imports.length) false else
(for (val x <- imports.zip(that.imports)) yield
(x._1.tree equalsStructure x._2.tree) && x._1.depth == x._2.depth).
foldLeft(true)((x,y) => x && y);
val a10 = prefix == that.prefix;
val a11 = inConstructorSuffix == that.inConstructorSuffix;
val a12 = implicitsEnabled == that.implicitsEnabled;
val a13 = checking == that.checking;
val a14 = retyping == that.retyping;
val a15 = savedTypeBounds == that.savedTypeBounds;
a0 && a1 && a2 && a3 && a4 && a5 && a6 && a7 && a8 && a9 && a10 && a11 && a12 && a13 && a14 && a15
case _ => false;
}
def undetparams = _undetparams
def undetparams_=(ps: List[Symbol]) = {
//System.out.println("undetparams = " + ps);//debug
_undetparams = ps
}
/**
* @param unit ...
* @param tree ...
* @param owner ...
* @param scope ...
* @param imports ...
* @return ...
*/
def make(unit: CompilationUnit, tree: Tree, owner: Symbol,
scope: Scope, imports: List[ImportInfo]): Context = {
val c = new Context
c.unit = unit
c.tree = tree
c.owner = owner
c.scope = scope
tree match {
case Template(_, _) | PackageDef(_, _) =>
c.enclClass = c
c.prefix = c.owner.thisType
c.inConstructorSuffix = false
case _ =>
c.enclClass = this.enclClass
c.prefix =
if (c.owner != this.owner && c.owner.isTerm) NoPrefix
else this.prefix
c.inConstructorSuffix = this.inConstructorSuffix
}
tree match {
case DefDef(_, _, _, _, _, _) =>
c.enclMethod = c
case _ =>
c.enclMethod = this.enclMethod
}
c.variance = this.variance
c.depth = if (scope == this.scope) this.depth else this.depth + 1
c.imports = imports
c.reportAmbiguousErrors = this.reportAmbiguousErrors
c.reportGeneralErrors = this.reportGeneralErrors
c.implicitsEnabled = this.implicitsEnabled
c.checking = this.checking
c.retyping = this.retyping
c.outer = this
c
}
def make(unit: CompilationUnit): Context = {
val c = make(unit, EmptyTree, owner, scope, imports)
c.reportAmbiguousErrors = true
c.reportGeneralErrors = true
c.implicitsEnabled = true
c
}
def makeNewImport(imp: Import): Context =
make(unit, imp, owner, scope, new ImportInfo(imp, depth) :: imports)
def make(tree: Tree, owner: Symbol, scope: Scope): Context =
make(unit, tree, owner, scope, imports)
def makeNewScope(tree: Tree, owner: Symbol): Context =
make(tree, owner, newScope(scope))
def make(tree: Tree, owner: Symbol): Context =
make(tree, owner, scope)
def make(tree: Tree): Context =
make(tree, owner)
def makeSilent(reportAmbiguousErrors: boolean): Context = {
val c = make(tree)
c.reportGeneralErrors = false
c.reportAmbiguousErrors = reportAmbiguousErrors
c
}
def makeImplicit(reportAmbiguousErrors: boolean) = {
val c = makeSilent(reportAmbiguousErrors)
c.implicitsEnabled = false
c
}
def makeConstructorContext = {
var baseContext = enclClass.outer
//todo: find out why we need next line
while (baseContext.tree.isInstanceOf[Template])
baseContext = baseContext.outer
val argContext = baseContext.makeNewScope(tree, owner)
for (val sym <- scope.toList) argContext.scope enter sym
argContext
}
def makeConstructorSuffixContext = {
val c = make(tree)
c.inConstructorSuffix = true
c
}
def error(pos: Int, err: Error) {
val msg = err.getMessage()
if (reportGeneralErrors)
unit.error(pos, if (checking) "**** ERROR DURING INTERNAL CHECKING ****\n" + msg else msg)
else
throw err
}
def error(pos: PositionType, msg: String) {
if (reportGeneralErrors)
unit.error(pos, if (checking) "**** ERROR DURING INTERNAL CHECKING ****\n" + msg else msg)
else
throw new TypeError(pos, msg)
}
def warning(pos: PositionType, msg: String) {
if (reportGeneralErrors) unit.warning(pos, msg)
}
/**
* @param pos ...
* @param pre ...
* @param sym1 ...
* @param sym2 ...
* @param rest ...
*/
def ambiguousError(pos: PositionType, pre: Type, sym1: Symbol,
sym2: Symbol, rest: String): unit = {
val msg =
("ambiguous reference to overloaded definition,\n" +
"both " + sym1 + sym1.locationString + " of type " + pre.memberType(sym1) +
"\nand " + sym2 + sym2.locationString + " of type " + pre.memberType(sym2) +
"\nmatch " + rest)
if (reportAmbiguousErrors) {
if (!pre.isErroneous && !sym1.isErroneous && !sym2.isErroneous)
unit.error(pos, msg)
} else throw new TypeError(pos, msg)
}
def outerContext(clazz: Symbol): Context = {
var c = this
while (c != NoContext && c.owner != clazz) c = c.outer.enclClass
c
}
def isLocal(): boolean = tree match {
case Block(_,_) => true
case PackageDef(_, _) => false
case EmptyTree => false
case _ => outer.isLocal()
}
def nextEnclosing(p: Context => boolean): Context =
if (this == NoContext || p(this)) this else outer.nextEnclosing(p)
override def toString(): String = {
if (this == NoContext) "NoContext"
else owner.toString() + " @ " + tree.getClass() +
" " + tree.toString() + ", scope = " + scope.hashCode() +
" " + scope.toList + "\n:: " + outer.toString()
}
/** Return closest enclosing context that defines a superclass of `clazz', or a
* companion module of a superclass of `clazz', or NoContext if none exists */
def enclosingSuperClassContext(clazz: Symbol): Context = {
var c = this.enclClass
while (c != NoContext &&
!clazz.isNonBottomSubClass(c.owner) &&
!(c.owner.isModuleClass && clazz.isNonBottomSubClass(c.owner.linkedClassOfModule)))
c = c.outer.enclClass
c
}
/** Return closest enclosing context that defines a subclass of `clazz', or NoContext
* if none exists */
def enclosingSubClassContext(clazz: Symbol): Context = {
var c = this.enclClass
while (c != NoContext && !c.owner.isNonBottomSubClass(clazz))
c = c.outer.enclClass
c
}
/** Is <code>sym</code> accessible as a member of tree `site' with type
* <code>pre</code> in current context?
*
* @param sym ...
* @param pre ...
* @param superAccess ...
* @return ...
*/
def isAccessible(sym: Symbol, pre: Type, superAccess: boolean): boolean = {
/** Are we inside definition of `owner'? */
def accessWithin(owner: Symbol): boolean = {
var c = this
while (c != NoContext && c.owner != owner) {
if (c.outer eq null) assert(false, "accessWithin(" + owner + ") " + c);//debug
if (c.outer.enclClass eq null) assert(false, "accessWithin(" + owner + ") " + c);//debug
c = c.outer.enclClass
}
c != NoContext
}
/** Is `clazz' a subclass of an enclosing class? */
def isSubClassOfEnclosing(clazz: Symbol): boolean =
enclosingSuperClassContext(clazz) != NoContext
def isSubThisType(pre: Type, clazz: Symbol): boolean = pre match {
case ThisType(pclazz) => pclazz isNonBottomSubClass clazz
case _ => false
}
(pre == NoPrefix) || {
val ab = sym.accessBoundary(sym.owner)
((ab == NoSymbol)
||
(accessWithin(ab) || accessWithin(ab.linkedClassOfClass)) &&
(!sym.hasFlag(LOCAL) ||
(sym hasFlag PROTECTED) && isSubThisType(pre, sym.owner) ||
pre =:= sym.owner.thisType)
||
(sym hasFlag PROTECTED) &&
(superAccess ||
(pre.widen.symbol.isNonBottomSubClass(sym.owner) &&
(isSubClassOfEnclosing(pre.widen.symbol) || phase.erasedTypes))))
// note: phase.erasedTypes disables last test, because fater addinterfaces
// implementation classes are not in the superclass chain. If we enable the
// test, bug780 fails.
}
}
def pushTypeBounds(sym: Symbol): unit = {
savedTypeBounds = (sym, sym.info) :: savedTypeBounds
}
def restoreTypeBounds(tp: Type): Type = {
var current = tp
for (val (sym, info) <- savedTypeBounds) {
if (settings.debug.value) log("resetting " + sym + " to " + info);
sym.info match {
case TypeBounds(lo, hi) if (hi <:< lo && lo <:< hi) =>
current = current.subst(List(sym), List(lo))
case _ =>
}
sym.setInfo(info)
}
savedTypeBounds = List()
current
}
private var implicitsCache: List[List[ImplicitInfo]] = null
private var implicitsRunId = NoRunId
private def collectImplicits(syms: List[Symbol], pre: Type): List[ImplicitInfo] =
for (val sym <- syms; sym.hasFlag(IMPLICIT) && isAccessible(sym, pre, false))
yield new ImplicitInfo(sym.name, pre, sym)
private def collectImplicitImports(imp: ImportInfo): List[ImplicitInfo] = {
val pre = imp.qual.tpe
def collect(sels: List[(Name, Name)]): List[ImplicitInfo] = sels match {
case List() => List()
case List((nme.WILDCARD, _)) => collectImplicits(pre.implicitMembers, pre)
case (from, to) :: sels1 =>
var impls = collect(sels1) filter (info => info.name != from)
if (to != nme.WILDCARD) {
val sym = imp.importedSymbol(to)
if (sym.hasFlag(IMPLICIT)) impls = new ImplicitInfo(to, pre, sym) :: impls
}
impls
}
if (settings.debug.value)
log("collect implicit imports " + imp + "=" + collect(imp.tree.selectors))//debug
collect(imp.tree.selectors)
}
def implicitss: List[List[ImplicitInfo]] = {
val nextOuter =
if (owner.isConstructor) {
if (outer.tree.isInstanceOf[Template]) outer.outer.outer
else outer.outer
} else outer
if (implicitsRunId != currentRunId) {
implicitsRunId = currentRunId
implicitsCache = List()
val newImplicits: List[ImplicitInfo] =
if (owner != nextOuter.owner && owner.isClass && !owner.isPackageClass) {
if (!owner.isInitialized) return nextOuter.implicitss
if (settings.debug.value)
log("collect member implicits " + owner + ", implicit members = " +
owner.thisType.implicitMembers)//debug
collectImplicits(owner.thisType.implicitMembers, owner.thisType)
} else if (scope != nextOuter.scope && !owner.isPackageClass) {
if (settings.debug.value)
log("collect local implicits " + scope.toList)//debug
collectImplicits(scope.toList, NoPrefix)
} else if (imports != nextOuter.imports) {
assert(imports.tail == nextOuter.imports)
collectImplicitImports(imports.head)
} else List()
implicitsCache = if (newImplicits.isEmpty) nextOuter.implicitss
else newImplicits :: nextOuter.implicitss
}
implicitsCache
}
}
class ImportInfo(val tree: Import, val depth: int) {
/** The prefix expression */
def qual: Tree = tree.symbol.info match {
case ImportType(expr) => expr
case _ => throw new FatalError("symbol " + tree.symbol + " has bad type: " + tree.symbol.info);//debug
}
/** Is name imported explicitly, not via wildcard? */
def isExplicitImport(name: Name): boolean =
tree.selectors exists (._2.==(name.toTermName))
/** The symbol with name <code>name</code> imported from import clause
* <code>tree</code>.
*/
def importedSymbol(name: Name): Symbol = {
var result: Symbol = NoSymbol
var renamed = false
var selectors = tree.selectors
while (selectors != Nil && result == NoSymbol) {
if (selectors.head._2 == name.toTermName)
result = qual.tpe.member(
if (name.isTypeName) selectors.head._1.toTypeName else selectors.head._1)
else if (selectors.head._1 == name.toTermName)
renamed = true
else if (selectors.head._1 == nme.WILDCARD && !renamed)
result = qual.tpe.member(name)
selectors = selectors.tail
}
result
}
override def toString() = tree.toString()
}
class ImplicitInfo(val name: Name, val pre: Type, val sym: Symbol) {
private var tpeCache: Type = null
def tpe: Type = {
if (tpeCache eq null) tpeCache = pre.memberType(sym)
tpeCache
}
override def toString = "ImplicitInfo(" + name + "," + pre + "," + sym + ")"
}
val NoImplicitInfo = new ImplicitInfo(null, null, null)
case class ImportType(expr: Tree) extends Type
}