package dotty.tools.dotc
package transform
import TreeTransforms._
import core.DenotTransformers._
import core.Denotations._
import core.SymDenotations._
import core.Contexts._
import core.Symbols._
import core.Types._
import core.Flags._
import core.Constants._
import core.StdNames._
import core.Decorators._
import core.TypeErasure.isErasedType
import core.Phases.Phase
import typer._
import typer.ErrorReporting._
import reporting.ThrowingReporter
import ast.Trees._
import ast.{tpd, untpd}
import util.SourcePosition
import collection.mutable
import ProtoTypes._
import java.lang.AssertionError
/** Run by -Ycheck option after a given phase, this class retypes all syntax trees
* and verifies that the type of each tree node so obtained conforms to the type found in the tree node.
* It also performs the following checks:
*
* - The owner of each definition is the same as the owner of the current typing context.
* - Ident nodes do not refer to a denotation that would need a select to be accessible
* (see tpd.needsSelect).
* - After typer, identifiers and select nodes refer to terms only (all types should be
* represented as TypeTrees then).
*/
class TreeChecker {
import ast.tpd._
private def previousPhases(phases: List[Phase])(implicit ctx: Context): List[Phase] = phases match {
case (phase: TreeTransformer) :: phases1 =>
val subPhases = phase.transformations.map(_.phase)
val previousSubPhases = previousPhases(subPhases.toList)
if (previousSubPhases.length == subPhases.length) previousSubPhases ::: previousPhases(phases1)
else previousSubPhases
case phase :: phases1 if phase ne ctx.phase =>
phase :: previousPhases(phases1)
case _ =>
Nil
}
def check(phasesToRun: Seq[Phase], ctx: Context) = {
val prevPhase = ctx.phase.prev // can be a mini-phase
val squahsedPhase = ctx.squashed(prevPhase)
println(s"checking ${ctx.compilationUnit} after phase ${squahsedPhase}")
val checkingCtx = ctx.fresh
.setTyperState(ctx.typerState.withReporter(new ThrowingReporter(ctx.typerState.reporter)))
val checker = new Checker(previousPhases(phasesToRun.toList)(ctx))
try checker.typedExpr(ctx.compilationUnit.tpdTree)(checkingCtx)
catch {
case ex: Throwable =>
implicit val ctx: Context = checkingCtx
println(i"*** error while checking after phase ${checkingCtx.phase.prev} ***")
throw ex
}
}
class Checker(phasesToCheck: Seq[Phase]) extends ReTyper {
val nowDefinedSyms = new mutable.HashSet[Symbol]
val everDefinedSyms = new mutable.HashMap[Symbol, Tree]
def withDefinedSym[T](tree: untpd.Tree)(op: => T)(implicit ctx: Context): T = tree match {
case tree: DefTree =>
val sym = tree.symbol
everDefinedSyms.get(sym) match {
case Some(t) =>
if(t ne tree)
ctx.warning(i"symbol ${sym.fullName} is defined at least twice in different parts of AST")
// should become an error
case None =>
everDefinedSyms(sym) = tree
}
assert(!nowDefinedSyms.contains(sym), i"doubly defined symbol: ${sym.fullName} in $tree")
if(ctx.settings.YcheckMods.value) {
tree match {
case t: MemberDef =>
if (t.name ne sym.name) ctx.warning(s"symbol ${sym.fullName} name doesn't correspond to AST: ${t}")
if (sym.flags != t.mods.flags) ctx.warning(s"symbol ${sym.fullName} flags ${sym.flags} doesn't match AST definition flags ${t.mods.flags}")
// todo: compare trees inside annotations
case _ =>
}
}
nowDefinedSyms += tree.symbol
//println(i"defined: ${tree.symbol}")
val res = op
nowDefinedSyms -= tree.symbol
//println(i"undefined: ${tree.symbol}")
res
case _ => op
}
def withDefinedSyms[T](trees: List[untpd.Tree])(op: => T)(implicit ctx: Context) =
trees.foldRightBN(op)(withDefinedSym(_)(_))
def withDefinedSymss[T](vparamss: List[List[untpd.ValDef]])(op: => T)(implicit ctx: Context): T =
vparamss.foldRightBN(op)(withDefinedSyms(_)(_))
def assertDefined(tree: untpd.Tree)(implicit ctx: Context) =
if (tree.symbol.maybeOwner.isTerm)
assert(nowDefinedSyms contains tree.symbol, i"undefined symbol ${tree.symbol}")
override def typedUnadapted(tree: untpd.Tree, pt: Type)(implicit ctx: Context): tpd.Tree = {
val res = tree match {
case _: untpd.UnApply =>
// can't recheck patterns
tree.asInstanceOf[tpd.Tree]
case _: untpd.TypedSplice | _: untpd.Thicket | _: EmptyValDef[_] =>
super.typedUnadapted(tree)
case _ if tree.isType =>
promote(tree)
case _ =>
val tree1 = super.typedUnadapted(tree, pt)
def isSubType(tp1: Type, tp2: Type) =
(tp1 eq tp2) || // accept NoType / NoType
(tp1 <:< tp2)
def divergenceMsg(tp1: Type, tp2: Type) =
s"""Types differ
|Original type : ${tree.typeOpt.show}
|After checking: ${tree1.tpe.show}
|Original tree : ${tree.show}
|After checking: ${tree1.show}
|Why different :
""".stripMargin + core.TypeComparer.explained((tp1 <:< tp2)(_))
if (tree.hasType) // it might not be typed because Typer sometimes constructs new untyped trees and resubmits them to typedUnadapted
assert(isSubType(tree1.tpe, tree.typeOpt), divergenceMsg(tree1.tpe, tree.typeOpt))
tree1
}
phasesToCheck.foreach(_.checkPostCondition(res))
res
}
override def typedIdent(tree: untpd.Ident, pt: Type)(implicit ctx: Context): Tree = {
assert(tree.isTerm || !ctx.isAfterTyper, tree.show + " at " + ctx.phase)
assert(tree.isType || !needsSelect(tree.tpe), i"bad type ${tree.tpe} for $tree # ${tree.uniqueId}")
assertDefined(tree)
super.typedIdent(tree, pt)
}
override def typedSelect(tree: untpd.Select, pt: Type)(implicit ctx: Context): Tree = {
assert(tree.isTerm || !ctx.isAfterTyper, tree.show + " at " + ctx.phase)
super.typedSelect(tree, pt)
}
private def checkOwner(tree: untpd.Tree)(implicit ctx: Context): Unit = {
def ownerMatches(symOwner: Symbol, ctxOwner: Symbol): Boolean =
symOwner == ctxOwner ||
ctxOwner.isWeakOwner && ownerMatches(symOwner, ctxOwner.owner)
assert(ownerMatches(tree.symbol.owner, ctx.owner),
i"bad owner; ${tree.symbol} has owner ${tree.symbol.owner}, expected was ${ctx.owner}\n" +
i"owner chain = ${tree.symbol.ownersIterator.toList}%, %, ctxOwners = ${ctx.outersIterator.map(_.owner).toList}%, %")
}
override def typedClassDef(cdef: untpd.TypeDef, cls: ClassSymbol)(implicit ctx: Context) = {
val TypeDef(_, impl @ Template(constr, _, _, _)) = cdef
assert(cdef.symbol == cls)
assert(impl.symbol.owner == cls)
assert(constr.symbol.owner == cls)
assert(cls.primaryConstructor == constr.symbol, i"mismatch, primary constructor ${cls.primaryConstructor}, in tree = ${constr.symbol}")
checkOwner(impl)
checkOwner(impl.constr)
super.typedClassDef(cdef, cls)
}
override def typedDefDef(ddef: untpd.DefDef, sym: Symbol)(implicit ctx: Context) =
withDefinedSyms(ddef.tparams) {
withDefinedSymss(ddef.vparamss) {
super.typedDefDef(ddef, sym)
}
}
override def typedCase(tree: untpd.CaseDef, pt: Type, selType: Type, gadtSyms: Set[Symbol])(implicit ctx: Context): CaseDef = {
withDefinedSyms(tree.pat.asInstanceOf[tpd.Tree].filterSubTrees(_.isInstanceOf[ast.Trees.Bind[_]])) {
super.typedCase(tree, pt, selType, gadtSyms)
}
}
override def typedBlock(tree: untpd.Block, pt: Type)(implicit ctx: Context) =
withDefinedSyms(tree.stats) { super.typedBlock(tree, pt) }
/** Check that all defined symbols have legal owners.
* An owner is legal if it is either the same as the context's owner
* or there's an owner chain of valdefs starting at the context's owner and
* reaching up to the symbol's owner. The reason for this relaxed matching
* is that we should be able to pull out an expression as an initializer
* of a helper value without having to do a change owner traversal of the expression.
*/
override def typedStats(trees: List[untpd.Tree], exprOwner: Symbol)(implicit ctx: Context): List[Tree] = {
for (tree <- trees) tree match {
case tree: untpd.DefTree => checkOwner(tree)
case _: untpd.Thicket => assert(false, i"unexpanded thicket $tree in statement sequence $trees%\n%")
case _ =>
}
super.typedStats(trees, exprOwner)
}
override def ensureNoLocalRefs(block: Block, pt: Type, forcedDefined: Boolean = false)(implicit ctx: Context): Tree =
block
override def adapt(tree: Tree, pt: Type, original: untpd.Tree = untpd.EmptyTree)(implicit ctx: Context) = {
def isPrimaryConstructorReturn =
ctx.owner.isPrimaryConstructor && pt.isRef(ctx.owner.owner) && tree.tpe.isRef(defn.UnitClass)
if (ctx.mode.isExpr &&
!tree.isEmpty &&
!isPrimaryConstructorReturn &&
!pt.isInstanceOf[FunProto])
assert(tree.tpe <:< pt,
s"error at ${sourcePos(tree.pos)}\n" +
err.typeMismatchStr(tree.tpe, pt) + "\ntree = " + tree)
tree
}
}
}
object TreeChecker extends TreeChecker