Adaptations to make pattern matcher in new world

Tests now always include erasure (before quite a few tests failed when erasure
was enableed). By contrast lazy vals creates problems with erasure, disabled
for now.

Some other small polishings on integration of pattern matcher with rest of dotc.

Deep recompilation of tools still fails, currently disabled.

Author: odersky

src/dotty/tools/dotc/Compiler.scala

@@ -46,7 +46,7 @@ class Compiler {
            new TailRec),
       List(new PatternMatcher,
            new ExplicitOuter,
-           new LazyValsTransform,
+           // new LazyValTranformContext().transformer, // disabled, awaiting fixes
            new Splitter),
       List(new ElimByName,
            new InterceptedMethods,

src/dotty/tools/dotc/ElimLocals.scala

@@ -19,4 +19,4 @@ class ElimLocals extends MiniPhaseTransform with SymTransformer { thisTransforme
   private def dropLocal(ref: SymDenotation)(implicit ctx: Context) =
     if (ref.flags is Local) ref.copySymDenotation(initFlags = ref.flags &~ Local)
     else ref
-}
+}

src/dotty/tools/dotc/Flatten.scala

@@ -12,4 +12,4 @@ class Flatten extends MiniPhaseTransform with SymTransformer { thisTransformer =
   override def phaseName = "flatten"
 
   def transformSym(ref: SymDenotation)(implicit ctx: Context) = ???
-}
+}

src/dotty/tools/dotc/ast/tpd.scala

@@ -44,9 +44,6 @@ object tpd extends Trees.Instance[Type] with TypedTreeInfo {
   def Apply(fn: Tree, args: List[Tree])(implicit ctx: Context): Apply =
     ta.assignType(untpd.Apply(fn, args), fn, args)
 
-  def ensureApplied(fn: Tree)(implicit ctx: Context): Tree =
-    if (fn.tpe.widen.isParameterless) fn else Apply(fn, Nil)
-
   def TypeApply(fn: Tree, args: List[Tree])(implicit ctx: Context): TypeApply =
     ta.assignType(untpd.TypeApply(fn, args), fn, args)
 
@@ -566,13 +563,6 @@ object tpd extends Trees.Instance[Type] with TypedTreeInfo {
 
     def appliedToNone(implicit ctx: Context): Apply = appliedToArgs(Nil)
 
-    def appliedIfMethod(implicit ctx: Context): Tree = {
-      tree.tpe.widen match {
-        case fntpe: MethodType => appliedToArgs(Nil)
-        case _ => tree
-      }
-    }
-
     def appliedToType(targ: Type)(implicit ctx: Context): Tree =
       appliedToTypes(targ :: Nil)
 
@@ -582,6 +572,9 @@ object tpd extends Trees.Instance[Type] with TypedTreeInfo {
     def appliedToTypeTrees(targs: List[Tree])(implicit ctx: Context): Tree =
       if (targs.isEmpty) tree else TypeApply(tree, targs)
 
+    def ensureApplied(implicit ctx: Context): Tree =
+      if (tree.tpe.widen.isParameterless) tree else tree.appliedToNone
+
     def isInstance(tp: Type)(implicit ctx: Context): Tree =
       tree.select(defn.Any_isInstanceOf).appliedToType(tp)
 
@@ -638,7 +631,7 @@ object tpd extends Trees.Instance[Type] with TypedTreeInfo {
     val mname      = ("to" + numericCls.name).toTermName
     val conversion = tree.tpe member mname
     if (conversion.symbol.exists)
-      ensureApplied(tree.select(conversion.symbol.termRef))
+      tree.select(conversion.symbol.termRef).ensureApplied
     else if (tree.tpe.widen isRef numericCls)
       tree
     else {

src/dotty/tools/dotc/core/Definitions.scala

@@ -4,7 +4,6 @@ package core
 
 import Types._, Contexts._, Symbols._, Denotations._, SymDenotations._, StdNames._, Names._
 import Flags._, Scopes._, Decorators._, NameOps._, util.Positions._
-import TypeApplications._
 import pickling.UnPickler.ensureConstructor
 import scala.annotation.{ switch, meta }
 import scala.collection.{ mutable, immutable }
@@ -192,6 +191,7 @@ class Definitions {
   lazy val ScalaStaticsClass = ScalaStaticsModule.moduleClass.asClass
 
     def staticsMethod(name: PreName) = ctx.requiredMethod(ScalaStaticsClass, name)
+    
   lazy val DottyPredefModule = ctx.requiredModule("dotty.DottyPredef")
   lazy val NilModule = ctx.requiredModule("scala.collection.immutable.Nil")
   lazy val PredefConformsClass = ctx.requiredClass("scala.Predef." + tpnme.Conforms)

src/dotty/tools/dotc/core/Phases.scala

@@ -175,7 +175,7 @@ object Phases {
     def refchecksPhase = refChecksCache.phase
     def erasurePhase = erasureCache.phase
     def flattenPhase = flattenCache.phase
-    def explicitOuter = explicitOuterCache.phase
+    def explicitOuterPhase = explicitOuterCache.phase
     def gettersSettersPhase = gettersSettersCache.phase
 
     def isAfterTyper(phase: Phase): Boolean = phase.id > typerPhase.id

src/dotty/tools/dotc/core/StdNames.scala

@@ -685,15 +685,6 @@ object StdNames {
     def newBitmapName(bitmapPrefix: TermName, n: Int): TermName = bitmapPrefix ++ n.toString
 
     def selectorName(n: Int): TermName = "_" + (n + 1)
-    /** Is name a variable name? */
-    def isVariableName(name: Name): Boolean = {
-      val first = name.firstChar
-      (    ((first.isLower && first.isLetter) || first == '_')
-        && (name != nme.false_)
-        && (name != nme.true_)
-        && (name != nme.null_)
-        )
-    }
 
     object primitive {
       val arrayApply: TermName  = "[]apply"

src/dotty/tools/dotc/transform/ExplicitOuter.scala

@@ -112,7 +112,7 @@ object ExplicitOuter {
   def ensureOuterAccessors(cls: ClassSymbol)(implicit ctx: Context): Unit = {
     //todo: implementing  #165 would simplify this logic
     val prevPhase = ctx.phase.prev
-    assert(prevPhase.id <= ctx.explicitOuter.id, "can add $outer symbols only before ExplicitOuter")
+    assert(prevPhase.id <= ctx.explicitOuterPhase.id, "can add $outer symbols only before ExplicitOuter")
     assert(prevPhase.isInstanceOf[DenotTransformer], "adding outerAccessors requires being DenotTransformer")
     if (!hasOuter(cls)) {
       newOuterAccessors(cls).foreach(_.enteredAfter(prevPhase.asInstanceOf[DenotTransformer]))

src/dotty/tools/dotc/transform/PatternMatcher.scala

@@ -20,7 +20,7 @@ import typer.ErrorReporting._
 import ast.Trees._
 import Applications._
 import TypeApplications._
-import TypeUtils._
+import SymUtils._, core.NameOps._
 
 import dotty.tools.dotc.util.Positions.Position
 import dotty.tools.dotc.core.Decorators._
@@ -112,7 +112,7 @@ class PatternMatcher extends MiniPhaseTransform with DenotTransformer {thisTrans
       def tupleSel(binder: Symbol)(i: Int): Tree = ref(binder).select(nme.productAccessorName(i))
       def index(tgt: Tree)(i: Int): Tree         = {
         if (i > 0) tgt.select(defn.Seq_apply).appliedTo(Literal(Constant(i)))
-        else tgt.select(defn.Seq_head).appliedIfMethod
+        else tgt.select(defn.Seq_head).ensureApplied
       }
 
       // Right now this blindly calls drop on the result of the unapplySeq
@@ -237,7 +237,7 @@ class PatternMatcher extends MiniPhaseTransform with DenotTransformer {thisTrans
         val matchFail = newSynthCaseLabel(ctx.freshName("matchFail"), MethodType(Nil, restpe))
         val catchAllDefBody = DefDef(matchFail, catchAllDef)
 
-        val nextCases = (caseSyms.tail ::: List(matchFail)).map(ref(_).appliedIfMethod)
+        val nextCases = (caseSyms.tail ::: List(matchFail)).map(ref(_).ensureApplied)
         val caseDefs = (cases zip caseSyms zip nextCases).foldRight[Tree](catchAllDefBody) {
           // dotty deviation
           //case (((mkCase, sym), nextCase), acc) =>
@@ -248,7 +248,7 @@ class PatternMatcher extends MiniPhaseTransform with DenotTransformer {thisTrans
 
             val caseBody = DefDef(sym, _ => Block(List(acc), body))
 
-            Block(List(caseBody),ref(sym).appliedIfMethod)
+            Block(List(caseBody),ref(sym).ensureApplied)
           }}
 
 
@@ -278,7 +278,7 @@ class PatternMatcher extends MiniPhaseTransform with DenotTransformer {thisTrans
           val isDefined = extractorMemberType(prev.tpe, nme.isDefined)
 
           if ((isDefined isRef defn.BooleanClass) && getTp.exists) {
-            val prevValue = ref(prevSym).select("get".toTermName).appliedIfMethod
+            val prevValue = ref(prevSym).select("get".toTermName).ensureApplied
               Block(
                 List(ValDef(prevSym, prev)),
                 // must be isEmpty and get as we don't control the target of the call (prev is an extractor call)
@@ -945,7 +945,7 @@ class PatternMatcher extends MiniPhaseTransform with DenotTransformer {thisTrans
 
     def isVarPattern(pat: Tree): Boolean = pat match {
       case x: BackquotedIdent => false
-      case x: Ident => nme.isVariableName(x.name)
+      case x: Ident => x.name.isVariableName
       case _ => false
     }
 
@@ -1391,7 +1391,7 @@ class PatternMatcher extends MiniPhaseTransform with DenotTransformer {thisTrans
         val accessors =
           if (defn.isProductSubType(binder.info))
             productSelectors(binder.info)
-          else binder.info.caseAccessors
+          else binder.caseAccessors
         val res =
         if (accessors.isDefinedAt(i - 1)) ref(binder).select(accessors(i - 1).name)
         else codegen.tupleSel(binder)(i) // this won't type check for case classes, as they do not inherit ProductN
@@ -1480,7 +1480,7 @@ class PatternMatcher extends MiniPhaseTransform with DenotTransformer {thisTrans
         * when `binderKnownNonNull` is `true`, `ProductExtractorTreeMaker` does not do a (redundant) null check on binder
         */
       def treeMaker(binder: Symbol, binderKnownNonNull: Boolean, pos: Position, binderTypeTested: Type): TreeMaker = {
-        val paramAccessors = binder.info.caseAccessors
+        val paramAccessors = binder.caseAccessors
         // binders corresponding to mutable fields should be stored (SI-5158, SI-6070)
         // make an exception for classes under the scala package as they should be well-behaved,
         // to optimize matching on List
@@ -1800,7 +1800,7 @@ class PatternMatcher extends MiniPhaseTransform with DenotTransformer {thisTrans
           if ((extractorMemberType(resultType, nme.isDefined) isRef defn.BooleanClass) && resultOfGet.exists)
             getUnapplySelectors(resultOfGet, args)
           else if (defn.isProductSubType(resultType)) productSelectorTypes(resultType)
-          else if (resultType =:= defn.BooleanType) Nil
+          else if (resultType isRef defn.BooleanClass) Nil
           else {
             ctx.error(i"invalid return type in Unapply node: $resultType")
             Nil

src/dotty/tools/dotc/transform/TreeChecker.scala

@@ -47,6 +47,7 @@ class TreeChecker {
     case _ =>
       Nil
   }
+
   def check(phasesToRun: Seq[Phase], ctx: Context) = {
     println(s"checking ${ctx.compilationUnit} after phase ${ctx.phase.prev}")
     val checkingCtx = ctx.fresh
@@ -99,8 +100,7 @@ class TreeChecker {
     private def checkOwner(tree: untpd.Tree)(implicit ctx: Context): Unit = {
       def ownerMatches(symOwner: Symbol, ctxOwner: Symbol): Boolean =
         symOwner == ctxOwner ||
-          ctxOwner.isWeakOwner && (!(ctxOwner is Method | Lazy | Mutable) || (ctxOwner is Label)) &&
-          ownerMatches(symOwner, ctxOwner.owner)
+        ctxOwner.isWeakOwner && ownerMatches(symOwner, ctxOwner.owner)
       if(!ownerMatches(tree.symbol.owner, ctx.owner)) {
         assert(ownerMatches(tree.symbol.owner, ctx.owner),
           i"bad owner; ${tree.symbol} has owner ${tree.symbol.owner}, expected was ${ctx.owner}\n" +