Merge pull request #261 from dotty-staging/fix/type-seqliteral

Fix/type seqliteral

Author: DarkDimius

src/dotty/tools/dotc/Compiler.scala

@@ -48,6 +48,7 @@ class Compiler {
            new ExplicitOuter,
            new Splitter),
       List(new ElimByName,
+           new SeqLiterals,
            new InterceptedMethods,
            new Literalize,
            new Getters,

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

@@ -129,7 +129,6 @@ object tpd extends Trees.Instance[Type] with TypedTreeInfo {
   def JavaSeqLiteral(elems: List[Tree])(implicit ctx: Context): SeqLiteral =
     ta.assignType(new untpd.JavaSeqLiteral(elems), elems)
 
-
   def TypeTree(original: Tree)(implicit ctx: Context): TypeTree =
     TypeTree(original.tpe, original)
 

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

@@ -394,7 +394,8 @@ class Definitions {
 
   object ArrayType {
     def apply(elem: Type)(implicit ctx: Context) =
-      ArrayClass.typeRef.appliedTo(elem :: Nil)
+      if (ctx.erasedTypes) JavaArrayType(elem)
+      else ArrayClass.typeRef.appliedTo(elem :: Nil)
     def unapply(tp: Type)(implicit ctx: Context) = tp.dealias match {
       case at: RefinedType if (at isRef ArrayClass) && at.argInfos.length == 1 => Some(at.argInfos.head)
       case _ => None

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

@@ -45,7 +45,7 @@ object Uniques {
     private def findPrevious(h: Int, prefix: Type, name: Name): NamedType = {
       var e = findEntryByHash(h)
       while (e != null) {
-        if ((e.prefix == prefix) && (e.name eq name)) return e
+        if ((e.prefix eq prefix) && (e.name eq name)) return e
         e = nextEntryByHash(h)
       }
       e
@@ -71,7 +71,7 @@ object Uniques {
     private def findPrevious(h: Int, lo: Type, hi: Type, variance: Int): TypeBounds = {
       var e = findEntryByHash(h)
       while (e != null) {
-        if ((e.lo == lo) && (e.hi == hi) && (e.variance == variance)) return e
+        if ((e.lo eq lo) && (e.hi eq hi) && (e.variance == variance)) return e
         e = nextEntryByHash(h)
       }
       e
@@ -87,7 +87,8 @@ object Uniques {
       if (h == NotCached) newBounds
       else {
         val r = findPrevious(h, lo, hi, variance)
-        if (r ne null) r else addEntryAfterScan(newBounds)
+        if (r ne null) r
+        else addEntryAfterScan(newBounds)
       }
     }
   }
@@ -99,7 +100,7 @@ object Uniques {
     private def findPrevious(h: Int, parent: Type, refinedName: Name, refinedInfo: Type): RefinedType = {
       var e = findEntryByHash(h)
       while (e != null) {
-        if ((e.parent == parent) && (e.refinedName eq refinedName) && (e.refinedInfo == refinedInfo))
+        if ((e.parent eq parent) && (e.refinedName eq refinedName) && (e.refinedInfo eq refinedInfo))
           return e
         e = nextEntryByHash(h)
       }

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

@@ -0,0 +1,49 @@
+package dotty.tools.dotc
+package transform
+
+import core._
+import Types._
+import dotty.tools.dotc.transform.TreeTransforms._
+import Contexts.Context
+import Symbols._
+import Phases._
+import Decorators._
+
+/** A transformer that eliminates SeqLiteral's, transforming `SeqLiteral(elems)` to an operation
+ *  equivalent to
+ *
+ *      JavaSeqLiteral(elems).toSeq
+ *
+ *  Instead of `toSeq`, which takes an implicit, the appropriate "wrapArray" method
+ *  is called directly. The reason for this step is that JavaSeqLiterals, being arrays
+ *  keep a precise type after erasure, whereas SeqLiterals only get the erased type `Seq`,
+ */
+class SeqLiterals extends MiniPhaseTransform { thisTransformer =>
+  import ast.tpd._
+
+  override def phaseName = "seqLiterals"
+  override def treeTransformPhase = thisTransformer.next
+  override def runsAfter: Set[Class[_ <: Phase]] = Set(classOf[PatternMatcher])
+
+  override def checkPostCondition(tree: Tree)(implicit ctx: Context): Unit = tree match {
+    case tpd: SeqLiteral => assert(tpd.isInstanceOf[JavaSeqLiteral])
+    case _ =>
+  }
+
+  override def transformSeqLiteral(tree: SeqLiteral)(implicit ctx: Context, info: TransformerInfo): Tree = tree match {
+    case tree: JavaSeqLiteral => tree
+    case _ =>
+      val arr = JavaSeqLiteral(tree.elems)
+      //println(i"trans seq $tree, arr = $arr: ${arr.tpe} ${arr.tpe.elemType}")
+      val elemtp = arr.tpe.elemType.bounds.hi
+      val elemCls = elemtp.classSymbol
+      val (wrapMethStr, targs) =
+        if (elemCls.isPrimitiveValueClass) (s"wrap${elemCls.name}Array", Nil)
+        else if (elemtp derivesFrom defn.ObjectClass) ("wrapRefArray", elemtp :: Nil)
+        else ("genericWrapArray", elemtp :: Nil)
+      ref(defn.ScalaPredefModule)
+        .select(wrapMethStr.toTermName)
+        .appliedToTypes(targs)
+        .appliedTo(arr)
+  }
+}

src/dotty/tools/dotc/typer/TypeAssigner.scala

@@ -324,7 +324,7 @@ trait TypeAssigner {
 
   def assignType(tree: untpd.SeqLiteral, elems: List[Tree])(implicit ctx: Context) = tree match {
     case tree: JavaSeqLiteral =>
-      tree.withType(defn.ArrayClass.typeRef.appliedTo(ctx.typeComparer.lub(elems.tpes)))
+      tree.withType(defn.ArrayType(ctx.typeComparer.lub(elems.tpes).widen))
     case _ =>
       val ownType =
         if (ctx.erasedTypes) defn.SeqType