Fix rechecking of SeqLiterals

Author: odersky

compiler/src/dotty/tools/dotc/transform/Recheck.scala

@@ -5,13 +5,14 @@ package transform
 import core.*
 import Symbols.*, Contexts.*, Types.*, ContextOps.*, Decorators.*, SymDenotations.*
 import Flags.*, SymUtils.*, NameKinds.*
+import ast.*
 import Phases.Phase
 import DenotTransformers.IdentityDenotTransformer
 import NamerOps.{methodType, linkConstructorParams}
 import NullOpsDecorator.stripNull
 import typer.ErrorReporting.err
-import ast.*
 import typer.ProtoTypes.*
+import typer.TypeAssigner.seqLitType
 import config.Printers.recheckr
 import util.Property
 import StdNames.nme
@@ -218,7 +219,7 @@ abstract class Recheck extends Phase, IdentityDenotTransformer:
         case elemtp => elemtp
       val declaredElemType = recheck(tree.elemtpt)
       val elemTypes = tree.elems.map(recheck(_, elemProto))
-      TypeComparer.lub(declaredElemType :: elemTypes)
+      seqLitType(tree, TypeComparer.lub(declaredElemType :: elemTypes))
 
     def recheckTypeTree(tree: TypeTree)(using Context): Type = tree match
       case tree: InferredTypeTree => reinfer(tree.tpe)

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

@@ -17,7 +17,8 @@ import reporting._
 import Checking.{checkNoPrivateLeaks, checkNoWildcard}
 
 trait TypeAssigner {
-  import tpd._
+  import tpd.*
+  import TypeAssigner.*
 
   /** The qualifying class of a this or super with prefix `qual` (which might be empty).
    *  @param packageOk   The qualifier may refer to a package.
@@ -435,13 +436,8 @@ trait TypeAssigner {
     if (cases.isEmpty) tree.withType(expr.tpe)
     else tree.withType(TypeComparer.lub(expr.tpe :: cases.tpes))
 
-  def assignType(tree: untpd.SeqLiteral, elems: List[Tree], elemtpt: Tree)(using Context): SeqLiteral = {
-    val ownType = tree match {
-      case tree: untpd.JavaSeqLiteral => defn.ArrayOf(elemtpt.tpe)
-      case _ => if (ctx.erasedTypes) defn.SeqType else defn.SeqType.appliedTo(elemtpt.tpe)
-    }
-    tree.withType(ownType)
-  }
+  def assignType(tree: untpd.SeqLiteral, elems: List[Tree], elemtpt: Tree)(using Context): SeqLiteral =
+    tree.withType(seqLitType(tree, elemtpt.tpe))
 
   def assignType(tree: untpd.SingletonTypeTree, ref: Tree)(using Context): SingletonTypeTree =
     tree.withType(ref.tpe)
@@ -527,5 +523,9 @@ trait TypeAssigner {
     tree.withType(pid.symbol.termRef)
 }
 
+object TypeAssigner extends TypeAssigner:
+  def seqLitType(tree: untpd.SeqLiteral, elemType: Type)(using Context) = tree match
+    case tree: untpd.JavaSeqLiteral => defn.ArrayOf(elemType)
+    case _ => if ctx.erasedTypes then defn.SeqType else defn.SeqType.appliedTo(elemType)
+
 
-object TypeAssigner extends TypeAssigner