Fix #6213: Convert RefinedTypeTrees to TypeTrees in ReTyper

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

@@ -65,6 +65,9 @@ class ReTyper extends Typer with ReChecking {
   override def typedTypeTree(tree: untpd.TypeTree, pt: Type)(implicit ctx: Context): TypeTree =
     promote(tree)
 
+  override def typedRefinedTypeTree(tree: untpd.RefinedTypeTree)(implicit ctx: Context): TypTree =
+    promote(TypeTree(tree.tpe).withSpan(tree.span))
+
   override def typedFunPart(fn: untpd.Tree, pt: Type)(implicit ctx: Context): Tree =
     typedExpr(fn, pt)
 

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

@@ -1273,7 +1273,7 @@ class Typer extends Namer
     assignType(cpy.SingletonTypeTree(tree)(ref1), ref1)
   }
 
-  def typedRefinedTypeTree(tree: untpd.RefinedTypeTree)(implicit ctx: Context): RefinedTypeTree = track("typedRefinedTypeTree") {
+  def typedRefinedTypeTree(tree: untpd.RefinedTypeTree)(implicit ctx: Context): TypTree = track("typedRefinedTypeTree") {
     val tpt1 = if (tree.tpt.isEmpty) TypeTree(defn.ObjectType) else typedAheadType(tree.tpt)
     val refineClsDef = desugar.refinedTypeToClass(tpt1, tree.refinements).withSpan(tree.span)
     val refineCls = createSymbol(refineClsDef).asClass

tests/pos/i6213.scala

@@ -0,0 +1,6 @@
+object Test {
+  class C { type T }
+  inline def foo[U] <: Any = (??? : C { type T = U })
+
+  foo[Int]
+}