Fix #11415: always expand bounds in type approximation

compiler/src/dotty/tools/dotc/core/Types.scala

@@ -5343,14 +5343,11 @@ object Types {
     def isExpandingBounds: Boolean = expandingBounds
 
     protected def expandBounds(tp: TypeBounds): Type =
-      if expandingBounds then tp
-      else {
-        val saved = expandingBounds
-        expandingBounds = true
-        val res = range(atVariance(-variance)(reapply(tp.lo)), reapply(tp.hi))
-        expandingBounds = saved
-        res
-      }
+      val saved = expandingBounds
+      expandingBounds = true
+      val res = range(atVariance(-variance)(reapply(tp.lo)), reapply(tp.hi))
+      expandingBounds = saved
+      res
 
     /** Try to widen a named type to its info relative to given prefix `pre`, where possible.
      *  The possible cases are listed inline in the code.

tests/pos/i11415.scala

@@ -0,0 +1,42 @@
+package example
+
+import scala.language.experimental.macros
+
+trait Context {
+
+  val universe: Universe
+
+  trait Universe {
+    type Tree >: Null <: AnyRef with TreeApi
+    type Literal >: Null <: LiteralApi with TermTree
+    type TermTree >: Null <: TermTreeApi with Tree
+
+    trait TermTreeApi extends TreeApi { this: TermTree => }
+    trait LiteralApi extends TermTreeApi { this: Literal => }
+    trait TreeApi extends Product { this: Tree => }
+  }
+}
+
+object MacroCompat {
+
+  object Bundles {
+    def mono: Int = macro Macros2.MacroImpl.mono
+    inline def mono: Int = ${ Macros3.monoImpl }
+  }
+
+  object Macros2 {
+    class MacroImpl(val c: Context) {
+      import c.universe._
+
+      def mono: Literal = ???
+    }
+  }
+
+  object Macros3 {
+    import quoted._
+
+    def monoImpl(using Quotes) = '{1}
+
+  }
+
+}