Fix desugaring of fields with qualified types

Author: mbovel

compiler/src/dotty/tools/dotc/ast/Desugar.scala

@@ -213,7 +213,11 @@ object desugar {
   def valDef(vdef0: ValDef)(using Context): Tree =
     val vdef @ ValDef(_, tpt, rhs) = vdef0
     val valName = normalizeName(vdef, tpt).asTermName
-    val tpt1 = desugarQualifiedTypes(tpt, valName)
+    val tpt1 =
+      if Feature.qualifiedTypesEnabled then
+        desugarQualifiedTypes(tpt, valName)
+      else
+        tpt
     var mods1 = vdef.mods
 
     val vdef1 = cpy.ValDef(vdef)(name = valName, tpt = tpt1).withMods(mods1)
@@ -747,7 +751,11 @@ object desugar {
         report.error(CaseClassMissingNonImplicitParamList(cdef), namePos)
         ListOfNil
       }
-      else originalVparamss.nestedMap(toMethParam(_, KeepAnnotations.All, keepDefault = true))
+      else
+        originalVparamss.nestedMap: param =>
+          val methParam = toMethParam(param, KeepAnnotations.All, keepDefault = true)
+          valDef(methParam).asInstanceOf[ValDef] // desugar early to handle qualified types
+
     val derivedTparams =
       constrTparams.zipWithConserve(impliedTparams)((tparam, impliedParam) =>
         derivedTypeParam(tparam).withAnnotations(impliedParam.mods.annotations))

tests/pos-custom-args/qualified-types/class_constraints.scala

@@ -1,3 +1,7 @@
-/*class foo(elem: Int with elem > 0)*/
+class foo(elem: Int with elem > 0)
+
+class Multi(x: Int with x > 0)(y: String with y.length > 2, z: Double with z >= 0.0)
+
+case class MultiCase(x: Int with x > 0)(val y: String with y.length > 2, val z: Double with z >= 0.0)
 
 @main def Test = ()