Add an explanatory comment

Author: abgruszecki

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

@@ -256,6 +256,10 @@ trait PatternTypeConstrainer { self: TypeComparer =>
               val variance = param.paramVarianceSign
               if variance != 0 && !assumeInvariantRefinement then true
               else if argS.isInstanceOf[TypeBounds] || argP.isInstanceOf[TypeBounds] then
+                // This line was added here as a quick fix for issue #13998, 
+                // to extract GADT constraints from wildcard type arguments.
+                // The proper fix would involve inspecting the bounds right here and performing the correct subtyping checks, the ones that are already performed by `isSubType` below,
+                // for the same reasons for which we stopped using `SkolemType` here to begin with (commit 10fe5374dc2d).
                 isSubType(SkolemType(patternTp), scrutineeTp)
               else {
                 var res = true