Fix scala#13947

Author: cchantep

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

@@ -36,7 +36,6 @@ import scala.annotation.internal.sharable
 import config.Printers.typr
 
 object Symbols {
-
   implicit def eqSymbol: CanEqual[Symbol, Symbol] = CanEqual.derived
 
   /** Tree attachment containing the identifiers in a tree as a sorted array */

compiler/src/scala/quoted/runtime/impl/QuotesImpl.scala

@@ -1749,6 +1749,10 @@ class QuotesImpl private (using val ctx: Context) extends Quotes, QuoteUnpickler
           dotc.core.Types.decorateTypeApplications(self).appliedTo(targs)
         def substituteTypes(from: List[Symbol], to: List[TypeRepr]): TypeRepr =
           self.subst(from, to)
+
+        def typeParams: List[TypeRepr] = self match
+          case AppliedType(_, args) => args
+          case _ => List.empty
       end extension
     end TypeReprMethods
 
@@ -2480,6 +2484,7 @@ class QuotesImpl private (using val ctx: Context) extends Quotes, QuoteUnpickler
 
         def name: String = self.denot.name.toString
         def fullName: String = self.denot.fullName.toString
+
         def pos: Option[Position] =
           if self.exists then Some(self.sourcePos) else None
 

library/src/scala/quoted/Quotes.scala

@@ -2571,6 +2571,9 @@ trait Quotes { self: runtime.QuoteUnpickler & runtime.QuoteMatching =>
         @experimental
         def substituteTypes(from: List[Symbol], to: List[TypeRepr]): TypeRepr
 
+        /** The type parameters */
+        @experimental
+        def typeParams: List[TypeRepr]
       end extension
     }