Add comment explaining param registration in LambdaType

Author: MatthieuSLR9

compiler/src/dotty/tools/dotc/semanticdb/TypeOps.scala

@@ -97,6 +97,8 @@ class TypeOps:
             // and register them to the symbol table with `(<y>, inner) -> <y>`
             // instead of `("y", outer) -> <y>`
             // We must also check for parameter shadowing such as def shadowParam(x: Int) = {val x = true}
+            // We skip param symbol check if owner is not a LambdaType for proper MatchType paramRef entry in the paramRefSymtab
+            // for more information: https://github.com/scala/scala3/pull/23161#discussion_r2097755983
 
             if (sym.is(Flags.Param) || !sym.owner.info.isInstanceOf[LambdaType]) &&  lam.paramNames.contains(sym.name) then
               paramRefSymtab((lam, sym.name)) = sym