Fix Scala 2 TASTy accessors in inline patterns reduction

Author: nicolasstucki

.github/workflows/ci.yaml

@@ -143,7 +143,7 @@ jobs:
           ./project/scripts/sbt ";sjsSandbox/run ;sjsSandbox/test ;sjsJUnitTests/test ;set sjsJUnitTests/scalaJSLinkerConfig ~= switchToESModules ;sjsJUnitTests/test ;sjsCompilerTests/test"
 
       - name: Test with Scala 2 library TASTy
-        run: ./project/scripts/sbt ";set ThisBuild/Build.useScala2LibraryTasty := true ;scala3-bootstrapped/testCompilation i5" # only test a subset of test to avoid doubling the CI execution time
+        run: ./project/scripts/sbt ";set ThisBuild/Build.useScala2LibraryTasty := true ;scala3-bootstrapped/testCompilation i5; scala3-bootstrapped/testCompilation tests/run/typelevel-peano.scala" # only test a subset of test to avoid doubling the CI execution time
         shell: cmd
 
   test_windows_fast:

compiler/src/dotty/tools/dotc/inlines/InlineReducer.scala

@@ -329,7 +329,7 @@ class InlineReducer(inliner: Inliner)(using Context):
               val paramCls = paramType.classSymbol
               if (paramCls.is(Case) && unapp.symbol.is(Synthetic) && scrut <:< paramType) {
                 val caseAccessors =
-                  if (paramCls.is(Scala2x)) paramCls.caseAccessors.filter(_.is(Method))
+                  if (paramCls.is(Scala2x, butNot = Scala2Tasty)) paramCls.caseAccessors.filter(_.is(Method))
                   else paramCls.asClass.paramAccessors
                 val selectors =
                   for (accessor <- caseAccessors)