UAST: Fix for unsafe cast for annotation (EA-109738)

plugins/uast-kotlin/src/org/jetbrains/uast/kotlin/KotlinAbstractUElement.kt

@@ -143,7 +143,7 @@ private fun findAnnotationClassFromConstructorParameter(parameter: KtParameter):
     val primaryConstructor = parameter.getStrictParentOfType<KtPrimaryConstructor>() ?: return null
     val containingClass = primaryConstructor.getContainingClassOrObject()
     if (containingClass.isAnnotation()) {
-        return KotlinUastLanguagePlugin().convertElementWithParent(containingClass, null) as UClass
+        return KotlinUastLanguagePlugin().convertElementWithParent(containingClass, null) as? UClass
     }
     return null
 }

plugins/uast-kotlin/tests/KotlinDetachedUastTest.kt

@@ -25,10 +25,10 @@ import org.jetbrains.kotlin.asJava.elements.KtLightElement
 import org.jetbrains.kotlin.idea.core.copied
 import org.jetbrains.kotlin.idea.test.KotlinLightCodeInsightFixtureTestCase
 import org.jetbrains.kotlin.idea.test.KotlinWithJdkAndRuntimeLightProjectDescriptor
+import org.jetbrains.kotlin.psi.KtPsiFactory
 import org.jetbrains.kotlin.psi.psiUtil.getParentOfType
-import org.jetbrains.uast.UClass
-import org.jetbrains.uast.getParentOfType
-import org.jetbrains.uast.toUElement
+import org.jetbrains.uast.*
+import org.jetbrains.uast.test.env.findUElementByTextFromPsi
 
 class KotlinDetachedUastTest : KotlinLightCodeInsightFixtureTestCase() {
 
@@ -61,6 +61,19 @@ class KotlinDetachedUastTest : KotlinLightCodeInsightFixtureTestCase() {
                             copied.originalFile.virtualFile)
     }
 
+    fun testParameterInAnnotationClassFromFactory() {
+
+        val detachedClass = KtPsiFactory(project).createClass("""
+        annotation class MyAnnotation(val myParam: String = "default")
+        """)
+
+        detachedClass.findUElementByTextFromPsi<UElement>("default")
+                .getParentOfType<UExpression>().let {
+            TestCase.assertNotNull("it should return something at least", it)
+        }
+
+    }
+
 }
 
 fun <T> T?.orFail(msg: String): T = this ?: error(msg)