Fix inspection fixes taht may use invalid elements

Fixes minecraft-dev/mcdev-error-report#1464

Author: RedNesto

src/main/kotlin/platform/bukkit/inspection/BukkitListenerImplementedInspection.kt

@@ -30,6 +30,7 @@ import com.siyeh.ig.BaseInspection
 import com.siyeh.ig.BaseInspectionVisitor
 import com.siyeh.ig.InspectionGadgetsFix
 import org.jetbrains.annotations.Nls
+import org.jetbrains.kotlin.psi.psiUtil.createSmartPointer
 
 class BukkitListenerImplementedInspection : BaseInspection() {
 
@@ -44,10 +45,10 @@ class BukkitListenerImplementedInspection : BaseInspection() {
         "All Bukkit @EventHandler methods must reside in a class that implements Listener."
 
     override fun buildFix(vararg infos: Any): InspectionGadgetsFix {
+        val classPointer = (infos[0] as PsiClass).createSmartPointer()
         return object : InspectionGadgetsFix() {
             override fun doFix(project: Project, descriptor: ProblemDescriptor) {
-                val psiClass = infos[0] as PsiClass
-                psiClass.addImplements(BukkitConstants.LISTENER_CLASS)
+                classPointer.element?.addImplements(BukkitConstants.LISTENER_CLASS)
             }
 
             @Nls
@@ -61,11 +62,7 @@ class BukkitListenerImplementedInspection : BaseInspection() {
     override fun buildVisitor(): BaseInspectionVisitor {
         return object : BaseInspectionVisitor() {
             override fun visitClass(aClass: PsiClass) {
-                if (
-                    aClass.methods.none {
-                        it.modifierList.findAnnotation(BukkitConstants.HANDLER_ANNOTATION) != null
-                    }
-                ) {
+                if (aClass.methods.none { it.hasAnnotation(BukkitConstants.HANDLER_ANNOTATION) }) {
                     return
                 }
 

src/main/kotlin/platform/bungeecord/inspection/BungeeCordListenerImplementedInspection.kt

@@ -30,6 +30,7 @@ import com.siyeh.ig.BaseInspection
 import com.siyeh.ig.BaseInspectionVisitor
 import com.siyeh.ig.InspectionGadgetsFix
 import org.jetbrains.annotations.Nls
+import org.jetbrains.kotlin.psi.psiUtil.createSmartPointer
 
 class BungeeCordListenerImplementedInspection : BaseInspection() {
 
@@ -43,10 +44,10 @@ class BungeeCordListenerImplementedInspection : BaseInspection() {
         "All BungeeCord @EventHandler methods must reside in a class that implements Listener."
 
     override fun buildFix(vararg infos: Any): InspectionGadgetsFix {
+        val classPointer = (infos[0] as PsiClass).createSmartPointer()
         return object : InspectionGadgetsFix() {
             override fun doFix(project: Project, descriptor: ProblemDescriptor) {
-                val psiClass = infos[0] as PsiClass
-                psiClass.addImplements(BungeeCordConstants.LISTENER_CLASS)
+                classPointer.element?.addImplements(BungeeCordConstants.LISTENER_CLASS)
             }
 
             @Nls

src/main/kotlin/platform/mcp/inspections/StackEmptyInspection.kt

@@ -40,6 +40,7 @@ import com.siyeh.ig.BaseInspection
 import com.siyeh.ig.BaseInspectionVisitor
 import com.siyeh.ig.InspectionGadgetsFix
 import org.jetbrains.annotations.Nls
+import org.jetbrains.kotlin.psi.psiUtil.createSmartPointer
 
 class StackEmptyInspection : BaseInspection() {
     companion object {
@@ -63,14 +64,17 @@ class StackEmptyInspection : BaseInspection() {
             " the stack should still be considered empty. Instead, isEmpty() should be called."
 
     override fun buildFix(vararg infos: Any): InspectionGadgetsFix {
+        val compareExpressionPointer = (infos[0] as PsiExpression).createSmartPointer()
+        val binaryExpressionPointer = (infos[2] as PsiBinaryExpression).createSmartPointer()
         return object : InspectionGadgetsFix() {
             override fun getFamilyName() = "Replace with .isEmpty()"
 
             override fun doFix(project: Project, descriptor: ProblemDescriptor) {
-                val compareExpression = infos[0] as PsiExpression
-                val binaryExpression = infos[2] as PsiBinaryExpression
                 val elementFactory = JavaPsiFacade.getElementFactory(project)
 
+                val compareExpression = compareExpressionPointer.element ?: return
+                val binaryExpression = binaryExpressionPointer.element ?: return
+
                 val mappedIsEmpty = compareExpression.findModule()?.getMappedMethod(IS_EMPTY_SRG)?.name ?: "isEmpty"
 
                 var expressionText = "${compareExpression.text}.$mappedIsEmpty()"