to avoid running resolve under ClsTypeElement lock, return empty modifier list if we're currently calculating the return type (the modifier list is requested to apply type annotations, and we don't care about them anyway)

#KT-12966 Fixed

compiler/frontend.java/src/org/jetbrains/kotlin/resolve/jvm/KotlinJavaPsiFacade.java

@@ -28,6 +28,7 @@ import com.intellij.psi.*;
 import com.intellij.psi.impl.PsiElementFinderImpl;
 import com.intellij.psi.impl.file.PsiPackageImpl;
 import com.intellij.psi.impl.file.impl.JavaFileManager;
+import com.intellij.psi.impl.light.LightModifierList;
 import com.intellij.psi.search.GlobalSearchScope;
 import com.intellij.psi.util.PsiModificationTracker;
 import com.intellij.reference.SoftReference;
@@ -41,6 +42,7 @@ import kotlin.collections.CollectionsKt;
 import kotlin.jvm.functions.Function1;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
+import org.jetbrains.kotlin.idea.KotlinLanguage;
 import org.jetbrains.kotlin.name.FqName;
 import org.jetbrains.kotlin.progress.ProgressIndicatorAndCompilationCanceledStatus;
 import org.jetbrains.kotlin.name.ClassId;
@@ -62,6 +64,7 @@ public class KotlinJavaPsiFacade {
     private volatile SoftReference<PackageCache> packageCache;
 
     private final Project project;
+    private final LightModifierList emptyModifierList;
 
     public static KotlinJavaPsiFacade getInstance(Project project) {
         return ServiceManager.getService(project, KotlinJavaPsiFacade.class);
@@ -70,6 +73,8 @@ public class KotlinJavaPsiFacade {
     public KotlinJavaPsiFacade(@NotNull Project project) {
         this.project = project;
 
+        emptyModifierList = new LightModifierList(PsiManager.getInstance(project), KotlinLanguage.INSTANCE);
+
         final PsiModificationTracker modificationTracker = PsiManager.getInstance(project).getModificationTracker();
         MessageBus bus = project.getMessageBus();
 
@@ -88,6 +93,10 @@ public class KotlinJavaPsiFacade {
         });
     }
 
+    public LightModifierList getEmptyModifierList() {
+        return emptyModifierList;
+    }
+
     public PsiClass findClass(@NotNull ClassId classId, @NotNull GlobalSearchScope scope) {
         ProgressIndicatorAndCompilationCanceledStatus.checkCanceled(); // We hope this method is being called often enough to cancel daemon processes smoothly