Fix check in JetQuickDocumentationProvider#isKotlinDeclaration

Always return true if we navigated to JetElement

idea/src/org/jetbrains/jet/plugin/JetQuickDocumentationProvider.java

@@ -19,7 +19,6 @@ package org.jetbrains.jet.plugin;
 import com.google.common.base.Predicate;
 import com.intellij.lang.documentation.AbstractDocumentationProvider;
 import com.intellij.lang.java.JavaDocumentationProvider;
-import com.intellij.openapi.project.Project;
 import com.intellij.openapi.util.text.StringUtil;
 import com.intellij.openapi.vfs.VirtualFile;
 import com.intellij.psi.PsiElement;
@@ -87,7 +86,7 @@ public class JetQuickDocumentationProvider extends AbstractDocumentationProvider
             @NotNull DeclarationDescriptor declarationDescriptor, @NotNull BindingContext bindingContext,
             PsiElement element, PsiElement originalElement, boolean mergeKotlinAndJava) {
         String renderedDecl = DescriptorRenderer.HTML.render(declarationDescriptor);
-        if (isKotlinDeclaration(declarationDescriptor, bindingContext, originalElement.getProject())) {
+        if (isKotlinDeclaration(declarationDescriptor, bindingContext, element)) {
             KDoc comment = findElementKDoc(element);
             if (comment != null) {
                 renderedDecl = renderedDecl + "<br/>" + kDocToHtml(comment);
@@ -105,16 +104,19 @@ public class JetQuickDocumentationProvider extends AbstractDocumentationProvider
         return null;
     }
 
-    private static boolean isKotlinDeclaration(DeclarationDescriptor descriptor, BindingContext bindingContext, Project project) {
+    private static boolean isKotlinDeclaration(
+            DeclarationDescriptor descriptor,
+            BindingContext bindingContext,
+            PsiElement element
+    ) {
+        if (JetLanguage.INSTANCE == element.getLanguage()) return true;
         PsiElement declaration = BindingContextUtils.descriptorToDeclaration(bindingContext, descriptor);
         if (declaration == null) {
-            BuiltInsReferenceResolver libraryReferenceResolver = project
-                    .getComponent(BuiltInsReferenceResolver.class);
+            BuiltInsReferenceResolver libraryReferenceResolver = element.getProject().getComponent(BuiltInsReferenceResolver.class);
             Collection<PsiElement> elements = libraryReferenceResolver.resolveBuiltInSymbol(descriptor);
             return !elements.isEmpty();
         }
 
-        if (JetLanguage.INSTANCE == declaration.getLanguage()) return true;
         ClsClassImpl clsClass = PsiTreeUtil.getParentOfType(declaration, ClsClassImpl.class);
         if (clsClass == null) return false;
         VirtualFile file = clsClass.getContainingFile().getVirtualFile();