Caller Hierarchy: NPE fix

#EA-66031 Fixed

idea/src/org/jetbrains/kotlin/idea/hierarchy/calls/KotlinCallHierarchyProvider.java

@@ -37,7 +37,10 @@ public class KotlinCallHierarchyProvider implements HierarchyProvider {
         Project project = CommonDataKeys.PROJECT.getData(dataContext);
         if (project == null) return null;
 
-        return HierarchyUtils.getCallHierarchyElement(getCurrentElement(dataContext, project));
+        PsiElement element = getCurrentElement(dataContext, project);
+        if (element == null) return null;
+
+        return HierarchyUtils.getCallHierarchyElement(element);
     }
 
     private static PsiElement getCurrentElement(DataContext dataContext, Project project) {

idea/testData/hierarchy/calls/callers/kotlinUnresolvedFunction/KotlinUnresolvedFunction_verification.xml

@@ -0,0 +1,3 @@
+<node text="foo()" base="true">
+
+</node>

idea/testData/hierarchy/calls/callers/kotlinUnresolvedFunction/main0.kt

@@ -0,0 +1,3 @@
+fun test() {
+    <caret>foo()
+}

idea/testData/hierarchy/calls/callers/kotlinUnresolvedFunction/messages.txt

@@ -0,0 +1 @@
+Cannot apply action for element at caret

idea/tests/org/jetbrains/kotlin/idea/hierarchy/AbstractHierarchyTest.java

@@ -30,6 +30,7 @@ import com.intellij.psi.PsiClass;
 import com.intellij.psi.PsiDocumentManager;
 import com.intellij.psi.PsiElement;
 import com.intellij.psi.PsiFile;
+import com.intellij.refactoring.util.CommonRefactoringUtil.RefactoringErrorHintException;
 import com.intellij.testFramework.MapDataContext;
 import com.intellij.util.ArrayUtil;
 import com.intellij.util.Processor;
@@ -162,7 +163,7 @@ public abstract class AbstractHierarchyTest extends KotlinHierarchyViewTestBase
 
     private PsiElement getElementAtCaret(HierarchyProvider provider) {
         PsiElement target = provider.getTarget(getDataContext());
-        assert target != null : "Cannot apply action for element at caret";
+        if (target == null) throw new RefactoringErrorHintException("Cannot apply action for element at caret");
         return target;
     }
 
@@ -195,6 +196,17 @@ public abstract class AbstractHierarchyTest extends KotlinHierarchyViewTestBase
         return ArrayUtil.toStringArray(files);
     }
 
+    @Override
+    protected void doHierarchyTest(Computable<HierarchyTreeStructure> treeStructureComputable, String... fileNames) throws Exception {
+        try {
+            super.doHierarchyTest(treeStructureComputable, fileNames);
+        }
+        catch (RefactoringErrorHintException e) {
+            String expectedMessage = FileUtil.loadFile(new File(folderName, "messages.txt"), true);
+            assertEquals(expectedMessage, e.getLocalizedMessage());
+        }
+    }
+
     @Override
     protected String getBasePath() {
         return folderName.substring("idea/testData/".length());

idea/tests/org/jetbrains/kotlin/idea/hierarchy/HierarchyTestGenerated.java

@@ -390,6 +390,12 @@ public class HierarchyTestGenerated extends AbstractHierarchyTest {
             String fileName = JetTestUtils.navigationMetadata("idea/testData/hierarchy/calls/callers/kotlinProperty/");
             doCallerHierarchyTest(fileName);
         }
+
+        @TestMetadata("kotlinUnresolvedFunction")
+        public void testKotlinUnresolvedFunction() throws Exception {
+            String fileName = JetTestUtils.navigationMetadata("idea/testData/hierarchy/calls/callers/kotlinUnresolvedFunction/");
+            doCallerHierarchyTest(fileName);
+        }
     }
 
     @TestMetadata("idea/testData/hierarchy/calls/callees")