Fix for KT-13400, KT-13389 Resolving FQN in quick doc

Problem related to not complete fix in KT-10398

idea/src/org/jetbrains/kotlin/idea/KotlinQuickDocumentationProvider.kt

@@ -19,7 +19,6 @@ package org.jetbrains.kotlin.idea
 import com.intellij.lang.documentation.AbstractDocumentationProvider
 import com.intellij.lang.java.JavaDocumentationProvider
 import com.intellij.openapi.diagnostic.Logger
-import com.intellij.openapi.util.text.StringUtil
 import com.intellij.psi.PsiElement
 import com.intellij.psi.PsiManager
 import org.jetbrains.kotlin.asJava.elements.KtLightDeclaration
@@ -57,7 +56,7 @@ class KotlinQuickDocumentationProvider : AbstractDocumentationProvider() {
         val bindingContext = navElement.analyze(BodyResolveMode.PARTIAL)
         val contextDescriptor = bindingContext[BindingContext.DECLARATION_TO_DESCRIPTOR, navElement] ?: return null
         val descriptors = resolveKDocLink(bindingContext, navElement.getResolutionFacade(),
-                                          contextDescriptor, null, StringUtil.split(link, ","))
+                                          contextDescriptor, null, link.split('.'))
         val target = descriptors.firstOrNull() ?: return null
         return DescriptorToSourceUtilsIde.getAnyDeclaration(psiManager.project, target)
     }

idea/testData/kdoc/navigate/qualifiedName.kt

@@ -0,0 +1,9 @@
+package a.b.c
+
+class D {
+
+}
+
+fun <caret>foo() {
+
+}

idea/testData/kdoc/navigate/topLevelFun.kt

@@ -0,0 +1,8 @@
+package doc
+
+fun topLevelFun() {}
+
+/**
+ * @see doc.topLevelFun
+ */
+class Doc<caret>Referrer

idea/testData/kdoc/navigate/topLevelProperty.kt

@@ -0,0 +1,8 @@
+package doc
+
+val topLevelProperty = "A"
+
+/**
+ * @see doc.topLevelProperty
+ */
+class Doc<caret>Referrer

idea/tests/org/jetbrains/kotlin/idea/editor/quickDoc/QuickDocNavigationTest.kt

@@ -24,7 +24,9 @@ import org.jetbrains.kotlin.idea.test.KotlinLightCodeInsightFixtureTestCase
 import org.jetbrains.kotlin.idea.test.PluginTestCaseBase
 import org.jetbrains.kotlin.idea.test.ProjectDescriptorWithStdlibSources
 import org.jetbrains.kotlin.psi.KtClass
+import org.jetbrains.kotlin.psi.KtDeclaration
 import org.jetbrains.kotlin.psi.KtFunction
+import org.jetbrains.kotlin.psi.KtProperty
 import org.jetbrains.kotlin.psi.psiUtil.getParentOfType
 import org.junit.Assert
 
@@ -58,9 +60,27 @@ class QuickDocNavigationTest() : KotlinLightCodeInsightFixtureTestCase() {
         Assert.assertEquals("InputStream", (secondaryTarget as PsiClass).name)
     }
 
+    fun testQualifiedName() {
+        val target = resolveDocLink("a.b.c.D")
+        UsefulTestCase.assertInstanceOf(target, KtClass::class.java)
+        Assert.assertEquals("D", (target as KtClass).name)
+    }
+
+    fun testTopLevelFun() {
+        val target = resolveDocLink("doc.topLevelFun")
+        UsefulTestCase.assertInstanceOf(target, KtFunction::class.java)
+        Assert.assertEquals("topLevelFun", (target as KtFunction).name)
+    }
+
+    fun testTopLevelProperty() {
+        val target = resolveDocLink("doc.topLevelProperty")
+        UsefulTestCase.assertInstanceOf(target, KtProperty::class.java)
+        Assert.assertEquals("topLevelProperty", (target as KtProperty).name)
+    }
+
     private fun resolveDocLink(linkText: String): PsiElement? {
         myFixture.configureByFile(getTestName(true) + ".kt")
-        val source = myFixture.elementAtCaret.getParentOfType<KtFunction>(false)
+        val source = myFixture.elementAtCaret.getParentOfType<KtDeclaration>(false)
         return KotlinQuickDocumentationProvider().getDocumentationElementForLink(
                 myFixture.psiManager, linkText, source)
     }