KT-10770 IDEA cannot keep import if a type is only referenced by kdoc.

#KT-10770 Fixed

idea/idea-analysis/src/org/jetbrains/kotlin/idea/references/referenceUtil.kt

@@ -189,7 +189,11 @@ fun KtExpression.readWriteAccess(useResolveForReadWrite: Boolean): ReferenceAcce
 
 fun KtReference.canBeResolvedViaImport(target: DeclarationDescriptor): Boolean {
     if (!target.canBeReferencedViaImport()) return false
+
+    if (this is KDocReference) return element.getQualifiedName().size == 1
+
     if (target.isExtension) return true // assume that any type of reference can use imports when resolved to extension
+
     val referenceExpression = this.element as? KtNameReferenceExpression ?: return false
     if (CallTypeAndReceiver.detect(referenceExpression).receiver != null) return false
     if (element.parent is KtThisExpression || element.parent is KtSuperExpression) return false // TODO: it's a bad design of PSI tree, we should change it

idea/testData/editor/optimizeImports/KDocReference.kt

@@ -0,0 +1,12 @@
+// RUNTIME
+import kotlin.concurrent.fixedRateTimer
+import kotlin.concurrent.read
+import java.util.ArrayList
+
+/**
+ * Reference to [ArrayList]
+ * Reference to [fixedRateTimer]
+ * Reference to [kotlin.concurrent.read]
+ */
+fun foo() {
+}

idea/testData/editor/optimizeImports/KDocReference.kt.after

@@ -0,0 +1,11 @@
+// RUNTIME
+import java.util.ArrayList
+import kotlin.concurrent.fixedRateTimer
+
+/**
+ * Reference to [ArrayList]
+ * Reference to [fixedRateTimer]
+ * Reference to [kotlin.concurrent.read]
+ */
+fun foo() {
+}

idea/testData/inspections/unusedImport/inspectionData/expected.xml

@@ -88,4 +88,13 @@
         <problem_class severity="WARNING" attribute_key="NOT_USED_ELEMENT_ATTRIBUTES">Unused import directive</problem_class>
         <description>Unused import directive</description>
     </problem>
+
+    <problem>
+        <file>kDocReferences.kt</file>
+        <line>2</line>
+        <module>light_idea_test_case</module>
+        <entry_point TYPE="file" FQNAME="kDocReferences.kt" />
+        <problem_class severity="WARNING" attribute_key="NOT_USED_ELEMENT_ATTRIBUTES">Unused import directive</problem_class>
+        <description>Unused import directive</description>
+    </problem>
 </problems>

idea/testData/inspections/unusedImport/kDocReferences.kt

@@ -0,0 +1,11 @@
+import kotlin.concurrent.fixedRateTimer
+import kotlin.concurrent.read
+import java.util.ArrayList
+
+/**
+ * Reference to [ArrayList]
+ * Reference to [fixedRateTimer]
+ * Reference to [kotlin.concurrent.read]
+ */
+fun foo() {
+}

idea/tests/org/jetbrains/kotlin/idea/imports/OptimizeImportsTestGenerated.java

@@ -137,6 +137,12 @@ public class OptimizeImportsTestGenerated extends AbstractOptimizeImportsTest {
         doTest(fileName);
     }
 
+    @TestMetadata("KDocReference.kt")
+    public void testKDocReference() throws Exception {
+        String fileName = KotlinTestUtils.navigationMetadata("idea/testData/editor/optimizeImports/KDocReference.kt");
+        doTest(fileName);
+    }
+
     @TestMetadata("KT10226.kt")
     public void testKT10226() throws Exception {
         String fileName = KotlinTestUtils.navigationMetadata("idea/testData/editor/optimizeImports/KT10226.kt");