KT-27601 keep imports for extension functions used in kdoc

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

@@ -10,9 +10,7 @@ import com.intellij.psi.*
 import com.intellij.psi.search.GlobalSearchScope
 import org.jetbrains.kotlin.asJava.unwrapped
 import org.jetbrains.kotlin.builtins.isExtensionFunctionType
-import org.jetbrains.kotlin.descriptors.DeclarationDescriptor
-import org.jetbrains.kotlin.descriptors.DeclarationDescriptorWithSource
-import org.jetbrains.kotlin.descriptors.PropertyDescriptor
+import org.jetbrains.kotlin.descriptors.*
 import org.jetbrains.kotlin.idea.caches.resolve.analyze
 import org.jetbrains.kotlin.idea.caches.resolve.resolveImportReference
 import org.jetbrains.kotlin.idea.caches.resolve.resolveToCall
@@ -287,7 +285,16 @@ fun KtExpression.readWriteAccessWithFullExpression(useResolveForReadWrite: Boole
 }
 
 fun KtReference.canBeResolvedViaImport(target: DeclarationDescriptor, bindingContext: BindingContext): Boolean {
-    if (this is KDocReference) return element.getQualifiedName().size == 1
+    if (this is KDocReference) {
+        val qualifier = element.getQualifier() ?: return true
+        return if (target.isExtension) {
+            val elementHasFunctionDescriptor = element.resolveMainReferenceToDescriptors().find { it is FunctionDescriptor } != null
+            val qualifierHasClassDescriptor = qualifier.resolveMainReferenceToDescriptors().find { it is ClassDescriptor } != null
+            elementHasFunctionDescriptor && qualifierHasClassDescriptor
+        } else {
+            false
+        }
+    }
     return element.canBeResolvedViaImport(target, bindingContext)
 }
 

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

@@ -1,11 +1,16 @@
 import kotlin.concurrent.fixedRateTimer
 import kotlin.concurrent.read
+import kotlin.concurrent.withLock
+import kotlin.concurrent.write
 import java.util.ArrayList
+import java.util.concurrent.locks.Lock
 
 /**
  * Reference to [ArrayList]
  * Reference to [fixedRateTimer]
  * Reference to [kotlin.concurrent.read]
+ * Reference to [Lock.withLock]
+ * Reference to [java.util.concurrent.locks.ReentrantReadWriteLock.write]
  */
 fun foo() {
 }

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

@@ -1,5 +1,8 @@
 import java.util.ArrayList
+import java.util.concurrent.locks.Lock
 import kotlin.concurrent.fixedRateTimer
+import kotlin.concurrent.withLock
+import kotlin.concurrent.write
 
 /**
  * Reference to [ArrayList]

idea/testData/inspections/unusedImport/kDocReferences.kt

@@ -1,11 +1,16 @@
 import kotlin.concurrent.fixedRateTimer
 import kotlin.concurrent.read
+import kotlin.concurrent.withLock
+import kotlin.concurrent.write
 import java.util.ArrayList
+import java.util.concurrent.locks.Lock
 
 /**
  * Reference to [ArrayList]
  * Reference to [fixedRateTimer]
  * Reference to [kotlin.concurrent.read]
+ * Reference to [Lock.withLock]
+ * Reference to [java.util.concurrent.locks.ReentrantReadWriteLock.write]
  */
 fun foo() {
 }