better filtering of elements in KDoc link completion

core/descriptors/src/org/jetbrains/kotlin/resolve/scopes/JetScope.kt

@@ -92,8 +92,8 @@ public interface JetScope {
  * The same as getDescriptors(kindFilter, nameFilter) but the result is guaranteed to be filtered by kind and name.
  */
 public fun JetScope.getDescriptorsFiltered(
-        kindFilter: DescriptorKindFilter,
-        nameFilter: (Name) -> Boolean
+        kindFilter: DescriptorKindFilter = DescriptorKindFilter.ALL,
+        nameFilter: (Name) -> Boolean = { true }
 ): Collection<DeclarationDescriptor> {
     if (kindFilter.kindMask == 0) return listOf()
     return getDescriptors(kindFilter, nameFilter).filter { kindFilter.accepts(it) && nameFilter(it.getName()) }

idea/idea-analysis/src/org/jetbrains/kotlin/idea/kdoc/KDocReference.kt

@@ -154,6 +154,9 @@ public fun getResolutionScope(resolutionFacade: ResolutionFacade, descriptor: De
         is PackageViewDescriptor ->
             descriptor.memberScope
 
+        is ClassDescriptorWithResolutionScopes ->
+                descriptor.getScopeForMemberDeclarationResolution()
+
         is ClassDescriptor ->
             getClassInnerScope(getOuterScope(descriptor, resolutionFacade), descriptor)
 

idea/idea-completion/src/org/jetbrains/kotlin/idea/completion/KDocCompletionContributor.kt

@@ -23,9 +23,12 @@ import com.intellij.codeInsight.lookup.LookupElementDecorator
 import com.intellij.patterns.PlatformPatterns.psiElement
 import com.intellij.patterns.StandardPatterns
 import com.intellij.util.ProcessingContext
+import org.jetbrains.kotlin.descriptors.CallableDescriptor
 import org.jetbrains.kotlin.descriptors.DeclarationDescriptor
 import org.jetbrains.kotlin.idea.kdoc.getParamDescriptors
 import org.jetbrains.kotlin.idea.kdoc.getResolutionScope
+import org.jetbrains.kotlin.idea.util.CallType
+import org.jetbrains.kotlin.idea.util.substituteExtensionIfCallable
 import org.jetbrains.kotlin.kdoc.lexer.KDocTokens
 import org.jetbrains.kotlin.kdoc.parser.KDocKnownTag
 import org.jetbrains.kotlin.kdoc.psi.impl.KDocLink
@@ -33,7 +36,10 @@ import org.jetbrains.kotlin.kdoc.psi.impl.KDocName
 import org.jetbrains.kotlin.psi.psiUtil.getParentOfType
 import org.jetbrains.kotlin.psi.psiUtil.getStrictParentOfType
 import org.jetbrains.kotlin.resolve.BindingContext
+import org.jetbrains.kotlin.resolve.calls.smartcasts.DataFlowInfo
+import org.jetbrains.kotlin.resolve.descriptorUtil.fqNameSafe
 import org.jetbrains.kotlin.resolve.scopes.DescriptorKindFilter
+import org.jetbrains.kotlin.resolve.scopes.getDescriptorsFiltered
 
 class KDocCompletionContributor(): CompletionContributor() {
     init {
@@ -86,7 +92,21 @@ class KDocNameCompletionSession(parameters: CompletionParameters,
 
     private fun addLinkCompletions(declarationDescriptor: DeclarationDescriptor) {
         val scope = getResolutionScope(resolutionFacade, declarationDescriptor)
-        scope.getDescriptors(nameFilter = descriptorNameFilter).forEach {
+        val implicitReceivers = scope.getImplicitReceiversHierarchy().map { it.value }
+
+        fun isApplicable(descriptor: DeclarationDescriptor): Boolean {
+            if (descriptor is CallableDescriptor) {
+                val extensionReceiver = descriptor.getExtensionReceiverParameter()
+                if (extensionReceiver != null) {
+                    val substituted = descriptor.substituteExtensionIfCallable(implicitReceivers, bindingContext, DataFlowInfo.EMPTY,
+                                                                               CallType.NORMAL, moduleDescriptor)
+                    return !substituted.isEmpty()
+                }
+            }
+            return true
+        }
+
+        scope.getDescriptorsFiltered(nameFilter = descriptorNameFilter).filter(::isApplicable).forEach {
             val element = lookupElementFactory.createLookupElement(it, false)
             collector.addElement(object: LookupElementDecorator<LookupElement>(element) {
                 override fun handleInsert(context: InsertionContext?) {

idea/idea-completion/testData/kdoc/MemberLink.kt

@@ -0,0 +1,18 @@
+class Foo {
+    /**
+     * [<caret>]
+     */
+    fun xyzzy() {
+
+    }
+
+    fun bar() {
+
+    }
+}
+
+fun Foo.quux() {
+}
+
+// EXIST: bar
+// EXIST: quux

idea/idea-completion/tests/org/jetbrains/kotlin/idea/completion/test/KDocCompletionTestGenerated.java

@@ -41,6 +41,12 @@ public class KDocCompletionTestGenerated extends AbstractJvmBasicCompletionTest
         doTest(fileName);
     }
 
+    @TestMetadata("MemberLink.kt")
+    public void testMemberLink() throws Exception {
+        String fileName = JetTestUtils.navigationMetadata("idea/idea-completion/testData/kdoc/MemberLink.kt");
+        doTest(fileName);
+    }
+
     @TestMetadata("NotTagName.kt")
     public void testNotTagName() throws Exception {
         String fileName = JetTestUtils.navigationMetadata("idea/idea-completion/testData/kdoc/NotTagName.kt");