KT-20884: Support receiver reference in KDoc comments

#KT-20884 fixed

compiler/frontend/src/org/jetbrains/kotlin/resolve/DescriptorToSourceUtils.kt

@@ -23,7 +23,9 @@ import org.jetbrains.kotlin.descriptors.CallableMemberDescriptor.Kind.SYNTHESIZE
 import org.jetbrains.kotlin.descriptors.annotations.AnnotationDescriptor
 import org.jetbrains.kotlin.descriptors.synthetic.SyntheticMemberDescriptor
 import org.jetbrains.kotlin.psi.KtAnnotationEntry
+import org.jetbrains.kotlin.psi.KtCallableDeclaration
 import org.jetbrains.kotlin.psi.KtFile
+import org.jetbrains.kotlin.resolve.scopes.receivers.ExtensionReceiver
 import org.jetbrains.kotlin.resolve.source.getPsi
 import java.util.*
 
@@ -51,7 +53,20 @@ object DescriptorToSourceUtils {
         return result
     }
 
+    // TODO Fix in descriptor
+    @JvmStatic private fun getSourceForExtensionReceiverParameterDescriptor(descriptor: ReceiverParameterDescriptor): PsiElement? {
+        // Only for extension receivers
+        if (descriptor.source != SourceElement.NO_SOURCE || descriptor.value !is ExtensionReceiver) return null
+        val containingDeclaration = descriptor.containingDeclaration as? CallableDescriptor ?: return null
+        val psi = containingDeclaration.source.getPsi() as? KtCallableDeclaration ?: return null
+        return psi.receiverTypeReference
+    }
+
     @JvmStatic fun getSourceFromDescriptor(descriptor: DeclarationDescriptor): PsiElement? {
+        if (descriptor is ReceiverParameterDescriptor) {
+            getSourceForExtensionReceiverParameterDescriptor(descriptor)?.let { return it }
+        }
+
         return (descriptor as? DeclarationDescriptorWithSource)?.source?.getPsi()
     }
 

idea/ide-common/src/org/jetbrains/kotlin/idea/kdoc/resolveKDocLink.kt

@@ -119,6 +119,10 @@ private fun resolveDefaultKDocLink(
         descriptorsByName.addAll(contextScope.collectFunctions(shortName, NoLookupLocation.FROM_IDE))
         descriptorsByName.addAll(contextScope.collectVariables(shortName, NoLookupLocation.FROM_IDE))
 
+        if (fromDescriptor is FunctionDescriptor && fromDescriptor.isExtension && shortName.asString() == "this") {
+            return listOfNotNull(fromDescriptor.extensionReceiverParameter)
+        }
+
         // Try to find a matching local descriptor (parameter or type parameter) first
         val localDescriptors = descriptorsByName.filter { it.containingDeclaration == fromDescriptor }
         if (localDescriptors.isNotEmpty()) return localDescriptors

idea/testData/kdoc/resolve/ReceiverReference.kt

@@ -0,0 +1,8 @@
+class Foo
+
+/**
+ * [<caret>this]
+ */
+fun Foo.bar {}
+
+// REF: Foo

idea/tests/org/jetbrains/kotlin/idea/kdoc/KdocResolveTestGenerated.java

@@ -157,6 +157,12 @@ public class KdocResolveTestGenerated extends AbstractReferenceResolveTest {
         doTest(fileName);
     }
 
+    @TestMetadata("ReceiverReference.kt")
+    public void testReceiverReference() throws Exception {
+        String fileName = KotlinTestUtils.navigationMetadata("idea/testData/kdoc/resolve/ReceiverReference.kt");
+        doTest(fileName);
+    }
+
     @TestMetadata("SeeReference.kt")
     public void testSeeReference() throws Exception {
         String fileName = KotlinTestUtils.navigationMetadata("idea/testData/kdoc/resolve/SeeReference.kt");