support @receiver KDoc tag; somewhat more precise tag name completion

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

@@ -32,8 +32,13 @@ 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.api.KDoc
 import org.jetbrains.kotlin.kdoc.psi.impl.KDocLink
 import org.jetbrains.kotlin.kdoc.psi.impl.KDocName
+import org.jetbrains.kotlin.psi.KtClassOrObject
+import org.jetbrains.kotlin.psi.KtDeclaration
+import org.jetbrains.kotlin.psi.KtNamedFunction
+import org.jetbrains.kotlin.psi.psiUtil.getNonStrictParentOfType
 import org.jetbrains.kotlin.psi.psiUtil.getParentOfType
 import org.jetbrains.kotlin.psi.psiUtil.getStrictParentOfType
 import org.jetbrains.kotlin.resolve.BindingContext
@@ -134,9 +139,19 @@ object KDocTagCompletionProvider: CompletionProvider<CompletionParameters>() {
         if (prefix.length > 0 && !prefix.startsWith('@')) {
             return
         }
+        val kdocOwner = parameters.position.getNonStrictParentOfType<KDoc>()?.getOwner()
         val resultWithPrefix = result.withPrefixMatcher(prefix)
         KDocKnownTag.values().forEach {
-            resultWithPrefix.addElement(LookupElementBuilder.create("@" + it.name.toLowerCase()))
+            if (kdocOwner == null || it.isApplicable(kdocOwner)) {
+                resultWithPrefix.addElement(LookupElementBuilder.create("@" + it.name.toLowerCase()))
+            }
         }
     }
+
+    private fun KDocKnownTag.isApplicable(declaration: KtDeclaration) = when(this) {
+        KDocKnownTag.CONSTRUCTOR, KDocKnownTag.PROPERTY -> declaration is KtClassOrObject
+        KDocKnownTag.RETURN -> declaration is KtNamedFunction
+        KDocKnownTag.RECEIVER -> declaration is KtNamedFunction && declaration.receiverTypeReference != null
+        else -> true
+    }
 }

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

@@ -7,3 +7,4 @@ fun f(x: Int): Int {
 // EXIST: @param
 // EXIST: @return
 // EXIST: @suppress
+// ABSENT: @receiver

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

@@ -0,0 +1,12 @@
+/**
+ * <caret>
+ */
+class C<T> {
+}
+
+// EXIST: @param
+// EXIST: @suppress
+// EXIST: @constructor
+// EXIST: @property
+// ABSENT: @return
+// ABSENT: @receiver

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

@@ -0,0 +1,12 @@
+/**
+ * <caret>
+ */
+fun Int.f(): Int {
+}
+
+// EXIST: @param
+// EXIST: @return
+// EXIST: @suppress
+// EXIST: @receiver
+// ABSENT: @constructor
+// ABSENT: @property

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

@@ -77,6 +77,18 @@ public class KDocCompletionTestGenerated extends AbstractJvmBasicCompletionTest
         doTest(fileName);
     }
 
+    @TestMetadata("TagNameInClass.kt")
+    public void testTagNameInClass() throws Exception {
+        String fileName = KotlinTestUtils.navigationMetadata("idea/idea-completion/testData/kdoc/TagNameInClass.kt");
+        doTest(fileName);
+    }
+
+    @TestMetadata("TagNameInExtensionFunction.kt")
+    public void testTagNameInExtensionFunction() throws Exception {
+        String fileName = KotlinTestUtils.navigationMetadata("idea/idea-completion/testData/kdoc/TagNameInExtensionFunction.kt");
+        doTest(fileName);
+    }
+
     @TestMetadata("TagNameMiddle.kt")
     public void testTagNameMiddle() throws Exception {
         String fileName = KotlinTestUtils.navigationMetadata("idea/idea-completion/testData/kdoc/TagNameMiddle.kt");