KT-35258 Add better completion for MixedNamedArgumentsInTheirOwnPosition feature

- When named parameter is on its own position, the completion of the next argument will not be limited by named arguments only
- The completion will not suggest already used arguments names
- ^KT-35258 Fixed

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

@@ -105,7 +105,7 @@ class BasicCompletionSession(
         if (OPERATOR_NAME.isApplicable())
             return OPERATOR_NAME
 
-        if (NamedArgumentCompletion.isOnlyNamedArgumentExpected(nameExpression)) {
+        if (NamedArgumentCompletion.isOnlyNamedArgumentExpected(nameExpression, resolutionFacade)) {
             return NAMED_ARGUMENTS_ONLY
         }
 

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

@@ -9,28 +9,42 @@ import com.intellij.codeInsight.completion.InsertHandler
 import com.intellij.codeInsight.completion.InsertionContext
 import com.intellij.codeInsight.lookup.LookupElement
 import com.intellij.codeInsight.lookup.LookupElementBuilder
+import org.jetbrains.kotlin.config.LanguageFeature
+import org.jetbrains.kotlin.descriptors.CallableDescriptor
 import org.jetbrains.kotlin.idea.KotlinIcons
+import org.jetbrains.kotlin.idea.caches.resolve.resolveToCall
 import org.jetbrains.kotlin.idea.completion.handlers.WithTailInsertHandler
 import org.jetbrains.kotlin.idea.core.ArgumentPositionData
 import org.jetbrains.kotlin.idea.core.ExpectedInfo
+import org.jetbrains.kotlin.idea.project.languageVersionSettings
+import org.jetbrains.kotlin.idea.resolve.ResolutionFacade
 import org.jetbrains.kotlin.idea.util.CallType
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.psi.KtCallElement
 import org.jetbrains.kotlin.psi.KtSimpleNameExpression
 import org.jetbrains.kotlin.psi.KtValueArgument
+import org.jetbrains.kotlin.psi.ValueArgument
 import org.jetbrains.kotlin.psi.psiUtil.getStrictParentOfType
 import org.jetbrains.kotlin.renderer.render
+import org.jetbrains.kotlin.resolve.calls.callUtil.getParameterForArgument
+import org.jetbrains.kotlin.resolve.calls.model.ResolvedCall
 import org.jetbrains.kotlin.types.KotlinType
 import java.util.*
 
 object NamedArgumentCompletion {
-    fun isOnlyNamedArgumentExpected(nameExpression: KtSimpleNameExpression): Boolean {
+    fun isOnlyNamedArgumentExpected(nameExpression: KtSimpleNameExpression, resolutionFacade: ResolutionFacade): Boolean {
         val thisArgument = nameExpression.parent as? KtValueArgument ?: return false
         if (thisArgument.isNamed()) return false
 
         val callElement = thisArgument.getStrictParentOfType<KtCallElement>() ?: return false
+        val argumentsBeforeThis = callElement.valueArguments.takeWhile { it != thisArgument }
 
-        return callElement.valueArguments.takeWhile { it != thisArgument }.any { it.isNamed() }
+        if (!nameExpression.languageVersionSettings.supportsFeature(LanguageFeature.MixedNamedArgumentsInTheirOwnPosition)) {
+            return argumentsBeforeThis.any { it.isNamed() }
+        }
+
+        val resolvedCall = callElement.resolveToCall(resolutionFacade) ?: return false
+        return argumentsBeforeThis.any { it.isNamed() && !it.placedOnItsOwnPositionInCall(resolvedCall) }
     }
 
     fun complete(collector: LookupElementsCollector, expectedInfos: Collection<ExpectedInfo>, callType: CallType<*>) {
@@ -68,3 +82,23 @@ object NamedArgumentCompletion {
         }
     }
 }
+
+/**
+ * Checks whether argument in the [resolvedCall] is on the same position as it listed in the callable definition.
+ *
+ * It is always true for the positional arguments, but may be untrue for the named arguments.
+ *
+ * ```
+ * fun foo(a: Int, b: Int, c: Int, d: Int) {}
+ *
+ * foo(
+ *     10,      // true
+ *     b = 10,  // true, possible since Kotlin 1.4 with `MixedNamedArgumentsInTheirOwnPosition` feature
+ *     d = 30,  // false, 3 vs 4
+ *     c = 40   // false, 4 vs 3
+ * )
+ * ```
+ */
+private fun ValueArgument.placedOnItsOwnPositionInCall(resolvedCall: ResolvedCall<out CallableDescriptor>): Boolean {
+    return resolvedCall.getParameterForArgument(this)?.index == resolvedCall.call.valueArguments.indexOf(this)
+}

idea/idea-completion/src/org/jetbrains/kotlin/idea/completion/smart/SmartCompletionSession.kt

@@ -63,7 +63,7 @@ class SmartCompletionSession(
         get() = smartCompletion?.expectedInfos ?: emptyList()
 
     override fun doComplete() {
-        if (nameExpression != null && NamedArgumentCompletion.isOnlyNamedArgumentExpected(nameExpression)) {
+        if (nameExpression != null && NamedArgumentCompletion.isOnlyNamedArgumentExpected(nameExpression, resolutionFacade)) {
             NamedArgumentCompletion.complete(collector, expectedInfos, callTypeAndReceiver.callType)
             return
         }

idea/idea-completion/testData/basic/common/namedArguments/NamedArgumentOnIncorrectPosition.kt

@@ -0,0 +1,10 @@
+fun foo(p1: Int, p2: Int, p3: Long) {}
+
+fun usage(param: Long) {
+    foo(p2 = 10, <caret>)
+}
+
+// LANGUAGE_VERSION: 1.4
+// EXIST: { itemText: "p1 =" }
+// EXIST: { itemText: "p3 =" }
+// NOTHING_ELSE

idea/idea-completion/testData/basic/common/namedArguments/NamedArgumentOnItsOwnPosition.kt

@@ -0,0 +1,11 @@
+fun foo(p1: Int, p2: Int, p3: Long) {}
+
+fun usage(param: Long) {
+    foo(p1 = 10, <caret>)
+}
+
+// LANGUAGE_VERSION: 1.4
+// EXIST: param
+// EXIST: { itemText: "p2 =" }
+// EXIST: { itemText: "p3 =" }
+// ABSENT: { itemText: "p1 =" }

idea/idea-completion/testData/basic/common/namedArguments/NamedArgumentOnItsOwnPosition2.kt

@@ -0,0 +1,13 @@
+fun foo(p1: Int, p2: Int, p3: Int, p4: Int, p5: Int) {}
+
+fun usage(param: Int) {
+    foo(0, p2 = 10, 20, p4 = 30, <caret>)
+}
+
+// LANGUAGE_VERSION: 1.4
+// EXIST: param
+// EXIST: { itemText: "p5 =" }
+// ABSENT: { itemText: "p1 =" }
+// ABSENT: { itemText: "p2 =" }
+// ABSENT: { itemText: "p3 =" }
+// ABSENT: { itemText: "p4 =" }

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

@@ -1799,6 +1799,21 @@ public class JSBasicCompletionTestGenerated extends AbstractJSBasicCompletionTes
                 runTest("idea/idea-completion/testData/basic/common/namedArguments/InParameterExpression.kt");
             }
 
+            @TestMetadata("NamedArgumentOnIncorrectPosition.kt")
+            public void testNamedArgumentOnIncorrectPosition() throws Exception {
+                runTest("idea/idea-completion/testData/basic/common/namedArguments/NamedArgumentOnIncorrectPosition.kt");
+            }
+
+            @TestMetadata("NamedArgumentOnItsOwnPosition.kt")
+            public void testNamedArgumentOnItsOwnPosition() throws Exception {
+                runTest("idea/idea-completion/testData/basic/common/namedArguments/NamedArgumentOnItsOwnPosition.kt");
+            }
+
+            @TestMetadata("NamedArgumentOnItsOwnPosition2.kt")
+            public void testNamedArgumentOnItsOwnPosition2() throws Exception {
+                runTest("idea/idea-completion/testData/basic/common/namedArguments/NamedArgumentOnItsOwnPosition2.kt");
+            }
+
             @TestMetadata("NamedArgumentsFromOverloads.kt")
             public void testNamedArgumentsFromOverloads() throws Exception {
                 runTest("idea/idea-completion/testData/basic/common/namedArguments/NamedArgumentsFromOverloads.kt");

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

@@ -1799,6 +1799,21 @@ public class JvmBasicCompletionTestGenerated extends AbstractJvmBasicCompletionT
                 runTest("idea/idea-completion/testData/basic/common/namedArguments/InParameterExpression.kt");
             }
 
+            @TestMetadata("NamedArgumentOnIncorrectPosition.kt")
+            public void testNamedArgumentOnIncorrectPosition() throws Exception {
+                runTest("idea/idea-completion/testData/basic/common/namedArguments/NamedArgumentOnIncorrectPosition.kt");
+            }
+
+            @TestMetadata("NamedArgumentOnItsOwnPosition.kt")
+            public void testNamedArgumentOnItsOwnPosition() throws Exception {
+                runTest("idea/idea-completion/testData/basic/common/namedArguments/NamedArgumentOnItsOwnPosition.kt");
+            }
+
+            @TestMetadata("NamedArgumentOnItsOwnPosition2.kt")
+            public void testNamedArgumentOnItsOwnPosition2() throws Exception {
+                runTest("idea/idea-completion/testData/basic/common/namedArguments/NamedArgumentOnItsOwnPosition2.kt");
+            }
+
             @TestMetadata("NamedArgumentsFromOverloads.kt")
             public void testNamedArgumentsFromOverloads() throws Exception {
                 runTest("idea/idea-completion/testData/basic/common/namedArguments/NamedArgumentsFromOverloads.kt");

idea/idea-core/src/org/jetbrains/kotlin/idea/core/Utils.kt

@@ -62,6 +62,10 @@ fun Call.mapArgumentsToParameters(targetDescriptor: CallableDescriptor): Map<Val
                 val parameter = parametersByName[argumentName]
                 if (parameter != null) {
                     map[argument] = parameter
+                    if (parameter.index == positionalArgumentIndex) {
+                        positionalArgumentIndex++
+                        continue
+                    }
                 }
                 positionalArgumentIndex = null
             } else {