KT-13025: when receiver of call of 'invoke' method is a Function, check whether receiver is an extension function and generate additional '.call' invocation. Fix #KT-13025

js/js.tests/test/org/jetbrains/kotlin/js/test/semantics/InvokeConventionTest.java

@@ -61,4 +61,8 @@ public final class InvokeConventionTest extends AbstractExpressionTest {
     public void testInvokeWithImplicitDispatchReceiverAndExtensionReceiver() throws Exception {
         checkFooBoxIsOk();
     }
+
+    public void testExtensionInvoke() throws Exception {
+        checkFooBoxIsOk();
+    }
 }

js/js.translator/src/org/jetbrains/kotlin/js/translate/callTranslator/FunctionCallCases.kt

@@ -18,6 +18,7 @@ package org.jetbrains.kotlin.js.translate.callTranslator
 
 import com.google.dart.compiler.backend.js.ast.*
 import org.jetbrains.kotlin.builtins.functions.FunctionInvokeDescriptor
+import org.jetbrains.kotlin.builtins.isExtensionFunctionType
 import org.jetbrains.kotlin.descriptors.CallableDescriptor
 import org.jetbrains.kotlin.descriptors.ConstructorDescriptor
 import org.jetbrains.kotlin.descriptors.Visibilities
@@ -179,7 +180,14 @@ object InvokeIntrinsic : FunctionCallCase() {
     }
 
     override fun FunctionCallInfo.dispatchReceiver(): JsExpression {
-        return JsInvocation(dispatchReceiver!!, argumentsInfo.translateArguments)
+        val receiver = resolvedCall.dispatchReceiver!!
+        val jsReceiver = if (receiver.type.isExtensionFunctionType) {
+            pureFqn(Namer.CALL_FUNCTION, dispatchReceiver)
+        }
+        else {
+            dispatchReceiver!!
+        }
+        return JsInvocation(jsReceiver, argumentsInfo.translateArguments)
     }
 
     /**

js/js.translator/testData/expression/invoke/cases/extensionInvoke.kt

@@ -0,0 +1,16 @@
+package foo
+
+class A(val f: (B.() -> Int)?)
+
+class B(val x: Int)
+
+fun test(g: (B.() -> Int)?): Int? {
+    val a = A(g)
+    val b = B(2)
+    return a.f?.invoke(b)
+}
+
+fun box(): String {
+    assertEquals(5, test { x + 3 })
+    return "OK"
+}