JVM IR: Avoid direct invokes in callable reference tests

Due to the direct invoke optimization, most callable reference tests
were not generating callable references/lambdas.

compiler/testData/codegen/box/callableReference/bound/arrayGetIntrinsic.kt

@@ -1,4 +1,4 @@
 
 fun box(): String {
-    return if ((arrayOf(1, 2, 3)::get)(1) == 2) "OK" else "Fail"
+    return if ((arrayOf(1, 2, 3)::get).let { it(1) } == 2) "OK" else "Fail"
 }

compiler/testData/codegen/box/callableReference/bound/companionObjectReceiver.kt

@@ -5,4 +5,4 @@ class A {
     }
 }
 
-fun box() = (A.Companion::ok)()
+fun box() = (A.Companion::ok).let { it() }

compiler/testData/codegen/box/callableReference/bound/emptyLHS.kt

@@ -7,11 +7,11 @@ class A {
     val aMemberProperty: Int get() = 42.also { result += "A.amp," }
 
     fun test(): String {
-        (::memberFunction)()
-        (::aExtensionFunction)()
+        (::memberFunction).let { it() }
+        (::aExtensionFunction).let { it() }
 
-        (::memberProperty)()
-        (::aExtensionProperty)()
+        (::memberProperty).let { it() }
+        (::aExtensionProperty).let { it() }
 
         return result
     }
@@ -21,17 +21,17 @@ class A {
         val memberProperty: Int get() = 42.also { result += "B.mp," }
 
         fun test(): String {
-            (::aMemberFunction)()
-            (::aExtensionFunction)()
+            (::aMemberFunction).let { it() }
+            (::aExtensionFunction).let { it() }
 
-            (::aMemberProperty)()
-            (::aExtensionProperty)()
+            (::aMemberProperty).let { it() }
+            (::aExtensionProperty).let { it() }
 
-            (::memberFunction)()
-            (::memberProperty)()
+            (::memberFunction).let { it() }
+            (::memberProperty).let { it() }
 
-            (::bExtensionFunction)()
-            (::bExtensionProperty)()
+            (::bExtensionFunction).let { it() }
+            (::bExtensionProperty).let { it() }
 
             return result
         }
@@ -53,28 +53,28 @@ fun box(): String {
 
     result = ""
     with(A()) {
-        (::memberFunction)()
-        (::aExtensionFunction)()
+        (::memberFunction).let { it() }
+        (::aExtensionFunction).let { it() }
 
-        (::memberProperty)()
-        (::aExtensionProperty)()
+        (::memberProperty).let { it() }
+        (::aExtensionProperty).let { it() }
     }
     if (result != "A.mf,A.ef,A.mp,A.ep,") return "Fail $result"
 
     result = ""
     with(A()) {
         with(B()) {
-            (::aMemberFunction)()
-            (::aExtensionFunction)()
+            (::aMemberFunction).let { it() }
+            (::aExtensionFunction).let { it() }
 
-            (::aMemberProperty)()
-            (::aExtensionProperty)()
+            (::aMemberProperty).let { it() }
+            (::aExtensionProperty).let { it() }
 
-            (::memberFunction)()
-            (::memberProperty)()
+            (::memberFunction).let { it() }
+            (::memberProperty).let { it() }
 
-            (::bExtensionFunction)()
-            (::bExtensionProperty)()
+            (::bExtensionFunction).let { it() }
+            (::bExtensionProperty).let { it() }
         }
     }
     if (result != "A.amf,A.ef,A.amp,A.ep,B.mf,B.mp,B.ef,B.ep,") return "Fail $result"

compiler/testData/codegen/box/callableReference/bound/genericValOnLHS.kt

@@ -7,6 +7,6 @@ class Host {
 
 fun box(): String {
     Generic(Host()).p::class
-    (Generic(Host()).p::t)()
-    return (Generic(Host()).p::v)()
+    (Generic(Host()).p::t).let { it() }
+    return (Generic(Host()).p::v).let { it() }
 }

compiler/testData/codegen/box/callableReference/bound/kt15446.kt

@@ -3,13 +3,13 @@
 fun box(): String {
     val a = intArrayOf(1, 2)
     val b = arrayOf("OK")
-    if ((a::component2)() != 2) {
+    if ((a::component2).let { it() } != 2) {
         return "fail"
     }
 
-    if ((a::get)(1) != 2) {
+    if ((a::get).let { it(1) } != 2) {
         return "fail"
     }
 
-    return (b::get)(0)
+    return (b::get).let { it(0) }
 }

compiler/testData/codegen/box/callableReference/bound/objectReceiver.kt

@@ -3,4 +3,4 @@ object Singleton {
     fun ok() = "OK"
 }
 
-fun box() = (Singleton::ok)()
+fun box() = (Singleton::ok).let { it() }

compiler/testData/codegen/box/callableReference/constructor.kt

@@ -10,6 +10,7 @@ class A {
 // FILE: 1.kt
 
 fun box(): String {
-    (::A)(0.0, 0)
+    val constructor = ::A
+    constructor(0.0, 0)
     return "OK"
 }

compiler/testData/codegen/box/callableReference/function/abstractClassMember.kt

@@ -6,4 +6,4 @@ class B : A() {
     override fun foo() = "OK"
 }
 
-fun box(): String = (A::foo)(B())
+fun box(): String = (A::foo).let { it(B()) }

compiler/testData/codegen/box/callableReference/function/booleanNotIntrinsic.kt

@@ -1,5 +1,5 @@
 fun box(): String {
-    if ((Boolean::not)(true) != false) return "Fail 1"
-    if ((Boolean::not)(false) != true) return "Fail 2"
+    if ((Boolean::not).let { it(true) } != false) return "Fail 1"
+    if ((Boolean::not).let { it(false) } != true) return "Fail 2"
     return "OK"
 }

compiler/testData/codegen/box/callableReference/function/classMemberFromClass.kt

@@ -1,7 +1,7 @@
 class A {
     fun foo(k: Int) = k
 
-    fun result() = (A::foo)(this, 111)
+    fun result() = (A::foo).let { it(this, 111) }
 }
 
 fun box(): String {

compiler/testData/codegen/box/callableReference/function/classMemberFromExtension.kt

@@ -3,7 +3,7 @@ class A {
     fun k(k: Int) = k
 }
 
-fun A.foo() = (A::o)(this) + (A::k)(this, 222)
+fun A.foo() = (A::o).let { it(this) } + (A::k).let { it(this, 222) }
 
 fun box(): String {
     val result = A().foo()

compiler/testData/codegen/box/callableReference/function/constructorFromTopLevelNoArgs.kt

@@ -2,4 +2,4 @@ class A {
     var result = "OK"
 }
 
-fun box() = (::A)().result
+fun box() = (::A).let { it() }.result

compiler/testData/codegen/box/callableReference/function/constructorFromTopLevelOneStringArg.kt

@@ -1,3 +1,3 @@
 class A(val result: String)
 
-fun box() = (::A)("OK").result
+fun box() = (::A).let { it("OK") }.result

compiler/testData/codegen/box/callableReference/function/equalsIntrinsic.kt

@@ -1,3 +1,3 @@
 class A
 
-fun box() = if ((A::equals)(A(), A())) "Fail" else "OK"
+fun box() = if ((A::equals).let { it(A(), A()) }) "Fail" else "OK"

compiler/testData/codegen/box/callableReference/function/extensionFromClass.kt

@@ -1,5 +1,5 @@
 class A {
-    fun result() = (A::foo)(this, "OK")
+    fun result() = (A::foo).let { it(this, "OK") }
 }
 
 fun A.foo(x: String) = x

compiler/testData/codegen/box/callableReference/function/extensionFromExtension.kt

@@ -1,6 +1,6 @@
 class A
 
-fun A.foo() = (A::bar)(this, "OK")
+fun A.foo() = (A::bar).let { it(this, "OK") }
 
 fun A.bar(x: String) = x
 

compiler/testData/codegen/box/callableReference/function/genericMember.kt

@@ -2,4 +2,4 @@ class A<T>(val t: T) {
     fun foo(): T = t
 }
 
-fun box() = (A<String>::foo)(A("OK"))
+fun box() = (A<String>::foo).let { it(A("OK")) }

compiler/testData/codegen/box/callableReference/function/innerConstructorFromClass.kt

@@ -4,7 +4,7 @@ class A {
         val k = 222
     }
     
-    fun result() = (A::Inner)(this).o + (A::Inner)(this).k
+    fun result() = (A::Inner).let { it(this) }.o + (A::Inner).let { it(this) }.k
 }
 
 fun box(): String {

compiler/testData/codegen/box/callableReference/function/innerConstructorFromExtension.kt

@@ -5,7 +5,7 @@ class A {
     }
 }
 
-fun A.foo() = (A::Inner)(this).o + (A::Inner)(this).k
+fun A.foo() = (A::Inner).let { it(this) }.o + (A::Inner).let { it(this) }.k
 
 fun box(): String {
     val result = A().foo()

compiler/testData/codegen/box/callableReference/function/innerConstructorFromTopLevelNoArgs.kt

@@ -6,7 +6,7 @@ class A {
 }
 
 fun box(): String {
-    val result = (A::Inner)((::A)()).o + (A::Inner)(A()).k
+    val result = (A::Inner).let { c -> c((::A).let { it() }).o } + (A::Inner).let { it(A()) }.k
     if (result != 333) return "Fail $result"
     return "OK"
 }

compiler/testData/codegen/box/callableReference/function/innerConstructorFromTopLevelOneStringArg.kt

@@ -3,7 +3,10 @@ class A {
 }
 
 fun box(): String {
-    val result = (A::Inner)((::A)(), 111).result + (A::Inner)(A(), 222).result
+    val result = (A::Inner).let { c -> c((::A).let { it() }, 111) }.result + (A::Inner).let { it(A(), 222) }.result
     if (result != 333) return "Fail $result"
     return "OK"
 }
+
+// CHECK_BYTECODE_TEXT
+// 3 Function[^.\n]*\.invoke

compiler/testData/codegen/box/callableReference/function/javaCollectionsStaticMethod.kt

@@ -10,6 +10,6 @@ fun box(): String {
     numbers.add(1)
     numbers.add(2)
     numbers.add(3)
-    (Collections::rotate)(numbers, 1)
+    (Collections::rotate).let { it(numbers, 1) }
     return if ("$numbers" == "[3, 1, 2]") "OK" else "Fail $numbers"
 }

compiler/testData/codegen/box/callableReference/function/local/constructor.kt

@@ -3,5 +3,5 @@ fun box(): String {
         val result = "OK"
     }
 
-    return (::A)().result
+    return (::A).let { it() }.result
 }

compiler/testData/codegen/box/callableReference/function/local/constructorWithInitializer.kt

@@ -6,5 +6,5 @@ fun box(): String {
         }
     }
 
-    return (::A)().result
+    return (::A).let { it() }.result
 }

compiler/testData/codegen/box/callableReference/function/local/extension.kt

@@ -2,5 +2,5 @@ class A
 
 fun box(): String {
     fun A.foo() = "OK"
-    return (A::foo)(A())
+    return (A::foo).let { it(A()) }
 }

compiler/testData/codegen/box/callableReference/function/local/extensionToLocalClass.kt

@@ -1,5 +1,5 @@
 fun box(): String {
     class A
     fun A.foo() = "OK"
-    return (A::foo)((::A)())
+    return (A::foo).let { c -> c((::A).let { it() }) }
 }

compiler/testData/codegen/box/callableReference/function/local/extensionToPrimitive.kt

@@ -1,4 +1,4 @@
 fun box(): String {
     fun Int.is42With(that: Int) = this + 2 * that == 42
-    return if ((Int::is42With)(16, 13)) "OK" else "Fail"
+    return if ((Int::is42With).let { it(16, 13) }) "OK" else "Fail"
 }

compiler/testData/codegen/box/callableReference/function/local/recursiveClosure.kt

@@ -1,7 +1,7 @@
 fun foo(until: Int): String {
     fun bar(x: Int): String =
         if (x == until) "OK" else bar(x + 1)
-    return (::bar)(0)
+    return (::bar).let { it(0) }
 }
 
 fun box() = foo(10)

compiler/testData/codegen/box/callableReference/function/local/simple.kt

@@ -1,4 +1,4 @@
 fun box(): String {
     fun foo() = "OK"
-    return (::foo)()
+    return (::foo).let { it() }
 }

compiler/testData/codegen/box/callableReference/function/local/simpleClosure.kt

@@ -3,5 +3,5 @@ fun box(): String {
 
     fun foo() = result
 
-    return (::foo)()
+    return (::foo).let { it() }
 }

compiler/testData/codegen/box/callableReference/function/local/simpleWithArg.kt

@@ -1,4 +1,4 @@
 fun box(): String {
     fun foo(s: String) = s
-    return (::foo)("OK")
+    return (::foo).let { it("OK") }
 }

compiler/testData/codegen/box/callableReference/function/nestedConstructorFromClass.kt

@@ -4,7 +4,7 @@ class A {
         val k = 222
     }
     
-    fun result() = (::Nested)().o + (A::Nested)().k
+    fun result() = (::Nested).let { it() }.o + (A::Nested).let { it() }.k
 }
 
 fun box(): String {

compiler/testData/codegen/box/callableReference/function/nestedConstructorFromTopLevelNoArgs.kt

@@ -4,4 +4,4 @@ class A {
     }
 }
 
-fun box() = (A::Nested)().result
+fun box() = (A::Nested).let { it() }.result

compiler/testData/codegen/box/callableReference/function/nestedConstructorFromTopLevelOneStringArg.kt

@@ -2,4 +2,4 @@ class A {
     class Nested(val result: String)
 }
 
-fun box() = (A::Nested)("OK").result
+fun box() = (A::Nested).let { it("OK") }.result

compiler/testData/codegen/box/callableReference/function/privateClassMember.kt

@@ -1,7 +1,7 @@
 class A {
     private fun foo() = "OK"
 
-    fun bar() = (A::foo)(this)
+    fun bar() = (A::foo).let { it(this) }
 }
 
 fun box() = A().bar()

compiler/testData/codegen/box/callableReference/function/topLevelFromClass.kt

@@ -5,7 +5,7 @@ fun <T> run(arg1: T, arg2: T, funRef:(T,T) -> T): T {
 fun foo(o: Int, k: Int) = o + k
 
 class A {
-    fun bar() = (::foo)(111, 222)
+    fun bar() = (::foo).let { it(111, 222) }
 }
 
 fun box(): String {

compiler/testData/codegen/box/callableReference/function/topLevelFromExtension.kt

@@ -6,7 +6,7 @@ fun foo(o: Int, k: Int) = o + k
 
 class A
 
-fun A.bar() = (::foo)(111, 222)
+fun A.bar() = (::foo).let { it(111, 222) }
 
 fun box(): String {
     val result = A().bar()

compiler/testData/codegen/box/callableReference/function/traitImplMethodWithClassReceiver.kt

@@ -4,7 +4,7 @@ interface T {
 
 class B : T {
     inner class C {
-        fun bar() = (T::foo)(this@B)
+        fun bar() = (T::foo).let { it(this@B) }
     }
 }
 

compiler/testData/codegen/box/callableReference/function/traitMember.kt

@@ -6,4 +6,4 @@ class B : A {
     override fun foo() = "OK"
 }
 
-fun box() = (A::foo)(B())
+fun box() = (A::foo).let { it(B()) }

compiler/testData/codegen/box/callableReference/staticMethod.kt

@@ -13,6 +13,6 @@ class A {
 
 fun box(): String {
     val args = arrayOf("Fail")
-    (A::main)(args)
+    (A::main).let { it(args) }
     return args[0]
 }

compiler/testData/codegen/box/classes/privateOuterFunctions.kt

@@ -6,7 +6,7 @@ class C {
         {
             "".ext()
             f()
-        }.invoke()
+        }.let { it.invoke() }
 
         object : Runnable {
             public override fun run() {

compiler/testData/codegen/box/classes/privateOuterProperty.kt

@@ -4,7 +4,7 @@ class C{
     public fun foo() : Int {
         {
             v = v + 1
-        }.invoke()
+        }.let { it.invoke() }
 
         object : Runnable {
             public override fun run() {

compiler/testData/codegen/box/closures/kt4137.kt

@@ -6,7 +6,7 @@ infix fun Int.foo(s: Int): Int {
     return this + s
 }
 
-open class B : A({ 1 foo 2} ())
+open class B : A({ 1 foo 2 }.let { it() })
 
 fun box(): String {
     return if (B().s == 3) "OK" else "Fail"

compiler/testData/codegen/box/closures/localFunInInit.kt

@@ -3,7 +3,7 @@ class A {
     init {
         val flag = "OK"
         fun getFlag(): String = flag
-        result = { getFlag() } ()
+        result = { getFlag() }.let { it() }
     }
 }
 fun box(): String = A().result

compiler/testData/codegen/box/controlStructures/kt2597.kt

@@ -5,6 +5,6 @@ fun box(): String {
             i++
         } else {
         }
-    }()
+    }.let { it() }
     return "OK"
 }

compiler/testData/codegen/box/coroutines/featureIntersection/callableReference/bound/emptyLHS.kt

@@ -16,8 +16,8 @@ class A {
     }
 
     suspend fun test(): String {
-        (::memberFunction)()
-        (::aExtensionFunction)()
+        (::memberFunction).let { it() }
+        (::aExtensionFunction).let { it() }
 
         return result
     }
@@ -28,12 +28,12 @@ class A {
         }
 
         suspend fun test(): String {
-            (::aMemberFunction)()
-            (::aExtensionFunction)()
+            (::aMemberFunction).let { it() }
+            (::aExtensionFunction).let { it() }
 
-            (::memberFunction)()
+            (::memberFunction).let { it() }
 
-            (::bExtensionFunction)()
+            (::bExtensionFunction).let { it() }
 
             return result
         }
@@ -69,8 +69,8 @@ fun box(): String {
     result = ""
     builder {
         with(A()) {
-            (::memberFunction)()
-            (::aExtensionFunction)()
+            (::memberFunction).let { it() }
+            (::aExtensionFunction).let { it() }
         }
     }
     if (result != "A.mf,A.ef,") return "Fail $result"
@@ -79,12 +79,12 @@ fun box(): String {
     builder {
         with(A()) {
             with(B()) {
-                (::aMemberFunction)()
-                (::aExtensionFunction)()
+                (::aMemberFunction).let { it() }
+                (::aExtensionFunction).let { it() }
 
-                (::memberFunction)()
+                (::memberFunction).let { it() }
 
-                (::bExtensionFunction)()
+                (::bExtensionFunction).let { it() }
             }
         }
     }

compiler/testData/codegen/box/coroutines/featureIntersection/callableReference/lambdaParameterUsed.kt

@@ -2,7 +2,7 @@
 
 import kotlin.coroutines.*
 
-fun box(): String = a { (::write)() }
+fun box(): String = a { (::write).let { it() } }
 
 fun builder(c: suspend () -> Unit) {
     c.startCoroutine(Continuation(EmptyCoroutineContext) {

compiler/testData/codegen/box/coroutines/localFunctions/named/rec.kt

@@ -44,7 +44,7 @@ suspend fun fooCallableReference(until: Int): String {
     val k = "K"
     val dot = "."
     suspend fun bar(x: Int): String =
-        if (x == until) dot else if (x < until) o + (::bar)(x * 2) else k + (::bar)(x - 1)
+        if (x == until) dot else if (x < until) o + (::bar).let { it(x * 2) } else k + (::bar).let { it(x - 1) }
     return bar(1)
 }
 
@@ -53,8 +53,8 @@ suspend fun fooCallableReferenceIndirectRecursion(until: Int): String {
     val k = "K"
     val dot = "."
     suspend fun bar(x: Int): String {
-        suspend fun innerO() = o + (::bar)(x * 2)
-        suspend fun innerK() = k + (::bar)(x - 1)
+        suspend fun innerO() = o + (::bar).let { it(x * 2) }
+        suspend fun innerK() = k + (::bar).let { it(x - 1) }
         return if (x == until) dot else if (x < until) innerO() else innerK()
     }
     return bar(1)

compiler/testData/codegen/box/coroutines/simpleSuspendCallableReference.kt

@@ -29,7 +29,7 @@ inline suspend fun K(block: suspend (String) -> String) = block("K")
 suspend fun ok(o: String): String {
     return o + run {
         if (o != "K") {
-            (::ok)("K")
+            (::ok).let { it("K") }
         } else ""
     }
 }

compiler/testData/codegen/box/defaultArguments/protected.kt

@@ -14,7 +14,7 @@ import foo.Foo
 
 class Bar() : Foo() {
     fun execute(): String {
-        return { foo() } ()
+        return { foo() }.let { it() }
     }
 }
 

compiler/testData/codegen/box/delegatedProperty/local/kt16864.kt

@@ -8,5 +8,5 @@ fun box(): String {
         object {
             val keys = key
         }.keys
-    } ()
+    }.let { it() }
 }

compiler/testData/codegen/box/directInvokeOptimization/boundInnerContructorRef.kt

@@ -1,6 +1,6 @@
 // CHECK_BYTECODE_TEXT
 // JVM_IR_TEMPLATES
-// 0 Function(^.)*.invoke
+// 0 invoke
 
 class Outer (val x: String) {
     inner class Inner(val y: String) {

compiler/testData/codegen/box/directInvokeOptimization/boundMemberRef.kt

@@ -1,6 +1,6 @@
 // CHECK_BYTECODE_TEXT
 // JVM_IR_TEMPLATES
-// 0 Function(^.)*.invoke
+// 0 invoke
 
 class C(val x: String) {
     fun foo(s: String) = x + s

compiler/testData/codegen/box/directInvokeOptimization/contructorRef.kt

@@ -1,6 +1,6 @@
 // CHECK_BYTECODE_TEXT
 // JVM_IR_TEMPLATES
-// 0 Function(^.)*.invoke
+// 0 invoke
 
 class C(x: String, y: String) {
     val yx = y + x

compiler/testData/codegen/box/directInvokeOptimization/nestedLambdas.kt

@@ -1,6 +1,6 @@
 // CHECK_BYTECODE_TEXT
 // JVM_IR_TEMPLATES
-// 0 Function(^.)*.invoke
+// 0 invoke
 
 fun box() =
     { k: String ->

compiler/testData/codegen/box/directInvokeOptimization/simpleAnonymousFun.kt

@@ -1,6 +1,6 @@
 // CHECK_BYTECODE_TEXT
 // JVM_IR_TEMPLATES
-// 0 Function(^.)*.invoke
+// 0 invoke
 
 fun box() =
     (fun (s: String): String {

compiler/testData/codegen/box/directInvokeOptimization/simpleFunRef.kt

@@ -1,6 +1,6 @@
 // CHECK_BYTECODE_TEXT
 // JVM_IR_TEMPLATES
-// 0 Function(^.)*.invoke
+// 0 invoke
 
 fun ok(s: String) = "O" + s
 

compiler/testData/codegen/box/directInvokeOptimization/simpleLambda.kt

@@ -1,6 +1,6 @@
 // CHECK_BYTECODE_TEXT
 // JVM_IR_TEMPLATES
-// 0 Function(^.)*.invoke
+// 0 invoke
 
 fun box() =
     { s: String ->

compiler/testData/codegen/box/directInvokeOptimization/unboundInnerContructorRef.kt

@@ -1,6 +1,6 @@
 // CHECK_BYTECODE_TEXT
 // JVM_IR_TEMPLATES
-// 0 Function(^.)*.invoke
+// 0 invoke
 
 class Outer (val x: String) {
     inner class Inner(val y: String) {

compiler/testData/codegen/box/directInvokeOptimization/unboundMemberRef.kt

@@ -1,2 +1,6 @@
+// CHECK_BYTECODE_TEXT
+// JVM_IR_TEMPLATES
+// 0 invoke
+
 fun box(): String =
     (String::plus)("O", "K")

compiler/testData/codegen/box/extensionFunctions/kt3298.kt

@@ -4,7 +4,7 @@ fun result(r: String) { result = r }
 object Foo {
     private operator fun String.unaryPlus() = "(" + this + ")"
 
-    fun foo() = { result(+"Stuff") }()
+    fun foo() = { result(+"Stuff") }.let { it() }
 }
 
 fun box(): String {

compiler/testData/codegen/box/functions/invoke/extensionInvokeOnExpr.kt

@@ -13,8 +13,8 @@ fun B.test(): String {
     if (foo()() != "##") return "fail3"
     if (foo()(42) != "#42") return "fail4"
     if ((foo())(42) != "#42") return "fail5"
-    if ({ -> A()}()() != "##") return "fail6"
-    if ({ -> A()}()(37) != "#37") return "fail7"
+    if ({ -> A()}.let { it() }() != "##") return "fail6"
+    if ({ -> A()}.let { it() }(37) != "#37") return "fail7"
     return "OK"
 }
 

compiler/testData/codegen/box/functions/invoke/invokeOnExprByConvention.kt

@@ -14,7 +14,7 @@ fun box(): String {
     if (foo()() != "##") return "fail3"
     if (foo()(42) != "#42") return "fail4"
     if ((foo())(42) != "#42") return "fail5"
-    if ({ -> A()}()() != "##") return "fail6"
-    if ({ -> A()}()(37) != "#37") return "fail7"
+    if ({ -> A()}.let { it() }() != "##") return "fail6"
+    if ({ -> A()}.let { it() }(37) != "#37") return "fail7"
     return "OK"
 }

compiler/testData/codegen/box/functions/kt2481.kt

@@ -9,6 +9,6 @@ public class B(): A(){
     public override fun method() : String {
         return ({
           super.method()
-        })()
+        }).let { it() }
     }
 }

compiler/testData/codegen/box/functions/localFunctions/kt2895.kt

@@ -3,7 +3,7 @@ fun outer() {
         if (i > 0){
             {
                 it: Int -> inner(0) // <- invocation of literal itself is generated instead
-            }.invoke(1)
+            }.let { it.invoke(1) }
         }
     }
     inner(1)

compiler/testData/codegen/box/functions/localFunctions/overloadedLocalFunction3.kt

@@ -14,7 +14,7 @@ fun box(): String {
         {
             foo(foo, 1)
             foo("K")
-        } ()
+        }.let { it() }
     }
 
     return s

compiler/testData/codegen/box/inlineClasses/callableReferences/boundInlineClassExtensionFun.kt

@@ -16,9 +16,9 @@ fun L.test() = x
 fun S.test() = x
 
 fun box(): String {
-    if (Z(42)::test.invoke() != 42) throw AssertionError()
-    if (L(1234L)::test.invoke() != 1234L) throw AssertionError()
-    if (S("abcdef")::test.invoke() != "abcdef") throw AssertionError()
+    if (Z(42)::test.let { it.invoke() } != 42) throw AssertionError()
+    if (L(1234L)::test.let { it.invoke() } != 1234L) throw AssertionError()
+    if (S("abcdef")::test.let { it.invoke() } != "abcdef") throw AssertionError()
 
     return "OK"
 }

compiler/testData/codegen/box/inlineClasses/callableReferences/boundInlineClassExtensionFunGeneric.kt

@@ -16,9 +16,9 @@ fun L<Long>.test() = x
 fun S<String>.test() = x
 
 fun box(): String {
-    if (Z(42)::test.invoke() != 42) throw AssertionError()
-    if (L(1234L)::test.invoke() != 1234L) throw AssertionError()
-    if (S("abcdef")::test.invoke() != "abcdef") throw AssertionError()
+    if (Z(42)::test.let { it.invoke() } != 42) throw AssertionError()
+    if (L(1234L)::test.let { it.invoke() } != 1234L) throw AssertionError()
+    if (S("abcdef")::test.let { it.invoke() } != "abcdef") throw AssertionError()
 
     return "OK"
 }

compiler/testData/codegen/box/inlineClasses/callableReferences/boundInlineClassMemberFun.kt

@@ -18,9 +18,9 @@ value class S(val x: String) {
 }
 
 fun box(): String {
-    if (Z(42)::test.invoke() != 42) throw AssertionError()
-    if (L(1234L)::test.invoke() != 1234L) throw AssertionError()
-    if (S("abcdef")::test.invoke() != "abcdef") throw AssertionError()
+    if (Z(42)::test.let { it.invoke() } != 42) throw AssertionError()
+    if (L(1234L)::test.let { it.invoke() } != 1234L) throw AssertionError()
+    if (S("abcdef")::test.let { it.invoke() } != "abcdef") throw AssertionError()
 
     return "OK"
 }

compiler/testData/codegen/box/inlineClasses/callableReferences/boundInlineClassMemberFunGeneric.kt

@@ -18,9 +18,9 @@ value class S<T: String>(val x: T) {
 }
 
 fun box(): String {
-    if (Z(42)::test.invoke() != 42) throw AssertionError()
-    if (L(1234L)::test.invoke() != 1234L) throw AssertionError()
-    if (S("abcdef")::test.invoke() != "abcdef") throw AssertionError()
+    if (Z(42)::test.let { it.invoke() } != 42) throw AssertionError()
+    if (L(1234L)::test.let { it.invoke() } != 1234L) throw AssertionError()
+    if (S("abcdef")::test.let { it.invoke() } != "abcdef") throw AssertionError()
 
     return "OK"
 }

compiler/testData/codegen/box/inlineClasses/callableReferences/constructorWithInlineClassParameters.kt

@@ -12,8 +12,8 @@ class Outer(val z1: Z) {
 }
 
 fun box(): String {
-    assertEquals(Z(1), ::Outer.invoke(Z(1)).z1)
-    assertEquals(Z(2), Outer::Inner.invoke(Outer(Z(1)), Z(2)).z2)
+    assertEquals(Z(1), ::Outer.let { it.invoke(Z(1)) }.z1)
+    assertEquals(Z(2), Outer::Inner.let { it.invoke(Outer(Z(1)), Z(2)) }.z2)
 
     return "OK"
-}
+}

compiler/testData/codegen/box/inlineClasses/callableReferences/constructorWithInlineClassParametersGeneric.kt

@@ -12,8 +12,8 @@ class Outer(val z1: Z<Int>) {
 }
 
 fun box(): String {
-    assertEquals(Z(1), ::Outer.invoke(Z(1)).z1)
-    assertEquals(Z(2), Outer::Inner.invoke(Outer(Z(1)), Z(2)).z2)
+    assertEquals(Z(1), ::Outer.let { it.invoke(Z(1)) }.z1)
+    assertEquals(Z(2), Outer::Inner.let { it.invoke(Outer(Z(1)), Z(2)) }.z2)
 
     return "OK"
-}
+}

compiler/testData/codegen/box/inlineClasses/callableReferences/funWithInlineClassParameters.kt

@@ -14,7 +14,7 @@ value class S(val x: String)
 fun test(aZ: Z, aL: L, aS: S) = "${aZ.x} ${aL.x} ${aS.x}"
 
 fun box(): String {
-    if (::test.invoke(Z(1), L(1L), S("abc")) != "1 1 abc") throw AssertionError()
+    if (::test.let { it.invoke(Z(1), L(1L), S("abc")) } != "1 1 abc") throw AssertionError()
 
     return "OK"
 }

compiler/testData/codegen/box/inlineClasses/callableReferences/funWithInlineClassParametersGeneric.kt

@@ -14,7 +14,7 @@ value class S<T: String>(val x: T)
 fun test(aZ: Z<Int>, aL: L<Long>, aS: S<String>) = "${aZ.x} ${aL.x} ${aS.x}"
 
 fun box(): String {
-    if (::test.invoke(Z(1), L(1L), S("abc")) != "1 1 abc") throw AssertionError()
+    if (::test.let { it.invoke(Z(1), L(1L), S("abc")) } != "1 1 abc") throw AssertionError()
 
     return "OK"
 }

compiler/testData/codegen/box/inlineClasses/callableReferences/inlineClassExtensionFun.kt

@@ -16,9 +16,9 @@ fun L.test() = x
 fun S.test() = x
 
 fun box(): String {
-    if (Z::test.invoke(Z(42)) != 42) throw AssertionError()
-    if (L::test.invoke(L(1234L)) != 1234L) throw AssertionError()
-    if (S::test.invoke(S("abcdef")) != "abcdef") throw AssertionError()
+    if (Z::test.let { it.invoke(Z(42)) } != 42) throw AssertionError()
+    if (L::test.let { it.invoke(L(1234L)) } != 1234L) throw AssertionError()
+    if (S::test.let { it.invoke(S("abcdef")) } != "abcdef") throw AssertionError()
 
     return "OK"
 }

compiler/testData/codegen/box/inlineClasses/callableReferences/inlineClassExtensionFunGeneric.kt

@@ -16,9 +16,9 @@ fun L<Long>.test() = x
 fun S<String>.test() = x
 
 fun box(): String {
-    if (Z<Int>::test.invoke(Z(42)) != 42) throw AssertionError()
-    if (L<Long>::test.invoke(L(1234L)) != 1234L) throw AssertionError()
-    if (S<String>::test.invoke(S("abcdef")) != "abcdef") throw AssertionError()
+    if (Z<Int>::test.let { it.invoke(Z(42)) } != 42) throw AssertionError()
+    if (L<Long>::test.let { it.invoke(L(1234L)) } != 1234L) throw AssertionError()
+    if (S<String>::test.let { it.invoke(S("abcdef")) } != "abcdef") throw AssertionError()
 
     return "OK"
 }

compiler/testData/codegen/box/inlineClasses/callableReferences/inlineClassMemberFun.kt

@@ -18,9 +18,9 @@ value class S(val x: String) {
 }
 
 fun box(): String {
-    if (Z::test.invoke(Z(42)) != 42) throw AssertionError()
-    if (L::test.invoke(L(1234L)) != 1234L) throw AssertionError()
-    if (S::test.invoke(S("abcdef")) != "abcdef") throw AssertionError()
+    if (Z::test.let { it.invoke(Z(42)) } != 42) throw AssertionError()
+    if (L::test.let { it.invoke(L(1234L)) } != 1234L) throw AssertionError()
+    if (S::test.let { it.invoke(S("abcdef")) } != "abcdef") throw AssertionError()
 
     return "OK"
 }

compiler/testData/codegen/box/inlineClasses/callableReferences/inlineClassMemberFunGeneric.kt

@@ -18,9 +18,9 @@ value class S<T: String>(val x: T) {
 }
 
 fun box(): String {
-    if (Z<Int>::test.invoke(Z(42)) != 42) throw AssertionError()
-    if (L<Long>::test.invoke(L(1234L)) != 1234L) throw AssertionError()
-    if (S<String>::test.invoke(S("abcdef")) != "abcdef") throw AssertionError()
+    if (Z<Int>::test.let { it.invoke(Z(42)) } != 42) throw AssertionError()
+    if (L<Long>::test.let { it.invoke(L(1234L)) } != 1234L) throw AssertionError()
+    if (S<String>::test.let { it.invoke(S("abcdef")) } != "abcdef") throw AssertionError()
 
     return "OK"
 }

compiler/testData/codegen/box/inlineClasses/callableReferencesWithInlineClasses.kt

@@ -14,7 +14,7 @@ fun box(): String {
     val result1 = function1.invoke(Foo("+argument+"), 42)
     if (result1.x != "original+argument+42") return "Fail first"
 
-    val result2 = Foo::bar.invoke(Foo("explicit"), Foo("+argument2+"), 10)
+    val result2 = Foo::bar.let { it.invoke(Foo("explicit"), Foo("+argument2+"), 10) }
     if (result2.x != "explicit+argument2+10") return "Fail second"
 
     return "OK"

compiler/testData/codegen/box/inlineClasses/callableReferencesWithInlineClassesGeneric.kt

@@ -14,7 +14,7 @@ fun box(): String {
     val result1 = function1.invoke(Foo("+argument+"), 42)
     if (result1.x != "original+argument+42") return "Fail first"
 
-    val result2 = Foo<String>::bar.invoke(Foo("explicit"), Foo("+argument2+"), 10)
+    val result2 = Foo<String>::bar.let { it.invoke(Foo("explicit"), Foo("+argument2+"), 10) }
     if (result2.x != "explicit+argument2+10") return "Fail second"
 
     return "OK"

compiler/testData/codegen/box/inlineClasses/contextsAndAccessors/accessPrivateInlineClassMethodFromLambda2.kt

@@ -4,7 +4,7 @@
 
 OPTIONAL_JVM_INLINE_ANNOTATION
 value class R(private val r: Long) {
-    fun test() = { ok() }()
+    fun test() = { ok() }.let { it() }
 
     private fun ok() = "OK"
 }

compiler/testData/codegen/box/inlineClasses/contextsAndAccessors/accessPrivateInlineClassMethodFromLambda2Generic.kt

@@ -4,7 +4,7 @@
 
 OPTIONAL_JVM_INLINE_ANNOTATION
 value class R<T: Long>(private val r: T) {
-    fun test() = { ok() }()
+    fun test() = { ok() }.let { it() }
 
     private fun ok() = "OK"
 }

compiler/testData/codegen/box/inlineClasses/contextsAndAccessors/captureInlineClassInstanceInLambda.kt

@@ -4,7 +4,7 @@
 
 OPTIONAL_JVM_INLINE_ANNOTATION
 value class R(private val r: Int) {
-    fun test() = { ok() }()
+    fun test() = { ok() }.let { it() }
 
     fun ok() = "OK"
 }

compiler/testData/codegen/box/inlineClasses/contextsAndAccessors/captureInlineClassInstanceInLambda2.kt

@@ -4,7 +4,7 @@
 
 OPTIONAL_JVM_INLINE_ANNOTATION
 value class R(private val r: Long) {
-    fun test() = { ok() }()
+    fun test() = { ok() }.let { it() }
 
     fun ok() = "OK"
 }

compiler/testData/codegen/box/inlineClasses/contextsAndAccessors/captureInlineClassInstanceInLambda2Generic.kt

@@ -4,7 +4,7 @@
 
 OPTIONAL_JVM_INLINE_ANNOTATION
 value class R<T: Long>(private val r: T) {
-    fun test() = { ok() }()
+    fun test() = { ok() }.let { it() }
 
     fun ok() = "OK"
 }

compiler/testData/codegen/box/inlineClasses/contextsAndAccessors/captureInlineClassInstanceInLambdaGeneric.kt

@@ -4,7 +4,7 @@
 
 OPTIONAL_JVM_INLINE_ANNOTATION
 value class R<T: Int>(private val r: T) {
-    fun test() = { ok() }()
+    fun test() = { ok() }.let { it() }
 
     fun ok() = "OK"
 }

compiler/testData/codegen/box/inlineClasses/propertyDelegation/captureLocalVarDelegatedToInlineClass.kt

@@ -67,7 +67,7 @@ private fun testDelegateStr() {
         localD = 1234
         if (localD != 1234) throw AssertionError()
         if (backing != 1234) throw AssertionError()
-    }()
+    }.let { it() }
 }
 
 private fun testDelegateInt() {
@@ -79,7 +79,7 @@ private fun testDelegateInt() {
         localD = 1234
         if (localD != 1234) throw AssertionError()
         if (backing != 1234) throw AssertionError()
-    }()
+    }.let { it() }
 }
 
 private fun testDelegateLong() {
@@ -91,5 +91,5 @@ private fun testDelegateLong() {
         localD = 1234
         if (localD != 1234) throw AssertionError()
         if (backing != 1234) throw AssertionError()
-    }()
+    }.let { it() }
 }

compiler/testData/codegen/box/inlineClasses/propertyDelegation/captureLocalVarDelegatedToInlineClassGeneric.kt

@@ -67,7 +67,7 @@ private fun testDelegateStr() {
         localD = 1234
         if (localD != 1234) throw AssertionError()
         if (backing != 1234) throw AssertionError()
-    }()
+    }.let { it() }
 }
 
 private fun testDelegateInt() {
@@ -79,7 +79,7 @@ private fun testDelegateInt() {
         localD = 1234
         if (localD != 1234) throw AssertionError()
         if (backing != 1234) throw AssertionError()
-    }()
+    }.let { it() }
 }
 
 private fun testDelegateLong() {
@@ -91,5 +91,5 @@ private fun testDelegateLong() {
         localD = 1234
         if (localD != 1234) throw AssertionError()
         if (backing != 1234) throw AssertionError()
-    }()
+    }.let { it() }
 }

compiler/testData/codegen/box/intrinsics/kt8666.kt

@@ -18,16 +18,16 @@ fun box(): String {
     if (MAX_LONG != ("" as String?) + Long.MAX_VALUE) return "fail \"\"? +"
     if (MAX_LONG != "".plus(Long.MAX_VALUE)) return "fail \"\".plus"
     if (MAX_LONG != ("" as String?).plus(Long.MAX_VALUE)) return "fail \"\"?.plus"
-    if (MAX_LONG != (String::plus)("", Long.MAX_VALUE)) return "fail String::plus"
+    if (MAX_LONG != (String::plus).let { it("", Long.MAX_VALUE) }) return "fail String::plus"
 //    if (MAX_LONG != stringPlus("", Long.MAX_VALUE)) return "fail stringPlus(\"\", Long.MAX_VALUE)"
 //    if (MAX_LONG != customToString("", Long.MAX_VALUE, String::plus)) return "fail customToString(\"\", Long.MAX_VALUE, String::plus)"
-    if (MAX_LONG != (String?::plus)("", Long.MAX_VALUE)) return "fail String?::plus"
+    if (MAX_LONG != (String?::plus).let { it("", Long.MAX_VALUE) }) return "fail String?::plus"
 //    if (MAX_LONG != stringNPlus("", Long.MAX_VALUE)) return "fail stringNPlus(\"\", Long.MAX_VALUE)"
 //    if (MAX_LONG != customToString("", Long.MAX_VALUE, String?::plus)) return "fail customToString(\"\", Long.MAX_VALUE, String?::plus)"
-    if (MAX_LONG != (""::plus)(Long.MAX_VALUE)) return "fail \"\"::plus"
+    if (MAX_LONG != (""::plus).let { it(Long.MAX_VALUE) }) return "fail \"\"::plus"
 //    if (MAX_LONG != emptyStringPlus(Long.MAX_VALUE)) return "fail emptyStringPlus(Long.MAX_VALUE)"
 //    if (MAX_LONG != customToString(Long.MAX_VALUE, ""::plus)) return "fail customToString(Long.MAX_VALUE, \"\"::plus)"
-    if (MAX_LONG != (("" as String?)::plus)(Long.MAX_VALUE)) return "fail \"\"?::plus"
+    if (MAX_LONG != (("" as String?)::plus).let { it(Long.MAX_VALUE) }) return "fail \"\"?::plus"
 //    if (MAX_LONG != emptyStringNPlus(Long.MAX_VALUE)) return "fail emptyStringPlus(Long.MAX_VALUE)"
 //    if (MAX_LONG != customToString(Long.MAX_VALUE, ("" as String?)::plus)) return "fail customToString(Long.MAX_VALUE, (\"\" as String?)::plus)"
 
@@ -36,16 +36,16 @@ fun box(): String {
     if (PREFIX + MAX_LONG != (PREFIX as String?) + Long.MAX_VALUE) return "fail \"$PREFIX\"? +"
     if (PREFIX + MAX_LONG != PREFIX.plus(Long.MAX_VALUE)) return "fail \"$PREFIX\".plus"
     if (PREFIX + MAX_LONG != (PREFIX as String?).plus(Long.MAX_VALUE)) return "fail \"$PREFIX\"?.plus"
-    if (PREFIX + MAX_LONG != (String::plus)(PREFIX, Long.MAX_VALUE)) return "fail String::plus(\"$PREFIX\", ...)"
+    if (PREFIX + MAX_LONG != (String::plus).let { it(PREFIX, Long.MAX_VALUE) }) return "fail String::plus(\"$PREFIX\", ...)"
 //    if (PREFIX + MAX_LONG != stringPlus(PREFIX, Long.MAX_VALUE)) return "fail stringPlus(\"$PREFIX\", Long.MAX_VALUE)"
 //    if (PREFIX + MAX_LONG != customToString(PREFIX, Long.MAX_VALUE, String::plus)) return "fail customToString(\"$PREFIX\", Long.MAX_VALUE, String::plus)"
-    if (PREFIX + MAX_LONG != (String?::plus)(PREFIX, Long.MAX_VALUE)) return "fail String?::plus(\"$PREFIX\", ...)"
+    if (PREFIX + MAX_LONG != (String?::plus).let { it(PREFIX, Long.MAX_VALUE) }) return "fail String?::plus(\"$PREFIX\", ...)"
 //    if (PREFIX + MAX_LONG != stringNPlus(PREFIX, Long.MAX_VALUE)) return "fail stringNPlus(\"$PREFIX\", Long.MAX_VALUE)"
 //    if (PREFIX + MAX_LONG != customToString(PREFIX, Long.MAX_VALUE, String?::plus)) return "fail customToString(\"$PREFIX\", Long.MAX_VALUE, String?::plus)"
-    if (PREFIX + MAX_LONG != (PREFIX::plus)(Long.MAX_VALUE)) return "fail \"$PREFIX\"::plus"
+    if (PREFIX + MAX_LONG != (PREFIX::plus).let { it(Long.MAX_VALUE) }) return "fail \"$PREFIX\"::plus"
 //    if (PREFIX + MAX_LONG != prefixPlus(Long.MAX_VALUE)) return "fail prefixPlus(Long.MAX_VALUE)"
 //    if (PREFIX + MAX_LONG != customToString(Long.MAX_VALUE, PREFIX::plus)) return "fail customToString(Long.MAX_VALUE, \"$PREFIX\"::plus)"
-    if (PREFIX + MAX_LONG != ((PREFIX as String?)::plus)(Long.MAX_VALUE)) return "fail \"$PREFIX\"?::plus"
+    if (PREFIX + MAX_LONG != ((PREFIX as String?)::plus).let { it(Long.MAX_VALUE) }) return "fail \"$PREFIX\"?::plus"
 //    if (PREFIX + MAX_LONG != prefixNPlus(Long.MAX_VALUE)) return "fail prefixNPlus(Long.MAX_VALUE)"
 //    if (PREFIX + MAX_LONG != customToString(Long.MAX_VALUE, (PREFIX as String?)::plus)) return "fail customToString(Long.MAX_VALUE, \"$PREFIX\"?::plus)"
 

compiler/testData/codegen/box/jvm8/defaults/accessor.kt

@@ -24,7 +24,7 @@ interface Test {
         return {
             foo = "O"
             foo + bar()
-        } ()
+        }.let { it() }
     }
 }
 

compiler/testData/codegen/box/jvm8/defaults/accessorsFromDefaultImpls.kt

@@ -14,7 +14,7 @@ interface Test {
     }
 
     fun call(): String {
-        return { foo + bar()} ()
+        return { foo + bar() }.let { it() }
     }
 }
 

compiler/testData/codegen/box/jvm8/defaults/allCompatibility/accessor.kt

@@ -21,7 +21,7 @@ interface Test {
         return {
             foo = "O"
             foo + bar()
-        } ()
+        }.let { it() }
     }
 }
 

compiler/testData/codegen/box/jvm8/defaults/callableReference.kt

@@ -12,7 +12,7 @@ interface Test {
         get() = "K"
 
     fun test(): String {
-        return (::foo)() + (::bar)()
+        return (::foo).let { it() } + (::bar).let { it() }
     }
 }
 

compiler/testData/codegen/box/jvm8/defaults/noDefaultImpls/accessor.kt

@@ -21,7 +21,7 @@ interface Test {
         return {
             foo = "O"
             foo + bar()
-        } ()
+        }.let { it() }
     }
 }
 

compiler/testData/codegen/box/jvmField/captureClassFields.kt

@@ -10,7 +10,7 @@ open class A {
     fun test(): String {
         return {
             publicField + internalField + protectedField
-        }()
+        }.let { it() }
     }
 }
 

compiler/testData/codegen/box/jvmName/callableReference.kt

@@ -6,7 +6,7 @@
 fun foo() = "foo"
 
 fun box(): String {
-    val f = (::foo)()
+    val f = (::foo).let { it() }
     if (f != "foo") return "Fail: $f"
 
     return "OK"

compiler/testData/codegen/box/jvmStatic/closure.kt

@@ -9,27 +9,27 @@ object A {
     @JvmStatic val c: String = "OK"
 
     @JvmStatic fun test1() : String {
-        return {b}()
+        return {b}.let { it() }
     }
 
     @JvmStatic fun test2() : String {
-        return {test1()}()
+        return {test1()}.let { it() }
     }
 
     fun test3(): String {
-        return {"1".test5()}()
+        return {"1".test5()}.let { it() }
     }
 
     @JvmStatic fun test4(): String {
-        return {"1".test5()}()
+        return {"1".test5()}.let { it() }
     }
 
     @JvmStatic fun String.test5() : String {
-        return {this + b}()
+        return {this + b}.let { it() }
     }
 
     fun test6(): String {
-        return {c}()
+        return {c}.let { it() }
     }
 }
 

compiler/testData/codegen/box/jvmStatic/functionReference.kt

@@ -10,4 +10,4 @@ object O {
 
 // FILE: u2.kt
 
-fun box() = (O::foo)()
+fun box() = (O::foo).let { it() }

compiler/testData/codegen/box/jvmStatic/kt21246a.kt

@@ -3,7 +3,7 @@
 
 object Test {
 
-    fun test() = { createWildcard("OK") }()
+    fun test() = { createWildcard("OK") }.let { it() }
 
     @JvmStatic
     private fun createWildcard(s: String) = Type<Any>(s).x

compiler/testData/codegen/box/labels/propertyAccessorFunctionLiteral.kt

@@ -2,7 +2,7 @@ val Int.getter: Int
     get() {
         return {
             this@getter
-        }.invoke()
+        }.let { it.invoke() }
     }
 
 fun box(): String {