Raw FIR: introduce lambda argument expressions

Without it we cannot distinguish lambda argument from just last argument

compiler/fir/psi2fir/src/org/jetbrains/kotlin/fir/builder/RawFirBuilder.kt

@@ -312,7 +312,11 @@ class RawFirBuilder(val session: FirSession, val stubMode: Boolean) {
 
         private fun KtCallElement.extractArgumentsTo(container: FirAbstractCall) {
             for (argument in this.valueArguments) {
-                container.arguments += argument.toFirExpression()
+                val argumentExpression = argument.toFirExpression()
+                container.arguments += when (argument) {
+                    is KtLambdaArgument -> FirLambdaArgumentExpressionImpl(session, argument, argumentExpression)
+                    else -> argumentExpression
+                }
             }
         }
 
@@ -1244,9 +1248,7 @@ class RawFirBuilder(val session: FirSession, val stubMode: Boolean) {
                 }
                 this.calleeReference = calleeReference
                 firFunctionCalls += this
-                for (argument in expression.valueArguments) {
-                    arguments += argument.toFirExpression()
-                }
+                expression.extractArgumentsTo(this)
                 for (typeArgument in expression.typeArguments) {
                     typeArguments += typeArgument.convert<FirTypeProjection>()
                 }

compiler/fir/psi2fir/testData/rawBuilder/expressions/lambda.txt

@@ -24,7 +24,7 @@ FILE: lambda.kt
 
         }
 
-        use#(use@fun <implicit>.<anonymous>(<destruct>: <implicit>): <implicit> {
+        use#(<L> = use@fun <implicit>.<anonymous>(<destruct>: <implicit>): <implicit> {
             ^  {
                 lval x: <implicit> = <destruct>#.component1()
                 lval y: <implicit> = <destruct>#.component2()
@@ -33,7 +33,7 @@ FILE: lambda.kt
 
         }
         )
-        ^foo use#(use@fun <implicit>.<anonymous>(): <implicit> {
+        ^foo use#(<L> = use@fun <implicit>.<anonymous>(): <implicit> {
             ^  {
                 when () {
                     ==(it#.x#, Int(0)) ->  {
@@ -50,7 +50,7 @@ FILE: lambda.kt
         )
     }
     public? final? fun bar(): Int {
-        ^bar use#(lambda@fun <implicit>.<anonymous>(): <implicit> {
+        ^bar use#(<L> = lambda@fun <implicit>.<anonymous>(): <implicit> {
             ^  {
                 when () {
                     ==(it#.x#, Int(0)) ->  {
@@ -68,7 +68,7 @@ FILE: lambda.kt
     }
     public? final? fun test(list: List<Int>): kotlin/Unit {
         lval map: <implicit> = mutableMapOf#<Int, String>()
-        list#.forEach#(forEach@fun <implicit>.<anonymous>(): <implicit> {
+        list#.forEach#(<L> = forEach@fun <implicit>.<anonymous>(): <implicit> {
             ^  {
                 lval <complex-set>: <implicit> = map#.getOrPut#(it#, getOrPut@fun <implicit>.<anonymous>(): <implicit> {
                     ^  {

compiler/fir/psi2fir/testData/rawBuilder/expressions/these.txt

@@ -26,7 +26,7 @@ FILE: these.kt
         ^extension this#.bar#()
     }
     public? final? fun test(some: Some): Int {
-        ^test with#(some#, with@fun <implicit>.<anonymous>(): <implicit> {
+        ^test with#(some#, <L> = with@fun <implicit>.<anonymous>(): <implicit> {
             ^  {
                 this#.foo#().plus#(this@with.extension#())
             }