[FIR] Keep vararg argument order in resolved calls (KT-17691).

compiler/testData/codegen/box/mixedNamedPosition/varargs.kt

@@ -19,6 +19,7 @@ fun foo3(
 ) = "$p1 $p2 ${p3[0].toInt()} ${p3[1].toInt()}"
 
 fun box(): String {
+    if (foo1(1, 2, p2 = "3", p3 = 4.0) != "1 2 3 4") return "fail 1"
     if (foo1(p1 = *intArrayOf(1, 2), "3", p3 = 4.0) != "1 2 3 4") return "fail 2"
 
     if (foo2(p1 = 1, "2", "3", p3 = 4.0) != "1 2 3 4") return "fail 3"

compiler/testData/codegen/box/mixedNamedPosition/varargsEvaluationOrder.kt

@@ -0,0 +1,46 @@
+// !LANGUAGE: +NewInference +MixedNamedArgumentsInTheirOwnPosition
+// IGNORE_BACKEND: JVM
+// See KT-17691: Wrong argument order in resolved call with varargs. (fixed in JVM_IR)
+
+var log = ""
+
+fun <T> logged(value: T): T =
+    value.also { log += " " + value }
+
+fun doTest(id: String, expected: String, expectedLog: String, test: () -> String) {
+    log = ""
+    val actual = test()
+    if (actual != expected) throw AssertionError("$id expected: $expected, actual: $actual")
+    if (log != expectedLog) throw AssertionError("$id expectedLog: $expectedLog, actual: $log")
+}
+
+fun foo1(
+    vararg p1: Int,
+    p2: String,
+    p3: Double
+) = "${p1[0]} ${p1[1]} $p2 ${p3.toInt()}"
+
+fun foo2(
+    p1: Int,
+    vararg p2: String,
+    p3: Double
+) = "$p1 ${p2[0]} ${p2[1]} ${p3.toInt()}"
+
+fun foo3(
+    p1: Int,
+    p2: String,
+    vararg p3: Double
+) = "$p1 $p2 ${p3[0].toInt()} ${p3[1].toInt()}"
+
+fun box(): String {
+    doTest("test1", "1 2 3 4", " 1 2 3 4.5") { foo1(logged(1), logged(2), p2 = logged("3"), p3 = logged(4.5)) }
+    doTest("test2", "1 2 3 4", " 1 2 3 4.5") { foo1(p1 = *intArrayOf(logged(1), logged(2)), logged("3"), p3 = logged(4.5)) }
+
+    doTest("test3", "1 2 3 4", " 1 2 3 4.5") { foo2(p1 = logged(1), logged("2"), logged("3"), p3 = logged(4.5)) }
+    doTest("test4", "1 2 3 4", " 1 2 3 4.5") { foo2(logged(1), p2 = *arrayOf(logged("2"), logged("3")), logged(4.5)) }
+
+    doTest("test5", "1 2 3 4", " 1 2 3.5 4.5") { foo3(p1 = logged(1), logged("2"), logged(3.5), logged(4.5)) }
+    doTest("test6", "1 2 3 4", " 1 2 3.5 4.5") { foo3(p1 = logged(1), logged("2"), p3 = *doubleArrayOf(logged(3.5), logged(4.5))) }
+
+    return "OK"
+}