Add test for for kt42457 wrong behaviour. Align runtime concatenation with it

#KT-42457

compiler/fir/fir2ir/tests/org/jetbrains/kotlin/codegen/ir/FirBlackBoxCodegenTestGenerated.java

@@ -30208,6 +30208,11 @@ public class FirBlackBoxCodegenTestGenerated extends AbstractFirBlackBoxCodegenT
             runTest("compiler/testData/codegen/box/strings/kt3652.kt");
         }
 
+        @TestMetadata("kt42457_old.kt")
+        public void testKt42457_old() throws Exception {
+            runTest("compiler/testData/codegen/box/strings/kt42457_old.kt");
+        }
+
         @TestMetadata("kt5389_stringBuilderGet.kt")
         public void testKt5389_stringBuilderGet() throws Exception {
             runTest("compiler/testData/codegen/box/strings/kt5389_stringBuilderGet.kt");

compiler/fir/fir2ir/tests/org/jetbrains/kotlin/codegen/ir/FirBytecodeTextTestGenerated.java

@@ -4551,6 +4551,11 @@ public class FirBytecodeTextTestGenerated extends AbstractFirBytecodeTextTest {
             runTest("compiler/testData/codegen/bytecodeText/stringOperations/kt19037.kt");
         }
 
+        @TestMetadata("kt42457_old.kt")
+        public void testKt42457_old() throws Exception {
+            runTest("compiler/testData/codegen/bytecodeText/stringOperations/kt42457_old.kt");
+        }
+
         @TestMetadata("multipleNestedConcat.kt")
         public void testMultipleNestedConcat() throws Exception {
             runTest("compiler/testData/codegen/bytecodeText/stringOperations/multipleNestedConcat.kt");

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/lower/JvmStringConcatenationLowering.kt

@@ -193,6 +193,9 @@ private class JvmDynamicStringConcatenationLowering(val context: JvmBackendConte
                 arguments.isEmpty() ->
                     irString("")
 
+                arguments.size == 1 ->
+                    lowerInlineClassArgument(arguments[0]) ?: callToString(arguments[0].unwrapImplicitNotNull())
+
                 else -> {
                     IrStringConcatenationImpl(
                         expression.startOffset,

compiler/testData/codegen/box/strings/kt42457_old.kt

@@ -0,0 +1,17 @@
+// TARGET_BACKEND: JVM
+// FILE: JavaClass.java
+
+public class JavaClass {
+    public String toString() {
+        return null;
+    }
+}
+
+// FILE: Kotlin.kt
+fun box(): String {
+    val toString: String? = JavaClass().toString()
+    if (toString != null) return "fail 1: $toString"
+    val template: String? = "${JavaClass()}"
+    if (template != null) return "fail 2: $template"
+    return "OK"
+}

compiler/testData/codegen/bytecodeText/stringOperations/kt42457_old.kt

@@ -0,0 +1,20 @@
+// IGNORE_BACKEND_FIR: JVM_IR
+// KOTLIN_CONFIGURATION_FLAGS: STRING_CONCAT=indy-with-constants
+// JVM_TARGET: 9
+// FILE: JavaClass.java
+
+public class JavaClass {
+    public String toString() {
+        return null;
+    }
+}
+
+// FILE: Kotlin.kt
+fun box() {
+    val toString: String? = JavaClass().toString()
+    val template: String = "${JavaClass()}"
+}
+// 0 INVOKEDYNAMIC makeConcat
+// 1 JavaClass.toString
+// 1 String.valueOf
+// 0 append

compiler/tests/org/jetbrains/kotlin/codegen/BlackBoxCodegenTestGenerated.java

@@ -31974,6 +31974,11 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
             runTest("compiler/testData/codegen/box/strings/kt3652.kt");
         }
 
+        @TestMetadata("kt42457_old.kt")
+        public void testKt42457_old() throws Exception {
+            runTest("compiler/testData/codegen/box/strings/kt42457_old.kt");
+        }
+
         @TestMetadata("kt5389_stringBuilderGet.kt")
         public void testKt5389_stringBuilderGet() throws Exception {
             runTest("compiler/testData/codegen/box/strings/kt5389_stringBuilderGet.kt");

compiler/tests/org/jetbrains/kotlin/codegen/BytecodeTextTestGenerated.java

@@ -4583,6 +4583,11 @@ public class BytecodeTextTestGenerated extends AbstractBytecodeTextTest {
             runTest("compiler/testData/codegen/bytecodeText/stringOperations/kt19037.kt");
         }
 
+        @TestMetadata("kt42457_old.kt")
+        public void testKt42457_old() throws Exception {
+            runTest("compiler/testData/codegen/bytecodeText/stringOperations/kt42457_old.kt");
+        }
+
         @TestMetadata("multipleNestedConcat.kt")
         public void testMultipleNestedConcat() throws Exception {
             runTest("compiler/testData/codegen/bytecodeText/stringOperations/multipleNestedConcat.kt");

compiler/tests/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java

@@ -29608,6 +29608,11 @@ public class LightAnalysisModeTestGenerated extends AbstractLightAnalysisModeTes
             runTest("compiler/testData/codegen/box/strings/kt3652.kt");
         }
 
+        @TestMetadata("kt42457_old.kt")
+        public void testKt42457_old() throws Exception {
+            runTest("compiler/testData/codegen/box/strings/kt42457_old.kt");
+        }
+
         @TestMetadata("kt5389_stringBuilderGet.kt")
         public void testKt5389_stringBuilderGet() throws Exception {
             runTest("compiler/testData/codegen/box/strings/kt5389_stringBuilderGet.kt");

compiler/tests/org/jetbrains/kotlin/codegen/ir/IrBlackBoxCodegenTestGenerated.java

@@ -30208,6 +30208,11 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
             runTest("compiler/testData/codegen/box/strings/kt3652.kt");
         }
 
+        @TestMetadata("kt42457_old.kt")
+        public void testKt42457_old() throws Exception {
+            runTest("compiler/testData/codegen/box/strings/kt42457_old.kt");
+        }
+
         @TestMetadata("kt5389_stringBuilderGet.kt")
         public void testKt5389_stringBuilderGet() throws Exception {
             runTest("compiler/testData/codegen/box/strings/kt5389_stringBuilderGet.kt");

compiler/tests/org/jetbrains/kotlin/codegen/ir/IrBytecodeTextTestGenerated.java

@@ -4551,6 +4551,11 @@ public class IrBytecodeTextTestGenerated extends AbstractIrBytecodeTextTest {
             runTest("compiler/testData/codegen/bytecodeText/stringOperations/kt19037.kt");
         }
 
+        @TestMetadata("kt42457_old.kt")
+        public void testKt42457_old() throws Exception {
+            runTest("compiler/testData/codegen/bytecodeText/stringOperations/kt42457_old.kt");
+        }
+
         @TestMetadata("multipleNestedConcat.kt")
         public void testMultipleNestedConcat() throws Exception {
             runTest("compiler/testData/codegen/bytecodeText/stringOperations/multipleNestedConcat.kt");