Propagate KotlinType into when expression codegen

This commit removes unneeded boxing when result expression of `when` is
 value of inline class type

compiler/backend/src/org/jetbrains/kotlin/codegen/ExpressionCodegen.java

@@ -4573,8 +4573,9 @@ The "returned" value of try expression with no finally is either the last expres
 
     public StackValue generateWhenExpression(KtWhenExpression expression, boolean isStatement) {
         Type resultType = isStatement ? Type.VOID_TYPE : expressionType(expression);
+        KotlinType resultKotlinType = isStatement ? null : kotlinType(expression);
 
-        return StackValue.operation(resultType, v -> {
+        return StackValue.operation(resultType, resultKotlinType, v -> {
             KtProperty subjectVariable = expression.getSubjectVariable();
             KtExpression subjectExpression = expression.getSubjectExpression();
 
@@ -4637,7 +4638,7 @@ The "returned" value of try expression with no finally is either the last expres
                 }
 
                 v.visitLabel(thisEntry);
-                gen(whenEntry.getExpression(), resultType);
+                gen(whenEntry.getExpression(), resultType, resultKotlinType);
                 mark.dropTo();
                 if (!whenEntry.isElse()) {
                     v.goTo(end);

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

@@ -0,0 +1,18 @@
+// !LANGUAGE: +InlineClasses
+
+inline class Foo<T>(val x: Any) {
+    fun bar() {}
+}
+
+fun <T, K> transform(f: Foo<T>): Foo<K> {
+    return when {
+        true -> f as Foo<K>
+        else -> TODO()
+    }
+}
+
+fun box(): String {
+    val f = Foo<Int>(42)
+    val t = transform<Int, Number>(f)
+    return if (t.x !is Number) "Fail" else "OK"
+}

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

@@ -11021,6 +11021,11 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
             runTest("compiler/testData/codegen/box/inlineClasses/callableReferencesWithInlineClasses.kt");
         }
 
+        @TestMetadata("castInsideWhenExpression.kt")
+        public void testCastInsideWhenExpression() throws Exception {
+            runTest("compiler/testData/codegen/box/inlineClasses/castInsideWhenExpression.kt");
+        }
+
         @TestMetadata("checkBoxUnboxOfArgumentsOnInlinedFunctions.kt")
         public void testCheckBoxUnboxOfArgumentsOnInlinedFunctions() throws Exception {
             runTest("compiler/testData/codegen/box/inlineClasses/checkBoxUnboxOfArgumentsOnInlinedFunctions.kt");

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

@@ -11021,6 +11021,11 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
             runTest("compiler/testData/codegen/box/inlineClasses/callableReferencesWithInlineClasses.kt");
         }
 
+        @TestMetadata("castInsideWhenExpression.kt")
+        public void testCastInsideWhenExpression() throws Exception {
+            runTest("compiler/testData/codegen/box/inlineClasses/castInsideWhenExpression.kt");
+        }
+
         @TestMetadata("checkBoxUnboxOfArgumentsOnInlinedFunctions.kt")
         public void testCheckBoxUnboxOfArgumentsOnInlinedFunctions() throws Exception {
             runTest("compiler/testData/codegen/box/inlineClasses/checkBoxUnboxOfArgumentsOnInlinedFunctions.kt");

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

@@ -11021,6 +11021,11 @@ public class LightAnalysisModeTestGenerated extends AbstractLightAnalysisModeTes
             runTest("compiler/testData/codegen/box/inlineClasses/callableReferencesWithInlineClasses.kt");
         }
 
+        @TestMetadata("castInsideWhenExpression.kt")
+        public void testCastInsideWhenExpression() throws Exception {
+            runTest("compiler/testData/codegen/box/inlineClasses/castInsideWhenExpression.kt");
+        }
+
         @TestMetadata("checkBoxUnboxOfArgumentsOnInlinedFunctions.kt")
         public void testCheckBoxUnboxOfArgumentsOnInlinedFunctions() throws Exception {
             runTest("compiler/testData/codegen/box/inlineClasses/checkBoxUnboxOfArgumentsOnInlinedFunctions.kt");

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

@@ -9671,6 +9671,11 @@ public class IrJsCodegenBoxTestGenerated extends AbstractIrJsCodegenBoxTest {
             runTest("compiler/testData/codegen/box/inlineClasses/callableReferencesWithInlineClasses.kt");
         }
 
+        @TestMetadata("castInsideWhenExpression.kt")
+        public void testCastInsideWhenExpression() throws Exception {
+            runTest("compiler/testData/codegen/box/inlineClasses/castInsideWhenExpression.kt");
+        }
+
         @TestMetadata("checkBoxUnboxOfArgumentsOnInlinedFunctions.kt")
         public void testCheckBoxUnboxOfArgumentsOnInlinedFunctions() throws Exception {
             runTest("compiler/testData/codegen/box/inlineClasses/checkBoxUnboxOfArgumentsOnInlinedFunctions.kt");

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

@@ -9671,6 +9671,11 @@ public class JsCodegenBoxTestGenerated extends AbstractJsCodegenBoxTest {
             runTest("compiler/testData/codegen/box/inlineClasses/callableReferencesWithInlineClasses.kt");
         }
 
+        @TestMetadata("castInsideWhenExpression.kt")
+        public void testCastInsideWhenExpression() throws Exception {
+            runTest("compiler/testData/codegen/box/inlineClasses/castInsideWhenExpression.kt");
+        }
+
         @TestMetadata("checkBoxUnboxOfArgumentsOnInlinedFunctions.kt")
         public void testCheckBoxUnboxOfArgumentsOnInlinedFunctions() throws Exception {
             runTest("compiler/testData/codegen/box/inlineClasses/checkBoxUnboxOfArgumentsOnInlinedFunctions.kt");