JS: apply boxing when initializing val parameter of type Char

See KT-20854

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

@@ -821,6 +821,12 @@ public class BoxJsTestGenerated extends AbstractBoxJsTest {
             doTest(fileName);
         }
 
+        @TestMetadata("charValParameter.kt")
+        public void testCharValParameter() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("js/js.translator/testData/box/coercion/charValParameter.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("classProperty.kt")
         public void testClassProperty() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("js/js.translator/testData/box/coercion/classProperty.kt");

js/js.translator/src/org/jetbrains/kotlin/js/translate/initializer/ClassInitializerTranslator.java

@@ -22,6 +22,7 @@ import org.jetbrains.kotlin.builtins.KotlinBuiltIns;
 import org.jetbrains.kotlin.descriptors.*;
 import org.jetbrains.kotlin.descriptors.impl.TypeAliasConstructorDescriptor;
 import org.jetbrains.kotlin.js.backend.ast.*;
+import org.jetbrains.kotlin.js.backend.ast.metadata.MetadataProperties;
 import org.jetbrains.kotlin.js.translate.callTranslator.CallTranslator;
 import org.jetbrains.kotlin.js.translate.context.Namer;
 import org.jetbrains.kotlin.js.translate.context.TranslationContext;
@@ -34,6 +35,7 @@ import org.jetbrains.kotlin.js.translate.reference.ReferenceTranslator;
 import org.jetbrains.kotlin.js.translate.utils.BindingUtils;
 import org.jetbrains.kotlin.js.translate.utils.JsAstUtils;
 import org.jetbrains.kotlin.js.translate.utils.JsDescriptorUtils;
+import org.jetbrains.kotlin.js.translate.utils.TranslationUtils;
 import org.jetbrains.kotlin.js.translate.utils.jsAstUtils.AstUtilsKt;
 import org.jetbrains.kotlin.lexer.KtTokens;
 import org.jetbrains.kotlin.name.Name;
@@ -376,11 +378,14 @@ public final class ClassInitializerTranslator extends AbstractTranslator {
         if (propertyDescriptor == null) {
             return;
         }
-        JsNameRef initialValueForProperty = jsParameter.getName().makeRef();
+        JsExpression initialValueForProperty = jsParameter.getName().makeRef();
+        MetadataProperties.setType(initialValueForProperty, propertyDescriptor.getType());
+        initialValueForProperty = TranslationUtils.coerce(context(), initialValueForProperty,
+                                                          TranslationUtils.getReturnTypeForCoercion(propertyDescriptor));
         addInitializerOrPropertyDefinition(initialValueForProperty, propertyDescriptor);
     }
 
-    private void addInitializerOrPropertyDefinition(@NotNull JsNameRef initialValue, @NotNull PropertyDescriptor propertyDescriptor) {
+    private void addInitializerOrPropertyDefinition(@NotNull JsExpression initialValue, @NotNull PropertyDescriptor propertyDescriptor) {
         initFunction.getBody().getStatements().add(
                 InitializerUtils.generateInitializerForProperty(context(), propertyDescriptor, initialValue));
     }

js/js.translator/testData/box/coercion/charValParameter.kt

@@ -0,0 +1,16 @@
+// EXPECTED_REACHABLE_NODES: 1127
+class A(val x: Char)
+
+fun typeOf(x: dynamic): String = js("typeof x")
+
+fun box(): String {
+    val a = A('0')
+
+    var r = typeOf(a.asDynamic().x)
+    if (r != "object") return "fail1: $r"
+
+    r = typeOf(a.x)
+    if (r != "number") return "fail2: $r"
+
+    return "OK"
+}