JS: fixed subSequence in CharSequence descendants (KT-14035) + added support for function intrics in delegation

js/js.frontend/src/org/jetbrains/kotlin/js/naming/NameSuggestion.kt

@@ -227,7 +227,6 @@ class NameSuggestion {
 
             if (overriddenDescriptor is FunctionDescriptor) {
                 when (overriddenDescriptor.fqNameUnsafe.asString()) {
-                    "kotlin.CharSequence.subSequence" -> return NameAndStability("substring", true)
                     "kotlin.CharSequence.get" -> return NameAndStability("charAt", true)
                     "kotlin.Any.equals" -> return NameAndStability("equals", true)
                 }

js/js.libraries/src/core/builtins.kt

@@ -36,4 +36,14 @@ internal fun arrayIterator(array: dynamic): MutableIterator<dynamic> {
 internal class PropertyMetadata(@JsName("callableName") val name: String)
 
 @JsName("noWhenBranchMatched")
-internal fun noWhenBranchMatched(): Nothing = throw NoWhenBranchMatchedException()
+internal fun noWhenBranchMatched(): Nothing = throw NoWhenBranchMatchedException()
+
+@JsName("subSequence")
+fun subSequence(c: CharSequence, startIndex: Int, endIndex: Int): CharSequence {
+    if (c is String) {
+        return c.substring(startIndex, endIndex)
+    }
+    else {
+        return c.asDynamic().`subSequence_vux9f0$`(startIndex, endIndex)
+    }
+}

js/js.translator/src/org/jetbrains/kotlin/js/translate/intrinsic/functions/factories/TopLevelFIF.java

@@ -63,6 +63,9 @@ public final class TopLevelFIF extends CompositeFIF {
     @NotNull
     public static final KotlinFunctionIntrinsic KOTLIN_EQUALS = new KotlinFunctionIntrinsic("equals");
 
+    @NotNull
+    public static final KotlinFunctionIntrinsic KOTLIN_SUBSEQUENCE = new KotlinFunctionIntrinsic("subSequence");
+
     @NotNull
     private static final DescriptorPredicate HASH_CODE_IN_ANY = pattern("kotlin", "Any", "hashCode");
     @NotNull
@@ -145,6 +148,16 @@ public final class TopLevelFIF extends CompositeFIF {
         }
     };
 
+    private static final FunctionIntrinsic STRING_SUBSTRING = new FunctionIntrinsic() {
+        @NotNull
+        @Override
+        public JsExpression apply(
+                @Nullable JsExpression receiver, @NotNull List<JsExpression> arguments, @NotNull TranslationContext context
+        ) {
+            return new JsInvocation(new JsNameRef("substring", receiver), arguments);
+        }
+    };
+
 
     @NotNull
     public static final KotlinFunctionIntrinsic TO_STRING = new KotlinFunctionIntrinsic("toString");
@@ -159,6 +172,8 @@ public final class TopLevelFIF extends CompositeFIF {
         add(HASH_CODE_IN_ANY, KOTLIN_HASH_CODE);
         add(pattern(NamePredicate.PRIMITIVE_NUMBERS, "equals"), KOTLIN_EQUALS);
         add(pattern("String|Boolean|Char|Number.equals"), KOTLIN_EQUALS);
+        add(pattern("String.subSequence"), STRING_SUBSTRING);
+        add(pattern("CharSequence.subSequence"), KOTLIN_SUBSEQUENCE);
         add(pattern("kotlin", "iterator").isExtensionOf(FQ_NAMES.iterator.asString()), RETURN_RECEIVER_INTRINSIC);
 
         add(pattern("kotlin.js", "Json", "get"), ArrayFIF.GET_INTRINSIC);

js/js.translator/src/org/jetbrains/kotlin/js/translate/utils/utils.kt

@@ -63,7 +63,15 @@ fun generateDelegateCall(
         args.add(JsNameRef(jsParamName))
     }
 
-    val functionObject = simpleReturnFunction(context.getScopeForDescriptor(fromDescriptor), JsInvocation(overriddenMemberFunctionRef, args))
+    val intrinsic = context.intrinsics().getFunctionIntrinsic(toDescriptor)
+    val invocation = if (intrinsic.exists()) {
+        intrinsic.apply(thisObject, args, context)
+    }
+    else {
+        JsInvocation(overriddenMemberFunctionRef, args)
+    }
+
+    val functionObject = simpleReturnFunction(context.getScopeForDescriptor(fromDescriptor), invocation)
     functionObject.parameters.addAll(parameters)
 
     context.addFunctionToPrototype(classDescriptor, fromDescriptor, functionObject)

js/js.translator/testData/box/expression/stringClass/subSequence.kt

@@ -1,5 +1,15 @@
 package foo
 
+class CC(val s: CharSequence) : CharSequence by s, MyCharSequence {}
+
+interface MyCharSequence {
+    val length: Int
+
+    operator fun get(index: Int): Char
+
+    fun subSequence(startIndex: Int, endIndex: Int): CharSequence
+}
+
 fun box(): String {
     val kotlin: String = "kotlin"
 
@@ -11,5 +21,20 @@ fun box(): String {
     val tlin = (kotlin as CharSequence).subSequence(2, 6)
     if (tlin.toString() != "tlin") return "Fail 2: $tlin"
 
+    val cc: CharSequence = CC(kotlin)
+    if (cc.length != 6) return "Fail 3: ${cc.length}"
+    if (cc.subSequence(0, 3) != kot) return "Fail 4"
+    if (cc[2] != 't') return "Fail 5: ${cc[2]}"
+
+    val mcc: MyCharSequence = CC(kotlin)
+    if (mcc.length != 6) return "Fail 6: ${mcc.length}"
+    if (mcc.subSequence(0, 3) != kot) return "Fail 7"
+    if (mcc[2] != 't') return "Fail 8: ${mcc[2]}"
+
+    val ccc = CC(cc)
+    if (ccc.length != 6) return "Fail 6: ${ccc.length}"
+    if (ccc.subSequence(0, 3) != kot) return "Fail 7"
+    if (ccc[2] != 't') return "Fail 8: ${ccc[2]}"
+
     return "OK"
 }