[K/JS] Move global interface id state into an object to prevent interface ids reinitialization ^Fixed KT-55758

js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/BoxJsTestGenerated.java

@@ -3889,6 +3889,12 @@ public class BoxJsTestGenerated extends AbstractBoxJsTest {
                 runTest("js/js.translator/testData/box/expression/typeCheck/complexIsInterface.kt");
             }
 
+            @Test
+            @TestMetadata("kt55758.kt")
+            public void testKt55758() throws Exception {
+                runTest("js/js.translator/testData/box/expression/typeCheck/kt55758.kt");
+            }
+
             @Test
             @TestMetadata("simpleAsClass.kt")
             public void testSimpleAsClass() throws Exception {

js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/fir/FirJsBoxTestGenerated.java

@@ -4505,6 +4505,12 @@ public class FirJsBoxTestGenerated extends AbstractFirJsBoxTest {
                 runTest("js/js.translator/testData/box/expression/typeCheck/complexIsInterface.kt");
             }
 
+            @Test
+            @TestMetadata("kt55758.kt")
+            public void testKt55758() throws Exception {
+                runTest("js/js.translator/testData/box/expression/typeCheck/kt55758.kt");
+            }
+
             @Test
             @TestMetadata("simpleAsClass.kt")
             public void testSimpleAsClass() throws Exception {

js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/ir/IrBoxJsTestGenerated.java

@@ -4505,6 +4505,12 @@ public class IrBoxJsTestGenerated extends AbstractIrBoxJsTest {
                 runTest("js/js.translator/testData/box/expression/typeCheck/complexIsInterface.kt");
             }
 
+            @Test
+            @TestMetadata("kt55758.kt")
+            public void testKt55758() throws Exception {
+                runTest("js/js.translator/testData/box/expression/typeCheck/kt55758.kt");
+            }
+
             @Test
             @TestMetadata("simpleAsClass.kt")
             public void testSimpleAsClass() throws Exception {

js/js.translator/testData/box/expression/typeCheck/kt55758.kt

@@ -0,0 +1,19 @@
+// EXPECTED_REACHABLE_NODES: 1403
+// MODULE_KIND: COMMON_JS
+
+package foo
+
+@JsExport
+interface Foo
+
+class Bar: Foo
+
+fun box(): String {
+    val foo : Foo = Bar()
+
+    if(foo is Collection<*>) {
+        return "Fail: Foo is a Collection!"
+    }
+
+    return "OK"
+}

libraries/stdlib/js-ir/runtime/typeCheckUtils.kt

@@ -31,8 +31,20 @@ internal fun setMetadataFor(
     }
 }
 
+// There was a problem with per-module compilation (KT-55758) when the top-level state (iid) was reinitialized during stdlib module initialization
+// As a result we miss already incremented iid and had the same iids in two different modules
+// So, to keep the state consistent it was moved into the object
+private object InterfaceIdService {
+    var iid: Int = 0
+}
+
+private fun InterfaceIdService.generateInterfaceId(): Int {
+    iid += 1
+    return iid
+}
+
 internal fun interfaceMeta(name: String?, associatedObjectKey: Number?, associatedObjects: dynamic, suspendArity: Array<Int>?): Metadata {
-    return createMetadata("interface", name, associatedObjectKey, associatedObjects, suspendArity, generateInterfaceId())
+    return createMetadata("interface", name, associatedObjectKey, associatedObjects, suspendArity, InterfaceIdService.generateInterfaceId())
 }
 
 internal fun objectMeta(name: String?, associatedObjectKey: Number?, associatedObjects: dynamic, suspendArity: Array<Int>?): Metadata {
@@ -85,19 +97,6 @@ internal external interface Ctor {
     val prototype: dynamic
 }
 
-private var iid: Int? = null
-
-@Suppress("SMARTCAST_IMPOSSIBLE")
-internal fun generateInterfaceId(): Int {
-    if (iid == null) {
-        iid = 1
-    } else {
-        iid += 1
-    }
-
-    return iid
-}
-
 @Suppress("UNUSED_PARAMETER")
 private fun getPrototypeOf(obj: dynamic) =
     js("Object.getPrototypeOf(obj)")