Report error if Java 9 module "kotlin.stdlib" is not found in the graph

Use "-Xallow-kotlin-package" to suppress this error

 #KT-19176 Fixed

compiler/cli/cli-common/src/org/jetbrains/kotlin/cli/common/arguments/CommonCompilerArguments.kt

@@ -76,7 +76,7 @@ abstract class CommonCompilerArguments : CommonToolArguments() {
     )
     var skipMetadataVersionCheck: Boolean by FreezableVar(false)
 
-    @Argument(value = "-Xallow-kotlin-package", description = "Allow compiling code in package 'kotlin'")
+    @Argument(value = "-Xallow-kotlin-package", description = "Allow compiling code in package 'kotlin' and allow not requiring kotlin.stdlib in module-info")
     var allowKotlinPackage: Boolean by FreezableVar(false)
 
     @Argument(value = "-Xreport-output-files", description = "Report source to output files mapping")

compiler/cli/src/org/jetbrains/kotlin/cli/jvm/compiler/ClasspathRootsResolver.kt

@@ -19,7 +19,6 @@ package org.jetbrains.kotlin.cli.jvm.compiler
 import com.intellij.openapi.vfs.StandardFileSystems
 import com.intellij.openapi.vfs.VfsUtilCore
 import com.intellij.openapi.vfs.VirtualFile
-import com.intellij.openapi.vfs.VirtualFileManager
 import com.intellij.psi.PsiJavaModule
 import com.intellij.psi.PsiManager
 import com.intellij.psi.impl.light.LightJavaModule
@@ -51,7 +50,8 @@ internal class ClasspathRootsResolver(
         private val messageCollector: MessageCollector?,
         private val additionalModules: List<String>,
         private val contentRootToVirtualFile: (JvmContentRoot) -> VirtualFile?,
-        private val javaModuleFinder: CliJavaModuleFinder
+        private val javaModuleFinder: CliJavaModuleFinder,
+        private val requireStdlibModule: Boolean
 ) {
     val javaModuleGraph = JavaModuleGraph(javaModuleFinder)
 
@@ -179,14 +179,15 @@ internal class ClasspathRootsResolver(
 
         if (javaModuleFinder.allObservableModules.none()) return
 
+        val sourceModule = sourceModules.singleOrNull()
         val addAllModulePathToRoots = "ALL-MODULE-PATH" in additionalModules
-        if (addAllModulePathToRoots && sourceModules.isNotEmpty()) {
+        if (addAllModulePathToRoots && sourceModule != null) {
             report(ERROR, "-Xadd-modules=ALL-MODULE-PATH can only be used when compiling the unnamed module")
             return
         }
 
         val rootModules = when {
-            sourceModules.isNotEmpty() -> listOf(sourceModules.single().name) + additionalModules
+            sourceModule != null -> listOf(sourceModule.name) + additionalModules
             addAllModulePathToRoots -> modules.map(JavaModule::name)
             else -> computeDefaultRootModules() + additionalModules
         }
@@ -217,6 +218,15 @@ internal class ClasspathRootsResolver(
                 ))
             }
         }
+
+        if (requireStdlibModule && sourceModule != null && "kotlin.stdlib" !in allDependencies) {
+            report(
+                    ERROR,
+                    "The Kotlin standard library is not found in the module graph. " +
+                    "Please ensure you have the 'requires kotlin.stdlib' clause in your module definition",
+                    sourceModule.moduleInfoFile
+            )
+        }
     }
 
     // See http://openjdk.java.net/jeps/261

compiler/cli/src/org/jetbrains/kotlin/cli/jvm/compiler/KotlinCoreEnvironment.kt

@@ -205,7 +205,8 @@ class KotlinCoreEnvironment private constructor(
                 messageCollector,
                 configuration.getList(JVMConfigurationKeys.ADDITIONAL_JAVA_MODULES),
                 this::contentRootToVirtualFile,
-                javaModuleFinder
+                javaModuleFinder,
+                !configuration.getBoolean(CLIConfigurationKeys.ALLOW_KOTLIN_PACKAGE)
         )
 
         val (initialRoots, javaModules) =