Fix the Array Visualisation

engine/polyglot-api/src/main/scala/org/enso/polyglot/Module.scala

@@ -27,8 +27,12 @@ class Module(private val value: Value) {
     * @param name the name of the method
     * @return the runtime representation of the method
     */
-  def getMethod(constructor: Value, name: String): Function =
-    new Function(value.invokeMember(GET_METHOD, constructor, name))
+  def getMethod(constructor: Value, name: String): Option[Function] = {
+    val newVal = value.invokeMember(GET_METHOD, constructor, name);
+    if (newVal.isNull) { None }  else {
+      Some(new Function(newVal))
+    }
+  }
 
   /** Evaluates an arbitrary expression as if it were placed in a function
     * body inside this module.

engine/runner/src/main/scala/org/enso/runner/Main.scala

@@ -1,8 +1,5 @@
 package org.enso.runner
 
-import java.io.File
-import java.util.UUID
-
 import akka.http.scaladsl.model.{IllegalUriException, Uri}
 import cats.implicits._
 import org.apache.commons.cli.{Option => CliOption, _}
@@ -12,8 +9,11 @@ import org.enso.loggingservice.LogLevel
 import org.enso.pkg.{Contact, PackageManager, SemVerEnsoVersion}
 import org.enso.polyglot.{LanguageInfo, Module, PolyglotContext}
 import org.enso.version.VersionDescription
-import org.graalvm.polyglot.{PolyglotException, Value}
+import org.graalvm.polyglot.PolyglotException
 
+import java.io.File
+import java.util.UUID
+import scala.Console.err
 import scala.jdk.CollectionConverters._
 import scala.util.Try
 
@@ -382,11 +382,18 @@ object Main {
     mainModule: Module,
     rootPkgPath: Option[File],
     mainMethodName: String = "main"
-  ): Value = {
+  ): Unit = {
     val mainCons = mainModule.getAssociatedConstructor
     val mainFun  = mainModule.getMethod(mainCons, mainMethodName)
     try {
-      mainFun.execute(mainCons.newInstance())
+      mainFun match {
+        case Some(main) => main.execute(mainCons.newInstance())
+        case None =>
+          err.println(
+            "Your module does not contain a `main` function. It could not " +
+            "be run."
+          )
+      }
     } catch {
       case e: PolyglotException =>
         printPolyglotException(e, rootPkgPath)

engine/runtime/src/main/java/org/enso/interpreter/runtime/Module.java

@@ -15,6 +15,7 @@
 import java.io.File;
 import java.io.IOException;
 
+import java.util.Map;
 import org.enso.compiler.core.IR;
 import org.enso.compiler.phase.StubIrBuilder;
 import org.enso.interpreter.Language;
@@ -405,7 +406,11 @@ static Object doInvoke(
       ModuleScope scope = module.compileScope(context);
       switch (member) {
         case MethodNames.Module.GET_METHOD:
-          return getMethod(scope, arguments);
+          var result = getMethod(scope, arguments);
+          if (result == null) {
+            return context.getBuiltins().nothing().newInstance();
+          }
+          return result;
         case MethodNames.Module.GET_CONSTRUCTOR:
           return getConstructor(scope, arguments);
         case MethodNames.Module.REPARSE: