java.lang.Throwable: The method designed for fully qualified names only. Got "null|string".

**Describe the bug** (*)

A clear and concise description of what the bug is.

```
java.lang.Throwable: The method designed for fully qualified names only. Got "null|string".
at com.intellij.openapi.diagnostic.Logger.error(Logger.java:202)
at com.jetbrains.php.util.PhpContractUtil.assertFqn(PhpContractUtil.java:19)
at com.jetbrains.php.codeInsight.PhpCodeInsightUtil.isSameNamespace(PhpCodeInsightUtil.java:1587)
at com.magento.idea.magento2plugin.actions.generation.references.PhpClassReferenceResolver.alreadyImported(PhpClassReferenceResolver.java:98)
at com.magento.idea.magento2plugin.actions.generation.references.PhpClassReferenceResolver.importWithConflictResolve(PhpClassReferenceResolver.java:135)
at com.magento.idea.magento2plugin.actions.generation.references.PhpClassReferenceResolver.importReferences(PhpClassReferenceResolver.java:68)
at com.magento.idea.magento2plugin.actions.generation.generator.PluginClassGenerator.lambda$generate$2(PluginClassGenerator.java:198)
at com.intellij.openapi.command.WriteCommandAction.lambda$runWriteCommandAction$4(WriteCommandAction.java:360)
at com.intellij.openapi.command.WriteCommandAction$BuilderImpl.lambda$doRunWriteCommandAction$1(WriteCommandAction.java:149)
at com.intellij.openapi.application.impl.ApplicationImpl.runWriteAction(ApplicationImpl.java:958)
at com.intellij.openapi.command.WriteCommandAction$BuilderImpl.lambda$doRunWriteCommandAction$2(WriteCommandAction.java:147)
at com.intellij.openapi.command.impl.CoreCommandProcessor.executeCommand(CoreCommandProcessor.java:219)
at com.intellij.openapi.command.impl.CoreCommandProcessor.executeCommand(CoreCommandProcessor.java:184)
at com.intellij.openapi.command.WriteCommandAction$BuilderImpl.doRunWriteCommandAction(WriteCommandAction.java:156)
at com.intellij.openapi.command.WriteCommandAction$BuilderImpl.run(WriteCommandAction.java:123)
at com.intellij.openapi.command.WriteCommandAction.runWriteCommandAction(WriteCommandAction.java:360)
at com.intellij.openapi.command.WriteCommandAction.runWriteCommandAction(WriteCommandAction.java:348)
at com.magento.idea.magento2plugin.actions.generation.generator.PluginClassGenerator.generate(PluginClassGenerator.java:96)
at com.magento.idea.magento2plugin.actions.generation.generator.FileGenerator.generate(FileGenerator.java:41)
at com.magento.idea.magento2plugin.actions.generation.dialog.CreateAPluginDialog.onOK(CreateAPluginDialog.java:187)
at com.magento.idea.magento2plugin.actions.generation.dialog.CreateAPluginDialog.lambda$new$0(CreateAPluginDialog.java:141)
at java.desktop/javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1972)
at java.desktop/javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2313)
at java.desktop/javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:405)
at java.desktop/javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:262)
at java.desktop/javax.swing.AbstractButton.doClick(AbstractButton.java:374)
at java.desktop/javax.swing.plaf.basic.BasicRootPaneUI$Actions.actionPerformed(BasicRootPaneUI.java:259)
at java.desktop/javax.swing.SwingUtilities.notifyAction(SwingUtilities.java:1810)
at java.desktop/javax.swing.JComponent.processKeyBinding(JComponent.java:2943)
at java.desktop/javax.swing.KeyboardManager.fireBinding(KeyboardManager.java:311)
at java.desktop/javax.swing.KeyboardManager.fireKeyboardAction(KeyboardManager.java:253)
at java.desktop/javax.swing.JComponent.processKeyBindingsForAllComponents(JComponent.java:3036)
at java.desktop/javax.swing.JComponent.processKeyBindings(JComponent.java:3028)
at java.desktop/javax.swing.JComponent.processKeyEvent(JComponent.java:2905)
at java.desktop/java.awt.Component.processEvent(Component.java:6433)
at java.desktop/java.awt.Container.processEvent(Container.java:2266)
at java.desktop/java.awt.Component.dispatchEventImpl(Component.java:5026)
at java.desktop/java.awt.Container.dispatchEventImpl(Container.java:2324)
at java.desktop/java.awt.Component.dispatchEvent(Component.java:4854)
at java.desktop/java.awt.KeyboardFocusManager.redispatchEvent(KeyboardFocusManager.java:1953)
at java.desktop/java.awt.DefaultKeyboardFocusManager.dispatchKeyEvent(DefaultKeyboardFocusManager.java:886)
at java.desktop/java.awt.DefaultKeyboardFocusManager.preDispatchKeyEvent(DefaultKeyboardFocusManager.java:1166)
at java.desktop/java.awt.DefaultKeyboardFocusManager.typeAheadAssertions(DefaultKeyboardFocusManager.java:1023)
at java.desktop/java.awt.DefaultKeyboardFocusManager.dispatchEvent(DefaultKeyboardFocusManager.java:849)
at com.intellij.ide.IdeKeyboardFocusManager.access$dispatchEvent$s1569605750(IdeKeyboardFocusManager.kt:18)
at com.intellij.ide.IdeKeyboardFocusManager$dispatchEvent$1.invoke(IdeKeyboardFocusManager.kt:25)
at com.intellij.ide.IdeKeyboardFocusManager$dispatchEvent$1.invoke(IdeKeyboardFocusManager.kt:25)
at com.intellij.ide.IdeEventQueueKt.performActivity$lambda$1(IdeEventQueue.kt:994)
at com.intellij.openapi.application.TransactionGuardImpl.performActivity(TransactionGuardImpl.java:105)
at com.intellij.ide.IdeEventQueueKt.performActivity(IdeEventQueue.kt:994)
at com.intellij.ide.IdeKeyboardFocusManager.dispatchEvent(IdeKeyboardFocusManager.kt:25)
at java.desktop/java.awt.Component.dispatchEventImpl(Component.java:4903)
at java.desktop/java.awt.Container.dispatchEventImpl(Container.java:2324)
at java.desktop/java.awt.Window.dispatchEventImpl(Window.java:2804)
at java.desktop/java.awt.Component.dispatchEvent(Component.java:4854)
at java.desktop/java.awt.EventQueue.dispatchEventImpl(EventQueue.java:790)
at java.desktop/java.awt.EventQueue$3.run(EventQueue.java:739)
at java.desktop/java.awt.EventQueue$3.run(EventQueue.java:731)
at java.base/java.security.AccessController.doPrivileged(AccessController.java:399)
at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:86)
at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:97)
at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:763)
at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:761)
at java.base/java.security.AccessCont
```

**To Reproduce** (*)

Steps to reproduce the behavior:
1. Go to '...'
2. Click on '....'
3. Scroll down to '....'
4. See error

**Expected behavior** (*)

A clear and concise description of what you expected to happen.

**Screenshots**

If applicable, add screenshots to help explain your problem.

**Please complete the following information:** (*)

- OS: Windows 11.0
- PhpStorm/Intellij version: 2023.1.1
- Plugin Version: 5.1.1

**Additional context**

Add any other context about the problem here.

Start by reading PhpClassReferenceResolver.alreadyImported and the surrounding import flow, then trace how PluginClassGenerator.generate reaches it from CreateAPluginDialog. Use the reported null|string failure as the reproduction target; done means plugin class generation no longer raises the fully qualified name assertion, though the issue does not define a concrete test or reproduction setup.

Written by the indexing model from the issue text.