JetBrains/intellij-community · warning · ConfigurationException

dialog.message.valid.identifier

Error message

dialog.message.valid.identifier

What it means

Thrown by RenameJavaImplicitClassProcessor's handler canRun() (RenameJavaImplicitClassProcessor.java:60) when renaming a Java implicit class (JEP 445+/java 21 preview feature) and the new name is not a legal identifier per PsiNameHelper. It also throws a silent ConfigurationException(null) when the new name equals the implicit class's current qualified name (no-op rename). Uses LangBundle ('dialog.message.valid.identifier') because the check is language-agnostic.

Source

Thrown at java/java-impl-refactorings/src/com/intellij/refactoring/rename/RenameJavaImplicitClassProcessor.java:60

    private final @Nullable String myExtension;

    private RenameJavaImplicitClassRenameDialog(@NotNull Project project, @NotNull PsiElement element, PsiElement nameSuggestionContext, Editor editor) {
      super(project, element, nameSuggestionContext, editor);
      myExtension = Optional.ofNullable(((PsiJavaFile)element).getVirtualFile())
        .map(file -> file.getExtension())
        .orElse(null);
    }

    public PsiImplicitClass getImplicitClass() {
      return Objects.requireNonNull(JavaImplicitClassUtil.getImplicitClassFor(getPsiElement()));
    }

    @Override
    protected void canRun() throws ConfigurationException {
      String name = super.getNewName();
      if (Comparing.strEqual(name, getImplicitClass().getQualifiedName())) throw new ConfigurationException(null);
      if (!PsiNameHelper.getInstance(getProject()).isIdentifier(name)) {
        throw new ConfigurationException(LangBundle.message("dialog.message.valid.identifier", getNewName()));
      }
    }

    @Override
    protected String getFullName() {
      PsiImplicitClass implicitClass = getImplicitClass();
      String name = DescriptiveNameUtil.getDescriptiveName(implicitClass);
      String type = UsageViewUtil.getType(implicitClass);
      return StringUtil.isEmpty(name) ? type : type + " '" + name + "'";
    }

    @Override
    public String[] getSuggestedNames() {
      String name = getImplicitClass().getQualifiedName();
      if (name != null) {
        return new String[]{name};
      }
      return super.getSuggestedNames();

View on GitHub (pinned to be881553f2)

Solutions

1. Type a valid Java identifier as the new name.
2. If the name is unchanged, actually modify it — equal-name renames are blocked by design (message-less ConfigurationException).
3. Check the project language level supports implicit classes so the element resolves as one at all.

Example fix

// before
// Rename implicit class 'Hello' to 'hello-world' -> invalid identifier error

// after
// Rename implicit class 'Hello' to 'HelloWorld' -> valid, proceeds

String newName = getNewName();
if (Comparing.strEqual(newName, implicitClass.getQualifiedName())) return; // no-op blocked silently
if (!PsiNameHelper.getInstance(project).isIdentifier(newName)) {
  // show inline error before invoking Rename
}

When it happens

Trigger: Rename (Shift+F6) on a Java implicit class (the class synthesized around the main method of a single-file program) with the new-name field containing a keyword, digit-leading token, or illegal characters. Renaming to the identical qualified name is silently blocked with a null message.

Common situations: Trying to rename the implicit class of a java 21+ single-file source to match the file name, but typing a keyword or a name with '-'/' '; or accepting the dialog without changing the name.

Related errors

• ''{0}'' is invalid extracted class name
• ''{0}'' is invalid field name for delegation
• ''{0}'' is invalid parameter name
• ''{0}'' is invalid inner class name
• ''{0}'' is invalid parameter class name

AI-assisted analysis of JetBrains/intellij-community@be881553f2 (2026-08-14). Data as JSON: /api/errors/e3ad90feca1e91bb. Report an issue: GitHub.