private @Nullable TypeElement findElement(String qualifiedName) {
      if (ClasspathFence.isInhibited(qualifiedName)) {
        return null;
      }
      try {
        TypeElement typeElement = processing()
            .getElementUtils()
            .getTypeElement(qualifiedName);
        return typeElement;
      } catch (Exception ex) {
        // to be visible during build
        ex.printStackTrace();
        // any type loading problems, which are unlikely (leftover?)
        return null;
      }
    }
Check if {@code qualifiedName} is known to current environment (annotation processor).
Retrieve (by canonical name) {@link TypeElement} from APT environment.
value-processor/src/org/immutables/value/processor/meta/Proto.java