src/Parser/Doctrine/DoctrineParser.php
final private function validateEmbeddableFieldPrefixes(array $embeddableFieldPrefixesToClasses, array $embeddableFieldPrefixesToEmbeddableClasses)
    {
        $prefixes = array_keys($embeddableFieldPrefixesToClasses);

        foreach ($prefixes as $prefix) {
            if (array_key_exists($prefix, $embeddableFieldPrefixesToEmbeddableClasses)) {
                throw new DuplicatePrefixException(sprintf(
                    'Duplicate embeddable field prefix %s, at class %s, for parser %s',
                    $prefix,
                    $this->className,
                    static::class
                ));
            }
        }
    }
final private function validateEmbeddableFieldPrefixes(array $embeddableFieldPrefixesToClasses, array $embeddableFieldPrefixesToEmbeddableClasses)
    {
        $prefixes = array_keys($embeddableFieldPrefixesToClasses);

        foreach ($prefixes as $prefix) {
            if (array_key_exists($prefix, $embeddableFieldPrefixesToEmbeddableClasses)) {
                throw new DuplicatePrefixException(sprintf(
                    'Duplicate embeddable field prefix %s, at class %s, for parser %s',
                    $prefix,
                    $this->className,
                    static::class
                ));
            }
        }
    }
There should be no repeated prefixes (keys) between the two arrays.

@param array $embeddableFieldPrefixesToClasses
@param array $embeddableFieldPrefixesToEmbeddableClasses