src/Language/Parser.php
private function parseImplementsInterfaces()
    {
        $types = [];
        if ($this->lexer->token->value === 'implements') {
            $this->lexer->advance();
            // Optional leading ampersand
            $this->skip(Token::AMP);
            do {
                $types[] = $this->parseNamedType();
            } while ($this->skip(Token::AMP) ||
            // Legacy support for the SDL?
            (! empty($this->lexer->options['allowLegacySDLImplementsInterfaces']) && $this->peek(Token::NAME))
            );
        }

        return $types;
    }
private function parseImplementsInterfaces()
    {
        $types = [];
        if ($this->lexer->token->value === 'implements') {
            $this->lexer->advance();
            // Optional leading ampersand
            $this->skip(Token::AMP);
            do {
                $types[] = $this->parseNamedType();
            } while ($this->skip(Token::AMP) ||
            // Legacy support for the SDL?
            (! empty($this->lexer->options['allowLegacySDLImplementsInterfaces']) && $this->peek(Token::NAME))
            );
        }

        return $types;
    }
ImplementsInterfaces :
- implements `&`? NamedType
- ImplementsInterfaces & NamedType

@return NamedTypeNode[]