Twitter’s diversity issue — like the growth problem that threatens to kill the company — won’t change, not with its current homogeneous workforce and leadership.

So says Leslie Miley, a manager-level engineer who spent three years at Twitter before leaving the company last month. Miley, who is black, took to Medium on Tuesday to describe a workplace whose failure at diversifying its workforce has crippled the company.

“Twitter’s issues with growth and engagement and the issues with internal diversity are somewhat related,” Miley wrote. “The over-reliance on a limited number of schools and workplaces for talent has caused a type of group think to dominate. Any change would be approved by people who all think alike. There was very little diversity in thought and almost no diversity in action.”

Miley described a meeting at the company in which a senior engineering executive suggested using potential job candidates’ names to predict their ethnicity and determine where in the hiring process these candidates were falling out.

“What I also found disconcerting is this otherwise highly sophisticated thinker could posit that an issue this complex could be addressed by name analysis,” Miley wrote. “I left that meeting wondering how I could, in good conscience, continue to work in an organization where the Sr. VP of Engineering could see himself as a technology visionary and be so unaware of this blind spot in his understanding of diversity. Leadership keeps citing the pipeline when the data does not support it. They continue to churn out ethnic and racial minorities and women but still claim a commitment to diversity.”

A Twitter spokesperson sent Re/code the following statement:

“We’re committed to making substantive progress in making Twitter more diverse and inclusive. This commitment includes the expansion of our inclusion and diversity programs, diversity recruiting, employee development and resource group-led initiatives. Beyond just disclosing our workforce representation statistics, we have also publicly disclosed our representation goals for women and under-represented minorities for 2016, making us the largest tech company to put hard numbers around its diversity commitment.”

It should be noted that Miley, who claims to have been the company’s most senior employee of color in engineering or product management, did not leave the company of his own accord. He was laid off as part of Twitter’s recent downsizing, he confirmed to Re/code. Miley had been pitching a new position internally to specifically address the lack of diversity on Twitter’s engineering team, and when he realized the position wasn’t going to materialize, he wasn’t upset about the departure.

Regardless, his words will echo across Silicon Valley, where white males dominate and companies like Facebook, Google and Apple have the numbers to prove it.

What makes this more troubling for Twitter is that the company has dealt with diversity-specific issues very recently. In July, a team within the company threw a frat-themed party, prompting CEO Jack Dorsey to address the issue at the company’s weekly all-hands meeting. Dorsey promised to make diversity more of a focus, and the company then came out with hiring goals specific to women and minorities in August.

That doesn’t mean Miley isn’t optimistic that things could change. “The return of Jack Dorsey has the potential to change the diversity trajectory for Twitter,” he wrote. “The leadership that Jack is showing has been long missing from Twitter and tech.”

Dorsey, if you’ll recall, was very publicly involved in the Ferguson protests that took place after an unarmed black man was killed by a white police officer near his hometown of St. Louis. “I was sitting here at my desk following my Twitter feed thinking ‘what the hell is Jack doing in Ferguson?'” Miley recalled in an interview with Re/code. “I started paying more attention to his tweets and more attention to his content, and [I realized] this is someone who understands the social impact and the societal impact of what’s been happening in Ferguson.”

Multiple people Re/code has spoken with over the past few months have said that Dorsey is also very conscious of the lack of women in tech leadership and staunchly supports trying to change that.

Here’s a video of former Twitter and current Periscope engineer Sara Haider talking about tech and diversity with Re/code back in August.

https://www.youtube.com/watch?v=LBdJpdkb4ek