[steveklabnik]

For everyone asking: in the talk, Lars mentions that they often rely on self-reported anonymous data. But in this case, Google is large enough that teams have developed similar systems and/or literally re-written things, and so this claim comes from analyzing projects before and after these re-writes, so you’re comparing like teams and like projects.

Timestamped: https://youtu.be/6mZRWFQRvmw?t=27012

Some additional context on these two specific claims:

Google found that porting Go to Rust "it takes about the same sized team about the same time to build it, so that's no loss of productivity" and "we do see some benefits from it, we see reduced memory usage [...] and we also see a decreased defect rate over time"

On re-writing C++ into Rust: "in every case, we've seen a decrease by more than 2x in the amount of effort required to both build the services written in Rust, as well as maintain and update those services. [...] C++ is very expensive for us to maintain."

[Mawr]

More timestamps:

- Graph on time to become sufficiently productive in Rust to comfortably contribute to a codebase: https://youtu.be/6mZRWFQRvmw?t=27149

- Graph on time to become as productive in Rust as in other languages: https://youtu.be/6mZRWFQRvmw?t=27240

- "Yes, it takes some time, but people do feel like they are as productive in Rust as they were in the language that they previously were writing in." https://youtu.be/6mZRWFQRvmw?t=27274

- Graph on the ease of code review in Rust vs other languages: https://youtu.be/6mZRWFQRvmw?t=27304

- Graph on confidence in Rust code correctness: https://youtu.be/6mZRWFQRvmw?t=27361

- Code example vs C++ #1: https://youtu.be/6mZRWFQRvmw?t=27431

- Code example vs C++ #2: https://youtu.be/6mZRWFQRvmw?t=27656

[summerlight]

I remember there were several pilots to rewrite some of C++ libraries in Rust at the exploration stage, keeping their behavior as close as possible. IIUC, the outcome was positive in general, consistent with the tweet's claim.

[blub]

Do you think “Lars”, as chair of the Rust Foundation board of directors and previous Servo project member could have a conflict of interest here?

Something that should be mentioned as a disclaimer when quoting his opinion on Rust vs. other languages and that would significantly water down the strength of their claims.

[steveklabnik]

Could? Sure, in an abstract sense.

What would the motivation be for someone so senior to lie on stage about this stuff? Just because he likes a programming language?

This is conspiracy style thinking.

Thankfully, if Lars is lying about this, there's tons of Google folks here on Hacker News. I haven't seen anyone yet make an actual claim with any evidence that he's not telling the truth here.