You are unfairly comparing ancient C with modern rust - Try comparing modern C with modern rust to avoid making a straw man argument. Like I said, I don't even disagree, I still think you are just doing everyone a disservice with this line of reasoning.
He said if he had used rust - I am saying if he had used C when rust was available 1. The bug would have been fixed. 2. He could have used valgrind. Modern C also has something called ubsan, and another thing called frama-C.
These tools may be inferior to what rust has, but ignoring they exist or comparing 10+ year old C with modern rust is a bad faith argument.
I agree, I don't think that a bug in GCC last millennium is a very strong argument for using Rust instead of C today, though such arguments do exist.
However, I also don't think they particularly help you to distinguish a compiler bug from an error in your understanding of the language semantics, although they sure do help a lot with everyday errors.
With respect to questions of inferiority or superiority, keep in mind that Valgrind and UBSan are only dynamic checkers; they don't help at all with errors that don't occur in your testing. Frama-C is a static checker more similar to Rust's capabilities, but much more limited, but also with cscope-like abilities for reverse-engineering existing source bases.
The great advantage these three tools (and ASan) have is that you don't have to rewrite your C in Rust in order to use them.
I agree because having a type system that directly provides the guarantee that whole classes of runtime error cannot happen provides fast feedback during development at a low cost.
I disagree because even in a press button (+ tuning) approach, you can prove things with Frama-C that the Rust compiler cannot prove (reason why there is runtime bound-checking, implementation defined behavior for integer overflow and so on in Rust). But also because you can prove much more advance properties than "just" absence of runtime errors.
He said if he had used rust - I am saying if he had used C when rust was available 1. The bug would have been fixed. 2. He could have used valgrind. Modern C also has something called ubsan, and another thing called frama-C.
These tools may be inferior to what rust has, but ignoring they exist or comparing 10+ year old C with modern rust is a bad faith argument.