rust-analyzer and scip

[astefano]

Hello,

I use rust-analyzer scip . and scip print --json index.scip > my_project.json (where scip is https://github.com/sourcegraph/scip/) to extract some sort of call graphs.
Say i use it on libsignal plus the dependency curve25519-dalek). I was trying to understand how operators such as "*=" (for instance, at this line) appear in the generated json but i don't find them. I can find:

• the scalar variable reference
• the Scalar type reference
• the Scalar::from() call
  But from what i see, the json does not capture the MulAssign::mul_assign() trait method call that the *= operator desugars to.
  So i would like to understand if either index.scip or scip does not track operator overloads and other compiler-desugared calls or if i overlook something.

Given that in VS Code, *= appears as the one from core::ops::arith::MulAssign:

is it correct to assume that the information should be in index.scip as generated by rust-analyzer scip . and thus the loss of information is more during the process of generating the json with scip?

Thank you,
Lacramioara

[lnicola]

This seems partly related to #21125. As far as I can tell, we mostly emit definitions. But even for something like:

use std::ops::AddAssign;

struct S;

impl AddAssign for S {
    fn add_assign(&mut self, _rhs: Self) {}
}

fn main() {
    let mut s = S;
    s += S;
    s += S;
    s += S;
}

I don't see the add_assign calls.

[astefano]

Thanks Laurențiu! Just to confirm: when you say "I don't see the add_assign calls", you mean they're missing from the JSON output you get from rust-analyzer scip . followed by scip print --json index.scip > out.json, correct?
Since index.scip is binary, I can't tell whether the add_assign call information is missing from the index itself, or if the scip tool just isn't extracting/displaying it.
Given that you mentioned that SCIP support in rust-analyzer is limited, are there better alternatives you'd recommend for obtaining more complete call graph information? Or is this roughly the best we can get with current tooling? (Which is already impressive— a huge thanks to all the rust-analyzer contributors!)

[lnicola]

I can't tell whether the add_assign call information is missing from the index itself, or if the scip tool just isn't extracting/displaying it.

I think they're missing from the SCIP index. The tool just deserializes and pretty-prints the file. CC @nicolas-guichard since you've touched SCIP and you're here these days, did you find our output lacking wrt. operator calls?

are there better alternatives you'd recommend for obtaining more complete call graph information

It's a lot more involved, but you could start from

rust-analyzer/crates/rust-analyzer/src/cli/analysis_stats.rs

Line 51 in cf4b1fa

pub fn run(self, verbosity: Verbosity) -> anyhow::Result<()> {

, which exercises most of our analysis features.

[nicolas-guichard]

Operator calls seem to be missing from the SCIP output indeed. I've opened #21127 to track this.

[astefano]

Thanks both!

[lnicola]

Btw @astefano, do you expect proper method resolution (with trait solving)? Because I don't think that's done for the SCIP index.