Feature request: Support trait implementations in `--start-from`

[oliver-butterley]

Problem

--start-from only supports simple path syntax and cannot handle trait implementations. The path parsing at translate_crate.rs:628 uses a naive :: split:

let path = path.split("::").collect_vec();

This breaks when specifying trait implementations like:

curve25519_dalek::backend::serial::curve_models::{core::clone::Clone for curve25519_dalek::backend::serial::curve_models::ProjectivePoint}

It seems that the {impl ...} syntax that works with --include, --opaque, and --exclude (which use the NamePattern parser) doesn't work with --start-from.

Desired Behaviour

--start-from should accept the same name-matcher syntax as --include/--opaque/--exclude, including:

• Trait implementations: {impl Trait for Type}
• Trait methods: {impl Trait for Type}::method

It would also be convenient, but less important, if --start-from accepts generic patterns (_ / *).

Use Case

When verifying specific functions in a large crate, I want to extract only specific trait implementations and their dependencies, without pulling in unrelated code that causes extraction errors.

[Nadrieril]

Agreed! I've implemented basic support for this in #959, let me know if that works for you.

[oliver-butterley]

Wow, you are efficient! Thanks so much.