result_large_err should be relative to the Ok variant

Summary

The current description for the lint is:

A Result is at least as large as the Err-variant. While we expect that variant to be seldomly used, the compiler needs to reserve and move that much memory every single time.

This should not be a problem if the Ok variant size is larger or not that smaller.

Lint Name

result_large_err

Reproducer

My code looks like this:

struct SomeContext<T> {
    outcome: T,
    // more fields
}

type SomeResult = Result<SomeContext<Good>, SomeContext<Bad>>;

In my case I believe the Good type is actually larger than the Bad one, and it is more convenient to embed the outcome in its surrounding context than embedding the context in both Good and Bad types.

It also doesn't bring any value to reference/box the context to avoid embedding it for this specific use case, it just adds one more indirection.

Version

rustc 1.66.1 (90743e729 2023-01-10) (Fedora 1.66.1-1.fc37)
binary: rustc
commit-hash: 90743e7298aca107ddaa0c202a4d3604e29bfeb6
commit-date: 2023-01-10
host: x86_64-unknown-linux-gnu
release: 1.66.1
LLVM version: 15.0.6

Additional Labels

No response

Start by locating the result_large_err lint implementation and its tests, then run the provided Rust reproducer to observe the current warning. Update the lint behavior and description so the warning is relative to the Ok variant, and confirm the Good-larger-than-Bad case is handled as intended.