Function diagnostics

pub fn diagnostics(output: &str, context: Context<'_>) -> Variations

For a given compiler output, produces the set of saved outputs against which the compiler’s output would be considered correct. If the test’s saved stderr file is identical to any one of these variations, the test will pass.

This is a set rather than just one normalized output in order to avoid breaking existing tests when introducing new normalization steps. Someone may have saved stderr snapshots with an older version of trybuild, and those tests need to continue to pass with newer versions of trybuild.

There is one “preferred” variation which is what we print when the stderr file is absent or not a match.