rustc 1.80 now complains about features not declared in Cargo.toml and cfg
keys/values not declared by build.rs to protect against typos or misuse (you
think you're using the right condition but you're not). See
rust-lang/cargo#10554 and rust-lang/rust#82450.
(We're not actually using TSAN under CI at this time, but I do want to re-enable
it at some point — especially if we get multithreaded execution going — using
the rust-native TSAN configuration.)
I'll be updating the `rsconf` crate and patching `build.rs` accordingly to also
handle the warnings about unknown cfg values, but tsan is a feature and not a
cfg and these can be dealt with in `Cargo.toml` directly.
Given "1(23)4", this function returns an inclusive range, from the opening
to the closing parenthesis. The subcommand is extracted by incrementing
the range start and interpreting the result as an exclusive range.
This is confusing, especially if we want to add multi-character quotes.
Change it to always return the full range (including parentheses) and provide
an easy way to access the command string.
While at it, switch to returning an enum.
This change is perhaps larger and more complex than necessary (sorry)
because it is mainly made with multi-character quotes in mind. Let's see
if that works out.
