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Add default and latest stable edition to --edition in rustc #106094

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Add default and latest stable edition to --edition in rustc #106094

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365bb99
Add default and latest stable edition to --edition in rustc
sigaloid Dec 23, 2022
f931d2d
Remove extra allocation
sigaloid Dec 25, 2022
d3ab288
Merge branch 'rust-lang:master' into master
sigaloid Jan 2, 2023
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3 changes: 2 additions & 1 deletion compiler/rustc_session/src/config.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -1345,7 +1345,8 @@ pub fn rustc_short_optgroups() -> Vec<RustcOptGroup> {
opt::opt_s(
"",
"edition",
"Specify which edition of the compiler to use when compiling code.",
Box::leak(format!("Specify which edition of the compiler to use when compiling code.\
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Could you please avoid this Box::leak call? It is possible to invoke rustc multiple times in the same process. Each time would leak memory. You should be able to inline the opt_s function to pub fn opt_s(a: S, b: S, c: &str, d: S) -> R { to allow strings with arbitrary lifetimes and then pass &format(...).

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Yep - I was actually pretty wary of this change but that's what I was recommended to do. I'll rewrite the type signature and see if it still works soon so we can avoid this leak.

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Unfortunately I cannot refactor this out as the reference needs to outlive 'static

error[E0521]: borrowed data escapes outside of function
    --> compiler/rustc_session/src/config.rs:1290:9
     |
1289 |     pub fn opt_s(a: S, b: S, c: &str, d: S) -> R {
     |                  -           -  - let's call the lifetime of this reference `'1`
     |                  |           |
     |                  |           `c` is a reference that is only valid in the function body
     |                  `a` declared here, outside of the function body
1290 |         stable(longer(a, b), move |opts| opts.optopt(a, b, c, d))
     |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
     |         |
     |         `c` escapes the function body here
     |         argument requires that `'1` must outlive `'static`

There's got to be something I'm missing - the enum variant for the formatted string are all static and embedded, and there's got to be a better option than either allocating, or just manually writing in the strings and commenting above the original variables, "this must be updated in xyz string". I don't know how but I think there might be a way to construct this statically somehow - it's just concatenating all-static strings.

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I see. Another option would be to use std::sync::LazyLock to compute the description. If you put it in a static it should allow you to get a single &'static str without leaking anything.

The default is {DEFAULT_EDITION} and the latest stable edition is {LATEST_STABLE_EDITION}.").into_boxed_str()),
EDITION_NAME_LIST,
),
opt::multi_s(
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