In the 2024 edition of Rust, `serde`s macros for `serialize_with` can
lead to a temporary lifetime error such as:
```
error[E0716]: temporary value dropped while borrowed
--> my-binary/src/main.rs:6:10
|
6 | #[derive(MyDerive)]
| ^^^^^^^-
| | |
| | temporary value is freed at the end of this statement
| creates a temporary value which is freed while still in use
| borrow later used by call
| in this derive macro expansion
|
::: /private/tmp/life/my-project/my-macro/src/lib.rs:6:1
|
6 | pub fn my_derive(_input: TokenStream) -> TokenStream {
| ---------------------------------------------------- in this expansion of `#[derive(MyDerive)]`
|
= note: consider using a `let` binding to create a longer lived value
```
This is because the macro code takes a reference to struct inside of a
block, which then goes out of scope when `serde` passes it to a
function.
To resolve this, we move the reference to outside of the block, to
ensure that the lifetime extends into the function call.
Signed-off-by: Andrew V. Teylu <andrew.teylu@vector.com>
Allow deprecated in the `Serialize`/`Deserialize`
derive implementations. This allows you to
deprecate structs, enums, struct fields, or enum
variants and not get compiler warnings/errors
about use of deprecated thing. We only do this
if `#[deprecated]` or `#[allow(deprecated)]` exist
on the root object or the variants of the root
object (if it is an enum).
Resolves#2195
warning: usage of a legacy numeric method
--> serde_derive/src/ser.rs:292:51
|
292 | assert!(fields.len() as u64 <= u64::from(u32::max_value()));
| ^^^^^^^^^^^
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#legacy_numeric_constants
= note: `#[warn(clippy::legacy_numeric_constants)]` on by default
help: use the associated constant instead
|
292 | assert!(fields.len() as u64 <= u64::from(u32::MAX));
| ~~~
warning: usage of a legacy numeric method
--> serde_derive/src/ser.rs:400:53
|
400 | assert!(variants.len() as u64 <= u64::from(u32::max_value()));
| ^^^^^^^^^^^
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#legacy_numeric_constants
help: use the associated constant instead
|
400 | assert!(variants.len() as u64 <= u64::from(u32::MAX));
| ~~~
warning: usage of a legacy numeric method
--> test_suite/tests/test_de_error.rs:1462:29
|
1462 | Token::U64(u64::max_value()),
| ^^^^^^^^^^^
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#legacy_numeric_constants
= note: `-W clippy::legacy-numeric-constants` implied by `-W clippy::all`
= help: to override `-W clippy::all` add `#[allow(clippy::legacy_numeric_constants)]`
help: use the associated constant instead
|
1462 | Token::U64(u64::MAX),
| ~~~
warning: usage of a legacy numeric method
--> test_suite/tests/test_de_error.rs:1479:29
|
1479 | Token::U64(u64::max_value()),
| ^^^^^^^^^^^
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#legacy_numeric_constants
help: use the associated constant instead
|
1479 | Token::U64(u64::MAX),
| ~~~
warning: usage of a legacy numeric method
--> test_suite/tests/test_de_error.rs:1493:29
|
1493 | Token::U64(u64::max_value()),
| ^^^^^^^^^^^
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#legacy_numeric_constants
help: use the associated constant instead
|
1493 | Token::U64(u64::MAX),
| ~~~
warning: usage of a legacy numeric method
--> test_suite/tests/test_de_error.rs:1510:29
|
1510 | Token::U64(u64::max_value()),
| ^^^^^^^^^^^
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#legacy_numeric_constants
help: use the associated constant instead
|
1510 | Token::U64(u64::MAX),
| ~~~
error: this expression borrows a reference (`&syn::Type`) that is immediately dereferenced by the compiler
--> serde_derive/src/internals/check.rs:399:37
|
399 | if let Type::Path(ty) = ungroup(&field.ty) {
| ^^^^^^^^^ help: change this to: `field.ty`
|
note: the lint level is defined here
--> serde_derive/src/lib.rs:18:9
|
18 | #![deny(clippy::all, clippy::pedantic)]
| ^^^^^^^^^^^
= note: `#[deny(clippy::needless_borrow)]` implied by `#[deny(clippy::all)]`
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_borrow
error: this expression borrows a reference (`&str`) that is immediately dereferenced by the compiler
--> serde_derive/src/de.rs:478:52
|
478 | &type_path, params, fields, false, cattrs, &expecting,
| ^^^^^^^^^^ help: change this to: `expecting`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_borrow
error: this expression borrows a reference (`&str`) that is immediately dereferenced by the compiler
--> serde_derive/src/de.rs:564:76
|
564 | let visit_seq = Stmts(deserialize_seq_in_place(params, fields, cattrs, &expecting));
| ^^^^^^^^^^ help: change this to: `expecting`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_borrow
error: this expression borrows a reference (`&str`) that is immediately dereferenced by the compiler
--> serde_derive/src/de.rs:925:51
|
925 | &type_path, params, fields, true, cattrs, &expecting,
| ^^^^^^^^^^ help: change this to: `expecting`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_borrow
error: this expression borrows a reference (`&str`) that is immediately dereferenced by the compiler
--> serde_derive/src/de.rs:1066:76
|
1066 | let visit_seq = Stmts(deserialize_seq_in_place(params, fields, cattrs, &expecting));
| ^^^^^^^^^^ help: change this to: `expecting`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_borrow
error: this expression borrows a reference (`&proc_macro2::TokenStream`) that is immediately dereferenced by the compiler
--> serde_derive/src/de.rs:2288:80
|
2288 | let fallthrough_borrowed_arm = fallthrough_borrowed.as_ref().unwrap_or(&fallthrough_arm);
| ^^^^^^^^^^^^^^^^ help: change this to: `fallthrough_arm`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_borrow
error: this expression borrows a reference (`&syn::Member`) that is immediately dereferenced by the compiler
--> serde_derive/src/ser.rs:1102:43
|
1102 | get_member(params, field, &member)
| ^^^^^^^ help: change this to: `member`
|
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_borrow
Both of these modules are doc(hidden) and commented "Not public API",
but incorrect downstream code sometimes still references them. Naming
the module __private will make it more likely to be noticed in code
review.
David Tolnay