jj/lib
Evan Mesterhazy 79518eafce Output better error messages when deriving ContentHash for an enum fails
Consider this code:
```
struct NoContentHash {}

#[derive(ContentHash)]
enum Hashable {
    NoCanHash(NoContentHash),
    Empty,
}
```

Before this commit, it generates an error like this:
```
error[E0277]: the trait bound `NoContentHash: ContentHash` is not satisfied
   --> lib/src/content_hash.rs:150:10
    |
150 | #[derive(ContentHash)]
    |          ^^^^^^^^^^^ the trait `ContentHash` is not implemented for `NoContentHash`
151 | enum Hashable {
152 |     NoCanHash(NoContentHash),
    |     --------- required by a bound introduced by this call
    |
    = help: the following other types implement trait `ContentHash`:
              bool
              i32
              i64
              u8
              u32
              u64
              std::collections::HashMap<K, V>
              BTreeMap<K, V>
            and 35 others

For more information about this error, try `rustc --explain E0277`.
```

After this commit, it generates a better error message:
```
error[E0277]: the trait bound `NoContentHash: ContentHash` is not satisfied
   --> lib/src/content_hash.rs:152:15
    |
152 |     NoCanHash(NoContentHash),
    |               ^^^^^^^^^^^^^ the trait `ContentHash` is not implemented for `NoContentHash`
    |
    = help: the following other types implement trait `ContentHash`:
              bool
              i32
              i64
              u8
              u32
              u64
              std::collections::HashMap<K, V>
              BTreeMap<K, V>
            and 35 others

For more information about this error, try `rustc --explain E0277`.
error: could not compile `jj-lib` (lib) due to 1 previous error
```

It also works for enum variants with named fields:
```
error[E0277]: the trait bound `NoContentHash: ContentHash` is not satisfied
   --> lib/src/content_hash.rs:152:23
    |
152 |     NoCanHash { named: NoContentHash },
    |                       ^^^^^^^^^^^^^ the trait `ContentHash` is not implemented for `NoContentHash`
    |
    = help: the following other types implement trait `ContentHash`:
              bool
              i32
              i64
              u8
              u32
              u64
              std::collections::HashMap<K, V>
              BTreeMap<K, V>
            and 35 others

For more information about this error, try `rustc --explain E0277`.
```
2024-02-20 16:29:25 -05:00
..
benches cargo: rename crates from jujutsu/jujutsu-lib to jj-cli/jj-lib 2023-07-09 06:40:43 +02:00
gen-protos Use { workspace = true } to appease VS Code's Cargo.toml parser 2023-08-22 21:38:53 -07:00
proc-macros Output better error messages when deriving ContentHash for an enum fails 2024-02-20 16:29:25 -05:00
src Replace uses of content_hash! with #[derive(ContentHash)] 2024-02-20 14:18:13 -05:00
tests clippy: run nightly cargo clippy --fix 2024-02-19 23:38:33 -08:00
testutils compile integration tests as a single binary 2024-02-06 18:19:41 -08:00
Cargo.toml Switch to ignore crate for gitignore handling. 2024-02-20 09:12:46 -08:00
LICENSE cargo: add LICENSE file to each crate we publish 2023-09-22 21:48:28 -07:00