cargo fix --edition breaks on serde deserialize_with attributes

[Kixunil]

I tried this code:

#[derive(Debug, Deserialize)]
struct OwnedPair<T>(
    T,
    #[serde(deserialize_with = "::serde_utils::hex_bytes::deserialize")]
    Vec<u8>,
);

And cargo fix --edition

I expected to see this happen: the code gets fixed

Instead, this happened: It attempted to fix it like this: #[serde(deserialize_with = crate::"::serde_utils::hex_bytes::deserialize")] and obviously failed.

Meta

rustc --version --verbose:

rustc 1.53.0 (53cb7b09b 2021-06-17)
binary: rustc
commit-hash: 53cb7b09b00cbea8754ffb78e7e3cb521cb8af4b
commit-date: 2021-06-17
host: x86_64-unknown-linux-gnu
release: 1.53.0
LLVM version: 12.0.1

Same happens on nightly, 1.36, and 1.48

Context: I tried to convert https://github.com/rust-bitcoin/rust-bitcoin/ to edition 2018

[Kixunil]

Note that after manually fixing bitcoin and applying --edition-idioms I get more errors - it seems to duplicate lifetime markers like this: <'_><'_>.

[ehuss]

Thanks for the report! I'm going to close as this is a duplicate of #56625.

To work around the issue, you can manually adjust the paths in the strings to start with crate:: before doing the migration. Alternatively, you can migrate with the --broken-code flag, and then fix the issues manually.

[Kixunil]

Damn, I didn't find #56625 I guess because of funny title. Yeah, --broken-code helped. Thanks!