False positive branches_sharing_code: different inferred type

[dtolnay]

fn main() {
    if true {
        let mut v = Vec::new();
        v.push(0);
    } else {
        let mut v = Vec::new();
        v.push("");
    };
}

$ cargo clippy
warning: all if blocks contain the same code at the start
 --> src/main.rs:2:5
  |
2 | /     if true {
3 | |         let mut v = Vec::new();
  | |_______________________________^
  |
  = note: `#[warn(clippy::branches_sharing_code)]` on by default
  = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#branches_sharing_code
help: consider moving the start statements out like this
  |
2 |     let mut v = Vec::new();
3 |     if true {
  |

Clippy's preferred code is the following, which does not compile.

fn main() {
    let mut v = Vec::new();
    if true {
        v.push(0);
    } else {
        v.push("");
    };
}

error[E0308]: mismatched types
 --> src/main.rs:6:16
  |
6 |         v.push("");
  |                ^^ expected integer, found `&str`

Meta

• cargo clippy -V: clippy 0.1.53 (2e495d2 2021-04-08)
• rustc -Vv:

  rustc 1.53.0-nightly (2e495d2e8 2021-04-08)
  binary: rustc
  commit-hash: 2e495d2e845cf27740e3665f718acfd3aa17253e
  commit-date: 2021-04-08
  host: x86_64-unknown-linux-gnu
  release: 1.53.0-nightly
  LLVM version: 12.0.0
  

Mentioning @xFrednet @phansch #6463

[xFrednet]

This is very interesting and sounds like a bug that is caused by the comparison function but i would need to dig into that.

Thank you for pinging me directly :)

@phansch should I submit a temporary PR to move this lint back to nursery in the mean time since it has only been in nightly so far? :)

@rustbot claim