if_same_then_else false positive on 'else if' #6099
Description
I tried this code:
pub fn demo(net_loop_movement: i64) -> i64 {
if net_loop_movement == 0 {
0
} else if net_loop_movement < 0 {
// Net movement was negative, so conservatively assume
// it was zero (e.g. the loop may run zero times).
0
} else {
// Net loop movement was positive, so we can't
// assume any bounds.
1
}
}I wouldn't expect if_same_then_else to fire in this case. I'm explicitly documenting why the second case is a fallback. This is a reduced reproduction from this original source code.
It produces the following message:
error: this `if` has identical blocks
--> src/bounds.rs:99:37
|
99 | } else if net_loop_movement < 0 {
| _____________________________________^
100 | | // Net movement was negative, so conservatively assume
101 | | // it was zero (e.g. the loop may run zero times).
102 | | 0
103 | | } else {
| |_____^
|
= note: `#[deny(clippy::if_same_then_else)]` on by default
note: same as this
--> src/bounds.rs:97:31
|
97 | if net_loop_movement == 0 {
| _______________________________^
98 | | 0
99 | | } else if net_loop_movement < 0 {
| |_____^
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#if_same_then_else
Could the check be more conservative? Perhaps not firing if there's an additional else later, or considering blocks to be different based on trivia like comments?
Meta
cargo clippy -V:clippy 0.0.212 (623fb90 2020-09-26)rustc -Vv:
$ rustc -Vv
rustc 1.48.0-nightly (623fb90b5 2020-09-26)
binary: rustc
commit-hash: 623fb90b5a1f324e0ec44085116bf858cef19a00
commit-date: 2020-09-26
host: x86_64-unknown-linux-gnu
release: 1.48.0-nightly
LLVM version: 11.0