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try_from_instead_of_from_str lint causes error when TryFrom::try_from parameter is not named 'value' #17877
Description
Summary
Clippy suggests a replacement that includes a hardcoded value: &str parameter, but the suggestion still uses the existing code's parameter name inside the function body.
Reproducer
Code:
#![allow(dead_code)]
struct Foo;
impl TryFrom<&str> for Foo {
type Error = std::io::Error;
fn try_from(s: &str) -> Result<Self, Self::Error> {
_ = s;
Ok(Self)
}
}Current output:
warning: `TryFrom<str>` could be `FromStr`
╭▸ src/lib.rs:5:1
│
5 │ ┏ impl TryFrom<&str> for Foo {
6 │ ┃ type Error = std::io::Error;
7 │ ┃
8 │ ┃ fn try_from(s: &str) -> Result<Self, Self::Error> {
‡ ┃
12 │ ┃ }
│ ┗━┛
│
├ help: `FromStr` can also be implemented alongside `TryFrom` if you want to avoid breaking changes
├ help: for further information visit https://rust-lang.github.io/rust-clippy/main/index.html#try_from_instead_of_from_str
╰ note: `#[warn(clippy::try_from_instead_of_from_str)]` on by default
help: replace with
╭╴
5 + impl core::str::FromStr for Foo {
6 + type Err = std::io::Error;
7 +
8 + fn from_str(value: &str) -> Result<Self, Self::Err> {
9 + let _ = s;
10 + Ok(Self)
11 + }
12 + }
╰╴
Desired output: The parameter should probably just use the same name as in the original impl, which would be a shorter diff than replacing all references in the body.
Version
rustc 1.101.0-nightly (822182db4 2026-10-13)
binary: rustc
commit-hash: 822182db4c4a1827256881d8c7aa685f0bcf2b11
commit-date: 2026-10-13
host: x86_64-unknown-linux-gnu
release: 1.101.0-nightly
LLVM version: 23.1.3
Additional Labels
@rustbot label +I-suggestion-causes-error
Activity
wasd243 commentedon Oct 14, 2026
@rustbot claim