clippy::useless_format slices {name} to am.to_string() #9234
Description
Summary
Fun with off-by-ones.
cc @compiler-errors didn't you just fix something similar to this in rustc or am I imagining things
Reproducer
I tried this code:
fn main() { let variable = "string"; let _ = format!("{variable}"); let abc = "abc"; let _ = format!("{abc}"); let x = "x"; let _ = format!("{x}"); let xx = "xx"; let _ = format!("{xx}"); }I expected to see this happen:
warning: useless use of `format!` --> src\main.rs:3:13 | 3 | let _ = format!("{variable}"); | ^^^^^^^^^^^^^^^^^^^^^ help: consider using `.to_string()`: `variable.to_string()` | = note: `#[warn(clippy::useless_format)]` on by default = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#useless_format warning: useless use of `format!` --> src\main.rs:6:13 | 6 | let _ = format!("{abc}"); | ^^^^^^^^^^^^^^^^ help: consider using `.to_string()`: `abc.to_string()` | = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#useless_format warning: useless use of `format!` --> src\main.rs:9:13 | 9 | let _ = format!("{x}"); | ^^^^^^^^^^^^^^ help: consider using `.to_string()`: `x.to_string()` | = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#useless_format warning: useless use of `format!` --> src\main.rs:9:13 | 12 | let _ = format!("{xx}"); | ^^^^^^^^^^^^^^^ help: consider using `.to_string()`: `xx.to_string()` | = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#useless_format Instead, this happened:
warning: useless use of `format!` --> src\main.rs:3:13 | 3 | let _ = format!("{variable}"); | ^^^^^^^^^^^^^^^^^^^^^ help: consider using `.to_string()`: `ariabl.to_string()` | = note: `#[warn(clippy::useless_format)]` on by default = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#useless_format warning: useless use of `format!` --> src\main.rs:6:13 | 6 | let _ = format!("{abc}"); | ^^^^^^^^^^^^^^^^ help: consider using `.to_string()`: `b.to_string()` | = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#useless_format warning: useless use of `format!` --> src\main.rs:9:13 | 9 | let _ = format!("{x}"); | ^^^^^^^^^^^^^^ help: consider using `.to_string()`: `x.to_string()` | = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#useless_format warning: useless use of `format!` --> src\main.rs:9:13 | 12 | let _ = format!("{xx}"); | ^^^^^^^^^^^^^^^ help: consider using `.to_string()`: `.to_string()` | = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#useless_format Note the suggestions: they've mangled the name of the bindings by slicing off the first and last character.
Version
rustc 1.64.0-nightly (f8588549c 2022-07-18) binary: rustc commit-hash: f8588549c3c3d45c32b404210cada01e2a45def3 commit-date: 2022-07-18 host: x86_64-pc-windows-msvc release: 1.64.0-nightly LLVM version: 14.0.6 Additional Labels
@rustbot label +I-suggestion-causes-error