Clippy lints / Complexity
Clippy lint · Complexity · checked with Clippy 0.1.99
clippy::temporary_assignment: assignment to temporary
What it meansChecks for construction of a structure or tuple just to assign a value in it. It is in the complexity group and warns by default.
What you see
warning: assignment to temporary --> main.rs:3:1 | 3 | (0, 0).0 = 1 | ^^^^^^^^^^^^ | = help: for further information visit https://rust-lang.github.io/rust-clippy/stable/index.html#temporary_assignment = note: `#[warn(clippy::temporary_assignment)]` on by default
Real output of Clippy 0.1.99 (Rust 1.99) on the example below. Names and line numbers in yours will differ.
Does it matter?
Readability. If the structure is only created to be updated, why not write the structure you want in the first place?
Code that does something simple in a complicated way. Warns by default.
How to fix it
Clippy does not fix this one automatically. Change the code by hand:
Flagged
(0, 0).0 = 1
Turn it off, or on
Allow it where it does not fit your code, as narrowly as you can:
On one item
#[allow(clippy::temporary_assignment)]
fn my_function() { /* ... */ }Whole crate (Cargo.toml)
[lints.clippy]
temporary_assignment = "allow"One run
cargo clippy -- -A clippy::temporary-assignmentThe [lints] table needs Rust 1.74 or newer. In a workspace, put it under [workspace.lints.clippy] and add [lints] workspace = true to each member.
Clippy's own documentation
What it does
Checks for construction of a structure or tuple just to assign a value in it.
Why is this bad?
Readability. If the structure is only created to be updated, why not write the structure you want in the first place?
Example
(0, 0).0 = 1
From the Clippy lint list (0.1.99), part of the Rust project, MIT or Apache-2.0. Official entry.
Related lints
- too_many_argumentsChecks for functions with too many parameters
- clone_on_copyusing `clone` on type `u64` which implements the `Copy` trait
- type_complexityChecks for types used in structs, parameters and let declarations above a certain complexity threshold
- string_from_utf8_as_bytescalling a slice of `as_bytes()` with `from_utf8` should be not necessary
- strlen_on_c_stringsChecks for usage of libc::strlen on a CString or CStr value, and suggest calling count_bytes() instead
- swap_with_temporaryswapping with a temporary value is inefficient
- transmute_bytes_to_strtransmute from a `&[u8]` to a `&str`
- transmute_int_to_booltransmute from a `u8` to a `bool`
All 847 Clippy lints · Rust compiler errors · Cargo.toml checker
Up next
Related lintclippy::too_many_argumentsChecks for functions with too many parametersRead it next →Did this answer your question?