clippy::type_complexity: Checks for types used in structs, parameters and let declarations above a certain complexity threshold

Does it matter?

Too complex types make the code less readable. Consider using a type definition to simplify them.

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

struct PointMatrixContainer {
    matrix: Rc<Vec<Vec<Box<(u32, u32, u32, u32)>>>>,
}

fn main() {
    let point_matrix: Vec<Vec<Box<(u32, u32, u32, u32)>>> = vec![
        vec![
            Box::new((1, 2, 3, 4)),
            Box::new((5, 6, 7, 8)),
        ],
        vec![
            Box::new((9, 10, 11, 12)),
        ],
    ];

    let shared_point_matrix: Rc<Vec<Vec<Box<(u32, u32, u32, u32)>>>> = Rc::new(point_matrix);

    let container = PointMatrixContainer {
        matrix: shared_point_matrix,
    };

    // ...
}

Write this instead

type PointMatrix = Vec<Vec<Box<(u32, u32, u32, u32)>>>;
type SharedPointMatrix = Rc<PointMatrix>;

struct PointMatrixContainer {
    matrix: SharedPointMatrix,
}

fn main() {
    let point_matrix: PointMatrix = vec![
        vec![
            Box::new((1, 2, 3, 4)),
            Box::new((5, 6, 7, 8)),
        ],
        vec![
            Box::new((9, 10, 11, 12)),
        ],
    ];

    let shared_point_matrix: SharedPointMatrix = Rc::new(point_matrix);

    let container = PointMatrixContainer {
        matrix: shared_point_matrix,
    };

    // ...
}

Turn it off, or on

Allow it where it does not fit your code, as narrowly as you can:

#[allow(clippy::type_complexity)]
fn my_function() { /* ... */ }

[lints.clippy]
type_complexity = "allow"

cargo clippy -- -A clippy::type-complexity

The [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.

Settings in clippy.toml

• type-complexity-threshold: The maximum complexity a type can have