cognitive_complexity lint includes code expanded from macro in calculated complexity

[KonaeAkira]

Summary

Code expanded from macros should not count towards cognitive complexity. Instead, a macro call should have the same cognitive complexity as a function call.

Lint Name

cognitive_complexity

Reproducer

I tried this code:

#![warn(clippy::cognitive_complexity)]

// exact content of the macro is not important
macro_rules! create_4d_vec {
    ( $dim_1:literal, $dim_2:literal, $dim_3:literal, $dim_4:literal) => {
        let mut vec = vec![vec![vec![vec![0; $dim_4]; $dim_3]; $dim_2]; $dim_1];
        for a in 0..$dim_1 {
            for b in 0..$dim_2 {
                for c in 0..$dim_3 {
                    for d in 0..$dim_4 {
                        vec[a][b][c][d] = a + b + c + d;
                    }
                }
            }
        }
    };
}

fn foo() {
    create_4d_vec!(1, 2, 3, 4);
    create_4d_vec!(1, 2, 3, 4);
    create_4d_vec!(1, 2, 3, 4);
    create_4d_vec!(1, 2, 3, 4);
    create_4d_vec!(1, 2, 3, 4);
    create_4d_vec!(1, 2, 3, 4);
    create_4d_vec!(1, 2, 3, 4);
}

I saw this happen:

warning: the function has a cognitive complexity of (29/25)
  --> src/main.rs:18:4
   |
18 | fn foo() {
   |    ^^^
   |
   = help: you could split it up into multiple smaller functions
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#cognitive_complexity

I expected to see this happen:

Lint does not trigger.

Version

rustc 1.87.0-nightly (ecade534c 2025-03-14)
binary: rustc
commit-hash: ecade534c66478c51c5d3c1d3682dc4beb0ac972
commit-date: 2025-03-14
host: x86_64-unknown-linux-gnu
release: 1.87.0-nightly
LLVM version: 20.1.0

Additional Labels

@rustbot label +L-nursery