Macro filecheck 

macro_rules! filecheck {
    ($input:expr, $checks:expr) => { ... };
    ($input:expr, $checks:expr, $config:expr) => { ... };
}

Use filecheck in a Rust test directly against an input value that implements Display.

Example

#![expect(unstable_name_collisions)]
use litcheck_filecheck::filecheck;
use itertools::Itertools;

let original = "abbc";
let modified = original.chars().intersperse('\n').collect::<String>();

filecheck!(modified, "
; CHECK: a
; CHECK-NEXT: b
; CHECK-NEXT: b
; CHECK-NEXT: c
");

If custom configuration is desired, you may instantiate the filecheck configuration (see Config) and pass it as an additional parameter:

#![expect(unstable_name_collisions)]
use litcheck_filecheck::{filecheck, Config, Options};
use itertools::Itertools;

let original = "abbc";
let modified = original.chars().intersperse('\n').collect::<String>();
let config = Config {
    options: Options {
        match_full_lines: true,
        ..Options::default()
    },
    ..Config::default()
};

filecheck!(modified, "
; CHECK: a
; CHECK-NEXT: b
; CHECK-NEXT: b
; CHECK-NEXT: c
");

If successful, the filecheck! macro returns the pattern matches produced by verifying the checks, allowing you to examine them in more detail.