You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: unused_variable.rs
    path of file: ./repos/solang/src/sema/yul/tests
    
    the code of the file until where you have to start completion: // SPDX-License-Identifier: Apache-2.0

use crate::sema::yul::tests::parse;

#[test]
fn unused_variables() {
    let file = r#"
contract testTypes {
    function testAsm() public {
        assembly {

            let a
            for {let i := 11
              } lt(i, 10) {i := add(i, 1)
            invalid()
        } {
                let x := shr(i, 2)
                let b := shr(6, 5)
                    x := mul(x, b)
                //stop()
            }
        }
    }
}
    "#;

    let ns = parse(file);
    assert!(ns
        .diagnostics
        .contains_message("yul variable 'a' has never been read or assigned"));

    
fn correct_contracts() {
    let file = r#"
    contract testTypes {
    function testAsm() public {
        assembly {

            for {let i := 11
                let c :=5
              } c {i := add(i, 1)
            invalid()
        } {
                let x := shr(i, 2)
                let b := shr(6, 5)
                    x := mul(x, b)
                //stop()
            }

            let x := 0
            if x {
                let y := add(1, 2)
                return(y, 0)
            }

            let y := 5
            let z
            switch y
            case 0 {z := 4}
            case 1 {z := add(z, 3)}

        }
    }
}    "#;

    let ns = parse(file);
    for item in ns.diagnostics.iter() {
        assert!(!item.message.starts_with("yul variable has never been"));
    }

    let file = r#"
    contract testTypes {
    uint b = 0;
    struct test {
        int a;
        int b;
    }
    test tt1;
    function testAsm(uint256[] calldata vl) view public {
        test storage tt2 = tt1;
        assembly {
            let g := vl.length
            let adr := add(g, tt2.slot)
            tt2.slot := sub(adr, b.slot)
        }
    }
}    "#;

    let ns = parse(file);
    assert_eq!(ns.diagnostics.len(), 1);
    assert!(ns
        .diagnostics
        .contains_message("found contract 'testTypes'"));
}