# Description
Fixes#14401 where expressions passed to `timeit` will execute twice.
This PR removes the expression support for `timeit`, as this behavior is
almost exclusive to `timeit` and can hinder migration to the IR
evaluator in the future. Additionally, `timeit` used to be able to take
a `block` as an argument. Blocks should probably only be allowed for
parser keywords, so this PR changes `timeit` to instead only take
closures as an argument. This also fixes an issue where environment
updates inside the `timeit` block would affect the parent scope and all
commands later in the pipeline.
```nu
> timeit { $env.FOO = 'bar' }; print $env.FOO
bar
```
# User-Facing Changes
`timeit` now only takes a closure as the first argument.
# After Submitting
Update examples in the book/docs if necessary.
# Description
Fixes: #11996
After this change `let t = timeit ^ls` will list current directory to
stdout.
```
❯ let t = timeit ^ls
CODE_OF_CONDUCT.md Cargo.lock Cross.toml README.md aaa benches devdocs here11 scripts target toolkit.nu wix
CONTRIBUTING.md Cargo.toml LICENSE a.txt assets crates docker rust-toolchain.toml src tests typos.toml
```
If user don't want such behavior, he can redirect the stdout to `std
null-stream` easily
```
> use std
> let t = timeit { ^ls o> (std null-device) }
```
# User-Facing Changes
NaN
# Tests + Formatting
Done
# After Submitting
Nan
---------
Co-authored-by: Ian Manske <ian.manske@pm.me>
