# Description
closes#8153
This PR allows different types of lists, like `list<string>` and
`list<any>` to be appended with the `++=` operator.
## Before
```
mut args = [ hello ("hello" | path join world)]
$args ++= [ foo bar ]
Error: nu::parser::type_mismatch (link)
× Type mismatch during operation.
╭─[entry #2:1:1]
1 │ $args ++= [ foo bar ]
· ─────┬─────
· ╰── expected list<any>, found list<string>
╰────
```
## After
```
mut args = [ hello ("hello" | path join world)]
$args ++= [ foo bar ]
$args
╭───┬─────────────╮
│ 0 │ hello │
│ 1 │ hello\world │
│ 2 │ foo │
│ 3 │ bar │
╰───┴─────────────╯
```
# User-Facing Changes
_(List of all changes that impact the user experience here. This helps
us keep track of breaking changes.)_
# Tests + Formatting
Don't forget to add tests that cover your changes.
Make sure you've run and fixed any issues with these commands:
- `cargo fmt --all -- --check` to check standard code formatting (`cargo
fmt --all` applies these changes)
- `cargo clippy --workspace -- -D warnings -D clippy::unwrap_used -A
clippy::needless_collect` to check that you're using the standard code
style
- `cargo test --workspace` to check that all tests pass
# After Submitting
If your PR had any user-facing changes, update [the
documentation](https://github.com/nushell/nushell.github.io) after the
PR is merged, if necessary. This will help us keep the docs up to date.
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