else statement captures mutable variables

[amtoine]

Describe the bug

from this discussion on the discord server with @fdncred and @jntrnr, it appears mutable variables showcase a strange behaviour when used in the last else statement in a for loop 🤔

How to reproduce

run the following script

mut m = ""

for el in (seq 1 10) {
  $m = $m
}

for el in (seq 1 10) {
  if ($el == 1) {
    $m = $m
  }
}

for el in (seq 1 10) {
  if ($el == 1) {
    $m = $m
  } else {
    $m = $m  # fails on this very line
  }
}

Expected behavior

here i simply expect the script to print nothing to the shell 😋

however i get

Error: nu::parser::expected_keyword (link)

  × Capture of mutable variable.
    ╭─[entry #52:16:1]
 16 │   } else {
 17 │     $m = $m
    ·     ─┬
    ·      ╰── capture of mutable variable
 18 │   }
    ╰────

Screenshots

No response

Configuration

key	value
version	0.72.0
branch
commit_hash
build_os	linux-x86_64
build_target	x86_64-unknown-linux-gnu
rust_version	rustc 1.65.0 (Arch Linux rust 1:1.65.0-1)
cargo_version	cargo 1.65.0
pkg_version	0.72.0
build_time	2022-12-03 18:27:13 +01:00
build_rust_channel	release
features	database, default, trash, which, zip
installed_plugins

Additional context

No response

[amtoine]

thanks a lot 😌 🎉