diff options
Diffstat (limited to 'info.toml')
| -rw-r--r-- | info.toml | 15 |
1 files changed, 9 insertions, 6 deletions
@@ -280,18 +280,21 @@ mode = "compile" hint = """ So you've got the "cannot borrow immutable local variable `vec1` as mutable" error on line 13, right? The fix for this is going to be adding one keyword, and the addition is NOT on line 13 -where the error is.""" +where the error is. + +Also: Try accessing `vec0` after having called `fill_vec()`. See what happens!""" [[exercises]] name = "move_semantics2" path = "exercises/move_semantics/move_semantics2.rs" mode = "compile" hint = """ -So `vec0` is being *moved* into the function `fill_vec` when we call it on -line 10, which means it gets dropped at the end of `fill_vec`, which means we -can't use `vec0` again on line 13 (or anywhere else in `main` after the -`fill_vec` call for that matter). We could fix this in a few ways, try them -all! +So, `vec0` is passed into the `fill_vec` function as an argument. In Rust, +when an argument is passed to a function and it's not explicitly returned, +you can't use the original variable anymore. We call this "moving" a variable. +Variables that are moved into a function (or block scope) and aren't explicitly +returned get "dropped" at the end of that function. This is also what happens here. +There's a few ways to fix this, try them all if you want: 1. Make another, separate version of the data that's in `vec0` and pass that to `fill_vec` instead. 2. Make `fill_vec` borrow its argument instead of taking ownership of it, |