Remove move_semantics4, add rest of move_semantics solutions

exercises/06_move_semantics/move_semantics4.rs

@@ -1,31 +1,18 @@
-// Refactor this code so that instead of passing `vec0` into the `fill_vec`
-// function, the Vector gets created in the function itself and passed back to
-// the test function.
-
-// `fill_vec()` no longer takes `vec: Vec<i32>` as argument - don't change this!
-fn fill_vec() -> Vec<i32> {
-    // Instead, let's create and fill the Vec in here - how do you do that?
-    let mut vec = vec;
-
-    vec.push(88);
-
-    vec
-}
-
 fn main() {
     // You can optionally experiment here.
 }
 
 #[cfg(test)]
 mod tests {
-    use super::*;
-
+    // TODO: Fix the compiler errors only by reordering the lines in the test.
+    // Don't add, change or remove any line.
     #[test]
-    fn move_semantics4() {
-        let vec0 = vec![22, 44, 66];
-
-        let vec1 = fill_vec(vec0);
-
-        assert_eq!(vec1, vec![22, 44, 66, 88]);
+    fn move_semantics5() {
+        let mut x = 100;
+        let y = &mut x;
+        let z = &mut x;
+        *y += 100;
+        *z += 1000;
+        assert_eq!(x, 1200);
     }
 }

exercises/06_move_semantics/move_semantics5.rs

@@ -1,21 +1,22 @@
-// Make me compile only by reordering the lines in the test, but without adding,
-// changing or removing any of them.
+// TODO: Fix the compiler erros. Don't change anything except adding or removing
+// references (the character `&`).
 
 fn main() {
-    // You can optionally experiment here.
+    let data = "Rust is great!".to_string();
+
+    get_char(data);
+
+    string_uppercase(&data);
 }
 
-#[cfg(test)]
-mod tests {
-    use super::*;
+// Shouldn't take ownership
+fn get_char(data: String) -> char {
+    data.chars().last().unwrap()
+}
 
-    #[test]
-    fn move_semantics5() {
-        let mut x = 100;
-        let y = &mut x;
-        let z = &mut x;
-        *y += 100;
-        *z += 1000;
-        assert_eq!(x, 1200);
-    }
+// Should take ownership
+fn string_uppercase(mut data: &String) {
+    data = &data.to_uppercase();
+
+    println!("{data}");
 }

exercises/06_move_semantics/move_semantics6.rs

@@ -1,21 +0,0 @@
-// You can't change anything except adding or removing references.
-
-fn main() {
-    let data = "Rust is great!".to_string();
-
-    get_char(data);
-
-    string_uppercase(&data);
-}
-
-// Should not take ownership
-fn get_char(data: String) -> char {
-    data.chars().last().unwrap()
-}
-
-// Should take ownership
-fn string_uppercase(mut data: &String) {
-    data = &data.to_uppercase();
-
-    println!("{}", data);
-}

rustlings-macros/info.toml

@@ -371,28 +371,15 @@ an existing binding to be a mutable binding instead of an immutable one :)"""
 name = "move_semantics4"
 dir = "06_move_semantics"
 hint = """
-Stop reading whenever you feel like you have enough direction :) Or try
-doing one step and then fixing the compiler errors that result!
-So the end goal is to:
-   - get rid of the first line in main that creates the new vector
-   - so then `vec0` doesn't exist, so we can't pass it to `fill_vec`
-   - `fill_vec` has had its signature changed, which our call should reflect
-   - since we're not creating a new vec in `main` anymore, we need to create
-     a new vec in `fill_vec`, and fill it with the expected values"""
-
-[[exercises]]
-name = "move_semantics5"
-dir = "06_move_semantics"
-hint = """
 Carefully reason about the range in which each mutable reference is in
 scope. Does it help to update the value of referent (`x`) immediately after
-the mutable reference is taken? Read more about 'Mutable References'
-in the book's section 'References and Borrowing':
+the mutable reference is taken?
+Read more about 'Mutable References' in the book's section 'References and Borrowing':
 https://doc.rust-lang.org/book/ch04-02-references-and-borrowing.html#mutable-references.
 """
 
 [[exercises]]
-name = "move_semantics6"
+name = "move_semantics5"
 dir = "06_move_semantics"
 test = false
 hint = """
@@ -401,14 +388,10 @@ https://doc.rust-lang.org/stable/book/ch04-02-references-and-borrowing.html
 
 The first problem is that `get_char` is taking ownership of the string. So
 `data` is moved and can't be used for `string_uppercase`. `data` is moved to
-`get_char` first, meaning that `string_uppercase` cannot manipulate the data.
+`get_char` first, meaning that `string_uppercase` can't manipulate the data.
 
 Once you've fixed that, `string_uppercase`'s function signature will also need
-to be adjusted.
-
-Can you figure out how?
-
-Another hint: it has to do with the `&` character."""
+to be adjusted."""
 
 # STRUCTS
 

solutions/06_move_semantics/move_semantics4.rs

@@ -1 +1,21 @@
-// Solutions will be available before the stable release. Thank you for testing the beta version 🥰
+fn main() {
+    // You can optionally experiment here.
+}
+
+#[cfg(test)]
+mod tests {
+    // TODO: Fix the compiler errors only by reordering the lines in the test.
+    // Don't add, change or remove any line.
+    #[test]
+    fn move_semantics5() {
+        let mut x = 100;
+        let y = &mut x;
+        // `y` used here.
+        *y += 100;
+        // The mutable reference `y` is not used anymore,
+        // therefore a new reference can be created.
+        let z = &mut x;
+        *z += 1000;
+        assert_eq!(x, 1200);
+    }
+}

solutions/06_move_semantics/move_semantics5.rs

@@ -1 +1,21 @@
-// Solutions will be available before the stable release. Thank you for testing the beta version 🥰
+fn main() {
+    let data = "Rust is great!".to_string();
+
+    get_char(&data);
+
+    string_uppercase(data);
+}
+
+// Borrows instead of taking ownership.
+// It is recommended to use `&str` instead of `&String` here. But this is
+// enough for now because we didn't handle strings yet.
+fn get_char(data: &String) -> char {
+    data.chars().last().unwrap()
+}
+
+// Takes ownership instead of borrowing.
+fn string_uppercase(mut data: String) {
+    data = data.to_uppercase();
+
+    println!("{data}");
+}

solutions/06_move_semantics/move_semantics6.rs

@@ -1 +0,0 @@
-// Solutions will be available before the stable release. Thank you for testing the beta version 🥰