feat(clippy): add clippy3

Author: manyinsects

.gitignore

@@ -9,3 +9,4 @@ rust-project.json
 .idea
 .vscode
 *.iml
+*.o

exercises/clippy/clippy1.rs

@@ -4,7 +4,7 @@
 //
 // For these exercises the code will fail to compile when there are clippy warnings
 // check clippy's suggestions from the output to solve the exercise.
-// Execute `rustlings hint clippy1` for hints :)
+// Execute `rustlings hint clippy1` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 

exercises/clippy/clippy2.rs

@@ -1,5 +1,5 @@
 // clippy2.rs
-// Make me compile! Execute `rustlings hint clippy2` for hints :)
+// Execute `rustlings hint clippy2` or use the `hint` watch subcommand for a hint.
 
 // I AM NOT DONE
 

exercises/clippy/clippy3.rs

@@ -0,0 +1,26 @@
+// clippy3.rs
+// Here's a couple more easy Clippy fixes, so you can see its utility.
+
+#[allow(unused_variables, unused_assignments)]
+fn main() {
+    let my_option: Option<()> = None;
+    if my_option.is_none() {
+        my_option.unwrap();
+    }
+
+    let my_arr = &[
+        -1, -2, -3
+        -4, -5, -6
+    ];
+    println!("My array! Here it is: {:?}", my_arr);
+
+    let my_empty_vec = vec![1, 2, 3, 4, 5].resize(0, 5);
+    println!("This Vec is empty, see? {:?}", my_empty_vec);
+
+    let mut value_a = 45;
+    let mut value_b = 66;
+    // Let's swap these two!
+    value_a = value_b;
+    value_b = value_a;
+    println!("value a: {}; value b: {}", value_a, value_b);
+}

info.toml

@@ -989,6 +989,12 @@ mode = "clippy"
 hint = """
 `for` loops over Option values are more clearly expressed as an `if let`"""
 
+[[exercises]]
+name = "clippy3"
+path = "exercises/clippy/clippy3.rs"
+mode = "clippy"
+hint = "No hints this time!"
+
 # TYPE CONVERSIONS
 
 [[exercises]]