style: replace let _ = by _ =

tests/matrix.rs

@@ -71,7 +71,7 @@ fn from_vec_empty_row_error() {
 #[test]
 #[should_panic(expected = "unable to create a matrix with empty rows")]
 fn new_empty_row_panic() {
-    let _ = Matrix::new(1, 0, 42);
+    _ = Matrix::new(1, 0, 42);
 }
 
 #[test]
@@ -221,19 +221,19 @@ fn non_square_rotate() {
 #[test]
 #[should_panic(expected = "this operation would create a matrix with empty rows")]
 fn no_rows_rotated_cw_panic() {
-    let _ = Matrix::<u32>::new_empty(10).rotated_cw(1);
+    _ = Matrix::<u32>::new_empty(10).rotated_cw(1);
 }
 
 #[test]
 #[should_panic(expected = "this operation would create a matrix with empty rows")]
 fn no_rows_rotated_ccw_panic() {
-    let _ = Matrix::<u32>::new_empty(10).rotated_ccw(1);
+    _ = Matrix::<u32>::new_empty(10).rotated_ccw(1);
 }
 
 #[test]
 fn no_rows_rotated_twice() {
-    let _ = Matrix::<u32>::new_empty(10).rotated_cw(2);
-    let _ = Matrix::<u32>::new_empty(10).rotated_ccw(2);
+    _ = Matrix::<u32>::new_empty(10).rotated_cw(2);
+    _ = Matrix::<u32>::new_empty(10).rotated_ccw(2);
 }
 
 #[test]
@@ -291,7 +291,7 @@ fn transpose() {
 #[test]
 #[should_panic(expected = "this operation would create a matrix with empty rows")]
 fn no_rows_transposed_panic() {
-    let _ = Matrix::<u32>::new_empty(10).transposed();
+    _ = Matrix::<u32>::new_empty(10).transposed();
 }
 
 #[test]
@@ -635,7 +635,7 @@ fn from_iter() {
 #[test]
 #[should_panic(expected = "provided data does not correspond to the expected length")]
 fn from_iter_error() {
-    let _ = (1..3)
+    _ = (1..3)
         .map(|n| (1..n).map(move |x| x * n))
         .collect::<Matrix<_>>();
 }

tests/ui/matrix.rs

@@ -2,8 +2,8 @@ use pathfinding::matrix;
 
 fn main() {
     // Empty matrix must be rejected
-    let _ = matrix!();
+    _ = matrix!();
     // Single comma and multiple commas at the end must be rejected
-    let _ = matrix!(,);
-    let _ = matrix!( [1, 2], [3, 4], ,);
+    _ = matrix!(,);
+    _ = matrix!( [1, 2], [3, 4], ,);
 }

tests/ui/matrix.stderr

@@ -1,16 +1,16 @@
 error: no rules expected the token `,`
- --> tests/ui/matrix.rs:7:21
+ --> tests/ui/matrix.rs:7:17
   |
-7 |     let _ = matrix!(,);
-  |                     ^ no rules expected this token in macro call
+7 |     _ = matrix!(,);
+  |                 ^ no rules expected this token in macro call
   |
   = note: while trying to match end of macro
 
 error: no rules expected the token `,`
- --> tests/ui/matrix.rs:8:38
+ --> tests/ui/matrix.rs:8:34
   |
-8 |     let _ = matrix!( [1, 2], [3, 4], ,);
-  |                                      ^ no rules expected this token in macro call
+8 |     _ = matrix!( [1, 2], [3, 4], ,);
+  |                                  ^ no rules expected this token in macro call
   |
 note: while trying to match meta-variable `$b:expr`
  --> src/matrix.rs