diff --git a/examples/connect5.rs b/examples/connect5.rs
index a569689fad..feb84fbef5 100644
--- a/examples/connect5.rs
+++ b/examples/connect5.rs
@@ -74,6 +74,7 @@ const SCORE_NONE: i32 = -EVAL_INF - 1;
 /// DIRECTION 2: top left to bottom right\
 /// DIRECTION 3: top right to bottom left
 #[rustfmt::skip]
+#[allow(clippy::identity_op)]
 const DIRECTION: [[i32; 5]; 4] = [ [1, 2, 3, 4, 5],
                                    [1 * (FILE_SIZE + 1), 2 * (FILE_SIZE + 1), 3 * (FILE_SIZE + 1), 4 * (FILE_SIZE + 1), 5 * (FILE_SIZE + 1)],
                                    [1 * (FILE_SIZE + 2), 2 * (FILE_SIZE + 2), 3 * (FILE_SIZE + 2), 4 * (FILE_SIZE + 2), 5 * (FILE_SIZE + 2)],
@@ -311,7 +312,7 @@ impl Pos {
 
         match self.p_turn {
             Color::Black => {
-                self.state[mv as usize] = Color::Black;
+                self.state[mv] = Color::Black;
                 // update black move and remove empty move in bitboard
                 self.bitboard[black][0][MAPMOVEIDX[0][mv] as usize] |= MAPMOVEVALUE[0][mv];
                 self.bitboard[empty][0][MAPMOVEIDX[0][mv] as usize] ^= MAPMOVEVALUE[0][mv];
@@ -323,7 +324,7 @@ impl Pos {
                 self.bitboard[empty][1][MAPMOVEIDX[3][mv] as usize] ^= MAPMOVEVALUE[3][mv];
             }
             Color::White => {
-                self.state[mv as usize] = Color::White;
+                self.state[mv] = Color::White;
                 // update white move and remove empty move in bitboard
                 self.bitboard[white][0][MAPMOVEIDX[0][mv] as usize] |= MAPMOVEVALUE[0][mv];
                 self.bitboard[empty][0][MAPMOVEIDX[0][mv] as usize] ^= MAPMOVEVALUE[0][mv];
@@ -345,11 +346,7 @@ impl Pos {
     }
 
     pub fn can_play(&self, from: Square) -> bool {
-        if self.state[from as usize] == Color::Empty {
-            true
-        } else {
-            false
-        }
+        self.state[from as usize] == Color::Empty
     }
 }
 
@@ -421,14 +418,14 @@ fn pos_is_draw(pos: &Pos) -> bool {
                 break;
             }
 
-            if found == false {
+            if !found {
                 break;
             }
         }
     }
 
-    let mut out: bool = false;
-    if found == true && !pos_is_winner(pos) {
+    let mut out = false;
+    if found && !pos_is_winner(pos) {
         out = true;
     }
 
@@ -447,19 +444,11 @@ unsafe fn pos_is_draw_avx512(pos: &Pos) -> bool {
     // if all empty is 0, all board is filled.
     let temp_mask = _mm512_mask_cmpneq_epi32_mask(0b11111111_11111111, answer, board0org);
 
-    if _popcnt32(temp_mask as i32) == 0 && !pos_is_winner_avx512(pos) {
-        return true;
-    } else {
-        return false;
-    }
+    _popcnt32(temp_mask as i32) == 0 && !pos_is_winner_avx512(pos)
 }
 
 fn pos_is_end(pos: &Pos) -> bool {
-    if pos_is_winner(pos) || pos_is_draw(pos) {
-        true
-    } else {
-        false
-    }
+    pos_is_winner(pos) || pos_is_draw(pos)
 }
 
 fn pos_disp(pos: &Pos) {
@@ -475,7 +464,7 @@ fn pos_disp(pos: &Pos) {
             }
         }
 
-        println!("");
+        println!();
     }
 
     match pos.turn() {
@@ -581,7 +570,7 @@ fn search(pos: &Pos, alpha: i32, beta: i32, depth: i32, _ply: i32) -> i32 {
         }
     }
 
-    assert!(bm != MOVE_NONE);
+    assert_ne!(bm, MOVE_NONE);
     assert!(bs >= -EVAL_INF && bs <= EVAL_INF);
 
     if _ply == 0 {
@@ -605,10 +594,8 @@ fn eval(pos: &Pos, _ply: i32) -> i32 {
                     return -4096;
                 }
             }
-        } else {
-            if check_patternlive4(pos, def) {
-                return -4096;
-            }
+        } else if check_patternlive4(pos, def) {
+            return -4096;
         }
     }
 
@@ -628,10 +615,8 @@ fn eval(pos: &Pos, _ply: i32) -> i32 {
                     return 2560;
                 }
             }
-        } else {
-            if check_patternlive4(pos, atk) {
-                return 2560;
-            }
+        } else if check_patternlive4(pos, atk) {
+            return 2560;
         }
     }
 
@@ -651,10 +636,8 @@ fn eval(pos: &Pos, _ply: i32) -> i32 {
                     return 2560;
                 }
             }
-        } else {
-            if check_patterndead4(pos, atk) > 0 {
-                return 2560;
-            }
+        } else if check_patterndead4(pos, atk) > 0 {
+            return 2560;
         }
     }
 
@@ -773,11 +756,7 @@ fn check_pattern5(pos: &Pos, sd: Side) -> bool {
         }
     }
 
-    if n > 0 {
-        true
-    } else {
-        false
-    }
+    n > 0
 }
 
 /// Check <b>-OOOO-</b>
@@ -809,11 +788,7 @@ fn check_patternlive4(pos: &Pos, sd: Side) -> bool {
         }
     }
 
-    if n > 0 {
-        true
-    } else {
-        false
-    }
+    n > 0
 }
 
 /// Check <b>OOOO-, OOO-O, OO-OO, O-OOO, -OOOO</b>
@@ -961,11 +936,7 @@ unsafe fn pos_is_winner_avx512(pos: &Pos) -> bool {
         }
     }
 
-    if count_match > 0 {
-        return true;
-    } else {
-        return false;
-    }
+    count_match > 0
 }
 
 #[target_feature(enable = "avx512f,avx512bw")]
@@ -1027,11 +998,7 @@ unsafe fn check_patternlive4_avx512(pos: &Pos, sd: Side) -> bool {
         }
     }
 
-    if count_match > 0 {
-        return true;
-    } else {
-        return false;
-    }
+    count_match > 0
 }
 
 #[target_feature(enable = "avx512f,avx512bw")]