Auto merge of #8117 - hotate29:issue7320, r=camsteffen

update: ```Sugg::not()``` replacing the comparison operator. #7320

fixes #7320

changelog: ```needless_bool```: Changed to make a smart suggestion.

tests/ui/manual_memcpy/with_loop_counters.stderr

@@ -43,7 +43,7 @@ LL | /     for i in 3..(3 + src.len()) {
 LL | |         dst[i] = src[count];
 LL | |         count += 1;
 LL | |     }
-   | |_____^ help: try replacing the loop by: `dst[3..(3 + src.len())].clone_from_slice(&src[..((3 + src.len()) - 3)]);`
+   | |_____^ help: try replacing the loop by: `dst[3..(3 + src.len())].clone_from_slice(&src[..(3 + src.len() - 3)]);`
 
 error: it looks like you're manually copying between slices
   --> $DIR/with_loop_counters.rs:35:5

tests/ui/needless_bool/fixable.fixed

@@ -41,6 +41,15 @@ fn main() {
     x;
     !x;
     !(x && y);
+    let a = 0;
+    let b = 1;
+
+    a != b;
+    a == b;
+    a >= b;
+    a > b;
+    a <= b;
+    a < b;
     if x {
         x
     } else {

tests/ui/needless_bool/fixable.rs

@@ -53,6 +53,39 @@ fn main() {
     } else {
         true
     };
+    let a = 0;
+    let b = 1;
+
+    if a == b {
+        false
+    } else {
+        true
+    };
+    if a != b {
+        false
+    } else {
+        true
+    };
+    if a < b {
+        false
+    } else {
+        true
+    };
+    if a <= b {
+        false
+    } else {
+        true
+    };
+    if a > b {
+        false
+    } else {
+        true
+    };
+    if a >= b {
+        false
+    } else {
+        true
+    };
     if x {
         x
     } else {

tests/ui/needless_bool/fixable.stderr

@@ -31,7 +31,67 @@ LL | |     };
    | |_____^ help: you can reduce it to: `!(x && y)`
 
 error: this if-then-else expression returns a bool literal
-  --> $DIR/fixable.rs:72:5
+  --> $DIR/fixable.rs:59:5
+   |
+LL | /     if a == b {
+LL | |         false
+LL | |     } else {
+LL | |         true
+LL | |     };
+   | |_____^ help: you can reduce it to: `a != b`
+
+error: this if-then-else expression returns a bool literal
+  --> $DIR/fixable.rs:64:5
+   |
+LL | /     if a != b {
+LL | |         false
+LL | |     } else {
+LL | |         true
+LL | |     };
+   | |_____^ help: you can reduce it to: `a == b`
+
+error: this if-then-else expression returns a bool literal
+  --> $DIR/fixable.rs:69:5
+   |
+LL | /     if a < b {
+LL | |         false
+LL | |     } else {
+LL | |         true
+LL | |     };
+   | |_____^ help: you can reduce it to: `a >= b`
+
+error: this if-then-else expression returns a bool literal
+  --> $DIR/fixable.rs:74:5
+   |
+LL | /     if a <= b {
+LL | |         false
+LL | |     } else {
+LL | |         true
+LL | |     };
+   | |_____^ help: you can reduce it to: `a > b`
+
+error: this if-then-else expression returns a bool literal
+  --> $DIR/fixable.rs:79:5
+   |
+LL | /     if a > b {
+LL | |         false
+LL | |     } else {
+LL | |         true
+LL | |     };
+   | |_____^ help: you can reduce it to: `a <= b`
+
+error: this if-then-else expression returns a bool literal
+  --> $DIR/fixable.rs:84:5
+   |
+LL | /     if a >= b {
+LL | |         false
+LL | |     } else {
+LL | |         true
+LL | |     };
+   | |_____^ help: you can reduce it to: `a < b`
+
+error: this if-then-else expression returns a bool literal
+  --> $DIR/fixable.rs:105:5
    |
 LL | /     if x {
 LL | |         return true;
@@ -41,7 +101,7 @@ LL | |     };
    | |_____^ help: you can reduce it to: `return x`
 
 error: this if-then-else expression returns a bool literal
-  --> $DIR/fixable.rs:80:5
+  --> $DIR/fixable.rs:113:5
    |
 LL | /     if x {
 LL | |         return false;
@@ -51,7 +111,7 @@ LL | |     };
    | |_____^ help: you can reduce it to: `return !x`
 
 error: this if-then-else expression returns a bool literal
-  --> $DIR/fixable.rs:88:5
+  --> $DIR/fixable.rs:121:5
    |
 LL | /     if x && y {
 LL | |         return true;
@@ -61,7 +121,7 @@ LL | |     };
    | |_____^ help: you can reduce it to: `return x && y`
 
 error: this if-then-else expression returns a bool literal
-  --> $DIR/fixable.rs:96:5
+  --> $DIR/fixable.rs:129:5
    |
 LL | /     if x && y {
 LL | |         return false;
@@ -71,7 +131,7 @@ LL | |     };
    | |_____^ help: you can reduce it to: `return !(x && y)`
 
 error: equality checks against true are unnecessary
-  --> $DIR/fixable.rs:104:8
+  --> $DIR/fixable.rs:137:8
    |
 LL |     if x == true {};
    |        ^^^^^^^^^ help: try simplifying it as shown: `x`
@@ -79,25 +139,25 @@ LL |     if x == true {};
    = note: `-D clippy::bool-comparison` implied by `-D warnings`
 
 error: equality checks against false can be replaced by a negation
-  --> $DIR/fixable.rs:108:8
+  --> $DIR/fixable.rs:141:8
    |
 LL |     if x == false {};
    |        ^^^^^^^^^^ help: try simplifying it as shown: `!x`
 
 error: equality checks against true are unnecessary
-  --> $DIR/fixable.rs:118:8
+  --> $DIR/fixable.rs:151:8
    |
 LL |     if x == true {};
    |        ^^^^^^^^^ help: try simplifying it as shown: `x`
 
 error: equality checks against false can be replaced by a negation
-  --> $DIR/fixable.rs:119:8
+  --> $DIR/fixable.rs:152:8
    |
 LL |     if x == false {};
    |        ^^^^^^^^^^ help: try simplifying it as shown: `!x`
 
 error: this if-then-else expression returns a bool literal
-  --> $DIR/fixable.rs:128:12
+  --> $DIR/fixable.rs:161:12
    |
 LL |       } else if returns_bool() {
    |  ____________^
@@ -108,7 +168,7 @@ LL | |     };
    | |_____^ help: you can reduce it to: `{ !returns_bool() }`
 
 error: this if-then-else expression returns a bool literal
-  --> $DIR/fixable.rs:141:5
+  --> $DIR/fixable.rs:174:5
    |
 LL | /     if unsafe { no(4) } & 1 != 0 {
 LL | |         true
@@ -118,16 +178,16 @@ LL | |     };
    | |_____^ help: you can reduce it to: `(unsafe { no(4) } & 1 != 0)`
 
 error: this if-then-else expression returns a bool literal
-  --> $DIR/fixable.rs:146:30
+  --> $DIR/fixable.rs:179:30
    |
 LL |     let _brackets_unneeded = if unsafe { no(4) } & 1 != 0 { true } else { false };
    |                              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: you can reduce it to: `unsafe { no(4) } & 1 != 0`
 
 error: this if-then-else expression returns a bool literal
-  --> $DIR/fixable.rs:149:9
+  --> $DIR/fixable.rs:182:9
    |
 LL |         if unsafe { no(4) } & 1 != 0 { true } else { false }
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: you can reduce it to: `(unsafe { no(4) } & 1 != 0)`
 
-error: aborting due to 15 previous errors
+error: aborting due to 21 previous errors
 

tests/ui/short_circuit_statement.fixed

@@ -6,7 +6,7 @@
 fn main() {
     if f() { g(); }
     if !f() { g(); }
-    if !(1 == 2) { g(); }
+    if 1 != 2 { g(); }
 }
 
 fn f() -> bool {

tests/ui/short_circuit_statement.stderr

@@ -16,7 +16,7 @@ error: boolean short circuit operator in statement may be clearer using an expli
   --> $DIR/short_circuit_statement.rs:9:5
    |
 LL |     1 == 2 || g();
-   |     ^^^^^^^^^^^^^^ help: replace it with: `if !(1 == 2) { g(); }`
+   |     ^^^^^^^^^^^^^^ help: replace it with: `if 1 != 2 { g(); }`
 
 error: aborting due to 3 previous errors