Remove check for duplicate parenthesis

It was an incorrect, and could lead to behavior changes in the
suggested code

Author: hcbarker

clippy_lints/src/operators/identity_op.rs

@@ -220,13 +220,7 @@ fn span_ineffective_operation(
         expr_snippet.into_owned()
     };
     let suggestion = match parens {
-        Parens::Needed => {
-            if !expr_snippet.starts_with('(') && !expr_snippet.ends_with(')') {
-                format!("({expr_snippet})")
-            } else {
-                expr_snippet
-            }
-        },
+        Parens::Needed => format!("({expr_snippet})"),
         Parens::Unneeded => expr_snippet,
     };
 

tests/ui/identity_op.fixed

@@ -116,7 +116,7 @@ fn main() {
     //~^ ERROR: this operation has no effect
     (match a { 0 => 10, _ => 20 }) + if b { 3 } else { 4 };
     //~^ ERROR: this operation has no effect
-    (if b { 1 } else { 2 });
+    ((if b { 1 } else { 2 }));
     //~^ ERROR: this operation has no effect
 
     ({ a }) + 3;
@@ -149,7 +149,7 @@ fn main() {
 
     2 * { a };
     //~^ ERROR: this operation has no effect
-    ({ a } + 4);
+    (({ a } + 4));
     //~^ ERROR: this operation has no effect
     1;
     //~^ ERROR: this operation has no effect
@@ -223,10 +223,10 @@ fn issue_13470() {
     let _: u64 = 1u64 & (x + y) as u64;
     //~^ ERROR: this operation has no effect
     // Same as above, but with extra redundant parenthesis
-    let _: u64 = 1u64 & (x + y) as u64;
+    let _: u64 = 1u64 & ((x + y)) as u64;
     //~^ ERROR: this operation has no effect
     // Should maintain parenthesis even if the surrounding expr has the same precedence
-    let _: u64 = 5u64 + (x + y) as u64;
+    let _: u64 = 5u64 + ((x + y)) as u64;
     //~^ ERROR: this operation has no effect
 
     // If we don't maintain the parens here, the behavior changes
@@ -244,7 +244,7 @@ fn issue_13470() {
     //~^ ERROR: this operation has no effect
     // But make sure that inner parens still exist
     let z = 1i32;
-    let _ = 2 + x + (y * z);
+    let _ = 2 + (x + (y * z));
     //~^ ERROR: this operation has no effect
     // Maintain parenthesis if the parent expr is of lower precedence
     // This is for clarity, and clippy will not warn on these being unnecessary
@@ -253,6 +253,6 @@ fn issue_13470() {
 
     let x = 1i16;
     let y = 1i16;
-    let _: u64 = 1u64 + (x as i32 + y as i32) as u64;
+    let _: u64 = 1u64 + ((x as i32 + y as i32) as u64);
     //~^ ERROR: this operation has no effect
 }

tests/ui/identity_op.stderr

@@ -149,7 +149,7 @@ error: this operation has no effect
   --> tests/ui/identity_op.rs:119:5
    |
 LL |     (if b { 1 } else { 2 }) + 0;
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider reducing it to: `(if b { 1 } else { 2 })`
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider reducing it to: `((if b { 1 } else { 2 }))`
 
 error: this operation has no effect
   --> tests/ui/identity_op.rs:122:5
@@ -221,7 +221,7 @@ error: this operation has no effect
   --> tests/ui/identity_op.rs:152:5
    |
 LL |     1 * ({ a } + 4);
-   |     ^^^^^^^^^^^^^^^ help: consider reducing it to: `({ a } + 4)`
+   |     ^^^^^^^^^^^^^^^ help: consider reducing it to: `(({ a } + 4))`
 
 error: this operation has no effect
   --> tests/ui/identity_op.rs:154:5
@@ -329,13 +329,13 @@ error: this operation has no effect
   --> tests/ui/identity_op.rs:226:25
    |
 LL |     let _: u64 = 1u64 & ((x + y) + 0i32) as u64;
-   |                         ^^^^^^^^^^^^^^^^ help: consider reducing it to: `(x + y)`
+   |                         ^^^^^^^^^^^^^^^^ help: consider reducing it to: `((x + y))`
 
 error: this operation has no effect
   --> tests/ui/identity_op.rs:229:25
    |
 LL |     let _: u64 = 5u64 + ((x + y) + 0i32) as u64;
-   |                         ^^^^^^^^^^^^^^^^ help: consider reducing it to: `(x + y)`
+   |                         ^^^^^^^^^^^^^^^^ help: consider reducing it to: `((x + y))`
 
 error: this operation has no effect
   --> tests/ui/identity_op.rs:233:14
@@ -365,7 +365,7 @@ error: this operation has no effect
   --> tests/ui/identity_op.rs:247:17
    |
 LL |     let _ = 2 + (x + (y * z) + 0);
-   |                 ^^^^^^^^^^^^^^^^^ help: consider reducing it to: `x + (y * z)`
+   |                 ^^^^^^^^^^^^^^^^^ help: consider reducing it to: `(x + (y * z))`
 
 error: this operation has no effect
   --> tests/ui/identity_op.rs:251:20
@@ -377,7 +377,7 @@ error: this operation has no effect
   --> tests/ui/identity_op.rs:256:25
    |
 LL |     let _: u64 = 1u64 + ((x as i32 + y as i32) as u64 + 0u64);
-   |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider reducing it to: `(x as i32 + y as i32) as u64`
+   |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider reducing it to: `((x as i32 + y as i32) as u64)`
 
 error: aborting due to 63 previous errors