remove parenthesis from unnecessary_cast suggestion

clippy_lints/src/casts/unnecessary_cast.rs

@@ -90,13 +90,20 @@ pub(super) fn check<'tcx>(
 
 fn lint_unnecessary_cast(cx: &LateContext<'_>, expr: &Expr<'_>, literal_str: &str, cast_from: Ty<'_>, cast_to: Ty<'_>) {
     let literal_kind_name = if cast_from.is_integral() { "integer" } else { "float" };
+    let replaced_literal;
+    let matchless = if literal_str.contains(['(', ')']) {
+        replaced_literal = literal_str.replace(['(', ')'], "");
+        &replaced_literal
+    } else {
+        literal_str
+    };
     span_lint_and_sugg(
         cx,
         UNNECESSARY_CAST,
         expr.span,
         &format!("casting {} literal to `{}` is unnecessary", literal_kind_name, cast_to),
         "try",
-        format!("{}_{}", literal_str.trim_end_matches('.'), cast_to),
+        format!("{}_{}", matchless.trim_end_matches('.'), cast_to),
         Applicability::MachineApplicable,
     );
 }

tests/ui/unnecessary_cast.fixed

@@ -88,4 +88,13 @@ mod fixable {
     }
 
     type I32Alias = i32;
+
+    fn issue_9380() {
+        let _: i32 = -1_i32;
+        let _: f32 = -(1) as f32;
+        let _: i64 = -1_i64;
+        let _: i64 = -(1.0) as i64;
+
+        let _ = -(1 + 1) as i64;
+    }
 }

tests/ui/unnecessary_cast.rs

@@ -88,4 +88,13 @@ mod fixable {
     }
 
     type I32Alias = i32;
+
+    fn issue_9380() {
+        let _: i32 = -(1) as i32;
+        let _: f32 = -(1) as f32;
+        let _: i64 = -(1) as i64;
+        let _: i64 = -(1.0) as i64;
+
+        let _ = -(1 + 1) as i64;
+    }
 }

tests/ui/unnecessary_cast.stderr

@@ -150,5 +150,17 @@ error: casting float literal to `f32` is unnecessary
 LL |         let _ = -1.0 as f32;
    |                 ^^^^^^^^^^^ help: try: `-1.0_f32`
 
-error: aborting due to 25 previous errors
+error: casting integer literal to `i32` is unnecessary
+  --> $DIR/unnecessary_cast.rs:93:22
+   |
+LL |         let _: i32 = -(1) as i32;
+   |                      ^^^^^^^^^^^ help: try: `-1_i32`
+
+error: casting integer literal to `i64` is unnecessary
+  --> $DIR/unnecessary_cast.rs:95:22
+   |
+LL |         let _: i64 = -(1) as i64;
+   |                      ^^^^^^^^^^^ help: try: `-1_i64`
+
+error: aborting due to 27 previous errors