Change subtracts_one to return an option

Author: pmk21

clippy_lints/src/implicit_saturating_sub.rs

@@ -63,7 +63,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for ImplicitSaturatingSub {
 
             // Check if assign operation is done
             if let StmtKind::Semi(ref e) = block.stmts[0].kind;
-            if let (true, Some(target)) = subtracts_one(cx, e);
+            if let Some(target) = subtracts_one(cx, e);
 
             // Extracting out the variable name
             if let ExprKind::Path(ref assign_path) = target.kind;
@@ -125,7 +125,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for ImplicitSaturatingSub {
     }
 }
 
-fn subtracts_one<'a>(cx: &LateContext<'_, '_>, expr: &Expr<'a>) -> (bool, Option<&'a Expr<'a>>) {
+fn subtracts_one<'a>(cx: &LateContext<'_, '_>, expr: &Expr<'a>) -> Option<&'a Expr<'a>> {
     match expr.kind {
         ExprKind::AssignOp(ref op1, ref target, ref value) => {
             if_chain! {
@@ -134,9 +134,9 @@ fn subtracts_one<'a>(cx: &LateContext<'_, '_>, expr: &Expr<'a>) -> (bool, Option
                 if let ExprKind::Lit(ref lit1) = value.kind;
                 if let LitKind::Int(1, _) = lit1.node;
                 then {
-                    (true, Option::Some(target))
+                    Some(target)
                 } else {
-                    (false, None)
+                    None
                 }
             }
         },
@@ -150,13 +150,13 @@ fn subtracts_one<'a>(cx: &LateContext<'_, '_>, expr: &Expr<'a>) -> (bool, Option
                 if let ExprKind::Lit(ref lit1) = right1.kind;
                 if let LitKind::Int(1, _) = lit1.node;
                 then {
-                    (true, Some(target))
+                    Some(target)
                 } else {
-                    (false, None)
+                    None
                 }
             }
         },
-        _ => (false, None),
+        _ => None,
     }
 }