Clean up unused cx parameters

Author: Manishearth

clippy_lints/src/unused_io_amount.rs

@@ -50,7 +50,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnusedIoAmount {
         };
 
         match expr.node {
-            hir::ExprKind::Match(ref res, _, _) if is_try(cx, expr).is_some() => {
+            hir::ExprKind::Match(ref res, _, _) if is_try(expr).is_some() => {
                 if let hir::ExprKind::Call(ref func, ref args) = res.node {
                     if let hir::ExprKind::Path(ref path) = func.node {
                         if match_qpath(path, &paths::TRY_INTO_RESULT) && args.len() == 1 {

clippy_lints/src/utils/mod.rs

@@ -950,8 +950,8 @@ pub fn iter_input_pats<'tcx>(decl: &FnDecl, body: &'tcx Body) -> impl Iterator<I
 
 /// Checks if a given expression is a match expression expanded from the `?`
 /// operator or the `try` macro.
-pub fn is_try<'a>(cx: &'_ LateContext<'_, '_>, expr: &'a Expr) -> Option<&'a Expr> {
-    fn is_ok(cx: &'_ LateContext<'_, '_>, arm: &Arm) -> bool {
+pub fn is_try(expr: &Expr) -> Option<&Expr> {
+    fn is_ok(arm: &Arm) -> bool {
         if_chain! {
             if let PatKind::TupleStruct(ref path, ref pat, None) = arm.pats[0].node;
             if match_qpath(path, &paths::RESULT_OK[1..]);
@@ -984,8 +984,8 @@ pub fn is_try<'a>(cx: &'_ LateContext<'_, '_>, expr: &'a Expr) -> Option<&'a Exp
             if arms.len() == 2;
             if arms[0].pats.len() == 1 && arms[0].guard.is_none();
             if arms[1].pats.len() == 1 && arms[1].guard.is_none();
-            if (is_ok(cx, &arms[0]) && is_err(&arms[1])) ||
-                (is_ok(cx, &arms[1]) && is_err(&arms[0]));
+            if (is_ok(&arms[0]) && is_err(&arms[1])) ||
+                (is_ok(&arms[1]) && is_err(&arms[0]));
             then {
                 return Some(expr);
             }