fall back to use if_chain

Author: J-ZhengLi

clippy_lints/src/lib.rs

@@ -5,7 +5,6 @@
 #![feature(control_flow_enum)]
 #![feature(drain_filter)]
 #![feature(iter_intersperse)]
-#![feature(let_chains)]
 #![feature(let_else)]
 #![feature(once_cell)]
 #![feature(rustc_private)]

clippy_lints/src/question_mark.rs

@@ -155,11 +155,13 @@ impl QuestionMark {
 
     /// Check whether the encountered expression contains `else if`
     fn expr_is_else_if(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
-        if let ExprKind::If(..) = expr.kind
-            && let Some(parent_expr) = clippy_utils::get_parent_expr(cx, expr)
-            && let ExprKind::If(..) = parent_expr.kind
-        {
-            return true;
+        if_chain! {
+            if let ExprKind::If(..) = expr.kind;
+            if let Some(parent_expr) = clippy_utils::get_parent_expr(cx, expr);
+            if let ExprKind::If(..) = parent_expr.kind;
+            then {
+                return true;
+            }
         }
         false
     }
@@ -245,16 +247,16 @@ impl QuestionMark {
             },
             ExprKind::Path(_) => path_to_local(expr).is_some() && path_to_local(expr) == path_to_local(cond_expr),
             ExprKind::Call(call_expr, args_expr) => {
-                if let ExprKind::Path(qpath) = &call_expr.kind
-                    && let QPath::Resolved(_, path) = qpath
-                    && let Some(segment) = path.segments.first()
-                    && let Some(pat_sym) = pat_symbol
-                    && let Some(arg) = args_expr.first()
-                    && let ExprKind::Path(arg_qpath) = &arg.kind
-                    && let QPath::Resolved(_, arg_path) = arg_qpath
-                    && let Some(PathSegment { ident, .. }) = arg_path.segments.first()
-                {
-                    return segment.ident.name == sym::Err && pat_sym == ident.name
+                if_chain! {
+                    if let ExprKind::Path(QPath::Resolved(_, path)) = &call_expr.kind;
+                    if let Some(segment) = path.segments.first();
+                    if let Some(pat_sym) = pat_symbol;
+                    if let Some(arg) = args_expr.first();
+                    if let ExprKind::Path(QPath::Resolved(_, arg_path)) = &arg.kind;
+                    if let Some(PathSegment { ident, .. }) = arg_path.segments.first();
+                    then {
+                        return segment.ident.name == sym::Err && pat_sym == ident.name;
+                    }
                 }
 
                 false