stacked_if_match done

Author: promptkp

clippy_lints/src/stacked_if_match.rs

@@ -1,11 +1,11 @@
+use clippy_utils::diagnostics::span_lint_and_sugg;
 use clippy_utils::source::snippet;
-use rustc_middle::lint::in_external_macro;
+use clippy_utils::visitors::{for_each_expr, Descend};
+use rustc_errors::Applicability;
 use rustc_hir::*;
 use rustc_lint::{LateContext, LateLintPass, LintContext};
+use rustc_middle::lint::in_external_macro;
 use rustc_session::declare_lint_pass;
-use rustc_errors::Applicability;
-use clippy_utils::visitors::{for_each_expr, Descend};
-use clippy_utils::diagnostics::span_lint_and_sugg;
 use std::ops::ControlFlow;
 
 declare_clippy_lint! {
@@ -47,7 +47,7 @@ declare_clippy_lint! {
 declare_lint_pass!(StackedIfMatch => [STACKED_IF_MATCH]);
 
 impl<'tcx> LateLintPass<'tcx> for StackedIfMatch {
-   fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
+    fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
         if expr.span.from_expansion() || in_external_macro(cx.sess(), expr.span) {
             return;
         }
@@ -74,15 +74,20 @@ impl<'tcx> LateLintPass<'tcx> for StackedIfMatch {
                 return ControlFlow::Continue(Descend::No);
             }
 
-            if (keyword == "if" && matches!(sub_expr.kind, ExprKind::If(..)))
-                || (keyword == "match" && matches!(sub_expr.kind, ExprKind::Match(.., MatchSource::Normal))) {
+            let sub_keyword = match sub_expr.kind {
+                ExprKind::If(..) => "if",
+                ExprKind::Match(.., MatchSource::Normal) => "match",
+                _ => "",
+            };
+
+            if keyword == sub_keyword {
                 let inner_snippet = snippet(cx, sub_expr.span, "..");
                 span_lint_and_sugg(
                     cx,
                     STACKED_IF_MATCH,
                     expr.span.with_hi(sub_expr.span.hi()),
-                    format!("avoid using `{keyword} {keyword}`"),
-                    format!("try binding inner `{keyword}` with `let`"),
+                    format!("avoid using `{keyword} {keyword}` by binding inner `{keyword}` with `let`"),
+                    format!("try"),
                     format!("let result = {inner_snippet}; {keyword} result"),
                     Applicability::MachineApplicable,
                 );

tests/ui/stacked_if_match.rs

@@ -1,22 +1,23 @@
 #![warn(clippy::stacked_if_match)]
 #![allow(unused)]
 
-
 fn stacked_if() {
     let x = 0;
-    if if x == 1 {
-        x == 2
-    } else {
-        x == 3
-    } {
+    if if x == 1 { x == 2 } else { x == 3 } {
+        println!("true");
+    }
+
+    if if x == 1 { 2 } else { 3 } == 4 {
         println!("true");
     }
 
     if if x == 1 {
-        2
+        let y = 2;
+        y == 2
     } else {
-        3
-    } == 4 {
+        let z = 3;
+        z == 3
+    } {
         println!("true");
     }
 }
@@ -35,7 +36,8 @@ fn stacked_match() {
     match match x {
         1 => 2,
         _ => 3,
-    } + 1 {
+    } + 1
+    {
         1 => {},
         2 => {},
         _ => {},
@@ -45,19 +47,11 @@ fn stacked_match() {
 fn if_no_lint() {
     let x = 0;
 
-    if (if x == 1 {
-        x == 2
-    } else {
-        x == 3
-    }) {
+    if (if x == 1 { x == 2 } else { x == 3 }) {
         println!("true");
     }
 
-    if 1 == if x == 1 {
-        1
-    } else {
-        2
-    } {
+    if 1 == if x == 1 { 1 } else { 2 } {
         println!("true");
     }
 }
@@ -85,11 +79,7 @@ fn match_no_lint() {
 
 macro_rules! if_macro {
     ($var:ident) => {
-        if $var == 1 {
-            true
-        } else {
-            false
-        }
+        if $var == 1 { true } else { false }
     };
 }
 
@@ -104,11 +94,7 @@ macro_rules! match_macro {
 
 macro_rules! if_if_macro {
     () => {
-        if if true {
-            true
-        } else {
-            false
-        } {
+        if if true { true } else { false } {
             println!("true");
         }
     };