misc

Author: ada4a

clippy_lints/src/matches/collapsible_match.rs

@@ -50,15 +50,17 @@ fn check_arm<'tcx>(
     if let Some(inner) = IfLetOrMatch::parse(cx, inner_expr)
         && let Some((inner_scrutinee, inner_then_pat, inner_else_body)) = match inner {
             IfLetOrMatch::IfLet(scrutinee, pat, _, els, _) => Some((scrutinee, pat, els)),
-            IfLetOrMatch::Match(scrutinee, arms, ..) => if arms.len() == 2 && arms.iter().all(|a| a.guard.is_none())
-                // if there are more than two arms, collapsing would be non-trivial
-                // one of the arms must be "wild-like"
-                && let Some(wild_idx) = arms.iter().rposition(|a| arm_is_wild_like(cx, a))
-            {
-                let (then, els) = (&arms[1 - wild_idx], &arms[wild_idx]);
-                Some((scrutinee, then.pat, Some(els.body)))
-            } else {
-                None
+            IfLetOrMatch::Match(scrutinee, arms, ..) => {
+                if arms.len() == 2 && arms.iter().all(|a| a.guard.is_none())
+                    // if there are more than two arms, collapsing would be non-trivial
+                    // one of the arms must be "wild-like"
+                    && let Some(wild_idx) = arms.iter().rposition(|a| arm_is_wild_like(cx, a))
+                {
+                    let (then, els) = (&arms[1 - wild_idx], &arms[wild_idx]);
+                    Some((scrutinee, then.pat, Some(els.body)))
+                } else {
+                    None
+                }
             },
         }
         && outer_pat.span.eq_ctxt(inner_scrutinee.span)
@@ -68,18 +70,16 @@ fn check_arm<'tcx>(
         && !pat_contains_disallowed_or(cx, inner_then_pat, msrv)
         // the binding must come from the pattern of the containing match arm
         // ..<local>.. => match <local> { .. }
-        && let (Some(binding_span), is_innermost_parent_pat_struct)
-            = find_pat_binding_and_is_innermost_parent_pat_struct(outer_pat, binding_id)
+        && let (Some(binding_span), is_innermost_parent_pat_struct) =
+            find_pat_binding_and_is_innermost_parent_pat_struct(outer_pat, binding_id)
         // the "else" branches must be equal
         && match (outer_else_body, inner_else_body) {
             (None, None) => true,
             (None, Some(e)) | (Some(e), None) => is_unit_expr(e),
             (Some(a), Some(b)) => SpanlessEq::new(cx).eq_expr(a, b),
         }
         // the binding must not be used in the if guard
-        && outer_guard.is_none_or(
-            |e| !is_local_used(cx, e, binding_id)
-        )
+        && outer_guard.is_none_or(|e| !is_local_used(cx, e, binding_id))
         // ...or anywhere in the inner expression
         && match inner {
             IfLetOrMatch::IfLet(_, _, body, els, _) => {

tests/ui/collapsible_match.rs

@@ -304,18 +304,6 @@ pub fn test_2(x: Issue9647) {
     }
 }
 
-// https://github.com/rust-lang/rust-clippy/issues/14281
-fn lint_emitted_at_right_node(opt: Option<Result<u64, String>>) {
-    let n = match opt {
-        #[expect(clippy::collapsible_match)]
-        Some(n) => match n {
-            Ok(n) => n,
-            _ => return,
-        },
-        None => return,
-    };
-}
-
 pub fn issue_14155() {
     let mut arr = ["a", "b", "c"];
     if let Some(last) = arr.last() {
@@ -357,6 +345,18 @@ pub fn issue_14155() {
     }
 }
 
+// https://github.com/rust-lang/rust-clippy/issues/14281
+fn lint_emitted_at_right_node(opt: Option<Result<u64, String>>) {
+    let n = match opt {
+        #[expect(clippy::collapsible_match)]
+        Some(n) => match n {
+            Ok(n) => n,
+            _ => return,
+        },
+        None => return,
+    };
+}
+
 fn make<T>() -> T {
     unimplemented!()
 }

tests/ui/collapsible_match.stderr

@@ -251,7 +251,7 @@ LL |         if let Some(u) = a {
    |                ^^^^^^^ with this pattern
 
 error: this `match` can be collapsed into the outer `if let`
-  --> tests/ui/collapsible_match.rs:322:9
+  --> tests/ui/collapsible_match.rs:310:9
    |
 LL | /         match *last {
 LL | |
@@ -263,7 +263,7 @@ LL | |         }
    | |_________^
    |
 help: the outer pattern can be modified to include the inner pattern
-  --> tests/ui/collapsible_match.rs:321:17
+  --> tests/ui/collapsible_match.rs:309:17
    |
 LL |     if let Some(last) = arr.last() {
    |                 ^^^^    ---------- use: `arr.last().copied()`
@@ -274,7 +274,7 @@ LL |             "a" | "b" => {
    |             ^^^^^^^^^ with this pattern
 
 error: this `match` can be collapsed into the outer `if let`
-  --> tests/ui/collapsible_match.rs:332:9
+  --> tests/ui/collapsible_match.rs:320:9
    |
 LL | /         match &last {
 LL | |
@@ -286,7 +286,7 @@ LL | |         }
    | |_________^
    |
 help: the outer pattern can be modified to include the inner pattern
-  --> tests/ui/collapsible_match.rs:331:17
+  --> tests/ui/collapsible_match.rs:319:17
    |
 LL |     if let Some(last) = arr.last() {
    |                 ^^^^    ---------- use: `arr.last().as_ref()`
@@ -297,7 +297,7 @@ LL |             &&"a" | &&"b" => {
    |             ^^^^^^^^^^^^^ with this pattern
 
 error: this `match` can be collapsed into the outer `if let`
-  --> tests/ui/collapsible_match.rs:342:9
+  --> tests/ui/collapsible_match.rs:330:9
    |
 LL | /         match &mut last {
 LL | |
@@ -309,7 +309,7 @@ LL | |         }
    | |_________^
    |
 help: the outer pattern can be modified to include the inner pattern
-  --> tests/ui/collapsible_match.rs:341:17
+  --> tests/ui/collapsible_match.rs:329:17
    |
 LL |     if let Some(mut last) = arr.last_mut() {
    |                 ^^^^^^^^    -------------- use: `arr.last_mut().as_mut()`