fix(match_like_matches_macro): FP with guards containing if let

clippy_lints/src/matches/match_like_matches.rs

@@ -1,7 +1,8 @@
 //! Lint a `match` or `if let .. { .. } else { .. }` expr that could be replaced by `matches!`
 
 use super::REDUNDANT_PATTERN_MATCHING;
-use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::diagnostics::span_lint_and_then;
+use clippy_utils::higher::has_let_expr;
 use clippy_utils::source::snippet_with_applicability;
 use clippy_utils::{is_lint_allowed, is_wild, span_contains_comment};
 use rustc_ast::LitKind;
@@ -43,18 +44,23 @@ pub(crate) fn check_if_let<'tcx>(
         {
             ex_new = ex_inner;
         }
-        span_lint_and_sugg(
+        span_lint_and_then(
             cx,
             MATCH_LIKE_MATCHES_MACRO,
             expr.span,
-            "if let .. else expression looks like `matches!` macro",
-            "try",
-            format!(
-                "{}matches!({}, {pat})",
-                if b0 { "" } else { "!" },
-                snippet_with_applicability(cx, ex_new.span, "..", &mut applicability),
-            ),
-            applicability,
+            "`if let .. else` expression looks like `matches!` macro",
+            |diag| {
+                diag.span_suggestion_verbose(
+                    expr.span,
+                    "use `matches!` directly",
+                    format!(
+                        "{}matches!({}, {pat})",
+                        if b0 { "" } else { "!" },
+                        snippet_with_applicability(cx, ex_new.span, "..", &mut applicability),
+                    ),
+                    applicability,
+                );
+            },
         );
     }
 }
@@ -87,7 +93,10 @@ pub(super) fn check_match<'tcx>(
             // ```rs
             // matches!(e, Either::Left $(if $guard)|+)
             // ```
-            middle_arms.is_empty()
+            //
+            // But if the guard _is_ present, it may not be an `if-let` guard, as `matches!` doesn't
+            // support these (currently?)
+            (middle_arms.is_empty() && first_arm.guard.is_none_or(|g| !has_let_expr(g)))
 
             // - (added in #6216) There are middle arms
             //
@@ -169,18 +178,23 @@ pub(super) fn check_match<'tcx>(
         {
             ex_new = ex_inner;
         }
-        span_lint_and_sugg(
+        span_lint_and_then(
             cx,
             MATCH_LIKE_MATCHES_MACRO,
             e.span,
             "match expression looks like `matches!` macro",
-            "try",
-            format!(
-                "{}matches!({}, {pat_and_guard})",
-                if b0 { "" } else { "!" },
-                snippet_with_applicability(cx, ex_new.span, "..", &mut applicability),
-            ),
-            applicability,
+            |diag| {
+                diag.span_suggestion_verbose(
+                    e.span,
+                    "use `matches!` directly",
+                    format!(
+                        "{}matches!({}, {pat_and_guard})",
+                        if b0 { "" } else { "!" },
+                        snippet_with_applicability(cx, ex_new.span, "..", &mut applicability),
+                    ),
+                    applicability,
+                );
+            },
         );
         true
     } else {

tests/ui/match_like_matches_macro.fixed

@@ -223,3 +223,10 @@ fn msrv_1_42() {
     let _y = matches!(Some(5), Some(0));
     //~^^^^ match_like_matches_macro
 }
+
+#[expect(clippy::option_option)]
+fn issue15841(opt: Option<Option<Option<i32>>>, value: i32) {
+    // Lint: no if-let _in the guard_
+    let _ = matches!(opt, Some(first) if (if let Some(second) = first { true } else { todo!() }));
+    //~^^^^ match_like_matches_macro
+}

tests/ui/match_like_matches_macro.rs

@@ -267,3 +267,13 @@ fn msrv_1_42() {
     };
     //~^^^^ match_like_matches_macro
 }
+
+#[expect(clippy::option_option)]
+fn issue15841(opt: Option<Option<Option<i32>>>, value: i32) {
+    // Lint: no if-let _in the guard_
+    let _ = match opt {
+        Some(first) if (if let Some(second) = first { true } else { todo!() }) => true,
+        _ => false,
+    };
+    //~^^^^ match_like_matches_macro
+}

tests/ui/match_like_matches_macro.stderr

@@ -6,10 +6,18 @@ LL |       let _y = match x {
 LL | |         Some(0) => true,
 LL | |         _ => false,
 LL | |     };
-   | |_____^ help: try: `matches!(x, Some(0))`
+   | |_____^
    |
    = note: `-D clippy::match-like-matches-macro` implied by `-D warnings`
    = help: to override `-D warnings` add `#[allow(clippy::match_like_matches_macro)]`
+help: use `matches!` directly
+   |
+LL -     let _y = match x {
+LL -         Some(0) => true,
+LL -         _ => false,
+LL -     };
+LL +     let _y = matches!(x, Some(0));
+   |
 
 error: redundant pattern matching, consider using `is_some()`
   --> tests/ui/match_like_matches_macro.rs:20:14
@@ -42,13 +50,28 @@ LL |       let _zz = match x {
 LL | |         Some(r) if r == 0 => false,
 LL | |         _ => true,
 LL | |     };
-   | |_____^ help: try: `!matches!(x, Some(r) if r == 0)`
+   | |_____^
+   |
+help: use `matches!` directly
+   |
+LL -     let _zz = match x {
+LL -         Some(r) if r == 0 => false,
+LL -         _ => true,
+LL -     };
+LL +     let _zz = !matches!(x, Some(r) if r == 0);
+   |
 
-error: if let .. else expression looks like `matches!` macro
+error: `if let .. else` expression looks like `matches!` macro
   --> tests/ui/match_like_matches_macro.rs:41:16
    |
 LL |     let _zzz = if let Some(5) = x { true } else { false };
-   |                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `matches!(x, Some(5))`
+   |                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+help: use `matches!` directly
+   |
+LL -     let _zzz = if let Some(5) = x { true } else { false };
+LL +     let _zzz = matches!(x, Some(5));
+   |
 
 error: match expression looks like `matches!` macro
   --> tests/ui/match_like_matches_macro.rs:66:20
@@ -59,7 +82,17 @@ LL | |             E::A(_) => true,
 LL | |             E::B(_) => true,
 LL | |             _ => false,
 LL | |         };
-   | |_________^ help: try: `matches!(x, E::A(_) | E::B(_))`
+   | |_________^
+   |
+help: use `matches!` directly
+   |
+LL -         let _ans = match x {
+LL -             E::A(_) => true,
+LL -             E::B(_) => true,
+LL -             _ => false,
+LL -         };
+LL +         let _ans = matches!(x, E::A(_) | E::B(_));
+   |
 
 error: match expression looks like `matches!` macro
   --> tests/ui/match_like_matches_macro.rs:77:20
@@ -71,7 +104,19 @@ LL | |                 true
 ...  |
 LL | |             _ => false,
 LL | |         };
-   | |_________^ help: try: `matches!(x, E::A(_) | E::B(_))`
+   | |_________^
+   |
+help: use `matches!` directly
+   |
+LL -         let _ans = match x {
+LL -             E::A(_) => {
+LL -                 true
+LL -             }
+LL -             E::B(_) => true,
+LL -             _ => false,
+LL -         };
+LL +         let _ans = matches!(x, E::A(_) | E::B(_));
+   |
 
 error: match expression looks like `matches!` macro
   --> tests/ui/match_like_matches_macro.rs:88:20
@@ -82,7 +127,17 @@ LL | |             E::B(_) => false,
 LL | |             E::C => false,
 LL | |             _ => true,
 LL | |         };
-   | |_________^ help: try: `!matches!(x, E::B(_) | E::C)`
+   | |_________^
+   |
+help: use `matches!` directly
+   |
+LL -         let _ans = match x {
+LL -             E::B(_) => false,
+LL -             E::C => false,
+LL -             _ => true,
+LL -         };
+LL +         let _ans = !matches!(x, E::B(_) | E::C);
+   |
 
 error: match expression looks like `matches!` macro
   --> tests/ui/match_like_matches_macro.rs:149:18
@@ -92,7 +147,16 @@ LL |           let _z = match &z {
 LL | |             Some(3) => true,
 LL | |             _ => false,
 LL | |         };
-   | |_________^ help: try: `matches!(z, Some(3))`
+   | |_________^
+   |
+help: use `matches!` directly
+   |
+LL -         let _z = match &z {
+LL -             Some(3) => true,
+LL -             _ => false,
+LL -         };
+LL +         let _z = matches!(z, Some(3));
+   |
 
 error: match expression looks like `matches!` macro
   --> tests/ui/match_like_matches_macro.rs:159:18
@@ -102,7 +166,16 @@ LL |           let _z = match &z {
 LL | |             Some(3) => true,
 LL | |             _ => false,
 LL | |         };
-   | |_________^ help: try: `matches!(&z, Some(3))`
+   | |_________^
+   |
+help: use `matches!` directly
+   |
+LL -         let _z = match &z {
+LL -             Some(3) => true,
+LL -             _ => false,
+LL -         };
+LL +         let _z = matches!(&z, Some(3));
+   |
 
 error: match expression looks like `matches!` macro
   --> tests/ui/match_like_matches_macro.rs:177:21
@@ -112,7 +185,16 @@ LL |               let _ = match &z {
 LL | |                 AnEnum::X => true,
 LL | |                 _ => false,
 LL | |             };
-   | |_____________^ help: try: `matches!(&z, AnEnum::X)`
+   | |_____________^
+   |
+help: use `matches!` directly
+   |
+LL -             let _ = match &z {
+LL -                 AnEnum::X => true,
+LL -                 _ => false,
+LL -             };
+LL +             let _ = matches!(&z, AnEnum::X);
+   |
 
 error: match expression looks like `matches!` macro
   --> tests/ui/match_like_matches_macro.rs:192:20
@@ -122,7 +204,16 @@ LL |           let _res = match &val {
 LL | |             &Some(ref _a) => true,
 LL | |             _ => false,
 LL | |         };
-   | |_________^ help: try: `matches!(&val, &Some(ref _a))`
+   | |_________^
+   |
+help: use `matches!` directly
+   |
+LL -         let _res = match &val {
+LL -             &Some(ref _a) => true,
+LL -             _ => false,
+LL -         };
+LL +         let _res = matches!(&val, &Some(ref _a));
+   |
 
 error: match expression looks like `matches!` macro
   --> tests/ui/match_like_matches_macro.rs:205:20
@@ -132,7 +223,16 @@ LL |           let _res = match &val {
 LL | |             &Some(ref _a) => true,
 LL | |             _ => false,
 LL | |         };
-   | |_________^ help: try: `matches!(&val, &Some(ref _a))`
+   | |_________^
+   |
+help: use `matches!` directly
+   |
+LL -         let _res = match &val {
+LL -             &Some(ref _a) => true,
+LL -             _ => false,
+LL -         };
+LL +         let _res = matches!(&val, &Some(ref _a));
+   |
 
 error: match expression looks like `matches!` macro
   --> tests/ui/match_like_matches_macro.rs:264:14
@@ -142,7 +242,35 @@ LL |       let _y = match Some(5) {
 LL | |         Some(0) => true,
 LL | |         _ => false,
 LL | |     };
-   | |_____^ help: try: `matches!(Some(5), Some(0))`
+   | |_____^
+   |
+help: use `matches!` directly
+   |
+LL -     let _y = match Some(5) {
+LL -         Some(0) => true,
+LL -         _ => false,
+LL -     };
+LL +     let _y = matches!(Some(5), Some(0));
+   |
+
+error: match expression looks like `matches!` macro
+  --> tests/ui/match_like_matches_macro.rs:274:13
+   |
+LL |       let _ = match opt {
+   |  _____________^
+LL | |         Some(first) if (if let Some(second) = first { true } else { todo!() }) => true,
+LL | |         _ => false,
+LL | |     };
+   | |_____^
+   |
+help: use `matches!` directly
+   |
+LL -     let _ = match opt {
+LL -         Some(first) if (if let Some(second) = first { true } else { todo!() }) => true,
+LL -         _ => false,
+LL -     };
+LL +     let _ = matches!(opt, Some(first) if (if let Some(second) = first { true } else { todo!() }));
+   |
 
-error: aborting due to 14 previous errors
+error: aborting due to 15 previous errors