From c8725f70e77a08974a1d51bd360345a2ab7fabc6 Mon Sep 17 00:00:00 2001
From: y21 <30553356+y21@users.noreply.github.com>
Date: Thu, 26 Sep 2024 17:44:59 +0200
Subject: [PATCH 1/2] add proc macro check to needless_return

---
 clippy_lints/src/returns.rs     |   2 +-
 tests/ui/needless_return.fixed  |   8 +++
 tests/ui/needless_return.rs     |   8 +++
 tests/ui/needless_return.stderr | 108 ++++++++++++++++----------------
 4 files changed, 71 insertions(+), 55 deletions(-)

diff --git a/clippy_lints/src/returns.rs b/clippy_lints/src/returns.rs
index 3754fdddedfd..6754912f7656 100644
--- a/clippy_lints/src/returns.rs
+++ b/clippy_lints/src/returns.rs
@@ -407,7 +407,7 @@ fn check_final_expr<'tcx>(
                 }
             }
 
-            if ret_span.from_expansion() {
+            if ret_span.from_expansion() || is_from_proc_macro(cx, expr) {
                 return;
             }
 
diff --git a/tests/ui/needless_return.fixed b/tests/ui/needless_return.fixed
index c5c570690b45..1507bc50a75e 100644
--- a/tests/ui/needless_return.fixed
+++ b/tests/ui/needless_return.fixed
@@ -1,3 +1,4 @@
+//@aux-build:proc_macros.rs
 #![feature(yeet_expr)]
 #![allow(unused)]
 #![allow(
@@ -9,6 +10,9 @@
 )]
 #![warn(clippy::needless_return)]
 
+extern crate proc_macros;
+use proc_macros::with_span;
+
 use std::cell::RefCell;
 
 macro_rules! the_answer {
@@ -359,4 +363,8 @@ fn issue12907() -> String {
     "".split("").next().unwrap().to_string()
 }
 
+fn issue13458() {
+    with_span!(span return);
+}
+
 fn main() {}
diff --git a/tests/ui/needless_return.rs b/tests/ui/needless_return.rs
index 738611391dfd..c59bfced6d6f 100644
--- a/tests/ui/needless_return.rs
+++ b/tests/ui/needless_return.rs
@@ -1,3 +1,4 @@
+//@aux-build:proc_macros.rs
 #![feature(yeet_expr)]
 #![allow(unused)]
 #![allow(
@@ -9,6 +10,9 @@
 )]
 #![warn(clippy::needless_return)]
 
+extern crate proc_macros;
+use proc_macros::with_span;
+
 use std::cell::RefCell;
 
 macro_rules! the_answer {
@@ -369,4 +373,8 @@ fn issue12907() -> String {
     return "".split("").next().unwrap().to_string();
 }
 
+fn issue13458() {
+    with_span!(span return);
+}
+
 fn main() {}
diff --git a/tests/ui/needless_return.stderr b/tests/ui/needless_return.stderr
index da0fa220d8c4..d3c2a6badc0f 100644
--- a/tests/ui/needless_return.stderr
+++ b/tests/ui/needless_return.stderr
@@ -1,5 +1,5 @@
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:25:5
+  --> tests/ui/needless_return.rs:29:5
    |
 LL |     return true;
    |     ^^^^^^^^^^^
@@ -13,7 +13,7 @@ LL +     true
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:29:5
+  --> tests/ui/needless_return.rs:33:5
    |
 LL |     return true;
    |     ^^^^^^^^^^^
@@ -25,7 +25,7 @@ LL +     true
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:34:5
+  --> tests/ui/needless_return.rs:38:5
    |
 LL |     return true;;;
    |     ^^^^^^^^^^^
@@ -37,7 +37,7 @@ LL +     true
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:39:5
+  --> tests/ui/needless_return.rs:43:5
    |
 LL |     return true;; ; ;
    |     ^^^^^^^^^^^
@@ -49,7 +49,7 @@ LL +     true
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:44:9
+  --> tests/ui/needless_return.rs:48:9
    |
 LL |         return true;
    |         ^^^^^^^^^^^
@@ -61,7 +61,7 @@ LL +         true
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:46:9
+  --> tests/ui/needless_return.rs:50:9
    |
 LL |         return false;
    |         ^^^^^^^^^^^^
@@ -73,7 +73,7 @@ LL +         false
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:52:17
+  --> tests/ui/needless_return.rs:56:17
    |
 LL |         true => return false,
    |                 ^^^^^^^^^^^^
@@ -84,7 +84,7 @@ LL |         true => false,
    |                 ~~~~~
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:54:13
+  --> tests/ui/needless_return.rs:58:13
    |
 LL |             return true;
    |             ^^^^^^^^^^^
@@ -96,7 +96,7 @@ LL +             true
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:61:9
+  --> tests/ui/needless_return.rs:65:9
    |
 LL |         return true;
    |         ^^^^^^^^^^^
@@ -108,7 +108,7 @@ LL +         true
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:63:16
+  --> tests/ui/needless_return.rs:67:16
    |
 LL |     let _ = || return true;
    |                ^^^^^^^^^^^
@@ -119,7 +119,7 @@ LL |     let _ = || true;
    |                ~~~~
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:67:5
+  --> tests/ui/needless_return.rs:71:5
    |
 LL |     return the_answer!();
    |     ^^^^^^^^^^^^^^^^^^^^
@@ -131,7 +131,7 @@ LL +     the_answer!()
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:70:21
+  --> tests/ui/needless_return.rs:74:21
    |
 LL |   fn test_void_fun() {
    |  _____________________^
@@ -146,7 +146,7 @@ LL + fn test_void_fun() {
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:75:11
+  --> tests/ui/needless_return.rs:79:11
    |
 LL |       if b {
    |  ___________^
@@ -161,7 +161,7 @@ LL +     if b {
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:77:13
+  --> tests/ui/needless_return.rs:81:13
    |
 LL |       } else {
    |  _____________^
@@ -176,7 +176,7 @@ LL +     } else {
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:85:14
+  --> tests/ui/needless_return.rs:89:14
    |
 LL |         _ => return,
    |              ^^^^^^
@@ -187,7 +187,7 @@ LL |         _ => (),
    |              ~~
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:93:24
+  --> tests/ui/needless_return.rs:97:24
    |
 LL |               let _ = 42;
    |  ________________________^
@@ -202,7 +202,7 @@ LL +             let _ = 42;
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:96:14
+  --> tests/ui/needless_return.rs:100:14
    |
 LL |         _ => return,
    |              ^^^^^^
@@ -213,7 +213,7 @@ LL |         _ => (),
    |              ~~
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:109:9
+  --> tests/ui/needless_return.rs:113:9
    |
 LL |         return String::from("test");
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -225,7 +225,7 @@ LL +         String::from("test")
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:111:9
+  --> tests/ui/needless_return.rs:115:9
    |
 LL |         return String::new();
    |         ^^^^^^^^^^^^^^^^^^^^
@@ -237,7 +237,7 @@ LL +         String::new()
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:133:32
+  --> tests/ui/needless_return.rs:137:32
    |
 LL |         bar.unwrap_or_else(|_| return)
    |                                ^^^^^^
@@ -248,7 +248,7 @@ LL |         bar.unwrap_or_else(|_| {})
    |                                ~~
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:137:21
+  --> tests/ui/needless_return.rs:141:21
    |
 LL |           let _ = || {
    |  _____________________^
@@ -263,7 +263,7 @@ LL +         let _ = || {
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:140:20
+  --> tests/ui/needless_return.rs:144:20
    |
 LL |         let _ = || return;
    |                    ^^^^^^
@@ -274,7 +274,7 @@ LL |         let _ = || {};
    |                    ~~
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:146:32
+  --> tests/ui/needless_return.rs:150:32
    |
 LL |         res.unwrap_or_else(|_| return Foo)
    |                                ^^^^^^^^^^
@@ -285,7 +285,7 @@ LL |         res.unwrap_or_else(|_| Foo)
    |                                ~~~
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:155:5
+  --> tests/ui/needless_return.rs:159:5
    |
 LL |     return true;
    |     ^^^^^^^^^^^
@@ -297,7 +297,7 @@ LL +     true
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:159:5
+  --> tests/ui/needless_return.rs:163:5
    |
 LL |     return true;
    |     ^^^^^^^^^^^
@@ -309,7 +309,7 @@ LL +     true
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:164:9
+  --> tests/ui/needless_return.rs:168:9
    |
 LL |         return true;
    |         ^^^^^^^^^^^
@@ -321,7 +321,7 @@ LL +         true
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:166:9
+  --> tests/ui/needless_return.rs:170:9
    |
 LL |         return false;
    |         ^^^^^^^^^^^^
@@ -333,7 +333,7 @@ LL +         false
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:172:17
+  --> tests/ui/needless_return.rs:176:17
    |
 LL |         true => return false,
    |                 ^^^^^^^^^^^^
@@ -344,7 +344,7 @@ LL |         true => false,
    |                 ~~~~~
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:174:13
+  --> tests/ui/needless_return.rs:178:13
    |
 LL |             return true;
    |             ^^^^^^^^^^^
@@ -356,7 +356,7 @@ LL +             true
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:181:9
+  --> tests/ui/needless_return.rs:185:9
    |
 LL |         return true;
    |         ^^^^^^^^^^^
@@ -368,7 +368,7 @@ LL +         true
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:183:16
+  --> tests/ui/needless_return.rs:187:16
    |
 LL |     let _ = || return true;
    |                ^^^^^^^^^^^
@@ -379,7 +379,7 @@ LL |     let _ = || true;
    |                ~~~~
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:187:5
+  --> tests/ui/needless_return.rs:191:5
    |
 LL |     return the_answer!();
    |     ^^^^^^^^^^^^^^^^^^^^
@@ -391,7 +391,7 @@ LL +     the_answer!()
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:190:33
+  --> tests/ui/needless_return.rs:194:33
    |
 LL |   async fn async_test_void_fun() {
    |  _________________________________^
@@ -406,7 +406,7 @@ LL + async fn async_test_void_fun() {
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:195:11
+  --> tests/ui/needless_return.rs:199:11
    |
 LL |       if b {
    |  ___________^
@@ -421,7 +421,7 @@ LL +     if b {
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:197:13
+  --> tests/ui/needless_return.rs:201:13
    |
 LL |       } else {
    |  _____________^
@@ -436,7 +436,7 @@ LL +     } else {
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:205:14
+  --> tests/ui/needless_return.rs:209:14
    |
 LL |         _ => return,
    |              ^^^^^^
@@ -447,7 +447,7 @@ LL |         _ => (),
    |              ~~
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:218:9
+  --> tests/ui/needless_return.rs:222:9
    |
 LL |         return String::from("test");
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -459,7 +459,7 @@ LL +         String::from("test")
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:220:9
+  --> tests/ui/needless_return.rs:224:9
    |
 LL |         return String::new();
    |         ^^^^^^^^^^^^^^^^^^^^
@@ -471,7 +471,7 @@ LL +         String::new()
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:236:5
+  --> tests/ui/needless_return.rs:240:5
    |
 LL |     return format!("Hello {}", "world!");
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -483,7 +483,7 @@ LL +     format!("Hello {}", "world!")
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:277:9
+  --> tests/ui/needless_return.rs:281:9
    |
 LL |         return true;
    |         ^^^^^^^^^^^
@@ -497,7 +497,7 @@ LL ~     }
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:279:9
+  --> tests/ui/needless_return.rs:283:9
    |
 LL |         return false;
    |         ^^^^^^^^^^^^
@@ -509,7 +509,7 @@ LL ~     }
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:286:13
+  --> tests/ui/needless_return.rs:290:13
    |
 LL |             return 10;
    |             ^^^^^^^^^
@@ -524,7 +524,7 @@ LL ~     }
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:289:13
+  --> tests/ui/needless_return.rs:293:13
    |
 LL |             return 100;
    |             ^^^^^^^^^^
@@ -537,7 +537,7 @@ LL ~     }
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:297:9
+  --> tests/ui/needless_return.rs:301:9
    |
 LL |         return 0;
    |         ^^^^^^^^
@@ -549,7 +549,7 @@ LL ~     }
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:304:13
+  --> tests/ui/needless_return.rs:308:13
    |
 LL |             return *(x as *const isize);
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -564,7 +564,7 @@ LL ~     }
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:306:13
+  --> tests/ui/needless_return.rs:310:13
    |
 LL |             return !*(x as *const isize);
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -577,7 +577,7 @@ LL ~     }
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:313:20
+  --> tests/ui/needless_return.rs:317:20
    |
 LL |           let _ = 42;
    |  ____________________^
@@ -594,7 +594,7 @@ LL +         let _ = 42;
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:320:20
+  --> tests/ui/needless_return.rs:324:20
    |
 LL |         let _ = 42; return;
    |                    ^^^^^^^
@@ -606,7 +606,7 @@ LL +         let _ = 42;
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:332:9
+  --> tests/ui/needless_return.rs:336:9
    |
 LL |         return Ok(format!("ok!"));
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -618,7 +618,7 @@ LL +         Ok(format!("ok!"))
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:334:9
+  --> tests/ui/needless_return.rs:338:9
    |
 LL |         return Err(format!("err!"));
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -630,7 +630,7 @@ LL +         Err(format!("err!"))
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:340:9
+  --> tests/ui/needless_return.rs:344:9
    |
 LL |         return if true { 1 } else { 2 };
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -642,7 +642,7 @@ LL +         if true { 1 } else { 2 }
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:344:9
+  --> tests/ui/needless_return.rs:348:9
    |
 LL |         return if b1 { 0 } else { 1 } | if b2 { 2 } else { 3 } | if b3 { 4 } else { 5 };
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -654,7 +654,7 @@ LL +         (if b1 { 0 } else { 1 } | if b2 { 2 } else { 3 } | if b3 { 4 } else
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:365:5
+  --> tests/ui/needless_return.rs:369:5
    |
 LL |     return { "a".to_string() } + "b" + { "c" };
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -666,7 +666,7 @@ LL +     ({ "a".to_string() } + "b" + { "c" })
    |
 
 error: unneeded `return` statement
-  --> tests/ui/needless_return.rs:369:5
+  --> tests/ui/needless_return.rs:373:5
    |
 LL |     return "".split("").next().unwrap().to_string();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

From 55834a362c1e849bbab9cb0adc641a22be598d7e Mon Sep 17 00:00:00 2001
From: y21 <30553356+y21@users.noreply.github.com>
Date: Thu, 26 Sep 2024 17:49:14 +0200
Subject: [PATCH 2/2] deal with differing syntax contexts for subexpressions in
 check_proc_macro

---
 clippy_utils/src/check_proc_macro.rs | 135 ++++++++++++++++-----------
 tests/ui/dbg_macro/dbg_macro.fixed   |   2 +-
 tests/ui/dbg_macro/dbg_macro.rs      |   2 +-
 3 files changed, 83 insertions(+), 56 deletions(-)

diff --git a/clippy_utils/src/check_proc_macro.rs b/clippy_utils/src/check_proc_macro.rs
index 9143d292f670..9a18bff3c7af 100644
--- a/clippy_utils/src/check_proc_macro.rs
+++ b/clippy_utils/src/check_proc_macro.rs
@@ -141,62 +141,89 @@ fn path_search_pat(path: &Path<'_>) -> (Pat, Pat) {
 
 /// Get the search patterns to use for the given expression
 fn expr_search_pat(tcx: TyCtxt<'_>, e: &Expr<'_>) -> (Pat, Pat) {
-    match e.kind {
-        ExprKind::ConstBlock(_) => (Pat::Str("const"), Pat::Str("}")),
-        // Parenthesis are trimmed from the text before the search patterns are matched.
-        // See: `span_matches_pat`
-        ExprKind::Tup([]) => (Pat::Str(")"), Pat::Str("(")),
-        ExprKind::Unary(UnOp::Deref, e) => (Pat::Str("*"), expr_search_pat(tcx, e).1),
-        ExprKind::Unary(UnOp::Not, e) => (Pat::Str("!"), expr_search_pat(tcx, e).1),
-        ExprKind::Unary(UnOp::Neg, e) => (Pat::Str("-"), expr_search_pat(tcx, e).1),
-        ExprKind::Lit(lit) => lit_search_pat(&lit.node),
-        ExprKind::Array(_) | ExprKind::Repeat(..) => (Pat::Str("["), Pat::Str("]")),
-        ExprKind::Call(e, []) | ExprKind::MethodCall(_, e, [], _) => (expr_search_pat(tcx, e).0, Pat::Str("(")),
-        ExprKind::Call(first, [.., last])
-        | ExprKind::MethodCall(_, first, [.., last], _)
-        | ExprKind::Binary(_, first, last)
-        | ExprKind::Tup([first, .., last])
-        | ExprKind::Assign(first, last, _)
-        | ExprKind::AssignOp(_, first, last) => (expr_search_pat(tcx, first).0, expr_search_pat(tcx, last).1),
-        ExprKind::Tup([e]) | ExprKind::DropTemps(e) => expr_search_pat(tcx, e),
-        ExprKind::Cast(e, _) | ExprKind::Type(e, _) => (expr_search_pat(tcx, e).0, Pat::Str("")),
-        ExprKind::Let(let_expr) => (Pat::Str("let"), expr_search_pat(tcx, let_expr.init).1),
-        ExprKind::If(..) => (Pat::Str("if"), Pat::Str("}")),
-        ExprKind::Loop(_, Some(_), _, _) | ExprKind::Block(_, Some(_)) => (Pat::Str("'"), Pat::Str("}")),
-        ExprKind::Loop(_, None, LoopSource::Loop, _) => (Pat::Str("loop"), Pat::Str("}")),
-        ExprKind::Loop(_, None, LoopSource::While, _) => (Pat::Str("while"), Pat::Str("}")),
-        ExprKind::Loop(_, None, LoopSource::ForLoop, _) | ExprKind::Match(_, _, MatchSource::ForLoopDesugar) => {
-            (Pat::Str("for"), Pat::Str("}"))
-        },
-        ExprKind::Match(_, _, MatchSource::Normal) => (Pat::Str("match"), Pat::Str("}")),
-        ExprKind::Match(e, _, MatchSource::TryDesugar(_)) => (expr_search_pat(tcx, e).0, Pat::Str("?")),
-        ExprKind::Match(e, _, MatchSource::AwaitDesugar) | ExprKind::Yield(e, YieldSource::Await { .. }) => {
-            (expr_search_pat(tcx, e).0, Pat::Str("await"))
-        },
-        ExprKind::Closure(&Closure { body, .. }) => (Pat::Str(""), expr_search_pat(tcx, tcx.hir().body(body).value).1),
-        ExprKind::Block(
-            Block {
-                rules: BlockCheckMode::UnsafeBlock(UnsafeSource::UserProvided),
-                ..
+    fn expr_search_pat_inner(tcx: TyCtxt<'_>, e: &Expr<'_>, outer_span: Span) -> (Pat, Pat) {
+        // The expression can have subexpressions in different contexts, in which case
+        // building up a search pattern from the macro expansion would lead to false positives;
+        // e.g. `return format!(..)` would be considered to be from a proc macro
+        // if we build up a pattern for the macro expansion and compare it to the invocation `format!()`.
+        // So instead we return an empty pattern such that `span_matches_pat` always returns true.
+        if !e.span.eq_ctxt(outer_span) {
+            return (Pat::Str(""), Pat::Str(""));
+        }
+
+        match e.kind {
+            ExprKind::ConstBlock(_) => (Pat::Str("const"), Pat::Str("}")),
+            // Parenthesis are trimmed from the text before the search patterns are matched.
+            // See: `span_matches_pat`
+            ExprKind::Tup([]) => (Pat::Str(")"), Pat::Str("(")),
+            ExprKind::Unary(UnOp::Deref, e) => (Pat::Str("*"), expr_search_pat_inner(tcx, e, outer_span).1),
+            ExprKind::Unary(UnOp::Not, e) => (Pat::Str("!"), expr_search_pat_inner(tcx, e, outer_span).1),
+            ExprKind::Unary(UnOp::Neg, e) => (Pat::Str("-"), expr_search_pat_inner(tcx, e, outer_span).1),
+            ExprKind::Lit(lit) => lit_search_pat(&lit.node),
+            ExprKind::Array(_) | ExprKind::Repeat(..) => (Pat::Str("["), Pat::Str("]")),
+            ExprKind::Call(e, []) | ExprKind::MethodCall(_, e, [], _) => {
+                (expr_search_pat_inner(tcx, e, outer_span).0, Pat::Str("("))
             },
-            None,
-        ) => (Pat::Str("unsafe"), Pat::Str("}")),
-        ExprKind::Block(_, None) => (Pat::Str("{"), Pat::Str("}")),
-        ExprKind::Field(e, name) => (expr_search_pat(tcx, e).0, Pat::Sym(name.name)),
-        ExprKind::Index(e, _, _) => (expr_search_pat(tcx, e).0, Pat::Str("]")),
-        ExprKind::Path(ref path) => qpath_search_pat(path),
-        ExprKind::AddrOf(_, _, e) => (Pat::Str("&"), expr_search_pat(tcx, e).1),
-        ExprKind::Break(Destination { label: None, .. }, None) => (Pat::Str("break"), Pat::Str("break")),
-        ExprKind::Break(Destination { label: Some(name), .. }, None) => (Pat::Str("break"), Pat::Sym(name.ident.name)),
-        ExprKind::Break(_, Some(e)) => (Pat::Str("break"), expr_search_pat(tcx, e).1),
-        ExprKind::Continue(Destination { label: None, .. }) => (Pat::Str("continue"), Pat::Str("continue")),
-        ExprKind::Continue(Destination { label: Some(name), .. }) => (Pat::Str("continue"), Pat::Sym(name.ident.name)),
-        ExprKind::Ret(None) => (Pat::Str("return"), Pat::Str("return")),
-        ExprKind::Ret(Some(e)) => (Pat::Str("return"), expr_search_pat(tcx, e).1),
-        ExprKind::Struct(path, _, _) => (qpath_search_pat(path).0, Pat::Str("}")),
-        ExprKind::Yield(e, YieldSource::Yield) => (Pat::Str("yield"), expr_search_pat(tcx, e).1),
-        _ => (Pat::Str(""), Pat::Str("")),
+            ExprKind::Call(first, [.., last])
+            | ExprKind::MethodCall(_, first, [.., last], _)
+            | ExprKind::Binary(_, first, last)
+            | ExprKind::Tup([first, .., last])
+            | ExprKind::Assign(first, last, _)
+            | ExprKind::AssignOp(_, first, last) => (
+                expr_search_pat_inner(tcx, first, outer_span).0,
+                expr_search_pat_inner(tcx, last, outer_span).1,
+            ),
+            ExprKind::Tup([e]) | ExprKind::DropTemps(e) => expr_search_pat_inner(tcx, e, outer_span),
+            ExprKind::Cast(e, _) | ExprKind::Type(e, _) => (expr_search_pat_inner(tcx, e, outer_span).0, Pat::Str("")),
+            ExprKind::Let(let_expr) => (Pat::Str("let"), expr_search_pat_inner(tcx, let_expr.init, outer_span).1),
+            ExprKind::If(..) => (Pat::Str("if"), Pat::Str("}")),
+            ExprKind::Loop(_, Some(_), _, _) | ExprKind::Block(_, Some(_)) => (Pat::Str("'"), Pat::Str("}")),
+            ExprKind::Loop(_, None, LoopSource::Loop, _) => (Pat::Str("loop"), Pat::Str("}")),
+            ExprKind::Loop(_, None, LoopSource::While, _) => (Pat::Str("while"), Pat::Str("}")),
+            ExprKind::Loop(_, None, LoopSource::ForLoop, _) | ExprKind::Match(_, _, MatchSource::ForLoopDesugar) => {
+                (Pat::Str("for"), Pat::Str("}"))
+            },
+            ExprKind::Match(_, _, MatchSource::Normal) => (Pat::Str("match"), Pat::Str("}")),
+            ExprKind::Match(e, _, MatchSource::TryDesugar(_)) => {
+                (expr_search_pat_inner(tcx, e, outer_span).0, Pat::Str("?"))
+            },
+            ExprKind::Match(e, _, MatchSource::AwaitDesugar) | ExprKind::Yield(e, YieldSource::Await { .. }) => {
+                (expr_search_pat_inner(tcx, e, outer_span).0, Pat::Str("await"))
+            },
+            ExprKind::Closure(&Closure { body, .. }) => (
+                Pat::Str(""),
+                expr_search_pat_inner(tcx, tcx.hir().body(body).value, outer_span).1,
+            ),
+            ExprKind::Block(
+                Block {
+                    rules: BlockCheckMode::UnsafeBlock(UnsafeSource::UserProvided),
+                    ..
+                },
+                None,
+            ) => (Pat::Str("unsafe"), Pat::Str("}")),
+            ExprKind::Block(_, None) => (Pat::Str("{"), Pat::Str("}")),
+            ExprKind::Field(e, name) => (expr_search_pat_inner(tcx, e, outer_span).0, Pat::Sym(name.name)),
+            ExprKind::Index(e, _, _) => (expr_search_pat_inner(tcx, e, outer_span).0, Pat::Str("]")),
+            ExprKind::Path(ref path) => qpath_search_pat(path),
+            ExprKind::AddrOf(_, _, e) => (Pat::Str("&"), expr_search_pat_inner(tcx, e, outer_span).1),
+            ExprKind::Break(Destination { label: None, .. }, None) => (Pat::Str("break"), Pat::Str("break")),
+            ExprKind::Break(Destination { label: Some(name), .. }, None) => {
+                (Pat::Str("break"), Pat::Sym(name.ident.name))
+            },
+            ExprKind::Break(_, Some(e)) => (Pat::Str("break"), expr_search_pat_inner(tcx, e, outer_span).1),
+            ExprKind::Continue(Destination { label: None, .. }) => (Pat::Str("continue"), Pat::Str("continue")),
+            ExprKind::Continue(Destination { label: Some(name), .. }) => {
+                (Pat::Str("continue"), Pat::Sym(name.ident.name))
+            },
+            ExprKind::Ret(None) => (Pat::Str("return"), Pat::Str("return")),
+            ExprKind::Ret(Some(e)) => (Pat::Str("return"), expr_search_pat_inner(tcx, e, outer_span).1),
+            ExprKind::Struct(path, _, _) => (qpath_search_pat(path).0, Pat::Str("}")),
+            ExprKind::Yield(e, YieldSource::Yield) => (Pat::Str("yield"), expr_search_pat_inner(tcx, e, outer_span).1),
+            _ => (Pat::Str(""), Pat::Str("")),
+        }
     }
+
+    expr_search_pat_inner(tcx, e, e.span)
 }
 
 fn fn_header_search_pat(header: FnHeader) -> Pat {
diff --git a/tests/ui/dbg_macro/dbg_macro.fixed b/tests/ui/dbg_macro/dbg_macro.fixed
index e35251914233..bda9221a5e1e 100644
--- a/tests/ui/dbg_macro/dbg_macro.fixed
+++ b/tests/ui/dbg_macro/dbg_macro.fixed
@@ -1,5 +1,5 @@
 #![warn(clippy::dbg_macro)]
-#![allow(clippy::unnecessary_operation, clippy::no_effect)]
+#![allow(clippy::unnecessary_operation, clippy::no_effect, clippy::unit_arg)]
 
 fn foo(n: u32) -> u32 {
     if let Some(n) = n.checked_sub(4) { n } else { n }
diff --git a/tests/ui/dbg_macro/dbg_macro.rs b/tests/ui/dbg_macro/dbg_macro.rs
index 80606c2db054..8244254026be 100644
--- a/tests/ui/dbg_macro/dbg_macro.rs
+++ b/tests/ui/dbg_macro/dbg_macro.rs
@@ -1,5 +1,5 @@
 #![warn(clippy::dbg_macro)]
-#![allow(clippy::unnecessary_operation, clippy::no_effect)]
+#![allow(clippy::unnecessary_operation, clippy::no_effect, clippy::unit_arg)]
 
 fn foo(n: u32) -> u32 {
     if let Some(n) = dbg!(n.checked_sub(4)) { n } else { n }