add parentheses to [let_and_return]'s suggestion

clippy_lints/src/returns.rs

@@ -243,11 +243,9 @@ impl<'tcx> LateLintPass<'tcx> for Return {
                 |err| {
                     err.span_label(local.span, "unnecessary `let` binding");
 
-                    if let Some(mut snippet) = snippet_opt(cx, initexpr.span) {
+                    if let Some(sugg) = clippy_utils::sugg::Sugg::hir_opt(cx, initexpr) {
+                        let mut snippet = sugg.maybe_par().to_string();
                         if !cx.typeck_results().expr_adjustments(retexpr).is_empty() {
-                            if !has_enclosing_paren(&snippet) {
-                                snippet = format!("({snippet})");
-                            }
                             snippet.push_str(" as _");
                         }
                         err.multipart_suggestion(

tests/ui/crashes/ice-8850.fixed

@@ -1,15 +1,15 @@
 fn fn_pointer_static() -> usize {
     static FN: fn() -> usize = || 1;
 
-    FN() + 1
+    (FN() + 1)
     //~^ ERROR: returning the result of a `let` binding from a block
     //~| NOTE: `-D clippy::let-and-return` implied by `-D warnings`
 }
 
 fn fn_pointer_const() -> usize {
     const FN: fn() -> usize = || 1;
 
-    FN() + 1
+    (FN() + 1)
     //~^ ERROR: returning the result of a `let` binding from a block
 }
 
@@ -24,7 +24,7 @@ fn deref_to_dyn_fn() -> usize {
     }
     static FN: Derefs = Derefs;
 
-    FN() + 1
+    (FN() + 1)
     //~^ ERROR: returning the result of a `let` binding from a block
 }
 

tests/ui/crashes/ice-8850.stderr

@@ -11,7 +11,7 @@ LL |     res
 help: return the expression directly
    |
 LL ~     
-LL ~     FN() + 1
+LL ~     (FN() + 1)
    |
 
 error: returning the result of a `let` binding from a block
@@ -25,7 +25,7 @@ LL |     res
 help: return the expression directly
    |
 LL ~     
-LL ~     FN() + 1
+LL ~     (FN() + 1)
    |
 
 error: returning the result of a `let` binding from a block
@@ -39,7 +39,7 @@ LL |     res
 help: return the expression directly
    |
 LL ~     
-LL ~     FN() + 1
+LL ~     (FN() + 1)
    |
 
 error: aborting due to 3 previous errors

tests/ui/let_and_return.fixed

@@ -168,7 +168,7 @@ mod issue_5729 {
     impl<T: Foo + 'static> FooStorage for FooStorageImpl<T> {
         fn foo_cloned(&self) -> Arc<dyn Foo> {
 
-            (Arc::clone(&self.foo)) as _
+            Arc::clone(&self.foo) as _
             //~^ ERROR: returning the result of a `let` binding from a block
         }
     }
@@ -210,4 +210,10 @@ fn issue9150() -> usize {
     x
 }
 
+fn issue12801() -> String {
+
+    (if true { "a".to_string() } else { "b".to_string() } + "c")
+    //~^ ERROR: returning the result of a `let` binding from a block
+}
+
 fn main() {}

tests/ui/let_and_return.rs

@@ -210,4 +210,10 @@ fn issue9150() -> usize {
     x
 }
 
+fn issue12801() -> String {
+    let s = if true { "a".to_string() } else { "b".to_string() } + "c";
+    s
+    //~^ ERROR: returning the result of a `let` binding from a block
+}
+
 fn main() {}

tests/ui/let_and_return.stderr

@@ -53,7 +53,7 @@ LL |             clone
 help: return the expression directly
    |
 LL ~             
-LL ~             (Arc::clone(&self.foo)) as _
+LL ~             Arc::clone(&self.foo) as _
    |
 
 error: returning the result of a `let` binding from a block
@@ -78,5 +78,19 @@ LL +                 E::B(x) => x,
 LL +             }) as _
    |
 
-error: aborting due to 5 previous errors
+error: returning the result of a `let` binding from a block
+  --> tests/ui/let_and_return.rs:215:5
+   |
+LL |     let s = if true { "a".to_string() } else { "b".to_string() } + "c";
+   |     ------------------------------------------------------------------- unnecessary `let` binding
+LL |     s
+   |     ^
+   |
+help: return the expression directly
+   |
+LL ~     
+LL ~     (if true { "a".to_string() } else { "b".to_string() } + "c")
+   |
+
+error: aborting due to 6 previous errors