Fix a false positive in unnecessary_wraps

Author: hkmatsumoto

clippy_lints/src/methods/mod.rs

@@ -3878,7 +3878,7 @@ fn is_bool(ty: &hir::Ty<'_>) -> bool {
 }
 
 // Returns `true` if `expr` contains a return expression
-fn contains_return(expr: &hir::Expr<'_>) -> bool {
+pub(crate) fn contains_return(expr: &hir::Expr<'_>) -> bool {
     struct RetCallFinder {
         found: bool,
     }

clippy_lints/src/unnecessary_wraps.rs

@@ -1,3 +1,4 @@
+use crate::methods::contains_return;
 use crate::utils::{
     in_macro, is_type_diagnostic_item, match_qpath, paths, return_ty, snippet, span_lint_and_then,
     visitors::find_all_ret_expressions,
@@ -95,6 +96,7 @@ impl<'tcx> LateLintPass<'tcx> for UnnecessaryWraps {
                 if let ExprKind::Path(ref qpath) = func.kind;
                 if match_qpath(qpath, path);
                 if args.len() == 1;
+                if !contains_return(&args[0]);
                 then {
                     suggs.push((ret_expr.span, snippet(cx, args[0].span.source_callsite(), "..").to_string()));
                     true

tests/ui/unnecessary_wraps.rs

@@ -109,6 +109,13 @@ impl B for A {
     }
 }
 
+fn issue_6384(s: &str) -> Option<&str> {
+    Some(match s {
+        "a" => "A",
+        _ => return None,
+    })
+}
+
 fn main() {
     // method calls are not linted
     func1(true, true);