fix: option_if_let_else don't suggest argless function for Result::map_or_else

closes rust-clippy/issues/15002

Signed-off-by: Zihan <[email protected]>

Author: zihan0822

clippy_lints/src/option_if_let_else.rs

@@ -225,7 +225,7 @@ fn try_get_option_occurrence<'tcx>(
         let mut app = Applicability::Unspecified;
 
         let (none_body, is_argless_call) = match none_body.kind {
-            ExprKind::Call(call_expr, []) if !none_body.span.from_expansion() => (call_expr, true),
+            ExprKind::Call(call_expr, []) if !none_body.span.from_expansion() && !is_result => (call_expr, true),
             _ => (none_body, false),
         };
 
@@ -242,7 +242,7 @@ fn try_get_option_occurrence<'tcx>(
             ),
             none_expr: format!(
                 "{}{}",
-                if method_sugg == "map_or" || is_argless_call {
+                if method_sugg == "map_or" || (is_argless_call && !is_result) {
                     ""
                 } else if is_result {
                     "|_| "

tests/ui/option_if_let_else.fixed

@@ -309,3 +309,8 @@ fn issue15379() {
     let _ = unsafe { (*opt_raw_ptr).map_or(1, |o| o) };
     //~^ option_if_let_else
 }
+
+fn issue15002() {
+    let res: Result<String, ()> = Ok("_".to_string());
+    let _ = res.map_or_else(|_| String::new(), |s| s.clone());
+}

tests/ui/option_if_let_else.rs

@@ -372,3 +372,12 @@ fn issue15379() {
     let _ = unsafe { if let Some(o) = *opt_raw_ptr { o } else { 1 } };
     //~^ option_if_let_else
 }
+
+fn issue15002() {
+    let res: Result<String, ()> = Ok("_".to_string());
+    let _ = match res {
+        //~^ option_if_let_else
+        Ok(s) => s.clone(),
+        Err(_) => String::new(),
+    };
+}

tests/ui/option_if_let_else.stderr

@@ -340,5 +340,16 @@ error: use Option::map_or instead of an if let/else
 LL |     let _ = unsafe { if let Some(o) = *opt_raw_ptr { o } else { 1 } };
    |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `(*opt_raw_ptr).map_or(1, |o| o)`
 
-error: aborting due to 26 previous errors
+error: use Option::map_or_else instead of an if let/else
+  --> tests/ui/option_if_let_else.rs:378:13
+   |
+LL |       let _ = match res {
+   |  _____________^
+LL | |
+LL | |         Ok(s) => s.clone(),
+LL | |         Err(_) => String::new(),
+LL | |     };
+   | |_____^ help: try: `res.map_or_else(|_| String::new(), |s| s.clone())`
+
+error: aborting due to 27 previous errors