fix option-if-let-else lint (#15394)

some simple twists
Fixes rust-lang/rust-clippy#15002
Fixes rust-lang/rust-clippy#15379

changelog: [`option_if_let_else`]: Don't remove raw pointer derefs in
suggestions
changelog: [`option_if_let_else`]: Don't suggest passing argless
functions to `Result::map_or_else`

clippy_lints/src/option_if_let_else.rs

@@ -127,7 +127,8 @@ fn try_get_option_occurrence<'tcx>(
     if_else: &'tcx Expr<'_>,
 ) -> Option<OptionOccurrence> {
     let cond_expr = match expr.kind {
-        ExprKind::Unary(UnOp::Deref, inner_expr) | ExprKind::AddrOf(_, _, inner_expr) => inner_expr,
+        ExprKind::AddrOf(_, _, inner_expr) => inner_expr,
+        ExprKind::Unary(UnOp::Deref, inner_expr) if !cx.typeck_results().expr_ty(inner_expr).is_raw_ptr() => inner_expr,
         _ => expr,
     };
     let (inner_pat, is_result) = try_get_inner_pat_and_is_result(cx, pat)?;
@@ -223,8 +224,8 @@ 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),
+        let (none_body, can_omit_arg) = match none_body.kind {
+            ExprKind::Call(call_expr, []) if !none_body.span.from_expansion() && !is_result => (call_expr, true),
             _ => (none_body, false),
         };
 
@@ -241,7 +242,7 @@ fn try_get_option_occurrence<'tcx>(
             ),
             none_expr: format!(
                 "{}{}",
-                if method_sugg == "map_or" || is_argless_call {
+                if method_sugg == "map_or" || can_omit_arg {
                     ""
                 } else if is_result {
                     "|_| "

tests/ui/option_if_let_else.fixed

@@ -302,3 +302,15 @@ mod issue11059 {
         if let Some(o) = o { o } else { &S }
     }
 }
+
+fn issue15379() {
+    let opt = Some(0usize);
+    let opt_raw_ptr = &opt as *const Option<usize>;
+    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

@@ -365,3 +365,19 @@ mod issue11059 {
         if let Some(o) = o { o } else { &S }
     }
 }
+
+fn issue15379() {
+    let opt = Some(0usize);
+    let opt_raw_ptr = &opt as *const Option<usize>;
+    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

@@ -334,5 +334,22 @@ error: use Option::map_or_else instead of an if let/else
 LL |     let mut _hm = if let Some(hm) = &opt { hm.clone() } else { new_map!() };
    |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `opt.as_ref().map_or_else(|| new_map!(), |hm| hm.clone())`
 
-error: aborting due to 25 previous errors
+error: use Option::map_or instead of an if let/else
+  --> tests/ui/option_if_let_else.rs:372:22
+   |
+LL |     let _ = unsafe { if let Some(o) = *opt_raw_ptr { o } else { 1 } };
+   |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `(*opt_raw_ptr).map_or(1, |o| o)`
+
+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