Don't suppress manual_let_else if question_mark is allowed

If question_mark is allowed, there is no overlap any more,
so we can just not suppress it.

Author: est31

clippy_lints/src/manual_let_else.rs

@@ -1,12 +1,10 @@
-use crate::question_mark::{pat_and_expr_can_be_question_mark, QuestionMark};
+use crate::question_mark::{pat_and_expr_can_be_question_mark, QuestionMark, QUESTION_MARK};
 use clippy_utils::diagnostics::span_lint_and_then;
 use clippy_utils::higher::IfLetOrMatch;
-use clippy_utils::msrvs;
-use clippy_utils::peel_blocks;
 use clippy_utils::source::snippet_with_context;
 use clippy_utils::ty::is_type_diagnostic_item;
 use clippy_utils::visitors::{Descend, Visitable};
-use if_chain::if_chain;
+use clippy_utils::{is_lint_allowed, msrvs, peel_blocks};
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_errors::Applicability;
 use rustc_hir::intravisit::{walk_expr, Visitor};
@@ -65,12 +63,14 @@ impl<'tcx> QuestionMark {
             let Some(if_let_or_match) = IfLetOrMatch::parse(cx, init)
         {
             match if_let_or_match {
-                IfLetOrMatch::IfLet(if_let_expr, let_pat, if_then, if_else) => if_chain! {
-                    if let Some(ident_map) = expr_simple_identity_map(local.pat, let_pat, if_then);
-                    if let Some(if_else) = if_else;
-                    if expr_diverges(cx, if_else);
-                    if pat_and_expr_can_be_question_mark(cx, let_pat, if_else).is_none();
-                    then {
+                IfLetOrMatch::IfLet(if_let_expr, let_pat, if_then, if_else) => {
+                    if
+                        let Some(ident_map) = expr_simple_identity_map(local.pat, let_pat, if_then) &&
+                        let Some(if_else) = if_else &&
+                        expr_diverges(cx, if_else) &&
+                        let qm_allowed = is_lint_allowed(cx, QUESTION_MARK, stmt.hir_id) &&
+                        (qm_allowed || pat_and_expr_can_be_question_mark(cx, let_pat, if_else).is_none())
+                    {
                         emit_manual_let_else(cx, stmt.span, if_let_expr, &ident_map, let_pat, if_else);
                     }
                 },

tests/ui/manual_let_else_question_mark.fixed

@@ -52,5 +52,12 @@ fn foo() -> Option<()> {
         let Some(v) = g() else { return None };
     }
 
+    // This is a copy of the case above where we'd fire the question_mark lint, but here we have allowed
+    // it. Make sure that manual_let_else is fired as the fallback.
+    #[allow(clippy::question_mark)]
+    {
+        let Some(v) = g() else { return None };
+    }
+
     Some(())
 }

tests/ui/manual_let_else_question_mark.rs

@@ -57,5 +57,12 @@ fn foo() -> Option<()> {
         };
     }
 
+    // This is a copy of the case above where we'd fire the question_mark lint, but here we have allowed
+    // it. Make sure that manual_let_else is fired as the fallback.
+    #[allow(clippy::question_mark)]
+    {
+        let v = if let Some(v_some) = g() { v_some } else { return None };
+    }
+
     Some(())
 }

tests/ui/manual_let_else_question_mark.stderr

@@ -45,5 +45,11 @@ LL | |             _ => return None,
 LL | |         };
    | |__________^ help: consider writing: `let Some(v) = g() else { return None };`
 
-error: aborting due to 5 previous errors
+error: this could be rewritten as `let...else`
+  --> $DIR/manual_let_else_question_mark.rs:64:9
+   |
+LL |         let v = if let Some(v_some) = g() { v_some } else { return None };
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider writing: `let Some(v) = g() else { return None };`
+
+error: aborting due to 6 previous errors