Stop linting else if let pattern in option_if_let_else lint

Author: ThibsG

clippy_lints/src/option_if_let_else.rs

@@ -2,7 +2,7 @@ use clippy_utils::diagnostics::span_lint_and_sugg;
 use clippy_utils::sugg::Sugg;
 use clippy_utils::ty::is_type_diagnostic_item;
 use clippy_utils::usage::contains_return_break_continue_macro;
-use clippy_utils::{eager_or_lazy, get_enclosing_block, in_macro, is_lang_ctor};
+use clippy_utils::{eager_or_lazy, get_enclosing_block, in_macro, is_else_clause, is_lang_ctor};
 use if_chain::if_chain;
 use rustc_errors::Applicability;
 use rustc_hir::LangItem::OptionSome;
@@ -161,13 +161,15 @@ fn detect_option_if_let_else<'tcx>(
     if_chain! {
         if !in_macro(expr.span); // Don't lint macros, because it behaves weirdly
         if let ExprKind::Match(cond_expr, arms, MatchSource::IfLetDesugar{contains_else_clause: true}) = &expr.kind;
+        if !is_else_clause(cx.tcx, expr);
         if arms.len() == 2;
         if !is_result_ok(cx, cond_expr); // Don't lint on Result::ok because a different lint does it already
         if let PatKind::TupleStruct(struct_qpath, &[inner_pat], _) = &arms[0].pat.kind;
         if is_lang_ctor(cx, struct_qpath, OptionSome);
         if let PatKind::Binding(bind_annotation, _, id, _) = &inner_pat.kind;
         if !contains_return_break_continue_macro(arms[0].body);
         if !contains_return_break_continue_macro(arms[1].body);
+
         then {
             let capture_mut = if bind_annotation == &BindingAnnotation::Mutable { "mut " } else { "" };
             let some_body = extract_body_from_arm(&arms[0])?;

tests/ui/option_if_let_else.fixed

@@ -10,7 +10,11 @@ fn bad1(string: Option<&str>) -> (bool, &str) {
 fn else_if_option(string: Option<&str>) -> Option<(bool, &str)> {
     if string.is_none() {
         None
-    } else { string.map_or(Some((false, "")), |x| Some((true, x))) }
+    } else if let Some(x) = string {
+        Some((true, x))
+    } else {
+        Some((false, ""))
+    }
 }
 
 fn unop_bad(string: &Option<&str>, mut num: Option<i32>) {

tests/ui/option_if_let_else.stderr

@@ -10,17 +10,6 @@ LL | |     }
    |
    = note: `-D clippy::option-if-let-else` implied by `-D warnings`
 
-error: use Option::map_or instead of an if let/else
-  --> $DIR/option_if_let_else.rs:17:12
-   |
-LL |       } else if let Some(x) = string {
-   |  ____________^
-LL | |         Some((true, x))
-LL | |     } else {
-LL | |         Some((false, ""))
-LL | |     }
-   | |_____^ help: try: `{ string.map_or(Some((false, "")), |x| Some((true, x))) }`
-
 error: use Option::map_or instead of an if let/else
   --> $DIR/option_if_let_else.rs:25:13
    |
@@ -159,5 +148,5 @@ error: use Option::map_or instead of an if let/else
 LL |     let _ = if let Some(x) = optional { x + 2 } else { 5 };
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `optional.map_or(5, |x| x + 2)`
 
-error: aborting due to 12 previous errors
+error: aborting due to 11 previous errors