Auto merge of rust-lang#10109 - Niki4tap:yeet_not_return, r=flip1995

Fix FP in needless_return when using yeet

Fixes rust-lang#9947

changelog: Fix: [`needless_return`]: don't lint when using `do yeet`
rust-lang#10109

Author: bors

clippy_lints/src/returns.rs

@@ -6,7 +6,7 @@ use core::ops::ControlFlow;
 use if_chain::if_chain;
 use rustc_errors::Applicability;
 use rustc_hir::intravisit::FnKind;
-use rustc_hir::{Block, Body, Expr, ExprKind, FnDecl, HirId, MatchSource, PatKind, StmtKind};
+use rustc_hir::{Block, Body, Expr, ExprKind, FnDecl, HirId, LangItem, MatchSource, PatKind, QPath, StmtKind};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
 use rustc_middle::lint::in_external_macro;
 use rustc_middle::ty::subst::GenericArgKind;
@@ -207,6 +207,12 @@ fn check_final_expr<'tcx>(
     match &peeled_drop_expr.kind {
         // simple return is always "bad"
         ExprKind::Ret(ref inner) => {
+            // if desugar of `do yeet`, don't lint
+            if let Some(inner_expr) = inner
+                && let ExprKind::Call(path_expr, _) = inner_expr.kind
+                && let ExprKind::Path(QPath::LangItem(LangItem::TryTraitFromYeet, _, _)) = path_expr.kind {
+                    return;
+            }
             if cx.tcx.hir().attrs(expr.hir_id).is_empty() {
                 let borrows = inner.map_or(false, |inner| last_statement_borrows(cx, inner));
                 if !borrows {

tests/ui/needless_return.fixed

@@ -1,6 +1,7 @@
 // run-rustfix
 
 #![feature(lint_reasons)]
+#![feature(yeet_expr)]
 #![allow(unused)]
 #![allow(
     clippy::if_same_then_else,
@@ -272,4 +273,8 @@ mod issue9416 {
     }
 }
 
+fn issue9947() -> Result<(), String> {
+    do yeet "hello";
+}
+
 fn main() {}

tests/ui/needless_return.rs

@@ -1,6 +1,7 @@
 // run-rustfix
 
 #![feature(lint_reasons)]
+#![feature(yeet_expr)]
 #![allow(unused)]
 #![allow(
     clippy::if_same_then_else,
@@ -282,4 +283,8 @@ mod issue9416 {
     }
 }
 
+fn issue9947() -> Result<(), String> {
+    do yeet "hello";
+}
+
 fn main() {}