Auto merge of #12097 - y21:issue9427-3, r=llogiq

don't change eagerness for struct literal syntax with significant drop

Fixes the bug reported by `@ju1ius` in #9427 (comment).

`eager_or_lazy` already understands to suppress eagerness changes when the expression type has a significant drop impl, but only for initialization of tuple structs or unit structs. This changes it to also avoid changing it for `Self { .. }` and `TypeWithDrop { .. }`

changelog: [`unnecessary_lazy_eval`]: don't suggest changing eagerness for struct literal syntax when type has a significant drop impl

Author: bors

clippy_utils/src/eager_or_lazy.rs

@@ -99,7 +99,10 @@ fn fn_eagerness(cx: &LateContext<'_>, fn_id: DefId, name: Symbol, have_one_arg:
 }
 
 fn res_has_significant_drop(res: Res, cx: &LateContext<'_>, e: &Expr<'_>) -> bool {
-    if let Res::Def(DefKind::Ctor(..) | DefKind::Variant, _) | Res::SelfCtor(_) = res {
+    if let Res::Def(DefKind::Ctor(..) | DefKind::Variant | DefKind::Enum | DefKind::Struct, _)
+    | Res::SelfCtor(_)
+    | Res::SelfTyAlias { .. } = res
+    {
         cx.typeck_results()
             .expr_ty(e)
             .has_significant_drop(cx.tcx, cx.param_env)
@@ -173,6 +176,13 @@ fn expr_eagerness<'tcx>(cx: &LateContext<'tcx>, e: &'tcx Expr<'_>) -> EagernessS
                     self.eagerness |= NoChange;
                     return;
                 },
+                #[expect(clippy::match_same_arms)] // arm pattern can't be merged due to `ref`, see rust#105778
+                ExprKind::Struct(path, ..) => {
+                    if res_has_significant_drop(self.cx.qpath_res(path, e.hir_id), self.cx, e) {
+                        self.eagerness = ForceNoChange;
+                        return;
+                    }
+                },
                 ExprKind::Path(ref path) => {
                     if res_has_significant_drop(self.cx.qpath_res(path, e.hir_id), self.cx, e) {
                         self.eagerness = ForceNoChange;
@@ -291,7 +301,6 @@ fn expr_eagerness<'tcx>(cx: &LateContext<'tcx>, e: &'tcx Expr<'_>) -> EagernessS
                 | ExprKind::Closure { .. }
                 | ExprKind::Field(..)
                 | ExprKind::AddrOf(..)
-                | ExprKind::Struct(..)
                 | ExprKind::Repeat(..)
                 | ExprKind::Block(Block { stmts: [], .. }, _)
                 | ExprKind::OffsetOf(..) => (),

tests/ui/unnecessary_lazy_eval.fixed

@@ -47,6 +47,18 @@ impl Drop for Issue9427FollowUp {
     }
 }
 
+struct Issue9427Followup2 {
+    ptr: *const (),
+}
+impl Issue9427Followup2 {
+    fn from_owned(ptr: *const ()) -> Option<Self> {
+        (!ptr.is_null()).then(|| Self { ptr })
+    }
+}
+impl Drop for Issue9427Followup2 {
+    fn drop(&mut self) {}
+}
+
 struct Issue10437;
 impl Deref for Issue10437 {
     type Target = u32;
@@ -128,6 +140,7 @@ fn main() {
     // Should not lint - bool
     let _ = (0 == 1).then(|| Issue9427(0)); // Issue9427 has a significant drop
     let _ = false.then(|| Issue9427FollowUp); // Issue9427FollowUp has a significant drop
+    let _ = false.then(|| Issue9427Followup2 { ptr: std::ptr::null() });
 
     // should not lint, bind_instead_of_map takes priority
     let _ = Some(10).and_then(|idx| Some(ext_arr[idx]));

tests/ui/unnecessary_lazy_eval.rs

@@ -47,6 +47,18 @@ impl Drop for Issue9427FollowUp {
     }
 }
 
+struct Issue9427Followup2 {
+    ptr: *const (),
+}
+impl Issue9427Followup2 {
+    fn from_owned(ptr: *const ()) -> Option<Self> {
+        (!ptr.is_null()).then(|| Self { ptr })
+    }
+}
+impl Drop for Issue9427Followup2 {
+    fn drop(&mut self) {}
+}
+
 struct Issue10437;
 impl Deref for Issue10437 {
     type Target = u32;
@@ -128,6 +140,7 @@ fn main() {
     // Should not lint - bool
     let _ = (0 == 1).then(|| Issue9427(0)); // Issue9427 has a significant drop
     let _ = false.then(|| Issue9427FollowUp); // Issue9427FollowUp has a significant drop
+    let _ = false.then(|| Issue9427Followup2 { ptr: std::ptr::null() });
 
     // should not lint, bind_instead_of_map takes priority
     let _ = Some(10).and_then(|idx| Some(ext_arr[idx]));