Auto merge of rust-lang#13288 - kyoto7250:fix-13184, r=y21

fix false positive in explicit_iter_loop with msrv

close rust-lang#13184

This PR fix false positive in explicit_iter_loop when msrv < 1.80

changelog: fix false positive in explicit_iter_loop when msrv < 1.80

Author: bors

clippy_config/src/msrvs.rs

@@ -18,6 +18,7 @@ macro_rules! msrv_aliases {
 // names may refer to stabilized feature flags or library items
 msrv_aliases! {
     1,81,0  { LINT_REASONS_STABILIZATION }
+    1,80,0 { BOX_INTO_ITER}
     1,77,0 { C_STR_LITERALS }
     1,76,0 { PTR_FROM_REF, OPTION_RESULT_INSPECT }
     1,71,0 { TUPLE_ARRAY_CONVERSIONS, BUILD_HASHER_HASH_ONE }

clippy_lints/src/loops/explicit_iter_loop.rs

@@ -3,7 +3,7 @@ use clippy_config::msrvs::{self, Msrv};
 use clippy_utils::diagnostics::span_lint_and_sugg;
 use clippy_utils::source::snippet_with_applicability;
 use clippy_utils::ty::{
-    implements_trait, implements_trait_with_env, is_copy, make_normalized_projection,
+    implements_trait, implements_trait_with_env, is_copy, is_type_lang_item, make_normalized_projection,
     make_normalized_projection_with_regions, normalize_with_regions,
 };
 use rustc_errors::Applicability;
@@ -20,9 +20,10 @@ pub(super) fn check(
     msrv: &Msrv,
     enforce_iter_loop_reborrow: bool,
 ) {
-    let Some((adjust, ty)) = is_ref_iterable(cx, self_arg, call_expr, enforce_iter_loop_reborrow) else {
+    let Some((adjust, ty)) = is_ref_iterable(cx, self_arg, call_expr, enforce_iter_loop_reborrow, msrv) else {
         return;
     };
+
     if let ty::Array(_, count) = *ty.peel_refs().kind() {
         if !ty.is_ref() {
             if !msrv.meets(msrvs::ARRAY_INTO_ITERATOR) {
@@ -109,6 +110,7 @@ fn is_ref_iterable<'tcx>(
     self_arg: &Expr<'_>,
     call_expr: &Expr<'_>,
     enforce_iter_loop_reborrow: bool,
+    msrv: &Msrv,
 ) -> Option<(AdjustKind, Ty<'tcx>)> {
     let typeck = cx.typeck_results();
     if let Some(trait_id) = cx.tcx.get_diagnostic_item(sym::IntoIterator)
@@ -128,6 +130,12 @@ fn is_ref_iterable<'tcx>(
         let self_ty = typeck.expr_ty(self_arg);
         let self_is_copy = is_copy(cx, self_ty);
 
+        if !msrv.meets(msrvs::BOX_INTO_ITER)
+            && is_type_lang_item(cx, self_ty.peel_refs(), rustc_hir::LangItem::OwnedBox)
+        {
+            return None;
+        }
+
         if adjustments.is_empty() && self_is_copy {
             // Exact type match, already checked earlier
             return Some((AdjustKind::None, self_ty));

tests/ui/explicit_iter_loop.fixed

@@ -153,3 +153,15 @@ fn main() {
     let r = &x;
     for _ in r {}
 }
+
+#[clippy::msrv = "1.79"]
+pub fn issue_13184() {
+    // https://github.com/rust-lang/rust-clippy/issues/13184
+    // No need to fix, as IntoIterator for Box is valid starting from 1.80
+    let mut values: Box<[u32]> = Box::new([1, 2]);
+    for _ in values.iter() {}
+    for _ in values.iter_mut() {}
+
+    let rvalues = &values;
+    for _ in rvalues.iter() {}
+}

tests/ui/explicit_iter_loop.rs

@@ -153,3 +153,15 @@ fn main() {
     let r = &x;
     for _ in r.iter() {}
 }
+
+#[clippy::msrv = "1.79"]
+pub fn issue_13184() {
+    // https://github.com/rust-lang/rust-clippy/issues/13184
+    // No need to fix, as IntoIterator for Box is valid starting from 1.80
+    let mut values: Box<[u32]> = Box::new([1, 2]);
+    for _ in values.iter() {}
+    for _ in values.iter_mut() {}
+
+    let rvalues = &values;
+    for _ in rvalues.iter() {}
+}