Auto merge of #11215 - MrNossiom:master, r=Jarcho

ptr_arg should ignore extern functions

Fixes: #11181

changelog: [`ptr_arg`]: ignore extern functions that are not

I am not sure whether we should ignore other Rust calling conventions like `rust-intrinsic`, `rust-call` or `rust-cold`.

clippy_lints/src/ptr.rs

@@ -26,6 +26,7 @@
 use rustc_span::source_map::Span;
 use rustc_span::sym;
 use rustc_span::symbol::Symbol;
+use rustc_target::spec::abi::Abi;
 use rustc_trait_selection::infer::InferCtxtExt as _;
 use rustc_trait_selection::traits::query::evaluate_obligation::InferCtxtExt as _;
 use std::{fmt, iter};
@@ -163,6 +164,12 @@ fn check_trait_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx TraitItem<'_>
             }
 
             check_mut_from_ref(cx, sig, None);
+
+            if !matches!(sig.header.abi, Abi::Rust) {
+                // Ignore `extern` functions with non-Rust calling conventions
+                return;
+            }
+
             for arg in check_fn_args(
                 cx,
                 cx.tcx.fn_sig(item.owner_id).subst_identity().skip_binder().inputs(),
@@ -218,6 +225,12 @@ fn check_body(&mut self, cx: &LateContext<'tcx>, body: &'tcx Body<'_>) {
         };
 
         check_mut_from_ref(cx, sig, Some(body));
+
+        if !matches!(sig.header.abi, Abi::Rust) {
+            // Ignore `extern` functions with non-Rust calling conventions
+            return;
+        }
+
         let decl = sig.decl;
         let sig = cx.tcx.fn_sig(item_id).subst_identity().skip_binder();
         let lint_args: Vec<_> = check_fn_args(cx, sig.inputs(), decl.inputs, &decl.output, body.params)

tests/ui/ptr_arg.rs

@@ -267,3 +267,16 @@ fn cow_good_ret_ty<'a>(input: &'a Cow<'a, str>) -> &str {
         todo!()
     }
 }
+
+mod issue_11181 {
+    extern "C" fn allowed(_v: &Vec<u32>) {}
+
+    struct S;
+    impl S {
+        extern "C" fn allowed(_v: &Vec<u32>) {}
+    }
+
+    trait T {
+        extern "C" fn allowed(_v: &Vec<u32>) {}
+    }
+}