From 30d06a810c8b8967d9d0ea2cb64d5adf8b357914 Mon Sep 17 00:00:00 2001
From: Milo Moisson <milomoisson@gmail.com>
Date: Sun, 23 Jul 2023 17:05:54 +0200
Subject: [PATCH 1/2] ptr_arg should ignore extern functions

---
 clippy_lints/src/ptr.rs | 11 +++++++++++
 tests/ui/ptr_arg.rs     | 13 +++++++++++++
 2 files changed, 24 insertions(+)

diff --git a/clippy_lints/src/ptr.rs b/clippy_lints/src/ptr.rs
index 82a55166aeae..4534b2ab28af 100644
--- a/clippy_lints/src/ptr.rs
+++ b/clippy_lints/src/ptr.rs
@@ -26,6 +26,7 @@ use rustc_session::{declare_lint_pass, declare_tool_lint};
 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};
@@ -162,6 +163,11 @@ impl<'tcx> LateLintPass<'tcx> for Ptr {
                 return;
             }
 
+            if !matches!(sig.header.abi, Abi::Rust) {
+                // Ignore `extern` functions with non-Rust calling conventions
+                return;
+            }
+
             check_mut_from_ref(cx, sig, None);
             for arg in check_fn_args(
                 cx,
@@ -217,6 +223,11 @@ impl<'tcx> LateLintPass<'tcx> for Ptr {
             _ => return,
         };
 
+        if !matches!(sig.header.abi, Abi::Rust) {
+            // Ignore `extern` functions with non-Rust calling conventions
+            return;
+        }
+
         check_mut_from_ref(cx, sig, Some(body));
         let decl = sig.decl;
         let sig = cx.tcx.fn_sig(item_id).subst_identity().skip_binder();
diff --git a/tests/ui/ptr_arg.rs b/tests/ui/ptr_arg.rs
index 13e993d247b2..08075c382a22 100644
--- a/tests/ui/ptr_arg.rs
+++ b/tests/ui/ptr_arg.rs
@@ -267,3 +267,16 @@ mod issue_9218 {
         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>) {}
+    }
+}

From 7b8598d6c0c28c4e60387f18fae8d5b021ce5907 Mon Sep 17 00:00:00 2001
From: Milo Moisson <milomoisson@gmail.com>
Date: Mon, 24 Jul 2023 01:23:35 +0200
Subject: [PATCH 2/2] ptr lint: check_mut_from_ref is checked independently of
 the function's ABI

---
 clippy_lints/src/ptr.rs | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/clippy_lints/src/ptr.rs b/clippy_lints/src/ptr.rs
index 4534b2ab28af..d32e58c1af90 100644
--- a/clippy_lints/src/ptr.rs
+++ b/clippy_lints/src/ptr.rs
@@ -163,12 +163,13 @@ impl<'tcx> LateLintPass<'tcx> for Ptr {
                 return;
             }
 
+            check_mut_from_ref(cx, sig, None);
+
             if !matches!(sig.header.abi, Abi::Rust) {
                 // Ignore `extern` functions with non-Rust calling conventions
                 return;
             }
 
-            check_mut_from_ref(cx, sig, None);
             for arg in check_fn_args(
                 cx,
                 cx.tcx.fn_sig(item.owner_id).subst_identity().skip_binder().inputs(),
@@ -223,12 +224,13 @@ impl<'tcx> LateLintPass<'tcx> for Ptr {
             _ => return,
         };
 
+        check_mut_from_ref(cx, sig, Some(body));
+
         if !matches!(sig.header.abi, Abi::Rust) {
             // Ignore `extern` functions with non-Rust calling conventions
             return;
         }
 
-        check_mut_from_ref(cx, sig, Some(body));
         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)