ptr_arg should ignore extern functions

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();

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>) {}
+    }
+}