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`.

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>) {}
+    }
+}