compiler: use is_rustic_abi in abi_check

warns on fewer ABIs now

Author: workingjubilee

compiler/rustc_monomorphize/src/mono_checks/abi_check.rs

@@ -1,6 +1,6 @@
 //! This module ensures that if a function's ABI requires a particular target feature,
 //! that target feature is enabled both on the callee and all callers.
-use rustc_abi::{BackendRepr, ExternAbi, RegKind};
+use rustc_abi::{BackendRepr, RegKind};
 use rustc_hir::CRATE_HIR_ID;
 use rustc_middle::mir::{self, traversal};
 use rustc_middle::ty::{self, Instance, InstanceKind, Ty, TyCtxt};
@@ -115,8 +115,8 @@ fn check_call_site_abi<'tcx>(
     span: Span,
     caller: InstanceKind<'tcx>,
 ) {
-    if callee.fn_sig(tcx).abi() == ExternAbi::Rust {
-        // "Rust" ABI never passes arguments in vector registers.
+    if callee.fn_sig(tcx).abi().is_rustic_abi() {
+        // we directly handle the soundness of Rust ABIs
         return;
     }
     let typing_env = ty::TypingEnv::fully_monomorphized();