Make sure FFI attrs aren't used on foreign statics

Previously, we verified that FFI attrs were used on foreign items,
but this allowed them on both foreign functions and foreign statics.
This change only allows them on foreign functions.

Author: inquisitivecrystal

compiler/rustc_passes/src/check_attr.rs

@@ -150,9 +150,9 @@ impl CheckAttrVisitor<'_> {
                 sym::rustc_has_incoherent_inherent_impls => {
                     self.check_has_incoherent_inherent_impls(&attr, span, target)
                 }
-                sym::ffi_pure => self.check_ffi_pure(hir_id, attr.span, attrs),
-                sym::ffi_const => self.check_ffi_const(hir_id, attr.span),
-                sym::ffi_returns_twice => self.check_ffi_returns_twice(hir_id, attr.span),
+                sym::ffi_pure => self.check_ffi_pure(attr.span, attrs, target),
+                sym::ffi_const => self.check_ffi_const(attr.span, target),
+                sym::ffi_returns_twice => self.check_ffi_returns_twice(attr.span, target),
                 sym::rustc_const_unstable
                 | sym::rustc_const_stable
                 | sym::unstable
@@ -1174,8 +1174,8 @@ impl CheckAttrVisitor<'_> {
         }
     }
 
-    fn check_ffi_pure(&self, hir_id: HirId, attr_span: Span, attrs: &[Attribute]) -> bool {
-        if !self.tcx.is_foreign_item(self.tcx.hir().local_def_id(hir_id)) {
+    fn check_ffi_pure(&self, attr_span: Span, attrs: &[Attribute], target: Target) -> bool {
+        if target != Target::ForeignFn {
             self.tcx.sess.emit_err(errors::FfiPureInvalidTarget { attr_span });
             return false;
         }
@@ -1188,17 +1188,17 @@ impl CheckAttrVisitor<'_> {
         }
     }
 
-    fn check_ffi_const(&self, hir_id: HirId, attr_span: Span) -> bool {
-        if self.tcx.is_foreign_item(self.tcx.hir().local_def_id(hir_id)) {
+    fn check_ffi_const(&self, attr_span: Span, target: Target) -> bool {
+        if target == Target::ForeignFn {
             true
         } else {
             self.tcx.sess.emit_err(errors::FfiConstInvalidTarget { attr_span });
             false
         }
     }
 
-    fn check_ffi_returns_twice(&self, hir_id: HirId, attr_span: Span) -> bool {
-        if self.tcx.is_foreign_item(self.tcx.hir().local_def_id(hir_id)) {
+    fn check_ffi_returns_twice(&self, attr_span: Span, target: Target) -> bool {
+        if target == Target::ForeignFn {
             true
         } else {
             self.tcx.sess.emit_err(errors::FfiReturnsTwiceInvalidTarget { attr_span });