self.check_rustc_args_required_const(&attr, span, target, item)
} else if self.tcx.sess.check_name(attr, sym::allow_internal_unstable) {
self.check_allow_internal_unstable(&attr, span, target, &attrs)
+ } else if self.tcx.sess.check_name(attr, sym::rustc_allow_const_fn_unstable) {
+ self.check_rustc_allow_const_fn_unstable(&attr, span, target)
} else {
// lint-only checks
if self.tcx.sess.check_name(attr, sym::cold) {
.emit();
false
}
+
+ /// Outputs an error for `#[allow_internal_unstable]` which can only be applied to macros.
+ /// (Allows proc_macro functions)
+ fn check_rustc_allow_const_fn_unstable(
+ &self,
+ attr: &Attribute,
+ span: &Span,
+ target: Target,
+ ) -> bool {
+ if let Target::Fn | Target::Method(_) = target {
+ // FIXME Check that this isn't just a function, but a const fn
+ return true;
+ }
+ self.tcx
+ .sess
+ .struct_span_err(attr.span, "attribute should be applied to `const fn`")
+ .span_label(*span, "not a `const fn`")
+ .emit();
+ false
+ }
}
impl Visitor<'tcx> for CheckAttrVisitor<'tcx> {