//! through, but errors for structured control flow in a `const` should be emitted here.
use rustc_attr as attr;
-use rustc_errors::struct_span_err;
use rustc_hir as hir;
use rustc_hir::def_id::LocalDefId;
use rustc_hir::intravisit::{self, Visitor};
use rustc_session::parse::feature_err;
use rustc_span::{sym, Span, Symbol};
+use crate::errors::{ConstImplConstTrait, ExprNotAllowedInContext};
+
/// An expression that is not *always* legal in a const context.
#[derive(Clone, Copy)]
enum NonConstExpr {
let const_kind =
const_kind.expect("`const_check_violated` may only be called inside a const context");
- let msg = format!("{} is not allowed in a `{}`", expr.name(), const_kind.keyword_name());
-
let required_gates = required_gates.unwrap_or(&[]);
let missing_gates: Vec<_> =
required_gates.iter().copied().filter(|&g| !features.enabled(g)).collect();
match missing_gates.as_slice() {
[] => {
- struct_span_err!(tcx.sess, span, E0744, "{}", msg).emit();
+ tcx.sess.emit_err(ExprNotAllowedInContext {
+ span,
+ expr: expr.name(),
+ context: const_kind.keyword_name(),
+ });
}
[missing_primary, ref missing_secondary @ ..] => {
+ let msg =
+ format!("{} is not allowed in a `{}`", expr.name(), const_kind.keyword_name());
let mut err = feature_err(&tcx.sess.parse_sess, *missing_primary, span, &msg);
// If multiple feature gates would be required to enable this expression, include
self.tcx.hir()
}
+ fn visit_item(&mut self, item: &'tcx hir::Item<'tcx>) {
+ let tcx = self.tcx;
+ if let hir::ItemKind::Impl(hir::Impl {
+ constness: hir::Constness::Const,
+ of_trait: Some(trait_ref),
+ ..
+ }) = item.kind
+ && let Some(def_id) = trait_ref.trait_def_id()
+ {
+ let source_map = tcx.sess.source_map();
+ if !tcx.has_attr(def_id, sym::const_trait) {
+ tcx.sess.emit_err(ConstImplConstTrait {
+ span: source_map.guess_head_span(item.span),
+ def_span: source_map.guess_head_span(tcx.def_span(def_id)),
+ });
+ }
+ }
+ intravisit::walk_item(self, item);
+ }
+
fn visit_anon_const(&mut self, anon: &'tcx hir::AnonConst) {
let kind = Some(hir::ConstContext::Const);
self.recurse_into(kind, None, |this| intravisit::walk_anon_const(this, anon));