Ban non-static lifetimes from AnonConst on AST.

The extra diagnostics come from the compiler no longer aborting before
typeck.

Author: cjgillot

compiler/rustc_resolve/src/late.rs

@@ -204,6 +204,11 @@ enum LifetimeRibKind {
     /// lifetimes in const generics. See issue #74052 for discussion.
     ConstGeneric,
 
+    /// Non-static lifetimes are prohibited in anonymous constants under `min_const_generics`.
+    /// This function will emit an error if `generic_const_exprs` is not enabled, the body identified by
+    /// `body_id` is an anonymous constant and `lifetime_ref` is non-static.
+    AnonConst,
+
     /// For **Modern** cases, create a new anonymous region parameter
     /// and reference that.
     ///
@@ -532,7 +537,9 @@ impl<'a: 'ast, 'ast> Visitor<'ast> for LateResolutionVisitor<'a, '_, 'ast> {
     }
     fn visit_anon_const(&mut self, constant: &'ast AnonConst) {
         // We deal with repeat expressions explicitly in `resolve_expr`.
-        self.resolve_anon_const(constant, IsRepeatExpr::No);
+        self.with_lifetime_rib(LifetimeRibKind::AnonConst, |this| {
+            this.resolve_anon_const(constant, IsRepeatExpr::No);
+        })
     }
     fn visit_expr(&mut self, expr: &'ast Expr) {
         self.resolve_expr(expr, None);
@@ -1117,7 +1124,7 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
                             this.ribs[TypeNS].push(forward_ty_ban_rib);
                             this.ribs[ValueNS].push(forward_const_ban_rib);
                             this.with_lifetime_rib(LifetimeRibKind::ConstGeneric, |this| {
-                                this.visit_anon_const(expr)
+                                this.resolve_anon_const(expr, IsRepeatExpr::No)
                             });
                             forward_const_ban_rib = this.ribs[ValueNS].pop().unwrap();
                             forward_ty_ban_rib = this.ribs[TypeNS].pop().unwrap();
@@ -1174,6 +1181,11 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
                     self.r.lifetimes_res_map.insert(lifetime.id, LifetimeRes::Error);
                     return;
                 }
+                LifetimeRibKind::AnonConst => {
+                    self.maybe_emit_forbidden_non_static_lifetime_error(lifetime);
+                    self.r.lifetimes_res_map.insert(lifetime.id, LifetimeRes::Error);
+                    return;
+                }
                 _ => {}
             }
         }
@@ -3076,9 +3088,7 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
             is_repeat,
             constant.value.is_potential_trivial_const_param(),
             None,
-            |this| {
-                visit::walk_anon_const(this, constant);
-            },
+            |this| visit::walk_anon_const(this, constant),
         );
     }
 
@@ -3229,7 +3239,12 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
             }
             ExprKind::Repeat(ref elem, ref ct) => {
                 self.visit_expr(elem);
-                self.resolve_anon_const(ct, IsRepeatExpr::Yes);
+                self.with_lifetime_rib(LifetimeRibKind::AnonConst, |this| {
+                    this.resolve_anon_const(ct, IsRepeatExpr::Yes)
+                });
+            }
+            ExprKind::ConstBlock(ref ct) => {
+                self.resolve_anon_const(ct, IsRepeatExpr::No);
             }
             ExprKind::Index(ref elem, ref idx) => {
                 self.resolve_expr(elem, Some(expr));

compiler/rustc_resolve/src/late/diagnostics.rs

@@ -1901,6 +1901,22 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
         )
         .emit();
     }
+
+    /// Non-static lifetimes are prohibited in anonymous constants under `min_const_generics`.
+    /// This function will emit an error if `generic_const_exprs` is not enabled, the body identified by
+    /// `body_id` is an anonymous constant and `lifetime_ref` is non-static.
+    crate fn maybe_emit_forbidden_non_static_lifetime_error(&self, lifetime_ref: &ast::Lifetime) {
+        let feature_active = self.r.session.features_untracked().generic_const_exprs;
+        if !feature_active {
+            feature_err(
+                &self.r.session.parse_sess,
+                sym::generic_const_exprs,
+                lifetime_ref.ident.span,
+                "a non-static lifetime is not allowed in a `const`",
+            )
+            .emit();
+        }
+    }
 }
 
 impl<'tcx> LifetimeContext<'_, 'tcx> {
@@ -2398,32 +2414,4 @@ impl<'tcx> LifetimeContext<'_, 'tcx> {
             _ => unreachable!(),
         }
     }
-
-    /// Non-static lifetimes are prohibited in anonymous constants under `min_const_generics`.
-    /// This function will emit an error if `generic_const_exprs` is not enabled, the body identified by
-    /// `body_id` is an anonymous constant and `lifetime_ref` is non-static.
-    crate fn maybe_emit_forbidden_non_static_lifetime_error(
-        &self,
-        body_id: hir::BodyId,
-        lifetime_ref: &'tcx hir::Lifetime,
-    ) {
-        let is_anon_const = matches!(
-            self.tcx.def_kind(self.tcx.hir().body_owner_def_id(body_id)),
-            hir::def::DefKind::AnonConst
-        );
-        let is_allowed_lifetime = matches!(
-            lifetime_ref.name,
-            hir::LifetimeName::Implicit | hir::LifetimeName::Static | hir::LifetimeName::Underscore
-        );
-
-        if !self.tcx.lazy_normalization() && is_anon_const && !is_allowed_lifetime {
-            feature_err(
-                &self.tcx.sess.parse_sess,
-                sym::generic_const_exprs,
-                lifetime_ref.span,
-                "a non-static lifetime is not allowed in a `const`",
-            )
-            .emit();
-        }
-    }
 }

compiler/rustc_resolve/src/late/lifetimes.rs

@@ -2243,10 +2243,6 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
         let result = loop {
             match *scope {
                 Scope::Body { id, s } => {
-                    // Non-static lifetimes are prohibited in anonymous constants without
-                    // `generic_const_exprs`.
-                    self.maybe_emit_forbidden_non_static_lifetime_error(id, lifetime_ref);
-
                     outermost_body = Some(id);
                     scope = s;
                 }