Rollup of 8 pull requests

compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs

@@ -29,10 +29,9 @@ use rustc_errors::codes::*;
 use rustc_errors::{
     Applicability, Diag, DiagCtxtHandle, ErrorGuaranteed, FatalError, struct_span_code_err,
 };
-use rustc_hir as hir;
 use rustc_hir::def::{CtorKind, CtorOf, DefKind, Namespace, Res};
 use rustc_hir::def_id::{DefId, LocalDefId};
-use rustc_hir::{GenericArg, GenericArgs, HirId};
+use rustc_hir::{self as hir, AnonConst, GenericArg, GenericArgs, HirId};
 use rustc_infer::infer::{InferCtxt, TyCtxtInferExt};
 use rustc_infer::traits::ObligationCause;
 use rustc_middle::middle::stability::AllowUnstable;
@@ -2089,7 +2088,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                 qpath.span(),
                 format!("Const::lower_const_arg: invalid qpath {qpath:?}"),
             ),
-            hir::ConstArgKind::Anon(anon) => self.lower_anon_const(anon.def_id),
+            hir::ConstArgKind::Anon(anon) => self.lower_anon_const(anon),
             hir::ConstArgKind::Infer(span) => self.ct_infer(None, span),
         }
     }
@@ -2180,27 +2179,22 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
     /// Literals and const generic parameters are eagerly converted to a constant, everything else
     /// becomes `Unevaluated`.
     #[instrument(skip(self), level = "debug")]
-    fn lower_anon_const(&self, def: LocalDefId) -> Const<'tcx> {
+    fn lower_anon_const(&self, anon: &AnonConst) -> Const<'tcx> {
         let tcx = self.tcx();
 
-        let body_id = match tcx.hir_node_by_def_id(def) {
-            hir::Node::AnonConst(ac) => ac.body,
-            node => span_bug!(
-                tcx.def_span(def.to_def_id()),
-                "from_anon_const can only process anonymous constants, not {node:?}"
-            ),
-        };
-
-        let expr = &tcx.hir().body(body_id).value;
+        let expr = &tcx.hir().body(anon.body).value;
         debug!(?expr);
 
-        let ty = tcx.type_of(def).no_bound_vars().expect("const parameter types cannot be generic");
+        let ty = tcx
+            .type_of(anon.def_id)
+            .no_bound_vars()
+            .expect("const parameter types cannot be generic");
 
         match self.try_lower_anon_const_lit(ty, expr) {
             Some(v) => v,
             None => ty::Const::new_unevaluated(tcx, ty::UnevaluatedConst {
-                def: def.to_def_id(),
-                args: ty::GenericArgs::identity_for_item(tcx, def.to_def_id()),
+                def: anon.def_id.to_def_id(),
+                args: ty::GenericArgs::identity_for_item(tcx, anon.def_id.to_def_id()),
             }),
         }
     }

compiler/rustc_middle/src/query/mod.rs

@@ -916,6 +916,12 @@ rustc_queries! {
         cache_on_disk_if { true }
     }
 
+    /// Checks well-formedness of tail calls (`become f()`).
+    query check_tail_calls(key: LocalDefId) -> Result<(), rustc_errors::ErrorGuaranteed> {
+        desc { |tcx| "tail-call-checking `{}`", tcx.def_path_str(key) }
+        cache_on_disk_if { true }
+    }
+
     /// Returns the types assumed to be well formed while "inside" of the given item.
     ///
     /// Note that we've liberated the late bound regions of function signatures, so

compiler/rustc_mir_build/src/build/mod.rs

@@ -50,6 +50,10 @@ pub(crate) fn mir_build<'tcx>(tcx: TyCtxtAt<'tcx>, def: LocalDefId) -> Body<'tcx
         return construct_error(tcx, def, e);
     }
 
+    if let Err(err) = tcx.check_tail_calls(def) {
+        return construct_error(tcx, def, err);
+    }
+
     let body = match tcx.thir_body(def) {
         Err(error_reported) => construct_error(tcx, def, error_reported),
         Ok((thir, expr)) => {