From 30fa84eceba7982c62ffa89e00401903bf5c0dc8 Mon Sep 17 00:00:00 2001
From: LeSeulArtichaut <leseulartichaut@gmail.com>
Date: Tue, 4 Aug 2020 15:06:34 +0200
Subject: [PATCH] Add `TyCtxtAt::{ty_error, ty_error_with_message}`

---
 src/librustc_middle/ty/context.rs | 22 +++++++++++++++++++---
 1 file changed, 19 insertions(+), 3 deletions(-)

diff --git a/src/librustc_middle/ty/context.rs b/src/librustc_middle/ty/context.rs
index 775d755444d7d..ed52981efc949 100644
--- a/src/librustc_middle/ty/context.rs
+++ b/src/librustc_middle/ty/context.rs
@@ -13,13 +13,14 @@ use crate::middle::stability;
 use crate::mir::interpret::{self, Allocation, ConstValue, Scalar};
 use crate::mir::{Body, Field, Local, Place, PlaceElem, ProjectionKind, Promoted};
 use crate::traits;
+use crate::ty::query::{self, TyCtxtAt};
 use crate::ty::steal::Steal;
 use crate::ty::subst::{GenericArg, GenericArgKind, InternalSubsts, Subst, SubstsRef, UserSubsts};
 use crate::ty::TyKind::*;
 use crate::ty::{
-    self, query, AdtDef, AdtKind, BindingMode, BoundVar, CanonicalPolyFnSig, Const, ConstVid,
-    DefIdTree, ExistentialPredicate, FloatVar, FloatVid, GenericParamDefKind, InferConst, InferTy,
-    IntVar, IntVid, List, ParamConst, ParamTy, PolyFnSig, Predicate, PredicateInner, PredicateKind,
+    self, AdtDef, AdtKind, BindingMode, BoundVar, CanonicalPolyFnSig, Const, ConstVid, DefIdTree,
+    ExistentialPredicate, FloatVar, FloatVid, GenericParamDefKind, InferConst, InferTy, IntVar,
+    IntVid, List, ParamConst, ParamTy, PolyFnSig, Predicate, PredicateInner, PredicateKind,
     ProjectionTy, Region, RegionKind, ReprOptions, TraitObjectVisitor, Ty, TyKind, TyS, TyVar,
     TyVid, TypeAndMut,
 };
@@ -2652,6 +2653,21 @@ impl<'tcx> TyCtxt<'tcx> {
     }
 }
 
+impl TyCtxtAt<'tcx> {
+    /// Constructs a `TyKind::Error` type and registers a `delay_span_bug` to ensure it gets used.
+    #[track_caller]
+    pub fn ty_error(self) -> Ty<'tcx> {
+        self.tcx.ty_error_with_message(self.span, "TyKind::Error constructed but no error reported")
+    }
+
+    /// Constructs a `TyKind::Error` type and registers a `delay_span_bug` with the given `msg to
+    /// ensure it gets used.
+    #[track_caller]
+    pub fn ty_error_with_message(self, msg: &str) -> Ty<'tcx> {
+        self.tcx.ty_error_with_message(self.span, msg)
+    }
+}
+
 pub trait InternAs<T: ?Sized, R> {
     type Output;
     fn intern_with<F>(self, f: F) -> Self::Output