Use ErrorGuaranteed more in ReError

Author: estebank

compiler/rustc_hir_analysis/src/astconv/mod.rs

@@ -1614,14 +1614,14 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                             "the lifetime bound for this object type cannot be deduced \
                              from context; please supply an explicit bound"
                         );
-                        if borrowed {
+                        let e = if borrowed {
                             // We will have already emitted an error E0106 complaining about a
                             // missing named lifetime in `&dyn Trait`, so we elide this one.
-                            err.delay_as_bug();
+                            err.delay_as_bug()
                         } else {
-                            err.emit();
-                        }
-                        tcx.re_error()
+                            err.emit()
+                        };
+                        tcx.re_error(e)
                     })
                 }
             })

compiler/rustc_infer/src/infer/lexical_region_resolve/mod.rs

@@ -216,7 +216,7 @@ impl<'cx, 'tcx> LexicalResolver<'cx, 'tcx> {
                 Ok(self.tcx().lifetimes.re_static)
             }
 
-            ReError(_) => Ok(self.tcx().re_error()),
+            ReError(_) => Ok(a_region),
 
             ReEarlyBound(_) | ReFree(_) => {
                 // All empty regions are less than early-bound, free,
@@ -548,7 +548,9 @@ impl<'cx, 'tcx> LexicalResolver<'cx, 'tcx> {
                 );
             }
 
-            (ReError(_), _) | (_, ReError(_)) => self.tcx().re_error(),
+            (ReError(_), _) => a,
+
+            (_, ReError(_)) => b,
 
             (ReStatic, _) | (_, ReStatic) => {
                 // nothing lives longer than `'static`
@@ -1044,7 +1046,7 @@ impl<'tcx> LexicalRegionResolutions<'tcx> {
             ty::ReVar(rid) => match self.values[rid] {
                 VarValue::Empty(_) => r,
                 VarValue::Value(r) => r,
-                VarValue::ErrorValue => tcx.re_error(),
+                VarValue::ErrorValue => tcx.re_error_misc(),
             },
             _ => r,
         };

compiler/rustc_middle/src/ty/context.rs

@@ -649,10 +649,16 @@ impl<'tcx> TyCtxt<'tcx> {
         self.mk_ty(Error(reported))
     }
 
+    /// Constructs a `RegionKind::ReError` lifetime.
+    #[track_caller]
+    pub fn re_error(self, reported: ErrorGuaranteed) -> Region<'tcx> {
+        self.mk_region(ty::ReError(reported))
+    }
+
     /// Constructs a `RegionKind::ReError` lifetime and registers a `delay_span_bug` to ensure it
     /// gets used.
     #[track_caller]
-    pub fn re_error(self) -> Region<'tcx> {
+    pub fn re_error_misc(self) -> Region<'tcx> {
         self.re_error_with_message(
             DUMMY_SP,
             "RegionKind::ReError constructed but no error reported",
@@ -664,10 +670,7 @@ impl<'tcx> TyCtxt<'tcx> {
     #[track_caller]
     pub fn re_error_with_message<S: Into<MultiSpan>>(self, span: S, msg: &str) -> Region<'tcx> {
         let reported = self.sess.delay_span_bug(span, msg);
-        let r = ty::ReError(reported);
-        Region(Interned::new_unchecked(
-            self.interners.region.intern(r, |r| InternedInSet(self.interners.arena.alloc(r))).0,
-        ))
+        self.re_error(reported)
     }
 
     /// Like [TyCtxt::ty_error] but for constants, with current `ErrorGuaranteed`

compiler/rustc_middle/src/ty/generics.rs

@@ -100,7 +100,7 @@ impl GenericParamDef {
         preceding_substs: &[ty::GenericArg<'tcx>],
     ) -> ty::GenericArg<'tcx> {
         match &self.kind {
-            ty::GenericParamDefKind::Lifetime => tcx.re_error().into(),
+            ty::GenericParamDefKind::Lifetime => tcx.re_error_misc().into(),
             ty::GenericParamDefKind::Type { .. } => tcx.ty_error().into(),
             ty::GenericParamDefKind::Const { .. } => {
                 tcx.const_error(tcx.bound_type_of(self.def_id).subst(tcx, preceding_substs)).into()

compiler/rustc_middle/src/ty/opaque_types.rs

@@ -127,7 +127,8 @@ impl<'tcx> TypeFolder<'tcx> for ReverseMapper<'tcx> {
             Some(u) => panic!("region mapped to unexpected kind: {:?}", u),
             None if self.do_not_error => self.tcx.lifetimes.re_static,
             None => {
-                self.tcx
+                let e = self
+                    .tcx
                     .sess
                     .struct_span_err(self.span, "non-defining opaque type use in defining scope")
                     .span_label(
@@ -140,7 +141,7 @@ impl<'tcx> TypeFolder<'tcx> for ReverseMapper<'tcx> {
                     )
                     .emit();
 
-                self.tcx().re_error()
+                self.tcx().re_error(e)
             }
         }
     }