Remove allows_infer now that every use of it is delegated to HirTyLowere

Author: oli-obk

compiler/rustc_hir_analysis/src/collect.rs

@@ -29,7 +29,9 @@ use rustc_infer::traits::ObligationCause;
 use rustc_middle::hir::nested_filter;
 use rustc_middle::query::Providers;
 use rustc_middle::ty::util::{Discr, IntTypeExt};
-use rustc_middle::ty::{self, AdtKind, Const, IsSuggestable, Ty, TyCtxt, Upcast};
+use rustc_middle::ty::{
+    self, AdtKind, Const, IsSuggestable, Ty, TyCtxt, TypeVisitableExt as _, Upcast,
+};
 use rustc_middle::{bug, span_bug};
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
 use rustc_span::{Span, DUMMY_SP};
@@ -372,8 +374,8 @@ impl<'tcx> HirTyLowerer<'tcx> for ItemCtxt<'tcx> {
         self.item_def_id
     }
 
-    fn allow_infer(&self) -> bool {
-        false
+    fn check_type(&self, ty: Ty<'tcx>) {
+        assert!(!ty.has_infer(), "{ty:?}")
     }
 
     fn re_infer(

compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs

@@ -90,8 +90,9 @@ pub trait HirTyLowerer<'tcx> {
     /// Returns the [`DefId`] of the overarching item whose constituents get lowered.
     fn item_def_id(&self) -> LocalDefId;
 
-    /// Returns `true` if the current context allows the use of inference variables.
-    fn allow_infer(&self) -> bool;
+    /// Checks if a type is valid for this context and panics otherwise.
+    /// This is used to prevent the use of inference variables in `ItemCtxt`.
+    fn check_type(&self, _: Ty<'tcx>);
 
     /// Returns the region to use when a lifetime is omitted (and not elided).
     ///
@@ -1204,7 +1205,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
         //
 
         let infcx = self.infcx();
-        assert!(self.allow_infer() || !self_ty.has_infer());
+        self.check_type(self_ty);
 
         // FIXME(inherent_associated_types): Acquiring the ParamEnv this early leads to cycle errors
         // when inside of an ADT (#108491) or where clause.
@@ -1368,7 +1369,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
         let tcx = self.tcx();
 
         let infcx = self.infcx();
-        assert!(self.allow_infer() || !qself_ty.has_infer());
+        self.check_type(qself_ty);
 
         tcx.all_traits()
             .filter(|trait_def_id| {

compiler/rustc_hir_typeck/src/fn_ctxt/mod.rs

@@ -222,8 +222,8 @@ impl<'a, 'tcx> HirTyLowerer<'tcx> for FnCtxt<'a, 'tcx> {
         self.body_id
     }
 
-    fn allow_infer(&self) -> bool {
-        true
+    fn check_type(&self, _: Ty<'tcx>) {
+        // Nothing to do, we allow all types
     }
 
     fn re_infer(