Remove some unnecessary erases

Author: compiler-errors

compiler/rustc_hir_typeck/src/cast.rs

@@ -490,11 +490,7 @@ impl<'a, 'tcx> CastCheck<'tcx> {
                         && let Some(from_trait) = fcx.tcx.get_diagnostic_item(sym::From)
                     {
                         let ty = fcx.resolve_vars_if_possible(self.cast_ty);
-                        // Erase regions to avoid panic in `prove_value` when calling
-                        // `type_implements_trait`.
-                        let ty = fcx.tcx.erase_regions(ty);
                         let expr_ty = fcx.resolve_vars_if_possible(self.expr_ty);
-                        let expr_ty = fcx.tcx.erase_regions(expr_ty);
                         if fcx
                             .infcx
                             .type_implements_trait(from_trait, [ty, expr_ty], fcx.param_env)

compiler/rustc_middle/src/ty/print/pretty.rs

@@ -1453,9 +1453,7 @@ pub trait PrettyPrinter<'tcx>: Printer<'tcx> + fmt::Write {
                                 // contain named regions. So we erase and anonymize everything
                                 // here to compare the types modulo regions below.
                                 let proj = cx.tcx().erase_regions(proj);
-                                let proj = cx.tcx().anonymize_bound_vars(proj);
                                 let super_proj = cx.tcx().erase_regions(super_proj);
-                                let super_proj = cx.tcx().anonymize_bound_vars(super_proj);
 
                                 proj == super_proj
                             });

compiler/rustc_mir_transform/src/add_subtyping_projections.rs

@@ -32,7 +32,7 @@ impl<'a, 'tcx> MutVisitor<'tcx> for SubTypeChecker<'a, 'tcx> {
         let mut rval_ty = rvalue.ty(self.local_decls, self.tcx);
         // Not erasing this causes `Free Regions` errors in validator,
         // when rval is `ReStatic`.
-        rval_ty = self.tcx.erase_regions_ty(rval_ty);
+        rval_ty = self.tcx.erase_regions(rval_ty);
         place_ty = self.tcx.erase_regions(place_ty);
         if place_ty != rval_ty {
             let temp = self