interpret: make typing_env field private

compiler/rustc_const_eval/src/const_eval/eval_queries.rs

@@ -7,7 +7,7 @@ use rustc_middle::bug;
 use rustc_middle::mir::interpret::{AllocId, ErrorHandled, InterpErrorInfo};
 use rustc_middle::mir::{self, ConstAlloc, ConstValue};
 use rustc_middle::query::TyCtxtAt;
-use rustc_middle::ty::layout::LayoutOf;
+use rustc_middle::ty::layout::{HasTypingEnv, LayoutOf};
 use rustc_middle::ty::print::with_no_trimmed_paths;
 use rustc_middle::ty::{self, Ty, TyCtxt};
 use rustc_span::def_id::LocalDefId;
@@ -30,7 +30,6 @@ fn eval_body_using_ecx<'tcx, R: InterpretationResult<'tcx>>(
     cid: GlobalId<'tcx>,
     body: &'tcx mir::Body<'tcx>,
 ) -> InterpResult<'tcx, R> {
-    trace!(?ecx.typing_env);
     let tcx = *ecx.tcx;
     assert!(
         cid.promoted.is_some()
@@ -220,7 +219,7 @@ pub(super) fn op_to_const<'tcx>(
                 let pointee_ty = imm.layout.ty.builtin_deref(false).unwrap(); // `false` = no raw ptrs
                 debug_assert!(
                     matches!(
-                        ecx.tcx.struct_tail_for_codegen(pointee_ty, ecx.typing_env).kind(),
+                        ecx.tcx.struct_tail_for_codegen(pointee_ty, ecx.typing_env()).kind(),
                         ty::Str | ty::Slice(..),
                     ),
                     "`ConstValue::Slice` is for slice-tailed types only, but got {}",