diff --git a/compiler/rustc_mir/src/borrow_check/diagnostics/conflict_errors.rs b/compiler/rustc_mir/src/borrow_check/diagnostics/conflict_errors.rs
index 11122b195c0..dca0d6d7790 100644
--- a/compiler/rustc_mir/src/borrow_check/diagnostics/conflict_errors.rs
+++ b/compiler/rustc_mir/src/borrow_check/diagnostics/conflict_errors.rs
@@ -336,10 +336,11 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                 };
                 if let ty::Param(param_ty) = ty.kind() {
                     let tcx = self.infcx.tcx;
-                    let generics = tcx.generics_of(self.mir_def_id);
+                    let generics = tcx.generics_of(self.mir_def_id());
                     let param = generics.type_param(&param_ty, tcx);
-                    if let Some(generics) =
-                        tcx.hir().get_generics(tcx.closure_base_def_id(self.mir_def_id.to_def_id()))
+                    if let Some(generics) = tcx
+                        .hir()
+                        .get_generics(tcx.closure_base_def_id(self.mir_def_id().to_def_id()))
                     {
                         suggest_constraining_type_param(
                             tcx,
@@ -1004,7 +1005,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                 format!("`{}` would have to be valid for `{}`...", name, region_name),
             );
 
-            let fn_hir_id = self.infcx.tcx.hir().local_def_id_to_hir_id(self.mir_def_id);
+            let fn_hir_id = self.mir_hir_id();
             err.span_label(
                 drop_span,
                 format!(
@@ -1019,7 +1020,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
                             match &self
                                 .infcx
                                 .tcx
-                                .typeck(self.mir_def_id)
+                                .typeck(self.mir_def_id())
                                 .node_type(fn_hir_id)
                                 .kind()
                             {
@@ -1369,7 +1370,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
     ) -> DiagnosticBuilder<'cx> {
         let tcx = self.infcx.tcx;
 
-        let (_, escapes_from) = tcx.article_and_description(self.mir_def_id.to_def_id());
+        let (_, escapes_from) = tcx.article_and_description(self.mir_def_id().to_def_id());
 
         let mut err =
             borrowck_errors::borrowed_data_escapes_closure(tcx, escape_span, escapes_from);
@@ -1708,15 +1709,15 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
     ) -> Option<AnnotatedBorrowFnSignature<'tcx>> {
         // Define a fallback for when we can't match a closure.
         let fallback = || {
-            let is_closure = self.infcx.tcx.is_closure(self.mir_def_id.to_def_id());
+            let is_closure = self.infcx.tcx.is_closure(self.mir_def_id().to_def_id());
             if is_closure {
                 None
             } else {
-                let ty = self.infcx.tcx.type_of(self.mir_def_id);
+                let ty = self.infcx.tcx.type_of(self.mir_def_id());
                 match ty.kind() {
                     ty::FnDef(_, _) | ty::FnPtr(_) => self.annotate_fn_sig(
-                        self.mir_def_id.to_def_id(),
-                        self.infcx.tcx.fn_sig(self.mir_def_id),
+                        self.mir_def_id().to_def_id(),
+                        self.infcx.tcx.fn_sig(self.mir_def_id()),
                     ),
                     _ => None,
                 }
diff --git a/compiler/rustc_mir/src/borrow_check/diagnostics/move_errors.rs b/compiler/rustc_mir/src/borrow_check/diagnostics/move_errors.rs
index 629e9be9ddd..b1cebbd1f38 100644
--- a/compiler/rustc_mir/src/borrow_check/diagnostics/move_errors.rs
+++ b/compiler/rustc_mir/src/borrow_check/diagnostics/move_errors.rs
@@ -331,7 +331,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                 self.cannot_move_out_of_interior_noncopy(span, ty, None)
             }
             ty::Closure(def_id, closure_substs)
-                if def_id.as_local() == Some(self.mir_def_id) && upvar_field.is_some() =>
+                if def_id.as_local() == Some(self.mir_def_id()) && upvar_field.is_some() =>
             {
                 let closure_kind_ty = closure_substs.as_closure().kind_ty();
                 let closure_kind = closure_kind_ty.to_opt_closure_kind();
diff --git a/compiler/rustc_mir/src/borrow_check/diagnostics/mutability_errors.rs b/compiler/rustc_mir/src/borrow_check/diagnostics/mutability_errors.rs
index d4cdf02104a..9728662c984 100644
--- a/compiler/rustc_mir/src/borrow_check/diagnostics/mutability_errors.rs
+++ b/compiler/rustc_mir/src/borrow_check/diagnostics/mutability_errors.rs
@@ -492,7 +492,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
         err.span_label(sp, format!("cannot {}", act));
 
         let hir = self.infcx.tcx.hir();
-        let closure_id = hir.local_def_id_to_hir_id(self.mir_def_id);
+        let closure_id = self.mir_hir_id();
         let fn_call_id = hir.get_parent_node(closure_id);
         let node = hir.get(fn_call_id);
         let item_id = hir.enclosing_body_owner(fn_call_id);
diff --git a/compiler/rustc_mir/src/borrow_check/diagnostics/region_errors.rs b/compiler/rustc_mir/src/borrow_check/diagnostics/region_errors.rs
index eb1f70099fc..b145e1d5fa3 100644
--- a/compiler/rustc_mir/src/borrow_check/diagnostics/region_errors.rs
+++ b/compiler/rustc_mir/src/borrow_check/diagnostics/region_errors.rs
@@ -515,7 +515,8 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
         let mut diag =
             self.infcx.tcx.sess.struct_span_err(*span, "lifetime may not live long enough");
 
-        let (_, mir_def_name) = self.infcx.tcx.article_and_description(self.mir_def_id.to_def_id());
+        let (_, mir_def_name) =
+            self.infcx.tcx.article_and_description(self.mir_def_id().to_def_id());
 
         let fr_name = self.give_region_a_name(*fr).unwrap();
         fr_name.highlight_region_name(&mut diag);
diff --git a/compiler/rustc_mir/src/borrow_check/diagnostics/region_name.rs b/compiler/rustc_mir/src/borrow_check/diagnostics/region_name.rs
index 5f64eb3dba8..2e5a231fef0 100644
--- a/compiler/rustc_mir/src/borrow_check/diagnostics/region_name.rs
+++ b/compiler/rustc_mir/src/borrow_check/diagnostics/region_name.rs
@@ -147,6 +147,14 @@ impl Display for RegionName {
 }
 
 impl<'tcx> MirBorrowckCtxt<'_, 'tcx> {
+    crate fn mir_def_id(&self) -> hir::def_id::LocalDefId {
+        self.body.source.def_id().as_local().unwrap()
+    }
+
+    crate fn mir_hir_id(&self) -> hir::HirId {
+        self.infcx.tcx.hir().local_def_id_to_hir_id(self.mir_def_id())
+    }
+
     /// Generate a synthetic region named `'N`, where `N` is the next value of the counter. Then,
     /// increment the counter.
     ///
@@ -266,12 +274,11 @@ impl<'tcx> MirBorrowckCtxt<'_, 'tcx> {
                 }
 
                 ty::BoundRegion::BrEnv => {
-                    let mir_hir_id = self.infcx.tcx.hir().local_def_id_to_hir_id(self.mir_def_id);
                     let def_ty = self.regioncx.universal_regions().defining_ty;
 
                     if let DefiningTy::Closure(_, substs) = def_ty {
                         let args_span = if let hir::ExprKind::Closure(_, _, _, span, _) =
-                            tcx.hir().expect_expr(mir_hir_id).kind
+                            tcx.hir().expect_expr(self.mir_hir_id()).kind
                         {
                             span
                         } else {
@@ -361,8 +368,7 @@ impl<'tcx> MirBorrowckCtxt<'_, 'tcx> {
         &self,
         argument_index: usize,
     ) -> Option<&hir::Ty<'tcx>> {
-        let mir_hir_id = self.infcx.tcx.hir().local_def_id_to_hir_id(self.mir_def_id);
-        let fn_decl = self.infcx.tcx.hir().fn_decl_by_hir_id(mir_hir_id)?;
+        let fn_decl = self.infcx.tcx.hir().fn_decl_by_hir_id(self.mir_hir_id())?;
         let argument_hir_ty: &hir::Ty<'_> = fn_decl.inputs.get(argument_index)?;
         match argument_hir_ty.kind {
             // This indicates a variable with no type annotation, like
@@ -649,9 +655,7 @@ impl<'tcx> MirBorrowckCtxt<'_, 'tcx> {
         let type_name =
             self.infcx.extract_inference_diagnostics_data(return_ty.into(), Some(highlight)).name;
 
-        let mir_hir_id = tcx.hir().local_def_id_to_hir_id(self.mir_def_id);
-
-        let (return_span, mir_description) = match tcx.hir().get(mir_hir_id) {
+        let (return_span, mir_description) = match tcx.hir().get(self.mir_hir_id()) {
             hir::Node::Expr(hir::Expr {
                 kind: hir::ExprKind::Closure(_, return_ty, _, span, gen_move),
                 ..
@@ -702,9 +706,7 @@ impl<'tcx> MirBorrowckCtxt<'_, 'tcx> {
         let type_name =
             self.infcx.extract_inference_diagnostics_data(yield_ty.into(), Some(highlight)).name;
 
-        let mir_hir_id = tcx.hir().local_def_id_to_hir_id(self.mir_def_id);
-
-        let yield_span = match tcx.hir().get(mir_hir_id) {
+        let yield_span = match tcx.hir().get(self.mir_hir_id()) {
             hir::Node::Expr(hir::Expr {
                 kind: hir::ExprKind::Closure(_, _, _, span, _), ..
             }) => (tcx.sess.source_map().end_point(*span)),
diff --git a/compiler/rustc_mir/src/borrow_check/mod.rs b/compiler/rustc_mir/src/borrow_check/mod.rs
index 3c72852e017..9b34db1de40 100644
--- a/compiler/rustc_mir/src/borrow_check/mod.rs
+++ b/compiler/rustc_mir/src/borrow_check/mod.rs
@@ -285,7 +285,6 @@ fn do_mir_borrowck<'a, 'tcx>(
                 infcx,
                 param_env,
                 body: promoted_body,
-                mir_def_id: def.did,
                 move_data: &move_data,
                 location_table: &LocationTable::new(promoted_body),
                 movable_generator,
@@ -319,7 +318,6 @@ fn do_mir_borrowck<'a, 'tcx>(
         infcx,
         param_env,
         body,
-        mir_def_id: def.did,
         move_data: &mdpe.move_data,
         location_table,
         movable_generator,
@@ -473,7 +471,6 @@ crate struct MirBorrowckCtxt<'cx, 'tcx> {
     crate infcx: &'cx InferCtxt<'cx, 'tcx>,
     param_env: ParamEnv<'tcx>,
     body: &'cx Body<'tcx>,
-    mir_def_id: LocalDefId,
     move_data: &'cx MoveData<'tcx>,
 
     /// Map from MIR `Location` to `LocationIndex`; created