Eliminate escape hatch

compiler/rustc_smir/src/rustc_internal/mod.rs

@@ -25,6 +25,15 @@ impl<'tcx> Index<stable_mir::DefId> for Tables<'tcx> {
     }
 }
 
+impl<'tcx> Index<stable_mir::ty::Span> for Tables<'tcx> {
+    type Output = Span;
+
+    #[inline(always)]
+    fn index(&self, index: stable_mir::ty::Span) -> &Self::Output {
+        &self.spans[index.0]
+    }
+}
+
 impl<'tcx> Tables<'tcx> {
     pub fn crate_item(&mut self, did: DefId) -> stable_mir::CrateItem {
         stable_mir::CrateItem(self.create_def_id(did))

compiler/rustc_smir/src/rustc_smir/mod.rs

@@ -44,6 +44,11 @@ impl<'tcx> Context for Tables<'tcx> {
         self.tcx.def_path_str(self[def_id])
     }
 
+    fn print_span(&self, span: stable_mir::ty::Span) -> String {
+        self.tcx.sess.source_map().span_to_diagnostic_string(self[span])
+    }
+
+
     fn span_of_an_item(&mut self, def_id: stable_mir::DefId) -> Span {
         self.tcx.def_span(self[def_id]).stable(self)
     }
@@ -104,10 +109,6 @@ impl<'tcx> Context for Tables<'tcx> {
         }
     }
 
-    fn rustc_tables(&mut self, f: &mut dyn FnMut(&mut Tables<'_>)) {
-        f(self)
-    }
-
     fn ty_kind(&mut self, ty: crate::stable_mir::ty::Ty) -> TyKind {
         self.types[ty.0].clone().stable(self)
     }

compiler/rustc_smir/src/stable_mir/mod.rs

@@ -15,10 +15,11 @@ use std::cell::Cell;
 use std::fmt;
 use std::fmt::Debug;
 
+use crate::rustc_internal::Opaque;
+
 use self::ty::{
     GenericPredicates, Generics, ImplDef, ImplTrait, Span, TraitDecl, TraitDef, Ty, TyKind,
 };
-use crate::rustc_smir::Tables;
 
 pub mod fold;
 pub mod mir;
@@ -79,6 +80,8 @@ pub struct Crate {
     pub is_local: bool,
 }
 
+pub type DefKind = Opaque;
+
 /// Holds information about an item in the crate.
 /// For now, it only stores the item DefId. Use functions inside `rustc_internal` module to
 /// use this item.
@@ -161,6 +164,7 @@ pub trait Context {
     /// Prints the name of given `DefId`
     fn name_of_def_id(&self, def_id: DefId) -> String;
 
+    fn print_span(&self, span: Span) -> String;
     /// `Span` of an item
     fn span_of_an_item(&mut self, def_id: DefId) -> Span;
 
@@ -169,10 +173,6 @@ pub trait Context {
 
     /// Create a new `Ty` from scratch without information from rustc.
     fn mk_ty(&mut self, kind: TyKind) -> Ty;
-
-    /// HACK: Until we have fully stable consumers, we need an escape hatch
-    /// to get `DefId`s out of `CrateItem`s.
-    fn rustc_tables(&mut self, f: &mut dyn FnMut(&mut Tables<'_>));
 }
 
 // A thread local variable that stores a pointer to the tables mapping between TyCtxt

compiler/rustc_smir/src/stable_mir/ty.rs

@@ -40,9 +40,10 @@ pub struct Span(pub(crate) usize);
 
 impl Debug for Span {
     fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
-        let mut span = None;
-        with(|context| context.rustc_tables(&mut |tables| span = Some(tables.spans[self.0])));
-        f.write_fmt(format_args!("{:?}", &span.unwrap()))
+        f.debug_struct("Span")
+            .field("id", &self.0)
+            .field("repr", &with(|cx| cx.print_span(*self)))
+            .finish()
     }
 }