Separate witness type computation from the generator transform.

Author: cjgillot

compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs

@@ -202,6 +202,7 @@ provide! { tcx, def_id, other, cdata,
     thir_abstract_const => { table }
     optimized_mir => { table }
     mir_for_ctfe => { table }
+    mir_generator_witnesses => { table }
     promoted_mir => { table }
     def_span => { table }
     def_ident_span => { table }

compiler/rustc_metadata/src/rmeta/encoder.rs

@@ -1414,6 +1414,10 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
             debug!("EntryBuilder::encode_mir({:?})", def_id);
             if encode_opt {
                 record!(self.tables.optimized_mir[def_id.to_def_id()] <- tcx.optimized_mir(def_id));
+
+                if let DefKind::Generator = self.tcx.def_kind(def_id) {
+                    record!(self.tables.mir_generator_witnesses[def_id.to_def_id()] <- tcx.mir_generator_witnesses(def_id));
+                }
             }
             if encode_const {
                 record!(self.tables.mir_for_ctfe[def_id.to_def_id()] <- tcx.mir_for_ctfe(def_id));

compiler/rustc_metadata/src/rmeta/mod.rs

@@ -376,6 +376,7 @@ define_tables! {
     object_lifetime_default: Table<DefIndex, LazyValue<ObjectLifetimeDefault>>,
     optimized_mir: Table<DefIndex, LazyValue<mir::Body<'static>>>,
     mir_for_ctfe: Table<DefIndex, LazyValue<mir::Body<'static>>>,
+    mir_generator_witnesses: Table<DefIndex, LazyValue<mir::GeneratorLayout<'static>>>,
     promoted_mir: Table<DefIndex, LazyValue<IndexVec<mir::Promoted, mir::Body<'static>>>>,
     // FIXME(compiler-errors): Why isn't this a LazyArray?
     thir_abstract_const: Table<DefIndex, LazyValue<ty::Const<'static>>>,

compiler/rustc_middle/src/query/mod.rs

@@ -471,6 +471,13 @@ rustc_queries! {
         }
     }
 
+    query mir_generator_witnesses(key: DefId) -> mir::GeneratorLayout<'tcx> {
+        arena_cache
+        desc { |tcx| "generator witness types for `{}`", tcx.def_path_str(key) }
+        cache_on_disk_if { key.is_local() }
+        separate_provide_extern
+    }
+
     /// MIR after our optimization passes have run. This is MIR that is ready
     /// for codegen. This is also the only query that can fetch non-local MIR, at present.
     query optimized_mir(key: DefId) -> &'tcx mir::Body<'tcx> {

compiler/rustc_middle/src/ty/parameterized.rs

@@ -117,6 +117,7 @@ macro_rules! parameterized_over_tcx {
 parameterized_over_tcx! {
     crate::middle::exported_symbols::ExportedSymbol,
     crate::mir::Body,
+    crate::mir::GeneratorLayout,
     ty::Ty,
     ty::FnSig,
     ty::GenericPredicates,

compiler/rustc_mir_build/src/build/matches/mod.rs

@@ -1747,8 +1747,9 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 };
                 let fake_borrow_deref_ty = matched_place.ty(&self.local_decls, tcx).ty;
                 let fake_borrow_ty = tcx.mk_imm_ref(tcx.lifetimes.re_erased, fake_borrow_deref_ty);
-                let fake_borrow_temp =
-                    self.local_decls.push(LocalDecl::new(fake_borrow_ty, temp_span));
+                let mut fake_borrow_temp = LocalDecl::new(fake_borrow_ty, temp_span);
+                fake_borrow_temp.internal = self.local_decls[matched_place.local].internal;
+                let fake_borrow_temp = self.local_decls.push(fake_borrow_temp);
 
                 (matched_place, fake_borrow_temp)
             })