Auto merge of rust-lang#107421 - cjgillot:drop-tracking-mir, r=oli-obk

Enable -Zdrop-tracking-mir by default

This PR enables the `drop-tracking-mir` flag by default. This flag was initially implemented in rust-lang#101692.

This flag computes auto-traits on generators based on their analysis MIR, instead of trying to compute on the HIR body. This removes the need for HIR-based drop-tracking, as we can now reuse the same code to compute generator witness types and to compute generator interior fields.

Author: bors

compiler/rustc_codegen_ssa/src/debuginfo/type_names.rs

@@ -426,7 +426,6 @@ fn push_debuginfo_type_name<'tcx>(
         | ty::Placeholder(..)
         | ty::Alias(..)
         | ty::Bound(..)
-        | ty::GeneratorWitnessMIR(..)
         | ty::GeneratorWitness(..) => {
             bug!(
                 "debuginfo: Trying to create type name for \

compiler/rustc_const_eval/src/const_eval/valtrees.rs

@@ -152,7 +152,7 @@ pub(crate) fn const_to_valtree_inner<'tcx>(
         // FIXME(oli-obk): we can probably encode closures just like structs
         | ty::Closure(..)
         | ty::Generator(..)
-        | ty::GeneratorWitness(..) |ty::GeneratorWitnessMIR(..)=> Err(ValTreeCreationError::NonSupportedType),
+        | ty::GeneratorWitness(..) => Err(ValTreeCreationError::NonSupportedType),
     }
 }
 
@@ -280,7 +280,6 @@ pub fn valtree_to_const_value<'tcx>(
         | ty::Closure(..)
         | ty::Generator(..)
         | ty::GeneratorWitness(..)
-        | ty::GeneratorWitnessMIR(..)
         | ty::FnPtr(_)
         | ty::RawPtr(_)
         | ty::Str

compiler/rustc_const_eval/src/interpret/eval_context.rs

@@ -963,7 +963,6 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                 | ty::Ref(..)
                 | ty::Generator(..)
                 | ty::GeneratorWitness(..)
-                | ty::GeneratorWitnessMIR(..)
                 | ty::Array(..)
                 | ty::Closure(..)
                 | ty::Never

compiler/rustc_const_eval/src/interpret/intrinsics.rs

@@ -100,8 +100,7 @@ pub(crate) fn eval_nullary_intrinsic<'tcx>(
             | ty::Dynamic(_, _, _)
             | ty::Closure(_, _)
             | ty::Generator(_, _, _)
-            | ty::GeneratorWitness(_)
-            | ty::GeneratorWitnessMIR(_, _)
+            | ty::GeneratorWitness(..)
             | ty::Never
             | ty::Tuple(_)
             | ty::Error(_) => ConstValue::from_target_usize(0u64, &tcx),

compiler/rustc_const_eval/src/interpret/validity.rs

@@ -583,7 +583,6 @@ impl<'rt, 'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> ValidityVisitor<'rt, 'mir, '
             | ty::Bound(..)
             | ty::Param(..)
             | ty::Alias(..)
-            | ty::GeneratorWitnessMIR(..)
             | ty::GeneratorWitness(..) => bug!("Encountered invalid type {:?}", ty),
         }
     }

compiler/rustc_const_eval/src/util/type_name.rs

@@ -64,8 +64,7 @@ impl<'tcx> Printer<'tcx> for AbsolutePathPrinter<'tcx> {
 
             ty::Alias(ty::Weak, _) => bug!("type_name: unexpected weak projection"),
             ty::Alias(ty::Inherent, _) => bug!("type_name: unexpected inherent projection"),
-            ty::GeneratorWitness(_) => bug!("type_name: unexpected `GeneratorWitness`"),
-            ty::GeneratorWitnessMIR(..) => bug!("type_name: unexpected `GeneratorWitnessMIR`"),
+            ty::GeneratorWitness(..) => bug!("type_name: unexpected `GeneratorWitness`"),
         }
     }
 

compiler/rustc_error_codes/src/error_codes/E0698.md

@@ -1,9 +1,11 @@
+#### Note: this error code is no longer emitted by the compiler.
+
 When using generators (or async) all type variables must be bound so a
 generator can be constructed.
 
 Erroneous code example:
 
-```edition2018,compile_fail,E0698
+```edition2018,compile_fail,E0282
 async fn bar<T>() -> () {}
 
 async fn foo() {

compiler/rustc_hir_analysis/src/check/check.rs

@@ -1579,13 +1579,7 @@ fn opaque_type_cycle_error(
                         label_match(capture.place.ty(), capture.get_path_span(tcx));
                     }
                     // Label any generator locals that capture the opaque
-                    for interior_ty in
-                        typeck_results.generator_interior_types.as_ref().skip_binder()
-                    {
-                        label_match(interior_ty.ty, interior_ty.span);
-                    }
-                    if tcx.sess.opts.unstable_opts.drop_tracking_mir
-                        && let DefKind::Generator = tcx.def_kind(closure_def_id)
+                    if let DefKind::Generator = tcx.def_kind(closure_def_id)
                         && let Some(generator_layout) = tcx.mir_generator_witnesses(closure_def_id)
                     {
                         for interior_ty in &generator_layout.field_tys {
@@ -1603,7 +1597,6 @@ fn opaque_type_cycle_error(
 }
 
 pub(super) fn check_generator_obligations(tcx: TyCtxt<'_>, def_id: LocalDefId) {
-    debug_assert!(tcx.sess.opts.unstable_opts.drop_tracking_mir);
     debug_assert!(matches!(tcx.def_kind(def_id), DefKind::Generator));
 
     let typeck = tcx.typeck(def_id);

compiler/rustc_hir_analysis/src/coherence/inherent_impls.rs

@@ -157,7 +157,6 @@ impl<'tcx> InherentCollect<'tcx> {
             | ty::Closure(..)
             | ty::Generator(..)
             | ty::GeneratorWitness(..)
-            | ty::GeneratorWitnessMIR(..)
             | ty::Bound(..)
             | ty::Placeholder(_)
             | ty::Infer(_) => {

compiler/rustc_hir_analysis/src/coherence/orphan.rs

@@ -245,7 +245,6 @@ fn do_orphan_check_impl<'tcx>(
             ty::Closure(..)
             | ty::Generator(..)
             | ty::GeneratorWitness(..)
-            | ty::GeneratorWitnessMIR(..)
             | ty::Bound(..)
             | ty::Placeholder(..)
             | ty::Infer(..) => {

compiler/rustc_hir_analysis/src/variance/constraints.rs

@@ -314,11 +314,7 @@ impl<'a, 'tcx> ConstraintContext<'a, 'tcx> {
                 // types, where we use Error as the Self type
             }
 
-            ty::Placeholder(..)
-            | ty::GeneratorWitness(..)
-            | ty::GeneratorWitnessMIR(..)
-            | ty::Bound(..)
-            | ty::Infer(..) => {
+            ty::Placeholder(..) | ty::GeneratorWitness(..) | ty::Bound(..) | ty::Infer(..) => {
                 bug!("unexpected type encountered in variance inference: {}", ty);
             }
         }

compiler/rustc_hir_typeck/src/cast.rs

@@ -129,7 +129,6 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             | ty::Float(_)
             | ty::Array(..)
             | ty::GeneratorWitness(..)
-            | ty::GeneratorWitnessMIR(..)
             | ty::RawPtr(_)
             | ty::Ref(..)
             | ty::FnDef(..)

compiler/rustc_hir_typeck/src/fn_ctxt/_impl.rs

@@ -509,21 +509,6 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         typeck_results.rvalue_scopes = rvalue_scopes;
     }
 
-    pub(in super::super) fn resolve_generator_interiors(&self, def_id: DefId) {
-        if self.tcx.sess.opts.unstable_opts.drop_tracking_mir {
-            self.save_generator_interior_predicates(def_id);
-            return;
-        }
-
-        self.select_obligations_where_possible(|_| {});
-
-        let mut generators = self.deferred_generator_interiors.borrow_mut();
-        for (_, body_id, interior, kind) in generators.drain(..) {
-            crate::generator_interior::resolve_interior(self, def_id, body_id, interior, kind);
-            self.select_obligations_where_possible(|_| {});
-        }
-    }
-
     /// Unify the inference variables corresponding to generator witnesses, and save all the
     /// predicates that were stalled on those inference variables.
     ///
@@ -533,7 +518,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
     /// We must not attempt to select obligations after this method has run, or risk query cycle
     /// ICE.
     #[instrument(level = "debug", skip(self))]
-    fn save_generator_interior_predicates(&self, def_id: DefId) {
+    pub(in super::super) fn resolve_generator_interiors(&self, def_id: DefId) {
         // Try selecting all obligations that are not blocked on inference variables.
         // Once we start unifying generator witnesses, trying to select obligations on them will
         // trigger query cycle ICEs, as doing so requires MIR.
@@ -550,7 +535,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 self.tcx,
                 self.tcx.typeck_root_def_id(expr_def_id.to_def_id()),
             );
-            let witness = Ty::new_generator_witness_mir(self.tcx, expr_def_id.to_def_id(), args);
+            let witness = Ty::new_generator_witness(self.tcx, expr_def_id.to_def_id(), args);
 
             // Unify `interior` with `witness` and collect all the resulting obligations.
             let span = self.tcx.hir().body(body_id).value.span;