Don't create interior type variable in check_closure

compiler/rustc_hir_typeck/src/check.rs

@@ -94,7 +94,7 @@ pub(super) fn check_fn<'a, 'tcx>(
         // Resume type defaults to `()` if the coroutine has no argument.
         let resume_ty = fn_sig.inputs().get(0).copied().unwrap_or_else(|| Ty::new_unit(tcx));
 
-        fcx.resume_yield_tys = Some((resume_ty, yield_ty));
+        fcx.coroutine_types = Some(CoroutineTypes { resume_ty, yield_ty });
     }
 
     GatherLocalsVisitor::new(fcx).visit_body(body);
@@ -146,20 +146,6 @@ pub(super) fn check_fn<'a, 'tcx>(
     fcx.require_type_is_sized(declared_ret_ty, return_or_body_span, traits::SizedReturnType);
     fcx.check_return_expr(body.value, false);
 
-    // We insert the deferred_coroutine_interiors entry after visiting the body.
-    // This ensures that all nested coroutines appear before the entry of this coroutine.
-    // resolve_coroutine_interiors relies on this property.
-    let coroutine_ty = if let Some(hir::ClosureKind::Coroutine(_)) = closure_kind {
-        let interior = fcx
-            .next_ty_var(TypeVariableOrigin { kind: TypeVariableOriginKind::MiscVariable, span });
-        fcx.deferred_coroutine_interiors.borrow_mut().push((fn_def_id, body.id(), interior));
-
-        let (resume_ty, yield_ty) = fcx.resume_yield_tys.unwrap();
-        Some(CoroutineTypes { resume_ty, yield_ty, interior })
-    } else {
-        None
-    };
-
     // Finalize the return check by taking the LUB of the return types
     // we saw and assigning it to the expected return type. This isn't
     // really expected to fail, since the coercions would have failed
@@ -195,7 +181,7 @@ pub(super) fn check_fn<'a, 'tcx>(
         check_lang_start_fn(tcx, fn_sig, fn_def_id);
     }
 
-    coroutine_ty
+    fcx.coroutine_types
 }
 
 fn check_panic_info_fn(tcx: TyCtxt<'_>, fn_id: LocalDefId, fn_sig: ty::FnSig<'_>) {

compiler/rustc_hir_typeck/src/closure.rs

@@ -105,59 +105,76 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             span: self.tcx.def_span(expr_def_id),
         });
 
-        if let Some(CoroutineTypes { resume_ty, yield_ty, interior }) = coroutine_types {
-            let coroutine_args = ty::CoroutineArgs::new(
-                self.tcx,
-                ty::CoroutineArgsParts {
-                    parent_args,
-                    resume_ty,
-                    yield_ty,
-                    return_ty: liberated_sig.output(),
-                    witness: interior,
-                    tupled_upvars_ty,
-                },
-            );
-
-            return Ty::new_coroutine(self.tcx, expr_def_id.to_def_id(), coroutine_args.args);
-        }
-
-        // Tuple up the arguments and insert the resulting function type into
-        // the `closures` table.
-        let sig = bound_sig.map_bound(|sig| {
-            self.tcx.mk_fn_sig(
-                [Ty::new_tup(self.tcx, sig.inputs())],
-                sig.output(),
-                sig.c_variadic,
-                sig.unsafety,
-                sig.abi,
-            )
-        });
-
-        debug!(?sig, ?opt_kind);
-
-        let closure_kind_ty = match opt_kind {
-            Some(kind) => Ty::from_closure_kind(self.tcx, kind),
+        match closure.kind {
+            hir::ClosureKind::Closure => {
+                assert_eq!(coroutine_types, None);
+                // Tuple up the arguments and insert the resulting function type into
+                // the `closures` table.
+                let sig = bound_sig.map_bound(|sig| {
+                    self.tcx.mk_fn_sig(
+                        [Ty::new_tup(self.tcx, sig.inputs())],
+                        sig.output(),
+                        sig.c_variadic,
+                        sig.unsafety,
+                        sig.abi,
+                    )
+                });
 
-            // Create a type variable (for now) to represent the closure kind.
-            // It will be unified during the upvar inference phase (`upvar.rs`)
-            None => self.next_root_ty_var(TypeVariableOrigin {
-                // FIXME(eddyb) distinguish closure kind inference variables from the rest.
-                kind: TypeVariableOriginKind::ClosureSynthetic,
-                span: expr_span,
-            }),
-        };
+                debug!(?sig, ?opt_kind);
+
+                let closure_kind_ty = match opt_kind {
+                    Some(kind) => Ty::from_closure_kind(self.tcx, kind),
+
+                    // Create a type variable (for now) to represent the closure kind.
+                    // It will be unified during the upvar inference phase (`upvar.rs`)
+                    None => self.next_root_ty_var(TypeVariableOrigin {
+                        // FIXME(eddyb) distinguish closure kind inference variables from the rest.
+                        kind: TypeVariableOriginKind::ClosureSynthetic,
+                        span: expr_span,
+                    }),
+                };
+
+                let closure_args = ty::ClosureArgs::new(
+                    self.tcx,
+                    ty::ClosureArgsParts {
+                        parent_args,
+                        closure_kind_ty,
+                        closure_sig_as_fn_ptr_ty: Ty::new_fn_ptr(self.tcx, sig),
+                        tupled_upvars_ty,
+                    },
+                );
 
-        let closure_args = ty::ClosureArgs::new(
-            self.tcx,
-            ty::ClosureArgsParts {
-                parent_args,
-                closure_kind_ty,
-                closure_sig_as_fn_ptr_ty: Ty::new_fn_ptr(self.tcx, sig),
-                tupled_upvars_ty,
-            },
-        );
+                Ty::new_closure(self.tcx, expr_def_id.to_def_id(), closure_args.args)
+            }
+            hir::ClosureKind::Coroutine(_) => {
+                let Some(CoroutineTypes { resume_ty, yield_ty }) = coroutine_types else {
+                    bug!("expected coroutine to have yield/resume types");
+                };
+                let interior = fcx.next_ty_var(TypeVariableOrigin {
+                    kind: TypeVariableOriginKind::MiscVariable,
+                    span: body.value.span,
+                });
+                fcx.deferred_coroutine_interiors.borrow_mut().push((
+                    expr_def_id,
+                    body.id(),
+                    interior,
+                ));
+
+                let coroutine_args = ty::CoroutineArgs::new(
+                    self.tcx,
+                    ty::CoroutineArgsParts {
+                        parent_args,
+                        resume_ty,
+                        yield_ty,
+                        return_ty: liberated_sig.output(),
+                        witness: interior,
+                        tupled_upvars_ty,
+                    },
+                );
 
-        Ty::new_closure(self.tcx, expr_def_id.to_def_id(), closure_args.args)
+                Ty::new_coroutine(self.tcx, expr_def_id.to_def_id(), coroutine_args.args)
+            }
+        }
     }
 
     /// Given the expected type, figures out what it can about this closure we

compiler/rustc_hir_typeck/src/expr.rs

@@ -15,6 +15,7 @@ use crate::errors::{
 use crate::fatally_break_rust;
 use crate::method::SelfSource;
 use crate::type_error_struct;
+use crate::CoroutineTypes;
 use crate::Expectation::{self, ExpectCastableToType, ExpectHasType, NoExpectation};
 use crate::{
     report_unexpected_variant_res, BreakableCtxt, Diverges, FnCtxt, Needs,
@@ -3164,8 +3165,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         expr: &'tcx hir::Expr<'tcx>,
         src: &'tcx hir::YieldSource,
     ) -> Ty<'tcx> {
-        match self.resume_yield_tys {
-            Some((resume_ty, yield_ty)) => {
+        match self.coroutine_types {
+            Some(CoroutineTypes { resume_ty, yield_ty }) => {
                 self.check_expr_coercible_to_type(value, yield_ty, None);
 
                 resume_ty

compiler/rustc_hir_typeck/src/fn_ctxt/mod.rs

@@ -5,7 +5,7 @@ mod checks;
 mod suggestions;
 
 use crate::coercion::DynamicCoerceMany;
-use crate::{Diverges, EnclosingBreakables, Inherited};
+use crate::{CoroutineTypes, Diverges, EnclosingBreakables, Inherited};
 use rustc_errors::{DiagCtxt, ErrorGuaranteed};
 use rustc_hir as hir;
 use rustc_hir::def_id::{DefId, LocalDefId};
@@ -68,7 +68,7 @@ pub struct FnCtxt<'a, 'tcx> {
     /// First span of a return site that we find. Used in error messages.
     pub(super) ret_coercion_span: Cell<Option<Span>>,
 
-    pub(super) resume_yield_tys: Option<(Ty<'tcx>, Ty<'tcx>)>,
+    pub(super) coroutine_types: Option<CoroutineTypes<'tcx>>,
 
     /// Whether the last checked node generates a divergence (e.g.,
     /// `return` will set this to `Always`). In general, when entering
@@ -122,7 +122,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             err_count_on_creation: inh.tcx.dcx().err_count(),
             ret_coercion: None,
             ret_coercion_span: Cell::new(None),
-            resume_yield_tys: None,
+            coroutine_types: None,
             diverges: Cell::new(Diverges::Maybe),
             enclosing_breakables: RefCell::new(EnclosingBreakables {
                 stack: Vec::new(),

compiler/rustc_hir_typeck/src/lib.rs

@@ -295,15 +295,13 @@ fn typeck_with_fallback<'tcx>(
 /// When `check_fn` is invoked on a coroutine (i.e., a body that
 /// includes yield), it returns back some information about the yield
 /// points.
+#[derive(Debug, PartialEq, Copy, Clone)]
 struct CoroutineTypes<'tcx> {
     /// Type of coroutine argument / values returned by `yield`.
     resume_ty: Ty<'tcx>,
 
     /// Type of value that is yielded.
     yield_ty: Ty<'tcx>,
-
-    /// Types that are captured (see `CoroutineInterior` for more).
-    interior: Ty<'tcx>,
 }
 
 #[derive(Copy, Clone, Debug, PartialEq, Eq)]