rm unnecessary OpaqueTypeDecl wrapper

compiler/rustc_borrowck/src/type_check/opaque_types.rs

@@ -25,8 +25,8 @@ pub(super) fn take_opaques_and_register_member_constraints<'tcx>(
     let opaque_types = infcx
         .take_opaque_types()
         .into_iter()
-        .map(|(opaque_type_key, decl)| {
-            let hidden_type = infcx.resolve_vars_if_possible(decl.hidden_type);
+        .map(|(opaque_type_key, hidden_type)| {
+            let hidden_type = infcx.resolve_vars_if_possible(hidden_type);
             register_member_constraints(
                 typeck,
                 &mut member_constraints,

compiler/rustc_hir_analysis/src/check/check.rs

@@ -436,9 +436,9 @@ fn check_opaque_meets_bounds<'tcx>(
     } else {
         // Check that any hidden types found during wf checking match the hidden types that `type_of` sees.
         for (mut key, mut ty) in infcx.take_opaque_types() {
-            ty.hidden_type.ty = infcx.resolve_vars_if_possible(ty.hidden_type.ty);
+            ty.ty = infcx.resolve_vars_if_possible(ty.ty);
             key = infcx.resolve_vars_if_possible(key);
-            sanity_check_found_hidden_type(tcx, key, ty.hidden_type)?;
+            sanity_check_found_hidden_type(tcx, key, ty)?;
         }
         Ok(())
     }
@@ -1873,7 +1873,7 @@ pub(super) fn check_coroutine_obligations(
         // Check that any hidden types found when checking these stalled coroutine obligations
         // are valid.
         for (key, ty) in infcx.take_opaque_types() {
-            let hidden_type = infcx.resolve_vars_if_possible(ty.hidden_type);
+            let hidden_type = infcx.resolve_vars_if_possible(ty);
             let key = infcx.resolve_vars_if_possible(key);
             sanity_check_found_hidden_type(tcx, key, hidden_type)?;
         }

compiler/rustc_hir_typeck/src/writeback.rs

@@ -562,9 +562,9 @@ impl<'cx, 'tcx> WritebackCx<'cx, 'tcx> {
         // types or by using this function at the end of writeback and running it as a
         // fixpoint.
         let opaque_types = self.fcx.infcx.clone_opaque_types();
-        for (opaque_type_key, decl) in opaque_types {
-            let hidden_type = self.resolve(decl.hidden_type, &decl.hidden_type.span);
-            let opaque_type_key = self.resolve(opaque_type_key, &decl.hidden_type.span);
+        for (opaque_type_key, hidden_type) in opaque_types {
+            let hidden_type = self.resolve(hidden_type, &hidden_type.span);
+            let opaque_type_key = self.resolve(opaque_type_key, &hidden_type.span);
 
             if !self.fcx.next_trait_solver() {
                 if let ty::Alias(ty::Opaque, alias_ty) = hidden_type.ty.kind()

compiler/rustc_infer/src/infer/canonical/query_response.rs

@@ -155,12 +155,12 @@ impl<'tcx> InferCtxt<'tcx> {
             .opaque_type_storage
             .opaque_types
             .iter()
-            .map(|(k, v)| (*k, v.hidden_type.ty))
+            .map(|(k, v)| (*k, v.ty))
             .collect()
     }
 
     fn take_opaque_types_for_query_response(&self) -> Vec<(ty::OpaqueTypeKey<'tcx>, Ty<'tcx>)> {
-        self.take_opaque_types().into_iter().map(|(k, v)| (k, v.hidden_type.ty)).collect()
+        self.take_opaque_types().into_iter().map(|(k, v)| (k, v.ty)).collect()
     }
 
     /// Given the (canonicalized) result to a canonical query,

compiler/rustc_infer/src/infer/mod.rs

@@ -234,7 +234,7 @@ impl<'tcx> InferCtxtInner<'tcx> {
     pub fn iter_opaque_types(
         &self,
     ) -> impl Iterator<Item = (ty::OpaqueTypeKey<'tcx>, ty::OpaqueHiddenType<'tcx>)> + '_ {
-        self.opaque_type_storage.opaque_types.iter().map(|(&k, v)| (k, v.hidden_type))
+        self.opaque_type_storage.opaque_types.iter().map(|(&k, &v)| (k, v))
     }
 }
 

compiler/rustc_infer/src/infer/opaque_types/mod.rs

@@ -19,20 +19,9 @@ use crate::traits::{self, Obligation, PredicateObligations};
 
 mod table;
 
-pub(crate) type OpaqueTypeMap<'tcx> = FxIndexMap<OpaqueTypeKey<'tcx>, OpaqueTypeDecl<'tcx>>;
+pub(crate) type OpaqueTypeMap<'tcx> = FxIndexMap<OpaqueTypeKey<'tcx>, OpaqueHiddenType<'tcx>>;
 pub(crate) use table::{OpaqueTypeStorage, OpaqueTypeTable};
 
-/// Information about the opaque types whose values we
-/// are inferring in this function (these are the `impl Trait` that
-/// appear in the return type).
-#[derive(Clone, Debug)]
-pub struct OpaqueTypeDecl<'tcx> {
-    /// The hidden types that have been inferred for this opaque type.
-    /// There can be multiple, but they are all `lub`ed together at the end
-    /// to obtain the canonical hidden type.
-    pub hidden_type: OpaqueHiddenType<'tcx>,
-}
-
 impl<'tcx> InferCtxt<'tcx> {
     /// This is a backwards compatibility hack to prevent breaking changes from
     /// lazy TAIT around RPIT handling.

compiler/rustc_infer/src/infer/opaque_types/table.rs

@@ -3,23 +3,27 @@ use rustc_middle::bug;
 use rustc_middle::ty::{self, OpaqueHiddenType, OpaqueTypeKey, Ty};
 use tracing::instrument;
 
-use super::{OpaqueTypeDecl, OpaqueTypeMap};
+use super::OpaqueTypeMap;
 use crate::infer::snapshot::undo_log::{InferCtxtUndoLogs, UndoLog};
 
 #[derive(Default, Debug, Clone)]
 pub(crate) struct OpaqueTypeStorage<'tcx> {
     /// Opaque types found in explicit return types and their
     /// associated fresh inference variable. Writeback resolves these
     /// variables to get the concrete type, which can be used to
-    /// 'de-opaque' OpaqueTypeDecl, after typeck is done with all functions.
+    /// 'de-opaque' OpaqueHiddenType, after typeck is done with all functions.
     pub opaque_types: OpaqueTypeMap<'tcx>,
 }
 
 impl<'tcx> OpaqueTypeStorage<'tcx> {
     #[instrument(level = "debug")]
-    pub(crate) fn remove(&mut self, key: OpaqueTypeKey<'tcx>, idx: Option<OpaqueHiddenType<'tcx>>) {
-        if let Some(idx) = idx {
-            self.opaque_types.get_mut(&key).unwrap().hidden_type = idx;
+    pub(crate) fn remove(
+        &mut self,
+        key: OpaqueTypeKey<'tcx>,
+        prev: Option<OpaqueHiddenType<'tcx>>,
+    ) {
+        if let Some(prev) = prev {
+            *self.opaque_types.get_mut(&key).unwrap() = prev;
         } else {
             // FIXME(#120456) - is `swap_remove` correct?
             match self.opaque_types.swap_remove(&key) {
@@ -59,13 +63,12 @@ impl<'a, 'tcx> OpaqueTypeTable<'a, 'tcx> {
         key: OpaqueTypeKey<'tcx>,
         hidden_type: OpaqueHiddenType<'tcx>,
     ) -> Option<Ty<'tcx>> {
-        if let Some(decl) = self.storage.opaque_types.get_mut(&key) {
-            let prev = std::mem::replace(&mut decl.hidden_type, hidden_type);
+        if let Some(entry) = self.storage.opaque_types.get_mut(&key) {
+            let prev = std::mem::replace(entry, hidden_type);
             self.undo_log.push(UndoLog::OpaqueTypes(key, Some(prev)));
             return Some(prev.ty);
         }
-        let decl = OpaqueTypeDecl { hidden_type };
-        self.storage.opaque_types.insert(key, decl);
+        self.storage.opaque_types.insert(key, hidden_type);
         self.undo_log.push(UndoLog::OpaqueTypes(key, None));
         None
     }