Hide allocator details from TryReserveError

library/std/src/collections/hash/map.rs

@@ -10,6 +10,7 @@ use hashbrown::hash_map as base;
 use crate::borrow::Borrow;
 use crate::cell::Cell;
 use crate::collections::TryReserveError;
+use crate::collections::TryReserveErrorKind;
 use crate::fmt::{self, Debug};
 #[allow(deprecated)]
 use crate::hash::{BuildHasher, Hash, Hasher, SipHasher13};
@@ -2966,9 +2967,11 @@ fn map_entry<'a, K: 'a, V: 'a>(raw: base::RustcEntry<'a, K, V>) -> Entry<'a, K,
 #[inline]
 pub(super) fn map_try_reserve_error(err: hashbrown::TryReserveError) -> TryReserveError {
     match err {
-        hashbrown::TryReserveError::CapacityOverflow => TryReserveError::CapacityOverflow,
+        hashbrown::TryReserveError::CapacityOverflow => {
+            TryReserveErrorKind::CapacityOverflow.into()
+        }
         hashbrown::TryReserveError::AllocError { layout } => {
-            TryReserveError::AllocError { layout, non_exhaustive: () }
+            TryReserveErrorKind::AllocError { layout, non_exhaustive: () }.into()
         }
     }
 }

library/std/src/collections/hash/map/tests.rs

@@ -3,7 +3,7 @@ use super::HashMap;
 use super::RandomState;
 use crate::cell::RefCell;
 use rand::{thread_rng, Rng};
-use realstd::collections::TryReserveError::*;
+use realstd::collections::TryReserveErrorKind::*;
 
 // https://github.com/rust-lang/rust/issues/62301
 fn _assert_hashmap_is_unwind_safe() {
@@ -821,12 +821,12 @@ fn test_try_reserve() {
 
     const MAX_USIZE: usize = usize::MAX;
 
-    if let Err(CapacityOverflow) = empty_bytes.try_reserve(MAX_USIZE) {
+    if let Err(CapacityOverflow) = empty_bytes.try_reserve(MAX_USIZE).map_err(|e| e.kind()) {
     } else {
         panic!("usize::MAX should trigger an overflow!");
     }
 
-    if let Err(AllocError { .. }) = empty_bytes.try_reserve(MAX_USIZE / 8) {
+    if let Err(AllocError { .. }) = empty_bytes.try_reserve(MAX_USIZE / 8).map_err(|e| e.kind()) {
     } else {
         panic!("usize::MAX / 8 should trigger an OOM!")
     }

library/std/src/collections/mod.rs

@@ -422,6 +422,12 @@ pub use self::hash_set::HashSet;
 
 #[unstable(feature = "try_reserve", reason = "new API", issue = "48043")]
 pub use alloc_crate::collections::TryReserveError;
+#[unstable(
+    feature = "try_reserve_kind",
+    reason = "Uncertain how much info should be exposed",
+    issue = "48043"
+)]
+pub use alloc_crate::collections::TryReserveErrorKind;
 
 mod hash;
 

library/std/src/lib.rs

@@ -325,6 +325,7 @@
 #![feature(trace_macros)]
 #![feature(try_blocks)]
 #![feature(try_reserve)]
+#![feature(try_reserve_kind)]
 #![feature(unboxed_closures)]
 #![feature(unsafe_cell_raw_get)]
 #![feature(unwind_attributes)]