Auto merge of #102318 - Amanieu:default_alloc_error_handler, r=oli-obk

Stabilize default_alloc_error_handler

Tracking issue: #66741

This turns `feature(default_alloc_error_handler)` on by default, which causes the compiler to automatically generate a default OOM handler which panics if `#[alloc_error_handler]` is not provided.

The FCP completed over 2 years ago but the stabilization was blocked due to an issue with unwinding. This was fixed by #88098 so stabilization can be unblocked.

Closes #66741

2 files changed, 3 insertions, 16 deletions

diff --git a/compiler/rustc_metadata/src/creader.rs b/compiler/rustc_metadata/src/creader.rs
index 01d7f3e03c5..9ce3ff98ba9 100644
--- a/compiler/rustc_metadata/src/creader.rs
+++ b/compiler/rustc_metadata/src/creader.rs
@@ -1,10 +1,9 @@
 //! Validates all used crates and extern libraries and loads their metadata
 
 use crate::errors::{
-    AllocFuncRequired, ConflictingAllocErrorHandler, ConflictingGlobalAlloc, CrateNotPanicRuntime,
-    GlobalAllocRequired, MissingAllocErrorHandler, NoMultipleAllocErrorHandler,
-    NoMultipleGlobalAlloc, NoPanicStrategy, NoTransitiveNeedsDep, NotProfilerRuntime,
-    ProfilerBuiltinsNeedsCore,
+    ConflictingAllocErrorHandler, ConflictingGlobalAlloc, CrateNotPanicRuntime,
+    GlobalAllocRequired, NoMultipleAllocErrorHandler, NoMultipleGlobalAlloc, NoPanicStrategy,
+    NoTransitiveNeedsDep, NotProfilerRuntime, ProfilerBuiltinsNeedsCore,
 };
 use crate::locator::{CrateError, CrateLocator, CratePaths};
 use crate::rmeta::{CrateDep, CrateMetadata, CrateNumMap, CrateRoot, MetadataBlob};
@@ -895,10 +894,6 @@ impl<'a> CrateLoader<'a> {
         } else {
             // The alloc crate provides a default allocation error handler if
             // one isn't specified.
-            if !self.sess.features_untracked().default_alloc_error_handler {
-                self.sess.emit_err(AllocFuncRequired);
-                self.sess.emit_note(MissingAllocErrorHandler);
-            }
             self.cstore.alloc_error_handler_kind = Some(AllocatorKind::Default);
         }
     }
diff --git a/compiler/rustc_metadata/src/errors.rs b/compiler/rustc_metadata/src/errors.rs
index 6f7e6e09ca5..de2a879f1d7 100644
--- a/compiler/rustc_metadata/src/errors.rs
+++ b/compiler/rustc_metadata/src/errors.rs
@@ -372,14 +372,6 @@ pub struct ConflictingAllocErrorHandler {
 pub struct GlobalAllocRequired;
 
 #[derive(Diagnostic)]
-#[diag(metadata_alloc_func_required)]
-pub struct AllocFuncRequired;
-
-#[derive(Diagnostic)]
-#[diag(metadata_missing_alloc_error_handler)]
-pub struct MissingAllocErrorHandler;
-
-#[derive(Diagnostic)]
 #[diag(metadata_no_transitive_needs_dep)]
 pub struct NoTransitiveNeedsDep<'a> {
     pub crate_name: Symbol,