From b267be921e3f95b96c7eafd6e47028822afe96e2 Mon Sep 17 00:00:00 2001
From: mejrs <59372212+mejrs@users.noreply.github.com>
Date: Wed, 23 Sep 2026 12:03:41 +0200
Subject: [PATCH] Remove `suggestion_for_allocator_api`

---
 compiler/rustc_middle/src/middle/stability.rs | 62 +++----------------
 compiler/rustc_resolve/src/macros.rs          |  1 -
 compiler/rustc_span/src/symbol.rs             |  1 -
 3 files changed, 7 insertions(+), 57 deletions(-)

diff --git a/compiler/rustc_middle/src/middle/stability.rs b/compiler/rustc_middle/src/middle/stability.rs
index 8213646b4625d..0235d5bb17224 100644
--- a/compiler/rustc_middle/src/middle/stability.rs
+++ b/compiler/rustc_middle/src/middle/stability.rs
@@ -7,7 +7,7 @@ use rustc_ast::NodeId;
 use rustc_attr_ir::{
     ConstStability, DefaultBodyStability, DeprecatedSince, Deprecation, Stability, StabilityLevel,
 };
-use rustc_errors::{Applicability, Diag, Diagnostic, LintBuffer, msg};
+use rustc_errors::{Diag, Diagnostic, LintBuffer, msg};
 use rustc_feature::GateIssue;
 use rustc_hir::def_id::{DefId, LocalDefId};
 use rustc_hir::{self as hir, HirId};
@@ -62,7 +62,6 @@ pub fn report_unstable(
     feature: Symbol,
     reason: Option<Symbol>,
     issue: Option<NonZero<u32>>,
-    suggestion: Option<(Span, String, String, Applicability)>,
     span: Span,
     kind: UnstableKind,
 ) {
@@ -77,9 +76,6 @@ pub fn report_unstable(
     };
 
     let mut err = feature_err_issue(sess, feature, span, GateIssue::Library(issue), msg);
-    if let Some((inner_types, msg, sugg, applicability)) = suggestion {
-        err.span_suggestion(inner_types, msg, sugg, applicability);
-    }
     if let UnstableKind::Const(kw) = kind {
         err.span_label(kw, "trait is not stable as const yet");
     }
@@ -260,42 +256,11 @@ pub enum EvalResult {
     Allow,
     /// We cannot use the item because it is unstable and we did not provide the
     /// corresponding feature gate.
-    Deny {
-        feature: Symbol,
-        reason: Option<Symbol>,
-        issue: Option<NonZero<u32>>,
-        suggestion: Option<(Span, String, String, Applicability)>,
-    },
+    Deny { feature: Symbol, reason: Option<Symbol>, issue: Option<NonZero<u32>> },
     /// The item does not have the `#[stable]` or `#[unstable]` marker assigned.
     Unmarked,
 }
 
-// See issue #83250.
-fn suggestion_for_allocator_api(
-    tcx: TyCtxt<'_>,
-    def_id: DefId,
-    span: Span,
-    feature: Symbol,
-) -> Option<(Span, String, String, Applicability)> {
-    if feature == sym::allocator_api {
-        if let Some(trait_) = tcx.opt_parent(def_id) {
-            if tcx.is_diagnostic_item(sym::Vec, trait_) {
-                let sm = tcx.sess.psess.source_map();
-                let inner_types = sm.span_extend_to_prev_char(span, '<', true);
-                if let Ok(snippet) = sm.span_to_snippet(inner_types) {
-                    return Some((
-                        inner_types,
-                        "consider wrapping the inner types in tuple".to_string(),
-                        format!("({snippet})"),
-                        Applicability::MaybeIncorrect,
-                    ));
-                }
-            }
-        }
-    }
-    None
-}
-
 /// An override option for eval_stability.
 pub enum AllowUnstable {
     /// Don't emit an unstable error for the item
@@ -425,8 +390,7 @@ impl<'tcx> TyCtxt<'tcx> {
                     return EvalResult::Allow;
                 }
 
-                let suggestion = suggestion_for_allocator_api(self, def_id, span, feature);
-                EvalResult::Deny { feature, reason: reason.to_opt_reason(), issue, suggestion }
+                EvalResult::Deny { feature, reason: reason.to_opt_reason(), issue }
             }
             Some(_) => {
                 // Stable APIs are always ok to call and deprecated APIs are
@@ -472,12 +436,7 @@ impl<'tcx> TyCtxt<'tcx> {
                     return EvalResult::Allow;
                 }
 
-                EvalResult::Deny {
-                    feature,
-                    reason: reason.to_opt_reason(),
-                    issue,
-                    suggestion: None,
-                }
+                EvalResult::Deny { feature, reason: reason.to_opt_reason(), issue }
             }
             Some(_) => {
                 // Stable APIs are always ok to call
@@ -559,15 +518,9 @@ impl<'tcx> TyCtxt<'tcx> {
         let is_allowed = matches!(eval_result, EvalResult::Allow);
         match eval_result {
             EvalResult::Allow => {}
-            EvalResult::Deny { feature, reason, issue, suggestion } => report_unstable(
-                self.sess,
-                feature,
-                reason,
-                issue,
-                suggestion,
-                span,
-                UnstableKind::Regular,
-            ),
+            EvalResult::Deny { feature, reason, issue } => {
+                report_unstable(self.sess, feature, reason, issue, span, UnstableKind::Regular)
+            }
             EvalResult::Unmarked => unmarked(span, def_id),
         }
 
@@ -628,7 +581,6 @@ impl<'tcx> TyCtxt<'tcx> {
                     feature,
                     reason.to_opt_reason(),
                     issue,
-                    None,
                     span,
                     UnstableKind::Const(const_kw_span),
                 );
diff --git a/compiler/rustc_resolve/src/macros.rs b/compiler/rustc_resolve/src/macros.rs
index 24a52d4143493..823a66dcd5d93 100644
--- a/compiler/rustc_resolve/src/macros.rs
+++ b/compiler/rustc_resolve/src/macros.rs
@@ -1098,7 +1098,6 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
                     feature,
                     reason.to_opt_reason(),
                     issue,
-                    None,
                     span,
                     stability::UnstableKind::Regular,
                 );
diff --git a/compiler/rustc_span/src/symbol.rs b/compiler/rustc_span/src/symbol.rs
index bd70e5acab4d7..f2ab04b41d938 100644
--- a/compiler/rustc_span/src/symbol.rs
+++ b/compiler/rustc_span/src/symbol.rs
@@ -413,7 +413,6 @@ symbols! {
         alloc_layout,
         alloc_zeroed,
         allocator,
-        allocator_api,
         allocator_internals,
         allow,
         allow_fail,