Auto merge of #145304 - m-ou-se:simplify-panic, r=oli-obk

Revert "Partially outline code inside the panic! macro".

This reverts https://github.com/rust-lang/rust/pull/115670

Without any tests/benchmarks that show some improvement, it's hard to know whether the change had any positive effect. (And if it did, whether that effect is still achieved today.)

5 files changed, 6 insertions, 9 deletions

diff --git a/compiler/rustc_const_eval/src/check_consts/check.rs b/compiler/rustc_const_eval/src/check_consts/check.rs
index 8e2c138282a..ca707b50d50 100644
--- a/compiler/rustc_const_eval/src/check_consts/check.rs
+++ b/compiler/rustc_const_eval/src/check_consts/check.rs
@@ -827,7 +827,7 @@ impl<'tcx> Visitor<'tcx> for Checker<'_, 'tcx> {
 
                 // At this point, we are calling a function, `callee`, whose `DefId` is known...
 
-                // `begin_panic` and `#[rustc_const_panic_str]` functions accept generic
+                // `begin_panic` and `panic_display` functions accept generic
                 // types other than str. Check to enforce that only str can be used in
                 // const-eval.
 
@@ -841,8 +841,8 @@ impl<'tcx> Visitor<'tcx> for Checker<'_, 'tcx> {
                     return;
                 }
 
-                // const-eval of `#[rustc_const_panic_str]` functions assumes the argument is `&&str`
-                if tcx.has_attr(callee, sym::rustc_const_panic_str) {
+                // const-eval of `panic_display` assumes the argument is `&&str`
+                if tcx.is_lang_item(callee, LangItem::PanicDisplay) {
                     match args[0].node.ty(&self.ccx.body.local_decls, tcx).kind() {
                         ty::Ref(_, ty, _) if matches!(ty.kind(), ty::Ref(_, ty, _) if ty.is_str()) =>
                             {}
diff --git a/compiler/rustc_const_eval/src/const_eval/machine.rs b/compiler/rustc_const_eval/src/const_eval/machine.rs
index a18ae79f318..da954cf4ed7 100644
--- a/compiler/rustc_const_eval/src/const_eval/machine.rs
+++ b/compiler/rustc_const_eval/src/const_eval/machine.rs
@@ -237,7 +237,7 @@ impl<'tcx> CompileTimeInterpCx<'tcx> {
     ) -> InterpResult<'tcx, Option<ty::Instance<'tcx>>> {
         let def_id = instance.def_id();
 
-        if self.tcx.has_attr(def_id, sym::rustc_const_panic_str)
+        if self.tcx.is_lang_item(def_id, LangItem::PanicDisplay)
             || self.tcx.is_lang_item(def_id, LangItem::BeginPanic)
         {
             let args = self.copy_fn_args(args);
diff --git a/compiler/rustc_feature/src/builtin_attrs.rs b/compiler/rustc_feature/src/builtin_attrs.rs
index ab6b8f92802..6fbedaf5b10 100644
--- a/compiler/rustc_feature/src/builtin_attrs.rs
+++ b/compiler/rustc_feature/src/builtin_attrs.rs
@@ -1159,10 +1159,6 @@ pub static BUILTIN_ATTRIBUTES: &[BuiltinAttribute] = &[
         EncodeCrossCrate::Yes, "`#[rustc_do_not_const_check]` skips const-check for this function's body",
     ),
     rustc_attr!(
-        rustc_const_panic_str, Normal, template!(Word), WarnFollowing,
-        EncodeCrossCrate::Yes, "`#[rustc_const_panic_str]` ensures the argument to this function is &&str during const-check",
-    ),
-    rustc_attr!(
         rustc_const_stable_indirect, Normal,
         template!(Word),
         WarnFollowing,
diff --git a/compiler/rustc_hir/src/lang_items.rs b/compiler/rustc_hir/src/lang_items.rs
index 75c04b23ed6..905b84a8cbe 100644
--- a/compiler/rustc_hir/src/lang_items.rs
+++ b/compiler/rustc_hir/src/lang_items.rs
@@ -286,6 +286,7 @@ language_item_table! {
     Panic,                   sym::panic,               panic_fn,                   Target::Fn,             GenericRequirement::Exact(0);
     PanicNounwind,           sym::panic_nounwind,      panic_nounwind,             Target::Fn,             GenericRequirement::Exact(0);
     PanicFmt,                sym::panic_fmt,           panic_fmt,                  Target::Fn,             GenericRequirement::None;
+    PanicDisplay,            sym::panic_display,       panic_display,              Target::Fn,             GenericRequirement::None;
     ConstPanicFmt,           sym::const_panic_fmt,     const_panic_fmt,            Target::Fn,             GenericRequirement::None;
     PanicBoundsCheck,        sym::panic_bounds_check,  panic_bounds_check_fn,      Target::Fn,             GenericRequirement::Exact(0);
     PanicMisalignedPointerDereference, sym::panic_misaligned_pointer_dereference, panic_misaligned_pointer_dereference_fn, Target::Fn, GenericRequirement::Exact(0);
diff --git a/compiler/rustc_span/src/symbol.rs b/compiler/rustc_span/src/symbol.rs
index 8e26aa9e77f..f4a6d0f5891 100644
--- a/compiler/rustc_span/src/symbol.rs
+++ b/compiler/rustc_span/src/symbol.rs
@@ -1593,6 +1593,7 @@ symbols! {
         panic_const_shl_overflow,
         panic_const_shr_overflow,
         panic_const_sub_overflow,
+        panic_display,
         panic_fmt,
         panic_handler,
         panic_impl,
@@ -1838,7 +1839,6 @@ symbols! {
         rustc_coherence_is_core,
         rustc_coinductive,
         rustc_confusables,
-        rustc_const_panic_str,
         rustc_const_stable,
         rustc_const_stable_indirect,
         rustc_const_unstable,