From 037e189783b6c689640b1c177cd32ccb385dc237 Mon Sep 17 00:00:00 2001
From: Gary Guo <gary@garyguo.net>
Date: Wed, 20 Oct 2021 19:32:54 +0100
Subject: [PATCH] Remove `box_alloc` from `Machine` trait.

---
 compiler/rustc_const_eval/src/const_eval/machine.rs     | 7 -------
 compiler/rustc_const_eval/src/interpret/eval_context.rs | 2 +-
 compiler/rustc_const_eval/src/interpret/machine.rs      | 6 ------
 compiler/rustc_mir_transform/src/const_prop.rs          | 7 -------
 4 files changed, 1 insertion(+), 21 deletions(-)

diff --git a/compiler/rustc_const_eval/src/const_eval/machine.rs b/compiler/rustc_const_eval/src/const_eval/machine.rs
index 8efe3eb868b..daf81b64ed9 100644
--- a/compiler/rustc_const_eval/src/const_eval/machine.rs
+++ b/compiler/rustc_const_eval/src/const_eval/machine.rs
@@ -406,13 +406,6 @@ impl<'mir, 'tcx> interpret::Machine<'mir, 'tcx> for CompileTimeInterpreter<'mir,
         Err(ConstEvalErrKind::NeedsRfc("pointer arithmetic or comparison".to_string()).into())
     }
 
-    fn box_alloc(
-        _ecx: &mut InterpCx<'mir, 'tcx, Self>,
-        _dest: &PlaceTy<'tcx>,
-    ) -> InterpResult<'tcx> {
-        Err(ConstEvalErrKind::NeedsRfc("heap allocations via `box` keyword".to_string()).into())
-    }
-
     fn before_terminator(ecx: &mut InterpCx<'mir, 'tcx, Self>) -> InterpResult<'tcx> {
         // The step limit has already been hit in a previous call to `before_terminator`.
         if ecx.machine.steps_remaining == 0 {
diff --git a/compiler/rustc_const_eval/src/interpret/eval_context.rs b/compiler/rustc_const_eval/src/interpret/eval_context.rs
index cf084faade8..5a654207a07 100644
--- a/compiler/rustc_const_eval/src/interpret/eval_context.rs
+++ b/compiler/rustc_const_eval/src/interpret/eval_context.rs
@@ -152,7 +152,7 @@ pub enum StackPopCleanup {
     /// `ret` stores the block we jump to on a normal return, while `unwind`
     /// stores the block used for cleanup during unwinding.
     Goto { ret: Option<mir::BasicBlock>, unwind: StackPopUnwind },
-    /// Just do nothing: Used by Main and for the `box_alloc` hook in miri.
+    /// Just do nothing: Used by Main and for TLS hooks in miri.
     /// `cleanup` says whether locals are deallocated. Static computation
     /// wants them leaked to intern what they need (and just throw away
     /// the entire `ecx` when it is done).
diff --git a/compiler/rustc_const_eval/src/interpret/machine.rs b/compiler/rustc_const_eval/src/interpret/machine.rs
index 323e102b872..4e13c2ff9f8 100644
--- a/compiler/rustc_const_eval/src/interpret/machine.rs
+++ b/compiler/rustc_const_eval/src/interpret/machine.rs
@@ -208,12 +208,6 @@ pub trait Machine<'mir, 'tcx>: Sized {
         right: &ImmTy<'tcx, Self::PointerTag>,
     ) -> InterpResult<'tcx, (Scalar<Self::PointerTag>, bool, Ty<'tcx>)>;
 
-    /// Heap allocations via the `box` keyword.
-    fn box_alloc(
-        ecx: &mut InterpCx<'mir, 'tcx, Self>,
-        dest: &PlaceTy<'tcx, Self::PointerTag>,
-    ) -> InterpResult<'tcx>;
-
     /// Called to read the specified `local` from the `frame`.
     /// Since reading a ZST is not actually accessing memory or locals, this is never invoked
     /// for ZST reads.
diff --git a/compiler/rustc_mir_transform/src/const_prop.rs b/compiler/rustc_mir_transform/src/const_prop.rs
index 17790ec91c8..f3169d7b85f 100644
--- a/compiler/rustc_mir_transform/src/const_prop.rs
+++ b/compiler/rustc_mir_transform/src/const_prop.rs
@@ -233,13 +233,6 @@ impl<'mir, 'tcx> interpret::Machine<'mir, 'tcx> for ConstPropMachine<'mir, 'tcx>
         throw_machine_stop_str!("pointer arithmetic or comparisons aren't supported in ConstProp")
     }
 
-    fn box_alloc(
-        _ecx: &mut InterpCx<'mir, 'tcx, Self>,
-        _dest: &PlaceTy<'tcx>,
-    ) -> InterpResult<'tcx> {
-        throw_machine_stop_str!("can't const prop heap allocations")
-    }
-
     fn access_local(
         _ecx: &InterpCx<'mir, 'tcx, Self>,
         frame: &Frame<'mir, 'tcx, Self::PointerTag, Self::FrameExtra>,