From cf5eaa75bb171f00d6baa475333b741b86f93f72 Mon Sep 17 00:00:00 2001
From: Dylan MacKenzie <ecstaticmorse@gmail.com>
Date: Wed, 4 Jul 2018 13:05:43 -0700
Subject: [PATCH] Move `Eq + Hash + Clone` bounds to `Machine`

---
 src/librustc_mir/interpret/eval_context.rs | 12 ++++--------
 src/librustc_mir/interpret/machine.rs      |  2 +-
 src/librustc_mir/interpret/step.rs         |  6 +-----
 3 files changed, 6 insertions(+), 14 deletions(-)

diff --git a/src/librustc_mir/interpret/eval_context.rs b/src/librustc_mir/interpret/eval_context.rs
index 363ad537b3f3..a92c81e046a0 100644
--- a/src/librustc_mir/interpret/eval_context.rs
+++ b/src/librustc_mir/interpret/eval_context.rs
@@ -163,7 +163,7 @@ pub(crate) struct InfiniteLoopDetector<'a, 'mir, 'tcx: 'a + 'mir, M: Machine<'mi
 }
 
 impl<'a, 'mir, 'tcx, M> Default for InfiniteLoopDetector<'a, 'mir, 'tcx, M>
-    where M: Eq + Hash + Machine<'mir, 'tcx>,
+    where M: Machine<'mir, 'tcx>,
           'tcx: 'a + 'mir,
 {
     fn default() -> Self {
@@ -175,7 +175,7 @@ impl<'a, 'mir, 'tcx, M> Default for InfiniteLoopDetector<'a, 'mir, 'tcx, M>
 }
 
 impl<'a, 'mir, 'tcx, M> InfiniteLoopDetector<'a, 'mir, 'tcx, M>
-    where M: Clone + Eq + Hash + Machine<'mir, 'tcx>,
+    where M: Machine<'mir, 'tcx>,
           'tcx: 'a + 'mir,
 {
     /// Returns `true` if the loop detector has not yet observed a snapshot.
@@ -302,9 +302,7 @@ impl<'a, 'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M
         param_env: ty::ParamEnv<'tcx>,
         machine: M,
         memory_data: M::MemoryData,
-    ) -> Self
-        where M: Eq + Hash
-    {
+    ) -> Self {
         EvalContext {
             machine,
             tcx,
@@ -612,9 +610,7 @@ impl<'a, 'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M
         &mut self,
         rvalue: &mir::Rvalue<'tcx>,
         place: &mir::Place<'tcx>,
-    ) -> EvalResult<'tcx>
-        where M: Clone + Eq + Hash,
-    {
+    ) -> EvalResult<'tcx> {
         let dest = self.eval_place(place)?;
         let dest_ty = self.place_ty(place);
 
diff --git a/src/librustc_mir/interpret/machine.rs b/src/librustc_mir/interpret/machine.rs
index f6491d7f1a46..e2086c57c7c7 100644
--- a/src/librustc_mir/interpret/machine.rs
+++ b/src/librustc_mir/interpret/machine.rs
@@ -15,7 +15,7 @@ use syntax::ast::Mutability;
 
 /// Methods of this trait signifies a point where CTFE evaluation would fail
 /// and some use case dependent behaviour can instead be applied
-pub trait Machine<'mir, 'tcx>: Sized {
+pub trait Machine<'mir, 'tcx>: Clone + Eq + Hash {
     /// Additional data that can be accessed via the Memory
     type MemoryData: Clone + Eq + Hash;
 
diff --git a/src/librustc_mir/interpret/step.rs b/src/librustc_mir/interpret/step.rs
index 25f45fff04d1..db90714d0e62 100644
--- a/src/librustc_mir/interpret/step.rs
+++ b/src/librustc_mir/interpret/step.rs
@@ -2,16 +2,12 @@
 //!
 //! The main entry point is the `step` method.
 
-use std::hash::Hash;
-
 use rustc::mir;
 
 use rustc::mir::interpret::EvalResult;
 use super::{EvalContext, Machine};
 
-impl<'a, 'mir, 'tcx, M: Machine<'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M>
-    where M: Clone + Eq + Hash,
-{
+impl<'a, 'mir, 'tcx, M: Machine<'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M> {
     pub fn inc_step_counter_and_detect_loops(&mut self) -> EvalResult<'tcx, ()> {
         /// The number of steps between loop detector snapshots.
         /// Should be a power of two for performance reasons.