Revert the `LazyConst` PR

2 files changed, 12 insertions, 20 deletions

diff --git a/src/librustc_codegen_ssa/mir/constant.rs b/src/librustc_codegen_ssa/mir/constant.rs
index 2bb68dc687c..a1d44b228a5 100644
--- a/src/librustc_codegen_ssa/mir/constant.rs
+++ b/src/librustc_codegen_ssa/mir/constant.rs
@@ -2,7 +2,6 @@ use rustc::mir::interpret::ErrorHandled;
 use rustc_mir::const_eval::const_field;
 use rustc::mir;
 use rustc_data_structures::indexed_vec::Idx;
-use rustc::mir::interpret::GlobalId;
 use rustc::ty::{self, Ty};
 use rustc::ty::layout;
 use syntax::source_map::Span;
@@ -11,35 +10,27 @@ use crate::traits::*;
 use super::FunctionCx;
 
 impl<'a, 'tcx: 'a, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
-    fn fully_evaluate(
+    pub fn eval_mir_constant(
         &mut self,
         bx: &Bx,
-        constant: &'tcx ty::LazyConst<'tcx>,
+        constant: &mir::Constant<'tcx>,
     ) -> Result<ty::Const<'tcx>, ErrorHandled> {
-        match *constant {
-            ty::LazyConst::Unevaluated(def_id, ref substs) => {
-                let tcx = bx.tcx();
-                let param_env = ty::ParamEnv::reveal_all();
-                let instance = ty::Instance::resolve(tcx, param_env, def_id, substs).unwrap();
-                let cid = GlobalId {
+        match constant.literal.val {
+            mir::interpret::ConstValue::Unevaluated(def_id, ref substs) => {
+                let substs = self.monomorphize(substs);
+                let instance = ty::Instance::resolve(
+                    bx.tcx(), ty::ParamEnv::reveal_all(), def_id, substs,
+                ).unwrap();
+                let cid = mir::interpret::GlobalId {
                     instance,
                     promoted: None,
                 };
-                tcx.const_eval(param_env.and(cid))
+                bx.tcx().const_eval(ty::ParamEnv::reveal_all().and(cid))
             },
-            ty::LazyConst::Evaluated(constant) => Ok(constant),
+            _ => Ok(*self.monomorphize(&constant.literal)),
         }
     }
 
-    pub fn eval_mir_constant(
-        &mut self,
-        bx: &Bx,
-        constant: &mir::Constant<'tcx>,
-    ) -> Result<ty::Const<'tcx>, ErrorHandled> {
-        let c = self.monomorphize(&constant.literal);
-        self.fully_evaluate(bx, c)
-    }
-
     /// process constant containing SIMD shuffle indices
     pub fn simd_shuffle_indices(
         &mut self,
diff --git a/src/librustc_codegen_ssa/mir/operand.rs b/src/librustc_codegen_ssa/mir/operand.rs
index 55a1eb016e0..e17a6e7b03f 100644
--- a/src/librustc_codegen_ssa/mir/operand.rs
+++ b/src/librustc_codegen_ssa/mir/operand.rs
@@ -76,6 +76,7 @@ impl<'a, 'tcx: 'a, V: CodegenObject> OperandRef<'tcx, V> {
         }
 
         let val = match val.val {
+            ConstValue::Unevaluated(..) => bug!("unevaluated constant in `OperandRef::from_const`"),
             ConstValue::Param(_) => bug!("encountered a ConstValue::Param in codegen"),
             ConstValue::Infer(_) => bug!("encountered a ConstValue::Infer in codegen"),
             ConstValue::Scalar(x) => {