make Machine::load_mir infallible

it doesn't need to return an `InterpResult`.

Author: fee1-dead

compiler/rustc_const_eval/src/const_eval/machine.rs

@@ -331,10 +331,10 @@ impl<'tcx> interpret::Machine<'tcx> for CompileTimeMachine<'tcx> {
     fn load_mir(
         ecx: &InterpCx<'tcx, Self>,
         instance: ty::InstanceKind<'tcx>,
-    ) -> InterpResult<'tcx, &'tcx mir::Body<'tcx>> {
+    ) -> &'tcx mir::Body<'tcx> {
         match instance {
-            ty::InstanceKind::Item(def) => interp_ok(ecx.tcx.mir_for_ctfe(def)),
-            _ => interp_ok(ecx.tcx.instance_mir(instance)),
+            ty::InstanceKind::Item(def) => ecx.tcx.mir_for_ctfe(def),
+            _ => ecx.tcx.instance_mir(instance),
         }
     }
 

compiler/rustc_const_eval/src/interpret/eval_context.rs

@@ -272,7 +272,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
             let def = instance.def_id();
             &self.tcx.promoted_mir(def)[promoted]
         } else {
-            M::load_mir(self, instance)?
+            M::load_mir(self, instance)
         };
         // do not continue if typeck errors occurred (can only occur in local crate)
         if let Some(err) = body.tainted_by_errors {

compiler/rustc_const_eval/src/interpret/machine.rs

@@ -189,8 +189,8 @@ pub trait Machine<'tcx>: Sized {
     fn load_mir(
         ecx: &InterpCx<'tcx, Self>,
         instance: ty::InstanceKind<'tcx>,
-    ) -> InterpResult<'tcx, &'tcx mir::Body<'tcx>> {
-        interp_ok(ecx.tcx.instance_mir(instance))
+    ) -> &'tcx mir::Body<'tcx> {
+        ecx.tcx.instance_mir(instance)
     }
 
     /// Entry point to all function calls.