make memory allocation hook infallible

Author: RalfJung

src/librustc/mir/interpret/allocation.rs

@@ -59,7 +59,7 @@ pub trait AllocationExtra<Tag, MemoryExtra>: ::std::fmt::Debug + Clone {
     fn memory_allocated(
         _size: Size,
         _memory_extra: &MemoryExtra
-    ) -> EvalResult<'tcx, Self>;
+    ) -> Self;
 
     /// Hook for performing extra checks on a memory read access.
     ///
@@ -102,8 +102,8 @@ impl AllocationExtra<(), ()> for () {
     fn memory_allocated(
         _size: Size,
         _memory_extra: &()
-    ) -> EvalResult<'tcx, Self> {
-        Ok(())
+    ) -> Self {
+        ()
     }
 }
 

src/librustc_mir/interpret/memory.rs

@@ -143,7 +143,7 @@ impl<'a, 'mir, 'tcx, M: Machine<'a, 'mir, 'tcx>> Memory<'a, 'mir, 'tcx, M> {
         align: Align,
         kind: MemoryKind<M::MemoryKinds>,
     ) -> EvalResult<'tcx, Pointer> {
-        let extra = AllocationExtra::memory_allocated(size, &self.extra)?;
+        let extra = AllocationExtra::memory_allocated(size, &self.extra);
         Ok(Pointer::from(self.allocate_with(Allocation::undef(size, align, extra), kind)?))
     }