test fix

Author: xacrimon

compiler/rustc_mir_build/src/builder/matches/match_pair.rs

@@ -58,10 +58,12 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
         if self.should_optimize_subslice(prefix) {
             let elem_ty = prefix[0].ty;
             let prefix_valtree = self.simplify_const_pattern_slice_into_valtree(prefix);
+            let prefix_len = prefix.len() as u64;
+            //let suffix_len = suffix.len() as u64;
 
             let src_path_subslice = place.clone_project(PlaceElem::Subslice {
                 from: 0 as u64,
-                to: prefix.len() as u64,
+                to: if exact_size { prefix_len } else { min_length - prefix_len }, // TODO: Is this correct?
                 from_end: !exact_size,
             });