clippy::complexity fixes

clone_on_copy
useless_format
bind_instead_of_map
filter_map_identity
useless_conversion
map_flatten
unnecessary_unwrap

compiler/rustc_codegen_ssa/src/mir/place.rs

@@ -462,7 +462,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
             }
         };
         for elem in place_ref.projection[base..].iter() {
-            cg_base = match elem.clone() {
+            cg_base = match *elem {
                 mir::ProjectionElem::Deref => {
                     // a box with a non-zst allocator should not be directly dereferenced
                     if cg_base.layout.ty.is_box() && !cg_base.layout.field(cx, 1).is_zst() {