Rollup merge of #93634 - matthiaskrgr:clippy_complexity_jan_2022, r=oli-obk

compiler: clippy::complexity fixes

useless_format
map_flatten
useless_conversion
needless_bool
filter_next
clone_on_copy
needless_option_as_deref

compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs

@@ -1437,8 +1437,7 @@ impl<'a, 'tcx> InferCtxtPrivExt<'a, 'tcx> for InferCtxt<'a, 'tcx> {
                                     self.tcx
                                         .associated_items(did)
                                         .in_definition_order()
-                                        .filter(|assoc| assoc.ident(self.tcx) == trait_assoc_ident)
-                                        .next()
+                                        .find(|assoc| assoc.ident(self.tcx) == trait_assoc_ident)
                                 },
                             )
                         })

compiler/rustc_trait_selection/src/traits/project.rs

@@ -959,7 +959,7 @@ fn opt_normalize_projection_type<'a, 'b, 'tcx>(
                 infcx.inner.borrow_mut().projection_cache().insert_term(cache_key, result.clone());
             }
             obligations.extend(result.obligations);
-            Ok(Some(result.value.into()))
+            Ok(Some(result.value))
         }
         Ok(Projected::NoProgress(projected_ty)) => {
             let result = Normalized { value: projected_ty, obligations: vec![] };