My solutions to the 4.6.0 version of the rustlings exersises.
$ rustlings verify
✓ Successfully ran exercises/intro/intro1.rs!
✓ Successfully ran exercises/intro/intro2.rs!
✓ Successfully ran exercises/variables/variables1.rs!
✓ Successfully ran exercises/variables/variables2.rs!
✓ Successfully ran exercises/variables/variables3.rs!
✓ Successfully ran exercises/variables/variables4.rs!
✓ Successfully ran exercises/variables/variables5.rs!
✓ Successfully ran exercises/variables/variables6.rs!
✓ Successfully ran exercises/functions/functions1.rs!
✓ Successfully ran exercises/functions/functions2.rs!
✓ Successfully ran exercises/functions/functions3.rs!
✓ Successfully ran exercises/functions/functions4.rs!
✓ Successfully ran exercises/functions/functions5.rs!
✓ Successfully tested exercises/if/if1.rs
✓ Successfully tested exercises/if/if2.rs
✓ Successfully tested exercises/quiz1.rs
✓ Successfully ran exercises/move_semantics/move_semantics1.rs!
✓ Successfully ran exercises/move_semantics/move_semantics2.rs!
✓ Successfully ran exercises/move_semantics/move_semantics3.rs!
✓ Successfully ran exercises/move_semantics/move_semantics4.rs!
✓ Successfully ran exercises/move_semantics/move_semantics5.rs!
✓ Successfully ran exercises/move_semantics/move_semantics6.rs!
✓ Successfully ran exercises/primitive_types/primitive_types1.rs!
✓ Successfully ran exercises/primitive_types/primitive_types2.rs!
✓ Successfully ran exercises/primitive_types/primitive_types3.rs!
✓ Successfully tested exercises/primitive_types/primitive_types4.rs
✓ Successfully ran exercises/primitive_types/primitive_types5.rs!
✓ Successfully tested exercises/primitive_types/primitive_types6.rs
✓ Successfully tested exercises/structs/structs1.rs
✓ Successfully tested exercises/structs/structs2.rs
✓ Successfully tested exercises/structs/structs3.rs
✓ Successfully ran exercises/enums/enums1.rs!
✓ Successfully ran exercises/enums/enums2.rs!
✓ Successfully tested exercises/enums/enums3.rs
✓ Successfully ran exercises/modules/modules1.rs!
✓ Successfully ran exercises/modules/modules2.rs!
✓ Successfully ran exercises/modules/modules3.rs!
✓ Successfully tested exercises/collections/vec1.rs
✓ Successfully tested exercises/collections/vec2.rs
✓ Successfully tested exercises/collections/hashmap1.rs
✓ Successfully tested exercises/collections/hashmap2.rs
✓ Successfully ran exercises/strings/strings1.rs!
✓ Successfully ran exercises/strings/strings2.rs!
✓ Successfully ran exercises/quiz2.rs!
✓ Successfully tested exercises/error_handling/errors1.rs
✓ Successfully tested exercises/error_handling/errors2.rs
✓ Successfully ran exercises/error_handling/errors3.rs!
✓ Successfully tested exercises/error_handling/errors4.rs
✓ Successfully ran exercises/error_handling/errors5.rs!
✓ Successfully tested exercises/error_handling/errors6.rs
✓ Successfully ran exercises/generics/generics1.rs!
✓ Successfully tested exercises/generics/generics2.rs
✓ Successfully tested exercises/generics/generics3.rs
✓ Successfully ran exercises/option/option1.rs!
✓ Successfully ran exercises/option/option2.rs!
✓ Successfully ran exercises/option/option3.rs!
✓ Successfully tested exercises/traits/traits1.rs
✓ Successfully tested exercises/traits/traits2.rs
✓ Successfully tested exercises/tests/tests1.rs
✓ Successfully tested exercises/tests/tests2.rs
✓ Successfully tested exercises/tests/tests3.rs
✓ Successfully tested exercises/quiz3.rs
✓ Successfully tested exercises/standard_library_types/box1.rs
✓ Successfully ran exercises/standard_library_types/arc1.rs!
✓ Successfully ran exercises/standard_library_types/iterators1.rs!
✓ Successfully tested exercises/standard_library_types/iterators2.rs
✓ Successfully tested exercises/standard_library_types/iterators3.rs
✓ Successfully tested exercises/standard_library_types/iterators4.rs
✓ Successfully tested exercises/standard_library_types/iterators5.rs
✓ Successfully ran exercises/threads/threads1.rs!
✓ Successfully ran exercises/macros/macros1.rs!
✓ Successfully ran exercises/macros/macros2.rs!
✓ Successfully ran exercises/macros/macros3.rs!
✓ Successfully ran exercises/macros/macros4.rs!
✓ Successfully tested exercises/quiz4.rs
✓ Successfully compiled exercises/clippy/clippy1.rs!
✓ Successfully compiled exercises/clippy/clippy2.rs!
✓ Successfully tested exercises/conversions/using_as.rs
✓ Successfully tested exercises/conversions/from_into.rs
✓ Successfully tested exercises/conversions/from_str.rs
✓ Successfully tested exercises/conversions/try_from_into.rs
✓ Successfully tested exercises/conversions/as_ref_mut.rs
✓ Successfully tested exercises/advanced_errors/advanced_errs1.rs
✓ Successfully tested exercises/advanced_errors/advanced_errs2.rs