Squashed 'third_party/flatbuffers/' changes from acc9990ab..d6a8dbd26

d6a8dbd26 Experimental fix for failing oss-fuzz coverage build (#6259)
ed391e177 BREAKING: Rust flexbuffers serde human readable set to false (#6257)
a49531414 Update to flags in fuzzing-cmake file (#6256)
de1f0342c Remove _POSIX_C_SOURCE and _XOPEN_SOURCE definitions when compiling o… (#6205)
d0d51e2a5 flatc should support --binary --schema with optional scalar fields. (#6252)
33ab26017 Bump version of rules_go to 0.24.5 (#6234)
febb9d87c Union As Accessors for C# (#6251)
8778dc7c2 Resets buffer without deallocating current pointer (#6247)
aae376e9a Add GetBufferSpan() function to bufferbuilder (#6235)
0ff047148 Modernize android build and sample (#6229)
46a8c7e95 Added required-nested-flatbuffer to monster_test and fixed rust (#6236)
bc56c553e Notify based on Labelling issues and PR (#6241)
07d7cd78a Converted globs to use single quotes (#6240)
cdef70e24 More adjustments to the auto labeler (#6239)
9dd44df35 Updated Lua labeller glob (#6238)
c9b29d088 Support size-prefixed buffers and add tests for size-prefixed messages (#6232)
fba93e0ab Removes duplicate swift in labeler (#6228)
d1a545b1f Added more labels for auto labeler (#6227)
ea92a668d [C#] Optional Scalars (#6217)
6034de286 [Label Bot] Add Java and Kotlin support for the label bot (#6226)
b08b0a440 Implement `Debug` trait for Rust flatbuffers. (#6207)
17ae48dec [Label Bot] Adds some languages to labeler bot (#6222)
fc8097925 Auto Labeler Setup, Just C# for now (#6221)
55658f523 Auto Labeler Setup, Just C# for now (#6218)
14ecfe423 Updated comments and fixed a fundamental type error. (#6214)
a0182cdb1 optional scalars for ts/js (#6215)
0dfcc0a37 Adds NetTest.bat to run .NET Core tests on Windows (#6216)
f9a18ea63 [Java] Implement optional scalars (#6212)
c7586e85a Empties the sharedString map on reset on go and csharp (#6187)
914c64601 Removed C# references from java generator. Move annotations closer to definitions (#6204)
42d7c7997 Adds readable size to asserts in read functions (#6210)
e68e8d7de Refactor idl_gen_rust (#6206)
84809be7e Fix typo in flatbuffers::span declaration. (#6202)
1606fb637 Kotlin test optional enum (#6201)
fe8e3c7e5 Mass Refactoring to use `IsString` and other BASE_TYPE helpers (#6193)
8f6fa4b71 Updated SupportsAdvancedUnionFeatures to look out for string (#6190)
b46db38f5 [JS/TS] Rewrite flexbuffers JS to TS (#6148)
9fa1d2705 Rework enums in rust. (#6098)
a402b3aba idl_gen_json_schema Fix generation of arrays of enums (#6184)
0e1415b99 fix(go_test): remove deprecated grpc call (#6183)
5cd713710 Add generation of JSON Schema to library (#6165)
5be777e1d Bump junit from 4.12 to 4.13.1 in /grpc/tests (#6173)
a49d440ec Bump junit from 4.12 to 4.13.1 in /grpc (#6172)
4ec5e8db9 [C++] Add option to not generate direct copy methods. (#6166)
04bec23a3 Add Array initialization from struct constructor (#5865) (#6147)
77d57fd07 Cast to right type for reserved_ subtraction (#6167)
543c1bbeb Fixed rust nested flatbuffers for tables other than self (#6062)
cb971eece [C++] Fix -Wnarrowing and -Woverflow due to signed bitfields on G++ ARM (#6163)
7b9e61fcc [TS] GRPC  Implementation (#6141)
3359e3042 Moved C++ to optional_scalars2 and added some tests. (#6162)
187a4787f [Rust] Upgrade flatbuffers library to 2018 edition (#6159)
08943aa26 Flatbuffer C++ UnpackTo optimization for vectors of non-bool bytes. (#6154)
5975658eb Enables optional enums in swift (#6160)
5d3cf440e Updated Lobster test for optional bools/enums
8ec8322f0 Ruopt enum (#6156)
bbcc85fd4 Fix generation of C++ code with Optional<Enum> (#6155)
0bdf2fa15 [C#] Fix and improve project files (#6142)
2eedc769d possibility to create a vector from an iterator (#6135)
ab01ae162 flatc should output a warning, when an attribute is attached more than once (#6146)
689bfafa7 [Python/JS/TS] Codegen SizeOf method for structs (#6136)
641309a5b unix2dos on tests/FlatBuffers.Test/FlatBuffers.Core.Test.csproj (#6133)
52e362879 SpanT is available in .Net Standard 2.0. (#6137)
dca12522a Add static cast to avoid implicit double promotion. (#6132)
e0bbaa6f9 [C#]Change to ENABLE_SPAN_T that doesn't require UNSAFE_BYTEBUFFER. (#6073)
ab139d6be Revert "[C#] Fix and improve project files (#6116)" (#6130)
34d67b425 Minireflect fixed array (#6129)
96d5e3597 [JS/TS] fix flatbuffers default export (#6123)
eb686a86f Add missed file generated by optional_scalar.fbs (#6125)
750281630 [C#] Fix and improve project files (#6116)
fb4e1c34f Add CharToLower and CharToUpper into util.s (#6126)
8c67b5b12 Add support of Optional<T> scalars to C++ code generator (#6092)
6228b66d3 [Kotlin] Support for optional scalars. (#6115)
e1be8aaad Bump version for latest swift version (#6121)
94873e595 [JS/TS] Modernize TypeScript / JavaScript flatbuffers support (#6095)
b8e87fafe [JS] Add getFullyQualifiedName() (#6119)
f96d1ef74 [Java] allowing larger buffer sizes when growing a byte buffer (#6118)
89435303b [Swift] Migrates struct write APIS to write directly to the buffer (#6093)
c75ae2429 Optional-ness in reflection (#6097)
338944d3d Rename Nullable scalars to Optional scalars (#6112)
f5ab24bc4 Avoid memcpy call for empty vectors (#6111)
92a8c1a0f [JS] FlexBuffers Fix for wrong type of offset and length values (#6107)
6cea45dcd fix c# json serializer commandline argument docs (#6104)
fec58aa12 Fix for issue 6100: incorrect shrinking logic in ResizeContext() (#6102)
71aca81ff [JS] FlexBuffers Support (#5973)
04d87ffec [C++] Small refactoring of the C++ code generator (#6091)
bb25956f0 Wrap verify file id condition in Check call (#6085)
49f4948f0 + Add `removable-media` plug to the snapcraft config (#6083)
eeacc53d2 Adds proper access types for swift object api & flatbuffers & grpc (#6081)
f3003e08d [Lobster] missed a test
d713a0084 [CMake] enabled multi-core builds in VS projects
77f966f89 [Lobster] optional scalars support
e86d5b8e9 [Kotlin] Attach JvmStatic annotation to each method in companion object (#6052)
db2aa9b4e [C#] Cleaned up .NET testing script for Mono (#6016)
63cc0eec4 Adds a serialize helper function to native table (#6059)
c30a87de6 [TS] Fix four bugs with imported types in TypeScript. (#6054)
a0fb30575 [Swift] Append namespace for Swift Grpc implementation (#6049)
77c18c1d6 export a __version__ variable for python module (#5309)
f1f23d08e adding fb import when no other imports are present (#6030)
f1025b284 [Feature] Checks for Nullable strings (#6050)
5d052f4e5 [Swift] RFC: Switch Swift namespace from public enum to ordinary concat with _ (#6045)
18b015d25 Rust codegen improvements and lint fixes (#6046)
d76e93f27 adds code gen for optional scalars in swift (#6038)
82fac326c [C++] Fix compiler error from deleted assignment operator (#6036) (#6047)
043b52bd4 Optional Scalars support for Rust (#6034)
c8fa0afdf Allow to run cpp tests under grpc/tests/ using bazel. (#6040)
6d0aae73c Fix git command executed in wrong folder when doing cmake superbuild (#6039)
ff1b73128 [Swift] Optional Scalars Preparation (#6028)
2e48c8dd3 tests: Check for both quiet and signaling NaN on mipsel/hppa (#6029)
6942704f2 support deprecated flag in json schema (#6022)
9ecd2e16c Flatc parser support for nullable scalars (#6026)
33e2d8079 [Dart] Generate constant values map for enums (#6025)
969d0f7a6 Using proper symbol name for reexport (#6021)
515a4052a Silence false positive "-Wstringop-overflow" on GCC 10.0 to 11.0 (#6020)
36fbe6f13 Updated FB import (#6019)
b69fc8cc9 [Java] Add support for shared strings on FlatBufferBuilder. (#6012)
ab6af18d9 Not using non-existent create method for obj api (#6015)
37a5dee10 Code cleanup + updates test and readme (#6004)
8a721f69a Serde with bytes maps to Blob (#6009)
e810635ea [Swift] FlatBuffers createMonster method doesn't treat struct properly (#5992)
4995e1527 Manage grpc dependency in Bazel's WORKSPACE file. (#5995)
60b6066fe Add warning to schema parser if field name is not snake_case. (#6005)
35d45cac7 [Rust] Flexbuffers dependency cleanup and fixes (#5998)
165a6e3d1 Re-added Evolution Schema Code Generation Command (#5999)
13d3fb2ea Fix RPM install conflict (#6003)
d64078eb2 [Swift] Initialize memory when clear ByteBuffer (#5982)
ca1190a3d [TS] Use proper TypedArray in create*Vector (#5991)
7571b2ac5 [C++] Updates real_path to be truly portable (#5787)
e5a8f76a4 [C++] Generate default member initializers for >= C++11 (#5989)
413bb9b55 [Kotlin] Fix Access to union of vector element (#5994)
f35184aef [Swift] Add parsing from unowned UnsafeMutableRawPointer for ByteBuffer (#5981)
b124b7625 Removed requirement that enums be declared in ascending order. (#5887)
0ec7600c6 Do not remove the last digit from float values (#5974)
14baf45c9 Mark GetBufferMinAlignment() const (#5985)
9abb2ec2c TypeScript/JavaScript docs improvements (#5984)
2e57d80b1 [Swift] Internal library improvements (#5965)
cfc7753a4 [Doc] Added missing letters to compiler options (#5976)
12ddc8a92 Rust Flexbuffers Documentation update (#5979)
24ad35709 [docs] typo: updates monsterdata.json to be valid json (#5978)
cc44a4442 [idl_parser] Mark typefield as deprecated (#5958)
9ab4a5c0e Deleted old stale bot
6682cfe87 Increased Operations per run in stale.yml
64922904b Adding Stale Action to clean up PR and Issues
8e505cb67 [C++] Fixed/Enabled --cpp-ptr-type std::shared_ptr [#5813] (#5959)
a28357d7a Propagate boolean default values from proto to fbs (#5964)
7cb4762a6 [Swift] Improving reallocation time by using memcpy and moving reallocation code to storage (#5960)
4e45f7c9e Fix error in SimpleQSort (#5955)
7ac026405 fix error on GRPC Python - ignore namespace tree if not specified (#5862) (#5922)
108e981db Required is now implemented in swift (#5952)
94a78e385 Fixed: Access violation and ASAN/UNSAN failures with sorted tables
53fb453e0 [rust] Add FlatBufferBuilder::force_defaults API (#5946)
17c1f35fa [FlexBuffer][Java] ReadWriteBuf and ReadBuf interface public (#5948)
2eaf57778 [Java] Grow ArrayReadWriteBuf enough to match requested capacity. (#5921)
666800da3 Adds bool support in structs + updates grpc support + CI upgrades (#5943)
38ed69eb3 fixed mutating inline values (#5942)
d026e6f07 Add static asserts to ensure that reflection API arrays are kept in sync (#5934)
988164f6e [C++] Got rid of memset's in constructors (#5938)
7179a5a8b General Codebase clean up (#5939)
a0da0c08c Add GetStringView like GetString, GetCstring (#5937)
ac203b209 [C#] Add file identifier to ObjectAPI Serialization Utility. (#5920)
8dd1bf25b not creating creation methods when using structs (#5919)
5aa443d98 [Dart] Adding FlexBuffers support (#5853)
0fa087657 [Dart] Getting tests/DartTest.sh to work on master. (#5915)
424a473e1 Schema parser: prohibit declaration of an array of pointers inside structs (#5907)
c3faa8346 Fix Cargo.toml dependencies (#5911)
91399ad05 fix union type names (#5902)
32782e4ad Update Rust Flexbuffers metadata before publishing (#5905)
e7f3b1690 [TS] Make Obj-API work with --short-names (#5898)
12ed1fe4a fixed invalid imports with --gen-all (#5895)
85ee4df7a [C#] Thread safe reads of Double and Float values from a ByteBuffer (#5900)
de89bd193 Implement flexbuffers in python (#5880)
8be05f6bd Rust Flexbuffers (#5669)
870ecbc09 [swift] Moves code to use VTablesStorage (#5888)
c2da8d5d8 [Java][FlexBuffers] Make FlexBuffersBuilder reusable by adding clear() (#5889) (#5890)
e84cbff67 Align package name to FindFlatBuffers.cmake (#5899)
f94e6c84e Small tutorial improvements - documentation only (#5894)
f12cca8bc Attempt at adding Github Actions CI
7e4124d6e Handle git program or .git folder absence (#5878)
a875d247a only add native_include_files if object based api is enabled (#5886)
6e9f5d981 Respect shared attribute in Parser (#5885)
ff1c78233 include/flatbuffers: typo fixes in comments (#5884)
2e9a19673 Updates swift docs for package management (#5883)
e3cb07d32 [Rust] idl_gen_rust.cpp: (Option/required-aware codegen for unions) (#5850)
712866d57 Propagate use_string_pooling in CopyTable (#5879)
44c919a9e Not using reexports with --gen-all (#5873)
99aa1ef21 Added INCLUDE_PREFIX option for flatbuffers_generate_headers (#5866)
40ba170c9 Fixed text in internals doc that implied structs can be root
cb4d0f72e [Swift] Object API support  (#5826)
003e16405 [TS] Add Obj API (#5788)
21cf300f4 fix cpp usage markdown error (#5845)
9655e12d6 Upgraded swift implementation for grpc (#5843)
fb96fadc2 [C#] Fix nested structs and arrays in Object API (#5765)
408f11fbd [ts] Fix empty source/dest namespaces when reexporting. (#5841)
a83caf591 Improves performance for the swift library by using structs + a storage class (#5835)
925fab6b1 [Java][FlexBuffers] Optimize Map access (#5735)
d9fecc332 [CMake] : Add precompiled header support with FLATBUFFERS_ENABLE_PCH (#5827)
e9d453240 Added flatbuffers_generate_headers and flatbuffers_generate_binary_files cmake functions. (#5830)
c37c989ed Correct calculation of vector element size (#5831)
6b271b7ec Fix Clang-trunk warnings about special members deprecated in C++20. (#5829)
90f3b8e8c Fix `float_constant` definition in './doc/Grammar.md` (#5828)
3af735934 [csharp] flatc should generate a 'Create…' method for tables with struct field… (#5818)
c4231c3cb Updated doxyfile - added missing files (#5824)
9657df184 Update Grammar.md (#5820)
97ffc590e Include CPack only when explictly packaging (#5817)
8b52af65b [C++] Add max_depth and max_tables parameters to reflection::Verify (#5815)
9b034eee1 Fix interpretation of 'nan(number)' by the idl_parser (#5810)
3e9ac3cff [Scripts] Adds swift to generated code (#5806)
697147a2e updated maven build files
6df40a247 pre-tag version bump for 1.12
0dba63909 Removes the inner loop in the endtable check written tables (#5803)
0e3fdd0ee Escape characters in jsonschema descriptions (#5644)
45a2b07cb Remove `noexcept` qualifier copy-ctor of `union` type (#5800) (#5802)
d10c16314 Replace 'assert' by 'FLATBUFFERS_ASSERT' inside idl_parser.cpp (#5799)
35abb7f89 Add non-nullable modifier to return type of functions never returning null (#5797)
9954e09ab [C++] Generate code for vector force_align attribute. (#5796)
95a21327f rust: pub export the VectorIter type (#5736)
89b6183ee Fix Python min alignment
5a98d65e8 [Rust] Add gen-name-strings for Rust (#5757)
f73d205bc Removed assert that wasn't backwards compatible.
7c37abe92 [C#] add ObjectAPI Serialization Utility (#5785)
4749e77b0 Fixed docs on how to obtain parser error.
6ff189841 Added --filename-suffix and --filename-ext to flatc (#5778)
c9a30c9ca Fixed refractoring issue in reflection/generate_code.sh. Also, mv deletes the original file, so I don't need to clean it up manually in that case. (#5777)
8c02d17be Skip writing reflection_generated.h if not changed (#5776)
34305c4ce [Swift] Adds GRPC to Swift (#5758)
cd88e6b2a [Java][FlexBuffers] Abstract buffer access from ByteBuffer (#5743)
3ec7a53c6 Adds cocoapods and a readme of how to get the package (#5771)
6d44cede7 [snap] Fix versioning (#5727)
cc08c0835 [Python] Fixed potential allignment issue (#5768)
54f8b787c Fix memory leak on cpp object api (#5761)
17557f913 [Python] Fixed issue #5499 (#5764)
d54af8cd4 [C++] Use strong enum type for vectors when scoped-enums is on. (#5750)
173e10fdf [C#] support Json Serialization (#5752)
8f56990f6 FlexBuffers: C++: scalar-only typed vectors were not aligned.
6400c9b05 Bump Rust port to 0.6.1 (#5747)
7418d8587 [C#] support Object API (#5710)
c580fa284 Adds min and max, comments, and all of swift's keywords + fix docs (#5737)
f2a127230 Use VS 2017 and 2019 on CI, fix cast issue in dart_idl (#5740)
316d7c208 Creates a flatbuffers validation function + small fix (#5725)
47026ea6b Added the code to embed the binary schema to the source (--bfbs-gen-embed). (#5701)
3f677f241 [Java][FlexBuffers] Deprecate typed vector strings due to design flaw (#5722)
a593a11e5 [Go] Implements a SharedStrings function (#5733)
7cdfc8475 [Swift] Fix padding function overflow when bufSize is 0 (#5721)
bab2b0db4 Add vcpkg installation instructions (#5732)
89418eb84 [Dart] Fix deprecated field support, inf/nan (#5724)
9cadf05d8 [typescript] Size-prefixed root accessors not taking into account size prefix (#5717)
6da1cf79d [rust] Add use declarations to Rust-generated bindings for imported FB definitions (#5645)
bee1df96d [Go] Replace references to hardcoded ”Monster" etc with idiomatic go wherever possible (#5716)
01189d7ed [C++] Fix for printing of enum in case output_enum_identifiers=1. (#5706)
c4b2b0a25 [Swift] Support create long string (#5709)
a4b2884e4 Added create function for swift (#5707)
04d80f255 [Swift] Swift implementation 🎉🎉 (#5603)
55686100a Changed direct calls to strtod to use StringToNumber
718351831 Document JSON compatibility guarantees. (#5704)
d1b34f0f2 Add CMake 'generated_code' target to simplify resolution of build dependencies (#5697)
21b706196 (Optionally) add an additional suffix namespace to generated fbs files. (#5698)
35daaf83d [Java] Replace Table.UTF8_CHARSET with StandardCharsets.UTF_8 (#5696)
3b458f7a1 Rust: Temporarily disable 2 endianness unit tests (#5695)
a5d9d0f7d [C++17] Add Traits class for Tables and Factory function within it. (#5678)
3cd9b6434 Removed code_generators.cpp from library targets
355dfd48d [rust] Make enum names public (#5690)
bcd58a159 Correct inverted logic around include prefixes. (#5689)
a2c12900a Optimize Pack method using numpy (#5662)
901b89e73 [C++] Add Builder and Table typedefs (#5685)
31f879908 Minor doc updates: FlexBuffers C#, Discord, CppUsage.
8023d99e2 Upgrade rules_go (#5684)
b4154405d Fix --incompatible_load_cc_rules_from_bzl (#5683)
04c17c7a7 Add support for absl::string_view when available (#5682)
62ec7d52c [Bazel] Add support for compatible_with and restricted_to (#5681)
7de668053 CI: New Docker tests for Python with numpy (#5677)
3a70e0b30 Fixed struct initialization error on older versions of C#
9b1320135 Fixed warnings in FlexBuffers.java
5e3916050 Fixed out of date licenses on gRPC Python files.
c95755051 Removed test proto output.
44bf71988 Add flatc '--cpp_std' switch (#5656)
3e8f15df9 Fix for FlexBuffers FBT_VECTOR_STRING size bit-width.
602721a73 Added Check to VerifyAlignment (#5675)
13c05f4da Improve import handling for proto conversion (#5673)
ce3a1c43a [Dart] Fix prepare space for writeListInt64 and writeListUint64 (#5654)
aa75e5734 Make Rust constants public (#5659)
2790fee25 Add namespace qualification to union types (#5666)
eddebec1b Bugfix for Rust generation of union fields named with language keywords (#5592)
030fee36a wrap multiple statements in do {} while(!IsConstTrue(true)) (#5655)
f9724d1bd [gRPC] Uncomment MessageBuilder (#5658)
b20801ca4 Supress unsigned-integer-overflow for PaddingBytes (#5647)
a8e800bd7 Add --force-empty-vectors option (#5653)
d7530ae96 Fixed enum min/max values not properly escaped.
99d11e279 Split Bazel targets into multiple packages (#5640)
4fd8eb214 Remove a static_assert (#5643)
65f870357 Flatbuffers Python Object API (#5616)
75823cc27 [Clang 10]: definition of implicit copy constructor for 'TableKeyComparatoris deprecated #5649 (#5650)
58e279244 [docs]: add missing semicolon (#5648)
3c964e10a [GO] Fix support for enums with underscores and Unions with imported members (#5600)
c3c32ec94 Fix ambiguity of a type deduction in TEST_EQ macro if arguments have `enum class` type. (#5630)
075e8d676 Simplify declarations of x-macro FLATBUFFERS_TD (#5638)
bcf1bd5c9 read vtable size through ReadScalar() (#5636)
136d75fa6 Changed null checks in test. Removed verifier pointer usage (#5634)
091fa1fd1 Add testing of C++ with sanitizers (CI-Docker) (#5631)
ff3781dc2 add namespace prefix in FLATBUFFERS_MAX_BUFFER_SIZE (#5629)
6beb9f49c Support for python grpc - continuing the work from the pull request #4270 #4705 (#5613)
80988ea86 Removed idl_gen_general.cpp and move contents to code_generators.cpp (#5625)
0f2ff7eaa Lua cleanup (#5624)
dda095023 [C++] Adds basic schema evolution tests (#5611)
adbcbba5d [C++, C#, Java] Separated C# and Java generators into their own classes (#5618)
cbbd6aca0 add check for root_type specified for json schema generation (#5622)
405c64e07 [Rust] Bump smallvec version to 1.0 (#5621)
42c08cbca Ran src/clang-format-all.sh (#5617)
33d5dd9bd Improved pull request & clang-format instructions.
105dd528e Change monster_extra generation to use flatbuffers::unique_ptr (#5612)
f0f0efe7b [C++] Refactor to conform to Google C++ style guide (#5608)
e837d5a29 Fixed deprecated method in GRPC Java test.
9834ee978 Fixed Apache license not using canonical version.
44b2ab087 include/flatbuffers/base.h: fix no_sanitize issue with old clang (#5610)
46ae3f80a [C++, Java, C#, TypeScript, JavaScript] Skip generation of mutable union types (#5599)
7b38aa71e flatbuffers.h: fix documentation warning (#5607)
661bedd83 Add Lua FlatbufferBuilder Clean() method to enable reuseable builders (#5606)
8526e12d7 [Kotlin] Fix union vector accessor after change in Java API (#5605)
3c7b660d6 [flatc] Remove an always true condition for flexbuffers (#5604)
964365ba6 [Go] Add UnPackTo functions (#5598)
32254b7ac [Go] Object API support (#5339)
521e255ad Rust: Add idiomatic iterator for Vector type (#5579)
1b85292fd Fix typos in comments (#5590)
480815447 C++ verifier for evolved union fields should return true (#5586)
8d5e424c6 Add ByteBuffer copy for vector of bytes in Java (#5587)
b4774d235 Rust: Fix Copy and Clone impls for a few generic types (#5577)
26f238c24 Add `--clean-first` to the cmake-build command (travis) (#5574)
e93c8c46e Fix Follow implementation for bool (#5554)
e21516b9d Fix issue #5557 (#5573)
fbc11e8ae Avoid intentional unsigned integer overflow getting caught by sanitizers (#5572)
e9d29c21a Python: Add forceDefaults opt to python Builder (#5564)
8bfafc76d Java: Don't annotate vector-of-tables item getters with @nullable. (#5562)
df3e8bf4a Fixed warnings generated by recent JSON sorting feature.
5665cfe49 [Java] byte buffer factory returned buffer capcity is used instead of the requested size (#5558)
5797540ed #5544 Fix of Array of table is not sorted if Create<type>Direct() is used (#5546)
7f1af7cb0 Fix build with gcc version 7.4.0 (#5570)
32f47ad24 Fixed JSON parser not sorting vectors of tables/structs with key.
842f672ba [FlexBuffers][Java] Cache size of Sized objects in FlexBuffers (#5551)
d4cae0a62 Fix issue #5542 (#5543)
f1147f65b Fixed Android STLPort related error.
69d3fec48 Fix namespaced struct/field name collision detection (#5540) (#5545)
cfb4ecf6f [flac] Add FlexBuffers option for generating data (#5519)
a92039687 Update Rust versions under test from 1.30.1 to 1.37.0 (#5538)
625338d09 Adds XOPEN_SOURCE for PATH_MAX and POSIX 1993 for stat (#5529)
3f8ce99c5 [FlexBuffers][Java] Add override Key::toString (#5533)
0798b7b69 [FlexBuffers][Java] Fix wrong access to a string using Reference::asString(). (#5532)
cbdf82e2f Fix Mutate() methods of Array<scalar/struct> (override 5508) (#5526)
e365c502f Java: Added access object for vector of struct and vector of tables. (#5233)
97f3aa917 Fixed DetachedBuffer self move assignment (#5521)
2f5bb2eec Fix buildifier warnings found in new bazel (#5517)
917687c7a Fixed Reflection Verifier not handling vectors of unions.
f9277e691 Fixed GenerateText not handling vectors of unions.
2706381ee Add element size parameter to __vector_as_arraysegment [c#] (#5512)
b5560fcd5 [Java][FlexBuffers] Improve documentation for FlexBuffers in Java. (#5506)
782b865c5 Annotate getters with @Pure when --java-checkerframework is specified. (#5510)
3bfc86eaf [Dart]fix: segment fault with empty namespace when generating dart file (#5507)
c0282873f Rust: Fixed cargo clippy on non-generated code (#5485)
4b870aca9 [Javascript] Fix syntax error for signed enum (#5503)
d0e3870c0 [C#] Fix retrieving enumeration vectors as arrays (#5457)
fb25eb87f Doc typo fixes (#5505)
cb35d3a0e Use all of the available space in the buffer returned by ByteBufferFactory to allow the factory to keep a pool of larger than initialsize sized buffers. (#5500)
8e6cabb31 [FlexBuffers][Java] Implementation of FlexBuffers API (#5476)
bd31dd242 Clarified value reuse in FlexBuffers
65b67d213 Fixed test build invocation of arrays_test.fbs
1fbb71132 FlexBuffers: allow any values to be shared.
cd75a3658 Android: remove app_dummy() calls
ec6b0bf29 Fixed STLPort Android compile error
c11b5d744 [bugfix]flexbuffers isvector bugfix (#5488)
4525c91be Fix incorrect padding in arrays of structs (Issue #5484) (#5491)
b97b342f5 Fixed missing generated code.
c1058a903 C++ IDL generation adds superfluous semicolon in GenTablePost, causing (#5483)
303044934 [go]add Name() for ForceCodec  interface (#5486)
a2485d4ec reflection: check for valid union enum value during object verification (#5475)
a20e71ac9 has_method support for primitive fields in java runtime. Changed: idl.h, FlatBufferBuilder.java ,  idl_gen_general.cpp, idl_parser.cpp, flatc.cpp (#5468)

Change-Id: I836f4b43e6818bb16425a87899e6234ac86242aa
git-subtree-dir: third_party/flatbuffers
git-subtree-split: d6a8dbd26ff08a8868e0d0c1b4b67d31b40e4a7f
diff --git a/src/idl_gen_rust.cpp b/src/idl_gen_rust.cpp
index 936ac83..3995a7f 100644
--- a/src/idl_gen_rust.cpp
+++ b/src/idl_gen_rust.cpp
@@ -23,27 +23,20 @@
 
 namespace flatbuffers {
 
-static std::string GeneratedFileName(const std::string &path,
-                                     const std::string &file_name) {
-  return path + file_name + "_generated.rs";
-}
-
 // Convert a camelCaseIdentifier or CamelCaseIdentifier to a
 // snake_case_indentifier.
 std::string MakeSnakeCase(const std::string &in) {
   std::string s;
   for (size_t i = 0; i < in.length(); i++) {
     if (i == 0) {
-      s += static_cast<char>(tolower(in[0]));
+      s += CharToLower(in[0]);
     } else if (in[i] == '_') {
       s += '_';
     } else if (!islower(in[i])) {
       // Prevent duplicate underscores for Upper_Snake_Case strings
       // and UPPERCASE strings.
-      if (islower(in[i - 1])) {
-        s += '_';
-      }
-      s += static_cast<char>(tolower(in[i]));
+      if (islower(in[i - 1])) { s += '_'; }
+      s += CharToLower(in[i]);
     } else {
       s += in[i];
     }
@@ -54,9 +47,7 @@
 // Convert a string to all uppercase.
 std::string MakeUpper(const std::string &in) {
   std::string s;
-  for (size_t i = 0; i < in.length(); i++) {
-    s += static_cast<char>(toupper(in[i]));
-  }
+  for (size_t i = 0; i < in.length(); i++) { s += CharToUpper(in[i]); }
   return s;
 }
 
@@ -96,7 +87,7 @@
 FullType GetFullType(const Type &type) {
   // N.B. The order of these conditionals matters for some types.
 
-  if (type.base_type == BASE_TYPE_STRING) {
+  if (IsString(type)) {
     return ftString;
   } else if (type.base_type == BASE_TYPE_STRUCT) {
     if (type.struct_def->fixed) {
@@ -104,7 +95,7 @@
     } else {
       return ftTable;
     }
-  } else if (type.base_type == BASE_TYPE_VECTOR) {
+  } else if (IsVector(type)) {
     switch (GetFullType(type.VectorType())) {
       case ftInteger: {
         return ftVectorOfInteger;
@@ -184,13 +175,21 @@
   }
 }
 
+bool IsBitFlagsEnum(const EnumDef &enum_def) {
+  return enum_def.attributes.Lookup("bit_flags") != nullptr;
+}
+bool IsBitFlagsEnum(const FieldDef &field) {
+  EnumDef* ed = field.value.type.enum_def;
+  return ed && IsBitFlagsEnum(*ed);
+}
+
 namespace rust {
 
 class RustGenerator : public BaseGenerator {
  public:
   RustGenerator(const Parser &parser, const std::string &path,
                 const std::string &file_name)
-      : BaseGenerator(parser, path, file_name, "", "::"),
+      : BaseGenerator(parser, path, file_name, "", "::", "rs"),
         cur_name_space_(nullptr) {
     const char *keywords[] = {
       // list taken from:
@@ -200,77 +199,19 @@
       // changes to that webpage in the future.
 
       // currently-used keywords
-      "as",
-      "break",
-      "const",
-      "continue",
-      "crate",
-      "else",
-      "enum",
-      "extern",
-      "false",
-      "fn",
-      "for",
-      "if",
-      "impl",
-      "in",
-      "let",
-      "loop",
-      "match",
-      "mod",
-      "move",
-      "mut",
-      "pub",
-      "ref",
-      "return",
-      "Self",
-      "self",
-      "static",
-      "struct",
-      "super",
-      "trait",
-      "true",
-      "type",
-      "unsafe",
-      "use",
-      "where",
-      "while",
+      "as", "break", "const", "continue", "crate", "else", "enum", "extern",
+      "false", "fn", "for", "if", "impl", "in", "let", "loop", "match", "mod",
+      "move", "mut", "pub", "ref", "return", "Self", "self", "static", "struct",
+      "super", "trait", "true", "type", "unsafe", "use", "where", "while",
 
       // future possible keywords
-      "abstract",
-      "alignof",
-      "become",
-      "box",
-      "do",
-      "final",
-      "macro",
-      "offsetof",
-      "override",
-      "priv",
-      "proc",
-      "pure",
-      "sizeof",
-      "typeof",
-      "unsized",
-      "virtual",
-      "yield",
+      "abstract", "alignof", "become", "box", "do", "final", "macro",
+      "offsetof", "override", "priv", "proc", "pure", "sizeof", "typeof",
+      "unsized", "virtual", "yield",
 
       // other rust terms we should not use
-      "std",
-      "usize",
-      "isize",
-      "u8",
-      "i8",
-      "u16",
-      "i16",
-      "u32",
-      "i32",
-      "u64",
-      "i64",
-      "u128",
-      "i128",
-      "f32",
-      "f64",
+      "std", "usize", "isize", "u8", "i8", "u16", "i16", "u32", "i32", "u64",
+      "i64", "u128", "i128", "f32", "f64",
 
       // These are terms the code generator can implement on types.
       //
@@ -281,13 +222,12 @@
       // implementation detail, and how we implement methods could change in
       // the future. as a result, we proactively block these out as reserved
       // words.
-      "follow",
-      "push",
-      "size",
-      "alignment",
-      "to_little_endian",
-      "from_little_endian",
-      nullptr };
+      "follow", "push", "size", "alignment", "to_little_endian",
+      "from_little_endian", nullptr,
+
+      // used by Enum constants
+      "ENUM_MAX", "ENUM_MIN", "ENUM_VALUES",
+    };
     for (auto kw = keywords; *kw; kw++) keywords_.insert(*kw);
   }
 
@@ -310,8 +250,7 @@
     // TODO(rw): Use a set data structure to reduce namespace evaluations from
     //           O(n**2) to O(n).
     for (auto ns_it = parser_.namespaces_.begin();
-         ns_it != parser_.namespaces_.end();
-         ++ns_it) {
+         ns_it != parser_.namespaces_.end(); ++ns_it) {
       const auto &ns = *ns_it;
 
       // Generate code for all the enum declarations.
@@ -357,7 +296,7 @@
     }
     if (cur_name_space_) SetNameSpace(nullptr);
 
-    const auto file_path = GeneratedFileName(path_, file_name_);
+    const auto file_path = GeneratedFileName(path_, file_name_, parser_.opts);
     const auto final_code = code_.ToString();
     return SaveFile(file_path.c_str(), final_code, false);
   }
@@ -381,8 +320,12 @@
       case ftBool:
       case ftEnumKey:
       case ftUnionKey:
-      case ftUnionValue: { return false; }
-      default: { return true; }
+      case ftUnionValue: {
+        return false;
+      }
+      default: {
+        return true;
+      }
     }
   }
 
@@ -393,35 +336,14 @@
     for (auto it = struct_def.fields.vec.begin();
          it != struct_def.fields.vec.end(); ++it) {
       const auto &field = **it;
-      if (field.deprecated) {
-        continue;
-      }
+      if (field.deprecated) { continue; }
 
-      if (TableBuilderTypeNeedsLifetime(field.value.type)) {
-        return true;
-      }
+      if (TableBuilderTypeNeedsLifetime(field.value.type)) { return true; }
     }
 
     return false;
   }
 
-  // Determine if a Type needs to be copied (for endian safety) when used in a
-  // Struct.
-  bool StructMemberAccessNeedsCopy(const Type &type) const {
-    switch (GetFullType(type)) {
-      case ftInteger:  // requires endian swap
-      case ftFloat: // requires endian swap
-      case ftBool: // no endian-swap, but do the copy for UX consistency
-      case ftEnumKey: { return true; } // requires endian swap
-      case ftStruct: { return false; } // no endian swap
-      default: {
-        // logic error: no other types can be struct members.
-        FLATBUFFERS_ASSERT(false && "invalid struct member type");
-        return false; // only to satisfy compiler's return analysis
-      }
-    }
-  }
-
   std::string EscapeKeyword(const std::string &name) const {
     return keywords_.find(name) == keywords_.end() ? name : name + "_";
   }
@@ -477,7 +399,7 @@
 
     auto s = src->components.begin();
     auto d = dst->components.begin();
-    for(;;) {
+    for (;;) {
       if (s == src->components.end()) { break; }
       if (d == dst->components.end()) { break; }
       if (*s != *d) { break; }
@@ -486,9 +408,7 @@
       ++i;
     }
 
-    for (; s != src->components.end(); ++s) {
-      stream << "super::";
-    }
+    for (; s != src->components.end(); ++s) { stream << "super::"; }
     for (; d != dst->components.end(); ++d) {
       stream << MakeSnakeCase(*d) + "::";
     }
@@ -509,19 +429,23 @@
       case ftFloat:
       case ftBool:
       case ftEnumKey:
-      case ftUnionKey: { break; }
-      default: { FLATBUFFERS_ASSERT(false && "incorrect type given");}
+      case ftUnionKey: {
+        break;
+      }
+      default: {
+        FLATBUFFERS_ASSERT(false && "incorrect type given");
+      }
     }
 
     // clang-format off
     static const char * const ctypename[] = {
     #define FLATBUFFERS_TD(ENUM, IDLTYPE, CTYPE, JTYPE, GTYPE, NTYPE, PTYPE, \
-                           RTYPE, KTYPE) \
-            #RTYPE,
-        FLATBUFFERS_GEN_TYPES(FLATBUFFERS_TD)
+                           RTYPE, ...) \
+      #RTYPE,
+      FLATBUFFERS_GEN_TYPES(FLATBUFFERS_TD)
     #undef FLATBUFFERS_TD
-      // clang-format on
     };
+    // clang-format on
 
     if (type.enum_def) { return WrapInNameSpace(*type.enum_def); }
     return ctypename[type.base_type];
@@ -535,15 +459,15 @@
       FLATBUFFERS_ASSERT(false && "precondition failed in GetEnumTypeForDecl");
     }
 
-    static const char *ctypename[] = {
     // clang-format off
+    static const char *ctypename[] = {
     #define FLATBUFFERS_TD(ENUM, IDLTYPE, CTYPE, JTYPE, GTYPE, NTYPE, PTYPE, \
-                           RTYPE, KTYPE) \
-            #RTYPE,
-        FLATBUFFERS_GEN_TYPES(FLATBUFFERS_TD)
+                           RTYPE, ...) \
+      #RTYPE,
+      FLATBUFFERS_GEN_TYPES(FLATBUFFERS_TD)
     #undef FLATBUFFERS_TD
-      // clang-format on
     };
+    // clang-format on
 
     // Enums can be bools, but their Rust representation must be a u8, as used
     // in the repr attribute (#[repr(bool)] is an invalid attribute).
@@ -560,21 +484,42 @@
       case ftBool:
       case ftEnumKey:
       case ftUnionKey: {
-        return GetTypeBasic(type); }
+        return GetTypeBasic(type);
+      }
       case ftTable: {
         return WrapInNameSpace(type.struct_def->defined_namespace,
-                               type.struct_def->name) + "<'a>"; }
+                               type.struct_def->name) +
+               "<'a>";
+      }
       default: {
         return WrapInNameSpace(type.struct_def->defined_namespace,
-                               type.struct_def->name); }
+                               type.struct_def->name);
+      }
     }
   }
 
-  std::string GetEnumValUse(const EnumDef &enum_def,
+  std::string GetEnumValue(const EnumDef &enum_def,
                             const EnumVal &enum_val) const {
     return Name(enum_def) + "::" + Name(enum_val);
   }
 
+  // 1 suffix since old C++ can't figure out the overload.
+  void ForAllEnumValues1(const EnumDef &enum_def,
+                        std::function<void(const EnumVal&)> cb) {
+    for (auto it = enum_def.Vals().begin(); it != enum_def.Vals().end(); ++it) {
+      const auto &ev = **it;
+      code_.SetValue("VARIANT", Name(ev));
+      code_.SetValue("VALUE", enum_def.ToString(ev));
+      cb(ev);
+    }
+  }
+  void ForAllEnumValues(const EnumDef &enum_def, std::function<void()> cb) {
+      std::function<void(const EnumVal&)> wrapped = [&](const EnumVal& unused) {
+        (void) unused;
+        cb();
+      };
+      ForAllEnumValues1(enum_def, wrapped);
+  }
   // Generate an enum declaration,
   // an enum string lookup table,
   // an enum match function,
@@ -582,61 +527,139 @@
   void GenEnum(const EnumDef &enum_def) {
     code_.SetValue("ENUM_NAME", Name(enum_def));
     code_.SetValue("BASE_TYPE", GetEnumTypeForDecl(enum_def.underlying_type));
-
-    GenComment(enum_def.doc_comment);
-    code_ += "#[allow(non_camel_case_types)]";
-    code_ += "#[repr({{BASE_TYPE}})]";
-    code_ += "#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]";
-    code_ += "pub enum " + Name(enum_def) + " {";
-
-    for (auto it = enum_def.Vals().begin(); it != enum_def.Vals().end(); ++it) {
-      const auto &ev = **it;
-
-      GenComment(ev.doc_comment, "  ");
-      code_.SetValue("KEY", Name(ev));
-      code_.SetValue("VALUE", enum_def.ToString(ev));
-      code_ += "  {{KEY}} = {{VALUE}},";
-    }
+    code_.SetValue("ENUM_NAME_SNAKE", MakeSnakeCase(Name(enum_def)));
+    code_.SetValue("ENUM_NAME_CAPS", MakeUpper(MakeSnakeCase(Name(enum_def))));
     const EnumVal *minv = enum_def.MinValue();
     const EnumVal *maxv = enum_def.MaxValue();
     FLATBUFFERS_ASSERT(minv && maxv);
-
-    code_ += "";
-    code_ += "}";
-    code_ += "";
-
-    code_.SetValue("ENUM_NAME", Name(enum_def));
-    code_.SetValue("ENUM_NAME_SNAKE", MakeSnakeCase(Name(enum_def)));
-    code_.SetValue("ENUM_NAME_CAPS", MakeUpper(MakeSnakeCase(Name(enum_def))));
     code_.SetValue("ENUM_MIN_BASE_VALUE", enum_def.ToString(*minv));
     code_.SetValue("ENUM_MAX_BASE_VALUE", enum_def.ToString(*maxv));
 
-    // Generate enum constants, and impls for Follow, EndianScalar, and Push.
-    code_ += "const ENUM_MIN_{{ENUM_NAME_CAPS}}: {{BASE_TYPE}} = \\";
-    code_ += "{{ENUM_MIN_BASE_VALUE}};";
-    code_ += "const ENUM_MAX_{{ENUM_NAME_CAPS}}: {{BASE_TYPE}} = \\";
-    code_ += "{{ENUM_MAX_BASE_VALUE}};";
+    if (IsBitFlagsEnum(enum_def)) {
+      // Defer to the convenient and canonical bitflags crate. We declare it in a
+      // module to #allow camel case constants in a smaller scope. This matches
+      // Flatbuffers c-modeled enums where variants are associated constants but
+      // in camel case.
+      code_ += "#[allow(non_upper_case_globals)]";
+      code_ += "mod bitflags_{{ENUM_NAME_SNAKE}} {";
+      code_ += "  flatbuffers::bitflags::bitflags! {";
+      GenComment(enum_def.doc_comment, "    ");
+      code_ += "    pub struct {{ENUM_NAME}}: {{BASE_TYPE}} {";
+      ForAllEnumValues1(enum_def, [&](const EnumVal &ev){
+        this->GenComment(ev.doc_comment, "      ");
+        code_ += "      const {{VARIANT}} = {{VALUE}};";
+      });
+      code_ += "    }";
+      code_ += "  }";
+      code_ += "}";
+      code_ += "pub use self::bitflags_{{ENUM_NAME_SNAKE}}::{{ENUM_NAME}};";
+      code_ += "";
+
+      // Generate Follow and Push so we can serialize and stuff.
+      code_ += "impl<'a> flatbuffers::Follow<'a> for {{ENUM_NAME}} {";
+      code_ += "  type Inner = Self;";
+      code_ += "  #[inline]";
+      code_ += "  fn follow(buf: &'a [u8], loc: usize) -> Self::Inner {";
+      code_ += "    let bits = flatbuffers::read_scalar_at::<{{BASE_TYPE}}>(buf, loc);";
+      code_ += "    unsafe { Self::from_bits_unchecked(bits) }";
+      code_ += "  }";
+      code_ += "}";
+      code_ += "";
+      code_ += "impl flatbuffers::Push for {{ENUM_NAME}} {";
+      code_ += "    type Output = {{ENUM_NAME}};";
+      code_ += "    #[inline]";
+      code_ += "    fn push(&self, dst: &mut [u8], _rest: &[u8]) {";
+      code_ += "        flatbuffers::emplace_scalar::<{{BASE_TYPE}}>"
+               "(dst, self.bits());";
+      code_ += "    }";
+      code_ += "}";
+      code_ += "";
+      code_ += "impl flatbuffers::EndianScalar for {{ENUM_NAME}} {";
+      code_ += "  #[inline]";
+      code_ += "  fn to_little_endian(self) -> Self {";
+      code_ += "    let bits = {{BASE_TYPE}}::to_le(self.bits());";
+      code_ += "    unsafe { Self::from_bits_unchecked(bits) }";
+      code_ += "  }";
+      code_ += "  #[inline]";
+      code_ += "  fn from_little_endian(self) -> Self {";
+      code_ += "    let bits = {{BASE_TYPE}}::from_le(self.bits());";
+      code_ += "    unsafe { Self::from_bits_unchecked(bits) }";
+      code_ += "  }";
+      code_ += "}";
+      code_ += "";
+      return;
+    }
+
+    // Deprecated associated constants;
+    code_ += "#[deprecated(since = \"1.13\", note = \"Use associated constants"
+             " instead. This will no longer be generated in 2021.\")]";
+    code_ += "pub const ENUM_MIN_{{ENUM_NAME_CAPS}}: {{BASE_TYPE}}"
+             " = {{ENUM_MIN_BASE_VALUE}};";
+    code_ += "#[deprecated(since = \"1.13\", note = \"Use associated constants"
+             " instead. This will no longer be generated in 2021.\")]";
+    code_ += "pub const ENUM_MAX_{{ENUM_NAME_CAPS}}: {{BASE_TYPE}}"
+             " = {{ENUM_MAX_BASE_VALUE}};";
+    auto num_fields = NumToString(enum_def.size());
+    code_ += "#[deprecated(since = \"1.13\", note = \"Use associated constants"
+             " instead. This will no longer be generated in 2021.\")]";
+    code_ += "#[allow(non_camel_case_types)]";
+    code_ += "pub const ENUM_VALUES_{{ENUM_NAME_CAPS}}: [{{ENUM_NAME}}; " +
+             num_fields + "] = [";
+    ForAllEnumValues1(enum_def, [&](const EnumVal &ev){
+      code_ += "  " + GetEnumValue(enum_def, ev) + ",";
+    });
+    code_ += "];";
     code_ += "";
+
+    GenComment(enum_def.doc_comment);
+    code_ +=
+        "#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]";
+    code_ += "#[repr(transparent)]";
+    code_ += "pub struct {{ENUM_NAME}}(pub {{BASE_TYPE}});";
+    code_ += "#[allow(non_upper_case_globals)]";
+    code_ += "impl {{ENUM_NAME}} {";
+    ForAllEnumValues1(enum_def, [&](const EnumVal &ev){
+      this->GenComment(ev.doc_comment, "  ");
+      code_ += "  pub const {{VARIANT}}: Self = Self({{VALUE}});";
+    });
+    code_ += "";
+    // Generate Associated constants
+    code_ += "  pub const ENUM_MIN: {{BASE_TYPE}} = {{ENUM_MIN_BASE_VALUE}};";
+    code_ += "  pub const ENUM_MAX: {{BASE_TYPE}} = {{ENUM_MAX_BASE_VALUE}};";
+    code_ += "  pub const ENUM_VALUES: &'static [Self] = &[";
+    ForAllEnumValues(enum_def, [&](){
+      code_ += "    Self::{{VARIANT}},";
+    });
+    code_ += "  ];";
+    code_ += "  /// Returns the variant's name or \"\" if unknown.";
+    code_ += "  pub fn variant_name(self) -> Option<&'static str> {";
+    code_ += "    match self {";
+    ForAllEnumValues(enum_def, [&](){
+      code_ += "      Self::{{VARIANT}} => Some(\"{{VARIANT}}\"),";
+    });
+    code_ += "      _ => None,";
+    code_ += "    }";
+    code_ += "  }";
+    code_ += "}";
+
+    // Generate Debug. Unknown variants are printed like "<UNKNOWN 42>".
+    code_ += "impl std::fmt::Debug for {{ENUM_NAME}} {";
+    code_ += "  fn fmt(&self, f: &mut std::fmt::Formatter) ->"
+             " std::fmt::Result {";
+    code_ += "    if let Some(name) = self.variant_name() {";
+    code_ += "      f.write_str(name)";
+    code_ += "    } else {";
+    code_ += "      f.write_fmt(format_args!(\"<UNKNOWN {:?}>\", self.0))";
+    code_ += "    }";
+    code_ += "  }";
+    code_ += "}";
+
+    // Generate Follow and Push so we can serialize and stuff.
     code_ += "impl<'a> flatbuffers::Follow<'a> for {{ENUM_NAME}} {";
     code_ += "  type Inner = Self;";
     code_ += "  #[inline]";
     code_ += "  fn follow(buf: &'a [u8], loc: usize) -> Self::Inner {";
-    code_ += "    flatbuffers::read_scalar_at::<Self>(buf, loc)";
-    code_ += "  }";
-    code_ += "}";
-    code_ += "";
-    code_ += "impl flatbuffers::EndianScalar for {{ENUM_NAME}} {";
-    code_ += "  #[inline]";
-    code_ += "  fn to_little_endian(self) -> Self {";
-    code_ += "    let n = {{BASE_TYPE}}::to_le(self as {{BASE_TYPE}});";
-    code_ += "    let p = &n as *const {{BASE_TYPE}} as *const {{ENUM_NAME}};";
-    code_ += "    unsafe { *p }";
-    code_ += "  }";
-    code_ += "  #[inline]";
-    code_ += "  fn from_little_endian(self) -> Self {";
-    code_ += "    let n = {{BASE_TYPE}}::from_le(self as {{BASE_TYPE}});";
-    code_ += "    let p = &n as *const {{BASE_TYPE}} as *const {{ENUM_NAME}};";
-    code_ += "    unsafe { *p }";
+    code_ += "    Self(flatbuffers::read_scalar_at::<{{BASE_TYPE}}>(buf, loc))";
     code_ += "  }";
     code_ += "}";
     code_ += "";
@@ -644,69 +667,23 @@
     code_ += "    type Output = {{ENUM_NAME}};";
     code_ += "    #[inline]";
     code_ += "    fn push(&self, dst: &mut [u8], _rest: &[u8]) {";
-    code_ += "        flatbuffers::emplace_scalar::<{{ENUM_NAME}}>"
-             "(dst, *self);";
+    code_ += "        flatbuffers::emplace_scalar::<{{BASE_TYPE}}>"
+             "(dst, self.0);";
     code_ += "    }";
     code_ += "}";
     code_ += "";
-
-    // Generate an array of all enumeration values.
-    auto num_fields = NumToString(enum_def.size());
-    code_ += "#[allow(non_camel_case_types)]";
-    code_ += "const ENUM_VALUES_{{ENUM_NAME_CAPS}}:[{{ENUM_NAME}}; " +
-              num_fields + "] = [";
-    for (auto it = enum_def.Vals().begin(); it != enum_def.Vals().end(); ++it) {
-      const auto &ev = **it;
-      auto value = GetEnumValUse(enum_def, ev);
-      auto suffix = *it != enum_def.Vals().back() ? "," : "";
-      code_ += "  " + value + suffix;
-    }
-    code_ += "];";
+    code_ += "impl flatbuffers::EndianScalar for {{ENUM_NAME}} {";
+    code_ += "  #[inline]";
+    code_ += "  fn to_little_endian(self) -> Self {";
+    code_ += "    Self({{BASE_TYPE}}::to_le(self.0))";
+    code_ += "  }";
+    code_ += "  #[inline]";
+    code_ += "  fn from_little_endian(self) -> Self {";
+    code_ += "    Self({{BASE_TYPE}}::from_le(self.0))";
+    code_ += "  }";
+    code_ += "}";
     code_ += "";
 
-    // Generate a string table for enum values.
-    // Problem is, if values are very sparse that could generate really big
-    // tables. Ideally in that case we generate a map lookup instead, but for
-    // the moment we simply don't output a table at all.
-    auto range = enum_def.Distance();
-    // Average distance between values above which we consider a table
-    // "too sparse". Change at will.
-    static const uint64_t kMaxSparseness = 5;
-    if (range / static_cast<uint64_t>(enum_def.size()) < kMaxSparseness) {
-      code_ += "#[allow(non_camel_case_types)]";
-      code_ += "const ENUM_NAMES_{{ENUM_NAME_CAPS}}:[&'static str; " +
-               NumToString(range + 1) + "] = [";
-
-      auto val = enum_def.Vals().front();
-      for (auto it = enum_def.Vals().begin(); it != enum_def.Vals().end();
-           ++it) {
-        auto ev = *it;
-        for (auto k = enum_def.Distance(val, ev); k > 1; --k) {
-          code_ += "    \"\",";
-        }
-        val = ev;
-        auto suffix = *it != enum_def.Vals().back() ? "," : "";
-        code_ += "    \"" + Name(*ev) + "\"" + suffix;
-      }
-      code_ += "];";
-      code_ += "";
-
-      code_ +=
-          "pub fn enum_name_{{ENUM_NAME_SNAKE}}(e: {{ENUM_NAME}}) -> "
-          "&'static str {";
-
-      code_ += "  let index = e as {{BASE_TYPE}}\\";
-      if (enum_def.MinValue()->IsNonZero()) {
-        auto vals = GetEnumValUse(enum_def, *enum_def.MinValue());
-        code_ += " - " + vals + " as {{BASE_TYPE}}\\";
-      }
-      code_ += ";";
-
-      code_ += "  ENUM_NAMES_{{ENUM_NAME_CAPS}}[index as usize]";
-      code_ += "}";
-      code_ += "";
-    }
-
     if (enum_def.is_union) {
       // Generate tyoesafe offset(s) for unions
       code_.SetValue("NAME", Name(enum_def));
@@ -719,30 +696,32 @@
     return "VT_" + MakeUpper(Name(field));
   }
 
-  std::string GetDefaultConstant(const FieldDef &field) {
-    return field.value.type.base_type == BASE_TYPE_FLOAT
-               ? field.value.constant + ""
-               : field.value.constant;
-  }
-
   std::string GetDefaultScalarValue(const FieldDef &field) {
     switch (GetFullType(field.value.type)) {
-      case ftInteger: { return GetDefaultConstant(field); }
-      case ftFloat: { return GetDefaultConstant(field); }
+      case ftInteger:
+      case ftFloat: {
+        return field.optional ? "None" : field.value.constant;
+      }
       case ftBool: {
-        return field.value.constant == "0" ? "false" : "true";
+        return field.optional ? "None"
+                              : field.value.constant == "0" ? "false" : "true";
       }
       case ftUnionKey:
       case ftEnumKey: {
+        if (field.optional) {
+            return "None";
+        }
         auto ev = field.value.type.enum_def->FindByValue(field.value.constant);
         assert(ev);
         return WrapInNameSpace(field.value.type.enum_def->defined_namespace,
-                               GetEnumValUse(*field.value.type.enum_def, *ev));
+                               GetEnumValue(*field.value.type.enum_def, *ev));
       }
 
       // All pointer-ish types have a default value of None, because they are
       // wrapped in Option.
-      default: { return "None"; }
+      default: {
+        return "None";
+      }
     }
   }
 
@@ -759,14 +738,14 @@
   // 3) return a hardcoded value because the vtable field value is set to zero.
   std::string TableBuilderArgsDefnType(const FieldDef &field,
                                        const std::string &lifetime) {
-    const Type& type = field.value.type;
+    const Type &type = field.value.type;
 
     switch (GetFullType(type)) {
       case ftInteger:
       case ftFloat:
       case ftBool: {
         const auto typname = GetTypeBasic(type);
-        return typname;
+        return field.optional ? "Option<" + typname + ">" : typname;
       }
       case ftStruct: {
         const auto typname = WrapInNameSpace(*type.struct_def);
@@ -774,7 +753,7 @@
       }
       case ftTable: {
         const auto typname = WrapInNameSpace(*type.struct_def);
-        return "Option<flatbuffers::WIPOffset<" + typname + "<" + lifetime + \
+        return "Option<flatbuffers::WIPOffset<" + typname + "<" + lifetime +
                ">>>";
       }
       case ftString: {
@@ -783,109 +762,87 @@
       case ftEnumKey:
       case ftUnionKey: {
         const auto typname = WrapInNameSpace(*type.enum_def);
-        return typname;
+        return field.optional ? "Option<" + typname + ">" : typname;
       }
       case ftUnionValue: {
         return "Option<flatbuffers::WIPOffset<flatbuffers::UnionWIPOffset>>";
       }
 
       case ftVectorOfInteger:
+      case ftVectorOfBool:
       case ftVectorOfFloat: {
         const auto typname = GetTypeBasic(type.VectorType());
-        return "Option<flatbuffers::WIPOffset<flatbuffers::Vector<" + \
-               lifetime + ",  " + typname + ">>>";
-      }
-      case ftVectorOfBool: {
-        return "Option<flatbuffers::WIPOffset<flatbuffers::Vector<" + \
-               lifetime + ", bool>>>";
+        return "Option<flatbuffers::WIPOffset<flatbuffers::Vector<" + lifetime +
+               ", " + typname + ">>>";
       }
       case ftVectorOfEnumKey: {
         const auto typname = WrapInNameSpace(*type.enum_def);
-        return "Option<flatbuffers::WIPOffset<flatbuffers::Vector<" + \
-               lifetime + ", " + typname + ">>>";
+        return "Option<flatbuffers::WIPOffset<flatbuffers::Vector<" + lifetime +
+               ", " + typname + ">>>";
       }
       case ftVectorOfStruct: {
         const auto typname = WrapInNameSpace(*type.struct_def);
-        return "Option<flatbuffers::WIPOffset<flatbuffers::Vector<" + \
-               lifetime + ", " + typname + ">>>";
+        return "Option<flatbuffers::WIPOffset<flatbuffers::Vector<" + lifetime +
+               ", " + typname + ">>>";
       }
       case ftVectorOfTable: {
         const auto typname = WrapInNameSpace(*type.struct_def);
-        return "Option<flatbuffers::WIPOffset<flatbuffers::Vector<" + \
-               lifetime + ", flatbuffers::ForwardsUOffset<" + typname + \
-               "<" + lifetime + ">>>>>";
+        return "Option<flatbuffers::WIPOffset<flatbuffers::Vector<" + lifetime +
+               ", flatbuffers::ForwardsUOffset<" + typname + "<" + lifetime +
+               ">>>>>";
       }
       case ftVectorOfString: {
-        return "Option<flatbuffers::WIPOffset<flatbuffers::Vector<" + \
-               lifetime + ", flatbuffers::ForwardsUOffset<&" + lifetime + \
-               " str>>>>";
+        return "Option<flatbuffers::WIPOffset<flatbuffers::Vector<" + lifetime +
+               ", flatbuffers::ForwardsUOffset<&" + lifetime + " str>>>>";
       }
       case ftVectorOfUnionValue: {
-        const auto typname = WrapInNameSpace(*type.enum_def) + \
-                             "UnionTableOffset";
-        return "Option<flatbuffers::WIPOffset<flatbuffers::Vector<" + \
-               lifetime + ", flatbuffers::ForwardsUOffset<"
-               "flatbuffers::Table<" + lifetime + ">>>>";
+        const auto typname =
+            WrapInNameSpace(*type.enum_def) + "UnionTableOffset";
+        return "Option<flatbuffers::WIPOffset<flatbuffers::Vector<" + lifetime +
+               ", flatbuffers::ForwardsUOffset<"
+               "flatbuffers::Table<" +
+               lifetime + ">>>>";
       }
     }
-    return "INVALID_CODE_GENERATION"; // for return analysis
-  }
-
-  std::string TableBuilderArgsDefaultValue(const FieldDef &field) {
-    return GetDefaultScalarValue(field);
-  }
-  std::string TableBuilderAddFuncDefaultValue(const FieldDef &field) {
-    // All branches of switch do the same action!
-    switch (GetFullType(field.value.type)) {
-      case ftUnionKey:
-      case ftEnumKey: {
-        const std::string basetype = GetTypeBasic(field.value.type); //<- never used
-        return GetDefaultScalarValue(field);
-      }
-
-      default: { return GetDefaultScalarValue(field); }
-    }
+    return "INVALID_CODE_GENERATION";  // for return analysis
   }
 
   std::string TableBuilderArgsAddFuncType(const FieldDef &field,
                                           const std::string &lifetime) {
-    const Type& type = field.value.type;
+    const Type &type = field.value.type;
 
     switch (GetFullType(field.value.type)) {
       case ftVectorOfStruct: {
         const auto typname = WrapInNameSpace(*type.struct_def);
-        return "flatbuffers::WIPOffset<flatbuffers::Vector<" + lifetime + \
-               ", " + typname + ">>";
+        return "flatbuffers::WIPOffset<flatbuffers::Vector<" + lifetime + ", " +
+               typname + ">>";
       }
       case ftVectorOfTable: {
         const auto typname = WrapInNameSpace(*type.struct_def);
-        return "flatbuffers::WIPOffset<flatbuffers::Vector<" + lifetime + \
-               ", flatbuffers::ForwardsUOffset<" + typname + \
-               "<" + lifetime + ">>>>";
+        return "flatbuffers::WIPOffset<flatbuffers::Vector<" + lifetime +
+               ", flatbuffers::ForwardsUOffset<" + typname + "<" + lifetime +
+               ">>>>";
       }
       case ftVectorOfInteger:
+      case ftVectorOfBool:
       case ftVectorOfFloat: {
         const auto typname = GetTypeBasic(type.VectorType());
-        return "flatbuffers::WIPOffset<flatbuffers::Vector<" + lifetime + \
-               ", " + typname + ">>";
-      }
-      case ftVectorOfBool: {
-        return "flatbuffers::WIPOffset<flatbuffers::Vector<" + lifetime + \
-               ", bool>>";
+        return "flatbuffers::WIPOffset<flatbuffers::Vector<" + lifetime + ", " +
+               typname + ">>";
       }
       case ftVectorOfString: {
-        return "flatbuffers::WIPOffset<flatbuffers::Vector<" + lifetime + \
+        return "flatbuffers::WIPOffset<flatbuffers::Vector<" + lifetime +
                ", flatbuffers::ForwardsUOffset<&" + lifetime + " str>>>";
       }
       case ftVectorOfEnumKey: {
         const auto typname = WrapInNameSpace(*type.enum_def);
-        return "flatbuffers::WIPOffset<flatbuffers::Vector<" + lifetime + \
-               ", " + typname + ">>";
+        return "flatbuffers::WIPOffset<flatbuffers::Vector<" + lifetime + ", " +
+               typname + ">>";
       }
       case ftVectorOfUnionValue: {
-        return "flatbuffers::WIPOffset<flatbuffers::Vector<" + lifetime + \
-               ", flatbuffers::ForwardsUOffset<flatbuffers::Table<" + \
-               lifetime + ">>>";
+        return "flatbuffers::WIPOffset<flatbuffers::Vector<" + lifetime +
+               ", flatbuffers::ForwardsUOffset<flatbuffers::Table<" + lifetime +
+               ">>>";
       }
       case ftEnumKey: {
         const auto typname = WrapInNameSpace(*type.enum_def);
@@ -893,19 +850,16 @@
       }
       case ftStruct: {
         const auto typname = WrapInNameSpace(*type.struct_def);
-        return "&" + lifetime + " " + typname + "";
+        return "&" + typname + "";
       }
       case ftTable: {
         const auto typname = WrapInNameSpace(*type.struct_def);
         return "flatbuffers::WIPOffset<" + typname + "<" + lifetime + ">>";
       }
       case ftInteger:
+      case ftBool:
       case ftFloat: {
-        const auto typname = GetTypeBasic(type);
-        return typname;
-      }
-      case ftBool: {
-        return "bool";
+        return GetTypeBasic(type);
       }
       case ftString: {
         return "flatbuffers::WIPOffset<&" + lifetime + " str>";
@@ -919,26 +873,27 @@
       }
     }
 
-    return "INVALID_CODE_GENERATION"; // for return analysis
+    return "INVALID_CODE_GENERATION";  // for return analysis
   }
 
   std::string TableBuilderArgsAddFuncBody(const FieldDef &field) {
-    const Type& type = field.value.type;
+    const Type &type = field.value.type;
 
     switch (GetFullType(field.value.type)) {
       case ftInteger:
+      case ftBool:
       case ftFloat: {
         const auto typname = GetTypeBasic(field.value.type);
-        return "self.fbb_.push_slot::<" + typname + ">";
+        return (field.optional ? "self.fbb_.push_slot_always::<"
+                               : "self.fbb_.push_slot::<") +
+               typname + ">";
       }
-      case ftBool: {
-        return "self.fbb_.push_slot::<bool>";
-      }
-
       case ftEnumKey:
       case ftUnionKey: {
         const auto underlying_typname = GetTypeBasic(type);
-        return "self.fbb_.push_slot::<" + underlying_typname + ">";
+        return (field.optional ?
+                   "self.fbb_.push_slot_always::<" :
+                   "self.fbb_.push_slot::<") + underlying_typname + ">";
       }
 
       case ftStruct: {
@@ -947,8 +902,8 @@
       }
       case ftTable: {
         const auto typname = WrapInNameSpace(*type.struct_def);
-        return "self.fbb_.push_slot_always::<flatbuffers::WIPOffset<" + \
-               typname +  ">>";
+        return "self.fbb_.push_slot_always::<flatbuffers::WIPOffset<" +
+               typname + ">>";
       }
 
       case ftUnionValue:
@@ -964,183 +919,265 @@
         return "self.fbb_.push_slot_always::<flatbuffers::WIPOffset<_>>";
       }
     }
-    return "INVALID_CODE_GENERATION"; // for return analysis
+    return "INVALID_CODE_GENERATION";  // for return analysis
   }
 
   std::string GenTableAccessorFuncReturnType(const FieldDef &field,
                                              const std::string &lifetime) {
-    const Type& type = field.value.type;
-
-    switch (GetFullType(field.value.type)) {
-      case ftInteger:
-      case ftFloat: {
-        const auto typname = GetTypeBasic(type);
-        return typname;
-      }
-      case ftBool: {
-        return "bool";
-      }
-      case ftStruct: {
-        const auto typname = WrapInNameSpace(*type.struct_def);
-        return WrapInOptionIfNotRequired("&" + lifetime + " " + typname, field.required);
-      }
-      case ftTable: {
-        const auto typname = WrapInNameSpace(*type.struct_def);
-        return WrapInOptionIfNotRequired(typname + "<" + lifetime + ">", field.required);
-      }
-      case ftEnumKey:
-      case ftUnionKey: {
-        const auto typname = WrapInNameSpace(*type.enum_def);
-        return typname;
-      }
-
-      case ftUnionValue: {
-        return WrapInOptionIfNotRequired("flatbuffers::Table<" + lifetime + ">", field.required);
-      }
-      case ftString: {
-         return WrapInOptionIfNotRequired("&" + lifetime + " str", field.required);
-      }
-      case ftVectorOfInteger:
-      case ftVectorOfFloat: {
-        const auto typname = GetTypeBasic(type.VectorType());
-        if (IsOneByte(type.VectorType().base_type)) {
-          return WrapInOptionIfNotRequired("&" + lifetime + " [" + typname + "]", field.required);
-        }
-        return WrapInOptionIfNotRequired("flatbuffers::Vector<" + lifetime + ", " + typname + ">", field.required);
-      }
-      case ftVectorOfBool: {
-        return WrapInOptionIfNotRequired("&" + lifetime + " [bool]", field.required);
-      }
-      case ftVectorOfEnumKey: {
-        const auto typname = WrapInNameSpace(*type.enum_def);
-        return WrapInOptionIfNotRequired("flatbuffers::Vector<" + lifetime + ", " + typname + ">", field.required);
-      }
-      case ftVectorOfStruct: {
-        const auto typname = WrapInNameSpace(*type.struct_def);
-        return WrapInOptionIfNotRequired("&" + lifetime + " [" + typname + "]", field.required);
-      }
-      case ftVectorOfTable: {
-        const auto typname = WrapInNameSpace(*type.struct_def);
-        return WrapInOptionIfNotRequired("flatbuffers::Vector<" + lifetime + ", flatbuffers::ForwardsUOffset<" + \
-               typname + "<" + lifetime + ">>>", field.required);
-      }
-      case ftVectorOfString: {
-        return WrapInOptionIfNotRequired("flatbuffers::Vector<" + lifetime + ", flatbuffers::ForwardsUOffset<&" + \
-               lifetime + " str>>", field.required);
-      }
-      case ftVectorOfUnionValue: {
-        FLATBUFFERS_ASSERT(false && "vectors of unions are not yet supported");
-        // TODO(rw): when we do support these, we should consider using the
-        //           Into trait to convert tables to typesafe union values.
-        return "INVALID_CODE_GENERATION"; // for return analysis
-      }
-    }
-    return "INVALID_CODE_GENERATION"; // for return analysis
-  }
-
-  std::string GenTableAccessorFuncBody(const FieldDef &field,
-                                       const std::string &lifetime,
-                                       const std::string &offset_prefix) {
-    const std::string offset_name = offset_prefix + "::" + \
-                                    GetFieldOffsetName(field);
-    const Type& type = field.value.type;
+    const Type &type = field.value.type;
 
     switch (GetFullType(field.value.type)) {
       case ftInteger:
       case ftFloat:
       case ftBool: {
         const auto typname = GetTypeBasic(type);
-        const auto default_value = GetDefaultScalarValue(field);
-        return "self._tab.get::<" + typname + ">(" + offset_name + ", Some(" + \
-               default_value + ")).unwrap()";
+        return field.optional ? "Option<" + typname + ">" : typname;
       }
       case ftStruct: {
         const auto typname = WrapInNameSpace(*type.struct_def);
-        return AddUnwrapIfRequired("self._tab.get::<" + typname + ">(" + offset_name + ", None)", field.required);
+        return WrapInOptionIfNotRequired("&" + lifetime + " " + typname,
+                                         field.required);
       }
       case ftTable: {
         const auto typname = WrapInNameSpace(*type.struct_def);
-        return AddUnwrapIfRequired("self._tab.get::<flatbuffers::ForwardsUOffset<" + \
-               typname + "<" + lifetime + ">>>(" + offset_name + ", None)", field.required);
+        return WrapInOptionIfNotRequired(typname + "<" + lifetime + ">",
+                                         field.required);
+      }
+      case ftEnumKey:
+      case ftUnionKey: {
+        const auto typname = WrapInNameSpace(*type.enum_def);
+        return field.optional ? "Option<" + typname + ">" : typname;
+      }
+
+      case ftUnionValue: {
+        return WrapInOptionIfNotRequired("flatbuffers::Table<" + lifetime + ">",
+                                         field.required);
+      }
+      case ftString: {
+        return WrapInOptionIfNotRequired("&" + lifetime + " str",
+                                         field.required);
+      }
+      case ftVectorOfInteger:
+      case ftVectorOfBool:
+      case ftVectorOfFloat: {
+        const auto typname = GetTypeBasic(type.VectorType());
+        if (IsOneByte(type.VectorType().base_type)) {
+          return WrapInOptionIfNotRequired(
+              "&" + lifetime + " [" + typname + "]", field.required);
+        }
+        return WrapInOptionIfNotRequired(
+            "flatbuffers::Vector<" + lifetime + ", " + typname + ">",
+            field.required);
+      }
+      case ftVectorOfEnumKey: {
+        const auto typname = WrapInNameSpace(*type.enum_def);
+        return WrapInOptionIfNotRequired(
+            "flatbuffers::Vector<" + lifetime + ", " + typname + ">",
+            field.required);
+      }
+      case ftVectorOfStruct: {
+        const auto typname = WrapInNameSpace(*type.struct_def);
+        return WrapInOptionIfNotRequired("&" + lifetime + " [" + typname + "]",
+                                         field.required);
+      }
+      case ftVectorOfTable: {
+        const auto typname = WrapInNameSpace(*type.struct_def);
+        return WrapInOptionIfNotRequired("flatbuffers::Vector<" + lifetime +
+                                             ", flatbuffers::ForwardsUOffset<" +
+                                             typname + "<" + lifetime + ">>>",
+                                         field.required);
+      }
+      case ftVectorOfString: {
+        return WrapInOptionIfNotRequired(
+            "flatbuffers::Vector<" + lifetime +
+                ", flatbuffers::ForwardsUOffset<&" + lifetime + " str>>",
+            field.required);
+      }
+      case ftVectorOfUnionValue: {
+        FLATBUFFERS_ASSERT(false && "vectors of unions are not yet supported");
+        // TODO(rw): when we do support these, we should consider using the
+        //           Into trait to convert tables to typesafe union values.
+        return "INVALID_CODE_GENERATION";  // for return analysis
+      }
+    }
+    return "INVALID_CODE_GENERATION";  // for return analysis
+  }
+
+  std::string GenTableAccessorFuncBody(const FieldDef &field,
+                                       const std::string &lifetime,
+                                       const std::string &offset_prefix) {
+    const std::string offset_name =
+        offset_prefix + "::" + GetFieldOffsetName(field);
+    const Type &type = field.value.type;
+
+    switch (GetFullType(field.value.type)) {
+      case ftInteger:
+      case ftFloat:
+      case ftBool: {
+        const auto typname = GetTypeBasic(type);
+        if (field.optional) {
+          return "self._tab.get::<" + typname + ">(" + offset_name + ", None)";
+        } else {
+          const auto default_value = GetDefaultScalarValue(field);
+          return "self._tab.get::<" + typname + ">(" + offset_name + ", Some(" +
+                 default_value + ")).unwrap()";
+        }
+      }
+      case ftStruct: {
+        const auto typname = WrapInNameSpace(*type.struct_def);
+        return AddUnwrapIfRequired(
+            "self._tab.get::<" + typname + ">(" + offset_name + ", None)",
+            field.required);
+      }
+      case ftTable: {
+        const auto typname = WrapInNameSpace(*type.struct_def);
+        return AddUnwrapIfRequired(
+            "self._tab.get::<flatbuffers::ForwardsUOffset<" + typname + "<" +
+                lifetime + ">>>(" + offset_name + ", None)",
+            field.required);
       }
       case ftUnionValue: {
-        return AddUnwrapIfRequired("self._tab.get::<flatbuffers::ForwardsUOffset<"
-               "flatbuffers::Table<" + lifetime + ">>>(" + offset_name + \
-               ", None)", field.required);
+        return AddUnwrapIfRequired(
+            "self._tab.get::<flatbuffers::ForwardsUOffset<"
+            "flatbuffers::Table<" +
+                lifetime + ">>>(" + offset_name + ", None)",
+            field.required);
       }
       case ftUnionKey:
       case ftEnumKey: {
-        const auto underlying_typname = GetTypeBasic(type); //<- never used
-        const auto typname = WrapInNameSpace(*type.enum_def);
-        const auto default_value = GetDefaultScalarValue(field);
-        return "self._tab.get::<" + typname + ">(" + offset_name + \
-               ", Some(" + default_value + ")).unwrap()";
+        const std::string typname = WrapInNameSpace(*type.enum_def);
+        const std::string default_value = GetDefaultScalarValue(field);
+        if (field.optional) {
+          return "self._tab.get::<" + typname + ">(" + offset_name + ", None)";
+        } else {
+          return "self._tab.get::<" + typname + ">(" + offset_name + ", Some(" +
+                 default_value + ")).unwrap()";
+        }
       }
       case ftString: {
-        return AddUnwrapIfRequired("self._tab.get::<flatbuffers::ForwardsUOffset<&str>>(" + \
-               offset_name + ", None)", field.required);
+        return AddUnwrapIfRequired(
+            "self._tab.get::<flatbuffers::ForwardsUOffset<&str>>(" +
+                offset_name + ", None)",
+            field.required);
       }
 
       case ftVectorOfInteger:
+      case ftVectorOfBool:
       case ftVectorOfFloat: {
         const auto typname = GetTypeBasic(type.VectorType());
-        std::string s = "self._tab.get::<flatbuffers::ForwardsUOffset<"
-                        "flatbuffers::Vector<" + lifetime + ", " + typname + \
-                        ">>>(" + offset_name + ", None)";
+        std::string s =
+            "self._tab.get::<flatbuffers::ForwardsUOffset<"
+            "flatbuffers::Vector<" +
+            lifetime + ", " + typname + ">>>(" + offset_name + ", None)";
         // single-byte values are safe to slice
         if (IsOneByte(type.VectorType().base_type)) {
           s += ".map(|v| v.safe_slice())";
         }
         return AddUnwrapIfRequired(s, field.required);
       }
-      case ftVectorOfBool: {
-        return AddUnwrapIfRequired("self._tab.get::<flatbuffers::ForwardsUOffset<"
-               "flatbuffers::Vector<" + lifetime + ", bool>>>(" + \
-               offset_name + ", None).map(|v| v.safe_slice())", field.required);
-      }
       case ftVectorOfEnumKey: {
         const auto typname = WrapInNameSpace(*type.enum_def);
-        return AddUnwrapIfRequired("self._tab.get::<flatbuffers::ForwardsUOffset<"
-               "flatbuffers::Vector<" + lifetime + ", " + typname + ">>>(" + \
-               offset_name + ", None)", field.required);
+        return AddUnwrapIfRequired(
+            "self._tab.get::<flatbuffers::ForwardsUOffset<"
+            "flatbuffers::Vector<" +
+                lifetime + ", " + typname + ">>>(" + offset_name + ", None)",
+            field.required);
       }
       case ftVectorOfStruct: {
         const auto typname = WrapInNameSpace(*type.struct_def);
-        return AddUnwrapIfRequired("self._tab.get::<flatbuffers::ForwardsUOffset<"
-               "flatbuffers::Vector<" + typname + ">>>(" + \
-               offset_name + ", None).map(|v| v.safe_slice() )", field.required);
+        return AddUnwrapIfRequired(
+            "self._tab.get::<flatbuffers::ForwardsUOffset<"
+            "flatbuffers::Vector<" +
+                typname + ">>>(" + offset_name +
+                ", None).map(|v| v.safe_slice() )",
+            field.required);
       }
       case ftVectorOfTable: {
         const auto typname = WrapInNameSpace(*type.struct_def);
-        return AddUnwrapIfRequired("self._tab.get::<flatbuffers::ForwardsUOffset<"
-               "flatbuffers::Vector<flatbuffers::ForwardsUOffset<" + typname + \
-               "<" + lifetime + ">>>>>(" + offset_name + ", None)", field.required);
+        return AddUnwrapIfRequired(
+            "self._tab.get::<flatbuffers::ForwardsUOffset<"
+            "flatbuffers::Vector<flatbuffers::ForwardsUOffset<" +
+                typname + "<" + lifetime + ">>>>>(" + offset_name + ", None)",
+            field.required);
       }
       case ftVectorOfString: {
-        return AddUnwrapIfRequired("self._tab.get::<flatbuffers::ForwardsUOffset<"
-               "flatbuffers::Vector<flatbuffers::ForwardsUOffset<&" + \
-               lifetime + " str>>>>(" + offset_name + ", None)", field.required);
+        return AddUnwrapIfRequired(
+            "self._tab.get::<flatbuffers::ForwardsUOffset<"
+            "flatbuffers::Vector<flatbuffers::ForwardsUOffset<&" +
+                lifetime + " str>>>>(" + offset_name + ", None)",
+            field.required);
       }
       case ftVectorOfUnionValue: {
         FLATBUFFERS_ASSERT(false && "vectors of unions are not yet supported");
-        return "INVALID_CODE_GENERATION"; // for return analysis
+        return "INVALID_CODE_GENERATION";  // for return analysis
       }
     }
-    return "INVALID_CODE_GENERATION"; // for return analysis
+    return "INVALID_CODE_GENERATION";  // for return analysis
   }
 
-  bool TableFieldReturnsOption(const Type& type) {
-    switch (GetFullType(type)) {
+  bool TableFieldReturnsOption(const FieldDef &field) {
+    if (field.optional) return true;
+    switch (GetFullType(field.value.type)) {
       case ftInteger:
       case ftFloat:
       case ftBool:
       case ftEnumKey:
-      case ftUnionKey:
-        return false;
+      case ftUnionKey: return false;
       default: return true;
     }
   }
 
+  // Generates a fully-qualified name getter for use with --gen-name-strings
+  void GenFullyQualifiedNameGetter(const StructDef &struct_def,
+                                   const std::string &name) {
+    code_ += "    pub const fn get_fully_qualified_name() -> &'static str {";
+    code_ += "        \"" +
+             struct_def.defined_namespace->GetFullyQualifiedName(name) + "\"";
+    code_ += "    }";
+    code_ += "";
+  }
+
+  void ForAllUnionVariantsBesidesNone(
+    const EnumDef &def,
+    std::function<void(const EnumVal &ev)> cb
+  ) {
+    FLATBUFFERS_ASSERT(def.is_union);
+
+    for (auto it = def.Vals().begin(); it != def.Vals().end(); ++it) {
+      const EnumVal & ev = **it;
+      // TODO(cneo): Can variants be deprecated, should we skip them?
+      if (ev.union_type.base_type == BASE_TYPE_NONE) { continue; }
+      code_.SetValue(
+          "U_ELEMENT_ENUM_TYPE",
+          WrapInNameSpace(def.defined_namespace, GetEnumValue(def, ev)));
+      code_.SetValue("U_ELEMENT_TABLE_TYPE",
+          WrapInNameSpace(ev.union_type.struct_def->defined_namespace,
+                          ev.union_type.struct_def->name));
+      code_.SetValue("U_ELEMENT_NAME", MakeSnakeCase(Name(ev)));
+      cb(ev);
+    }
+  }
+
+  void ForAllTableFields(
+    const StructDef &struct_def,
+    std::function<void(const FieldDef&)> cb, bool reversed=false) {
+    // TODO(cneo): Remove `reversed` overload. It's only here to minimize the
+    // diff when refactoring to the `ForAllX` helper functions.
+    auto go = [&](const FieldDef& field) {
+      if (field.deprecated) return;
+      code_.SetValue("OFFSET_NAME", GetFieldOffsetName(field));
+      code_.SetValue("OFFSET_VALUE", NumToString(field.value.offset));
+      code_.SetValue("FIELD_NAME", Name(field));
+      code_.SetValue("DEFAULT_VALUE", GetDefaultScalarValue(field));
+      cb(field);
+    };
+    const auto &fields = struct_def.fields.vec;
+    if (reversed) {
+      for (auto it = fields.rbegin(); it != fields.rend(); ++it) go(**it);
+    } else {
+      for (auto it = fields.begin(); it != fields.end(); ++it) go(**it);
+    }
+  }
   // Generate an accessor struct, builder struct, and create function for a
   // table.
   void GenTable(const StructDef &struct_def) {
@@ -1151,7 +1188,7 @@
     // Generate an offset type, the base type, the Follow impl, and the
     // init_from_table impl.
     code_ += "pub enum {{OFFSET_TYPELABEL}} {}";
-    code_ += "#[derive(Copy, Clone, Debug, PartialEq)]";
+    code_ += "#[derive(Copy, Clone, PartialEq)]";
     code_ += "";
 
     GenComment(struct_def.doc_comment);
@@ -1164,16 +1201,20 @@
     code_ += "    type Inner = {{STRUCT_NAME}}<'a>;";
     code_ += "    #[inline]";
     code_ += "    fn follow(buf: &'a [u8], loc: usize) -> Self::Inner {";
-    code_ += "        Self {";
-    code_ += "            _tab: flatbuffers::Table { buf: buf, loc: loc },";
-    code_ += "        }";
+    code_ += "        Self { _tab: flatbuffers::Table { buf, loc } }";
     code_ += "    }";
     code_ += "}";
     code_ += "";
     code_ += "impl<'a> {{STRUCT_NAME}}<'a> {";
+
+    if (parser_.opts.generate_name_strings) {
+      GenFullyQualifiedNameGetter(struct_def, struct_def.name);
+    }
+
     code_ += "    #[inline]";
-    code_ += "    pub fn init_from_table(table: flatbuffers::Table<'a>) -> "
-             "Self {";
+    code_ +=
+        "    pub fn init_from_table(table: flatbuffers::Table<'a>) -> "
+        "Self {";
     code_ += "        {{STRUCT_NAME}} {";
     code_ += "            _tab: table,";
     code_ += "        }";
@@ -1181,57 +1222,44 @@
 
     // Generate a convenient create* function that uses the above builder
     // to create a table in one function call.
-    code_.SetValue("MAYBE_US",
-        struct_def.fields.vec.size() == 0 ? "_" : "");
+    code_.SetValue("MAYBE_US", struct_def.fields.vec.size() == 0 ? "_" : "");
     code_.SetValue("MAYBE_LT",
-        TableBuilderArgsNeedsLifetime(struct_def) ? "<'args>" : "");
+                   TableBuilderArgsNeedsLifetime(struct_def) ? "<'args>" : "");
     code_ += "    #[allow(unused_mut)]";
     code_ += "    pub fn create<'bldr: 'args, 'args: 'mut_bldr, 'mut_bldr>(";
-    code_ += "        _fbb: "
-             "&'mut_bldr mut flatbuffers::FlatBufferBuilder<'bldr>,";
-    code_ += "        {{MAYBE_US}}args: &'args {{STRUCT_NAME}}Args{{MAYBE_LT}})"
-             " -> flatbuffers::WIPOffset<{{STRUCT_NAME}}<'bldr>> {";
+    code_ +=
+        "        _fbb: "
+        "&'mut_bldr mut flatbuffers::FlatBufferBuilder<'bldr>,";
+    code_ +=
+        "        {{MAYBE_US}}args: &'args {{STRUCT_NAME}}Args{{MAYBE_LT}})"
+        " -> flatbuffers::WIPOffset<{{STRUCT_NAME}}<'bldr>> {";
 
     code_ += "      let mut builder = {{STRUCT_NAME}}Builder::new(_fbb);";
     for (size_t size = struct_def.sortbysize ? sizeof(largest_scalar_t) : 1;
          size; size /= 2) {
-      for (auto it = struct_def.fields.vec.rbegin();
-           it != struct_def.fields.vec.rend(); ++it) {
-        const auto &field = **it;
-        // TODO(rw): fully understand this sortbysize usage
-        if (!field.deprecated && (!struct_def.sortbysize ||
-                                  size == SizeOf(field.value.type.base_type))) {
-          code_.SetValue("FIELD_NAME", Name(field));
-          if (TableFieldReturnsOption(field.value.type)) {
-            code_ += "      if let Some(x) = args.{{FIELD_NAME}} "
-                     "{ builder.add_{{FIELD_NAME}}(x); }";
-          } else {
-            code_ += "      builder.add_{{FIELD_NAME}}(args.{{FIELD_NAME}});";
-          }
+      ForAllTableFields(struct_def, [&](const FieldDef &field) {
+        if (struct_def.sortbysize && size != SizeOf(field.value.type.base_type))
+          return;
+        if (TableFieldReturnsOption(field)) {
+          code_ +=
+              "      if let Some(x) = args.{{FIELD_NAME}} "
+              "{ builder.add_{{FIELD_NAME}}(x); }";
+        } else {
+          code_ += "      builder.add_{{FIELD_NAME}}(args.{{FIELD_NAME}});";
         }
-      }
+      }, /*reverse=*/true);
     }
     code_ += "      builder.finish()";
     code_ += "    }";
     code_ += "";
 
     // Generate field id constants.
-    if (struct_def.fields.vec.size() > 0) {
-      for (auto it = struct_def.fields.vec.begin();
-           it != struct_def.fields.vec.end(); ++it) {
-        const auto &field = **it;
-        if (field.deprecated) {
-          // Deprecated fields won't be accessible.
-          continue;
-        }
-
-        code_.SetValue("OFFSET_NAME", GetFieldOffsetName(field));
-        code_.SetValue("OFFSET_VALUE", NumToString(field.value.offset));
-        code_ += "    pub const {{OFFSET_NAME}}: flatbuffers::VOffsetT = "
-                 "{{OFFSET_VALUE}};";
-      }
-      code_ += "";
-    }
+    ForAllTableFields(struct_def, [&](const FieldDef &unused){
+      (void) unused;
+      code_ += "    pub const {{OFFSET_NAME}}: flatbuffers::VOffsetT = "
+               "{{OFFSET_VALUE}};";
+    });
+    if (struct_def.fields.vec.size() > 0) code_ += "";
 
     // Generate the accessors. Each has one of two forms:
     //
@@ -1245,30 +1273,20 @@
     //     self._tab.get::<internal_type>(offset, defaultval).unwrap()
     //   }
     const auto offset_prefix = Name(struct_def);
-    for (auto it = struct_def.fields.vec.begin();
-         it != struct_def.fields.vec.end(); ++it) {
-      const auto &field = **it;
-      if (field.deprecated) {
-        // Deprecated fields won't be accessible.
-        continue;
-      }
-
-      code_.SetValue("FIELD_NAME", Name(field));
+    ForAllTableFields(struct_def, [&](const FieldDef &field) {
       code_.SetValue("RETURN_TYPE",
                      GenTableAccessorFuncReturnType(field, "'a"));
       code_.SetValue("FUNC_BODY",
                      GenTableAccessorFuncBody(field, "'a", offset_prefix));
 
-      GenComment(field.doc_comment, "  ");
+      this->GenComment(field.doc_comment, "  ");
       code_ += "  #[inline]";
       code_ += "  pub fn {{FIELD_NAME}}(&self) -> {{RETURN_TYPE}} {";
       code_ += "    {{FUNC_BODY}}";
       code_ += "  }";
 
       // Generate a comparison function for this field if it is a key.
-      if (field.key) {
-        GenKeyFieldMethods(field);
-      }
+      if (field.key) { GenKeyFieldMethods(field); }
 
       // Generate a nested flatbuffer field, if applicable.
       auto nested = field.attributes.Lookup("nested_flatbuffer");
@@ -1281,80 +1299,84 @@
           nested_root = parser_.LookupStruct(qualified_name);
         }
         FLATBUFFERS_ASSERT(nested_root);  // Guaranteed to exist by parser.
-        (void)nested_root;
 
-        code_.SetValue("OFFSET_NAME",
-                       offset_prefix + "::" + GetFieldOffsetName(field));
-        code_ += "  pub fn {{FIELD_NAME}}_nested_flatbuffer(&'a self) -> "
-                 " Option<{{STRUCT_NAME}}<'a>> {";
-        code_ += "     match self.{{FIELD_NAME}}() {";
-        code_ += "         None => { None }";
-        code_ += "         Some(data) => {";
-        code_ += "             use self::flatbuffers::Follow;";
-        code_ += "             Some(<flatbuffers::ForwardsUOffset"
-                 "<{{STRUCT_NAME}}<'a>>>::follow(data, 0))";
-        code_ += "         },";
-        code_ += "     }";
+        code_.SetValue("NESTED", WrapInNameSpace(*nested_root));
+        code_ +=
+            "  pub fn {{FIELD_NAME}}_nested_flatbuffer(&'a self) -> \\";
+        if (field.required) {
+          code_ += "{{NESTED}}<'a> {";
+          code_ += "    let data = self.{{FIELD_NAME}}();";
+          code_ += "    use flatbuffers::Follow;";
+          code_ += "    <flatbuffers::ForwardsUOffset<{{NESTED}}<'a>>>"
+                   "::follow(data, 0)";
+        } else {
+          code_ += "Option<{{NESTED}}<'a>> {";
+          code_ += "    self.{{FIELD_NAME}}().map(|data| {";
+          code_ += "      use flatbuffers::Follow;";
+          code_ += "      <flatbuffers::ForwardsUOffset<{{NESTED}}<'a>>>"
+                   "::follow(data, 0)";
+          code_ += "    })";
+        }
         code_ += "  }";
       }
-    }
+    });
 
     // Explicit specializations for union accessors
-    for (auto it = struct_def.fields.vec.begin();
-         it != struct_def.fields.vec.end(); ++it) {
-      const auto &field = **it;
-      if (field.deprecated || field.value.type.base_type != BASE_TYPE_UNION) {
-        continue;
-      }
-
-      auto u = field.value.type.enum_def;
-
-      code_.SetValue("FIELD_NAME", Name(field));
-
-      for (auto u_it = u->Vals().begin(); u_it != u->Vals().end(); ++u_it) {
-        auto &ev = **u_it;
-        if (ev.union_type.base_type == BASE_TYPE_NONE) { continue; }
-
-        auto table_init_type = WrapInNameSpace(
-          ev.union_type.struct_def->defined_namespace,
-          ev.union_type.struct_def->name);
-
-          code_.SetValue("U_ELEMENT_ENUM_TYPE",
-              WrapInNameSpace(u->defined_namespace, GetEnumValUse(*u, ev)));
-        code_.SetValue("U_ELEMENT_TABLE_TYPE", table_init_type);
-        code_.SetValue("U_ELEMENT_NAME", MakeSnakeCase(Name(ev)));
-
+    ForAllTableFields(struct_def, [&](const FieldDef &field) {
+      if (field.value.type.base_type != BASE_TYPE_UNION) return;
+      code_.SetValue("FIELD_TYPE_FIELD_NAME", field.name);
+      ForAllUnionVariantsBesidesNone(
+        *field.value.type.enum_def, [&](const EnumVal &unused){
+        (void) unused;
         code_ += "  #[inline]";
         code_ += "  #[allow(non_snake_case)]";
-        code_ += "  pub fn {{FIELD_NAME}}_as_{{U_ELEMENT_NAME}}(&self) -> "
-                 "Option<{{U_ELEMENT_TABLE_TYPE}}<'a>> {";
-        code_ += "    if self.{{FIELD_NAME}}_type() == {{U_ELEMENT_ENUM_TYPE}} {";
-        code_ += "      self.{{FIELD_NAME}}().map(|u| "
-                 "{{U_ELEMENT_TABLE_TYPE}}::init_from_table(u))";
+        code_ +=
+            "  pub fn {{FIELD_NAME}}_as_{{U_ELEMENT_NAME}}(&self) -> "
+            "Option<{{U_ELEMENT_TABLE_TYPE}}<'a>> {";
+        // If the user defined schemas name a field that clashes with a
+        // language reserved word, flatc will try to escape the field name by
+        // appending an underscore. This works well for most cases, except
+        // one. When generating union accessors (and referring to them
+        // internally within the code generated here), an extra underscore
+        // will be appended to the name, causing build failures.
+        //
+        // This only happens when unions have members that overlap with
+        // language reserved words.
+        //
+        // To avoid this problem the type field name is used unescaped here:
+        code_ +=
+            "    if self.{{FIELD_TYPE_FIELD_NAME}}_type() == "
+            "{{U_ELEMENT_ENUM_TYPE}} {";
+
+        // The following logic is not tested in the integration test,
+        // as of April 10, 2020
+        if (field.required) {
+          code_ += "      let u = self.{{FIELD_NAME}}();";
+          code_ += "      Some({{U_ELEMENT_TABLE_TYPE}}::init_from_table(u))";
+        } else {
+          code_ +=
+              "      self.{{FIELD_NAME}}().map("
+              "{{U_ELEMENT_TABLE_TYPE}}::init_from_table)";
+        }
         code_ += "    } else {";
         code_ += "      None";
         code_ += "    }";
         code_ += "  }";
         code_ += "";
-      }
-    }
 
+      });
+    });
     code_ += "}";  // End of table impl.
     code_ += "";
 
     // Generate an args struct:
     code_.SetValue("MAYBE_LT",
-        TableBuilderArgsNeedsLifetime(struct_def) ? "<'a>" : "");
+                   TableBuilderArgsNeedsLifetime(struct_def) ? "<'a>" : "");
     code_ += "pub struct {{STRUCT_NAME}}Args{{MAYBE_LT}} {";
-    for (auto it = struct_def.fields.vec.begin();
-         it != struct_def.fields.vec.end(); ++it) {
-      const auto &field = **it;
-      if (!field.deprecated) {
-        code_.SetValue("PARAM_NAME", Name(field));
-        code_.SetValue("PARAM_TYPE", TableBuilderArgsDefnType(field, "'a "));
-        code_ += "    pub {{PARAM_NAME}}: {{PARAM_TYPE}},";
-      }
-    }
+    ForAllTableFields(struct_def, [&](const FieldDef &field) {
+      code_.SetValue("PARAM_TYPE", TableBuilderArgsDefnType(field, "'a"));
+      code_ += "    pub {{FIELD_NAME}}: {{PARAM_TYPE}},";
+    });
     code_ += "}";
 
     // Generate an impl of Default for the *Args type:
@@ -1362,16 +1384,10 @@
     code_ += "    #[inline]";
     code_ += "    fn default() -> Self {";
     code_ += "        {{STRUCT_NAME}}Args {";
-    for (auto it = struct_def.fields.vec.begin();
-        it != struct_def.fields.vec.end(); ++it) {
-      const auto &field = **it;
-      if (!field.deprecated) {
-        code_.SetValue("PARAM_VALUE", TableBuilderArgsDefaultValue(field));
-        code_.SetValue("REQ", field.required ? " // required field" : "");
-        code_.SetValue("PARAM_NAME", Name(field));
-        code_ += "            {{PARAM_NAME}}: {{PARAM_VALUE}},{{REQ}}";
-      }
-    }
+    ForAllTableFields(struct_def, [&](const FieldDef &field) {
+      code_ += "            {{FIELD_NAME}}: {{DEFAULT_VALUE}},\\";
+      code_ += field.required ? " // required field" : "";
+    });
     code_ += "        }";
     code_ += "    }";
     code_ += "}";
@@ -1379,49 +1395,42 @@
     // Generate a builder struct:
     code_ += "pub struct {{STRUCT_NAME}}Builder<'a: 'b, 'b> {";
     code_ += "  fbb_: &'b mut flatbuffers::FlatBufferBuilder<'a>,";
-    code_ += "  start_: flatbuffers::WIPOffset<"
-             "flatbuffers::TableUnfinishedWIPOffset>,";
+    code_ +=
+        "  start_: flatbuffers::WIPOffset<"
+        "flatbuffers::TableUnfinishedWIPOffset>,";
     code_ += "}";
 
     // Generate builder functions:
     code_ += "impl<'a: 'b, 'b> {{STRUCT_NAME}}Builder<'a, 'b> {";
-    for (auto it = struct_def.fields.vec.begin();
-         it != struct_def.fields.vec.end(); ++it) {
-      const auto &field = **it;
-      if (!field.deprecated) {
-        const bool is_scalar = IsScalar(field.value.type.base_type);
-
-        std::string offset = GetFieldOffsetName(field);
-
-        // Generate functions to add data, which take one of two forms.
-        //
-        // If a value has a default:
-        //   fn add_x(x_: type) {
-        //     fbb_.push_slot::<type>(offset, x_, Some(default));
-        //   }
-        //
-        // If a value does not have a default:
-        //   fn add_x(x_: type) {
-        //     fbb_.push_slot_always::<type>(offset, x_);
-        //   }
-        code_.SetValue("FIELD_NAME", Name(field));
-        code_.SetValue("FIELD_OFFSET", Name(struct_def) + "::" + offset);
-        code_.SetValue("FIELD_TYPE", TableBuilderArgsAddFuncType(field, "'b "));
-        code_.SetValue("FUNC_BODY", TableBuilderArgsAddFuncBody(field));
-        code_ += "  #[inline]";
-        code_ += "  pub fn add_{{FIELD_NAME}}(&mut self, {{FIELD_NAME}}: "
-                 "{{FIELD_TYPE}}) {";
-        if (is_scalar) {
-          code_.SetValue("FIELD_DEFAULT_VALUE",
-                         TableBuilderAddFuncDefaultValue(field));
-          code_ += "    {{FUNC_BODY}}({{FIELD_OFFSET}}, {{FIELD_NAME}}, "
-                   "{{FIELD_DEFAULT_VALUE}});";
-        } else {
-          code_ += "    {{FUNC_BODY}}({{FIELD_OFFSET}}, {{FIELD_NAME}});";
-        }
-        code_ += "  }";
+    ForAllTableFields(struct_def, [&](const FieldDef &field) {
+      const bool is_scalar = IsScalar(field.value.type.base_type);
+      std::string offset = GetFieldOffsetName(field);
+      // Generate functions to add data, which take one of two forms.
+      //
+      // If a value has a default:
+      //   fn add_x(x_: type) {
+      //     fbb_.push_slot::<type>(offset, x_, Some(default));
+      //   }
+      //
+      // If a value does not have a default:
+      //   fn add_x(x_: type) {
+      //     fbb_.push_slot_always::<type>(offset, x_);
+      //   }
+      code_.SetValue("FIELD_OFFSET", Name(struct_def) + "::" + offset);
+      code_.SetValue("FIELD_TYPE", TableBuilderArgsAddFuncType(field, "'b "));
+      code_.SetValue("FUNC_BODY", TableBuilderArgsAddFuncBody(field));
+      code_ += "  #[inline]";
+      code_ += "  pub fn add_{{FIELD_NAME}}(&mut self, {{FIELD_NAME}}: "
+               "{{FIELD_TYPE}}) {";
+      if (is_scalar && !field.optional) {
+        code_ +=
+            "    {{FUNC_BODY}}({{FIELD_OFFSET}}, {{FIELD_NAME}}, "
+            "{{DEFAULT_VALUE}});";
+      } else {
+        code_ += "    {{FUNC_BODY}}({{FIELD_OFFSET}}, {{FIELD_NAME}});";
       }
-    }
+      code_ += "  }";
+    });
 
     // Struct initializer (all fields required);
     code_ += "  #[inline]";
@@ -1438,24 +1447,60 @@
 
     // finish() function.
     code_ += "  #[inline]";
-    code_ += "  pub fn finish(self) -> "
-             "flatbuffers::WIPOffset<{{STRUCT_NAME}}<'a>> {";
+    code_ +=
+        "  pub fn finish(self) -> "
+        "flatbuffers::WIPOffset<{{STRUCT_NAME}}<'a>> {";
     code_ += "    let o = self.fbb_.end_table(self.start_);";
 
-    for (auto it = struct_def.fields.vec.begin();
-         it != struct_def.fields.vec.end(); ++it) {
-      const auto &field = **it;
-      if (!field.deprecated && field.required) {
-        code_.SetValue("FIELD_NAME", MakeSnakeCase(Name(field)));
-        code_.SetValue("OFFSET_NAME", GetFieldOffsetName(field));
-        code_ += "    self.fbb_.required(o, {{STRUCT_NAME}}::{{OFFSET_NAME}},"
-                 "\"{{FIELD_NAME}}\");";
-      }
-    }
+    ForAllTableFields(struct_def, [&](const FieldDef &field) {
+      if (!field.required) return;
+      code_ +=
+          "    self.fbb_.required(o, {{STRUCT_NAME}}::{{OFFSET_NAME}},"
+          "\"{{FIELD_NAME}}\");";
+    });
     code_ += "    flatbuffers::WIPOffset::new(o.value())";
     code_ += "  }";
     code_ += "}";
     code_ += "";
+
+    code_ += "impl std::fmt::Debug for {{STRUCT_NAME}}<'_> {";
+    code_ += "  fn fmt(&self, f: &mut std::fmt::Formatter<'_>"
+             ") -> std::fmt::Result {";
+    code_ += "    let mut ds = f.debug_struct(\"{{STRUCT_NAME}}\");";
+    ForAllTableFields(struct_def, [&](const FieldDef &field) {
+      if (GetFullType(field.value.type) == ftUnionValue) {
+        // Generate a match statement to handle unions properly.
+        code_.SetValue("KEY_TYPE", GenTableAccessorFuncReturnType(field, ""));
+        code_.SetValue("FIELD_TYPE_FIELD_NAME", field.name);
+        code_.SetValue("UNION_ERR", "&\"InvalidFlatbuffer: Union discriminant"
+                                    " does not match value.\"");
+
+        code_ += "      match self.{{FIELD_NAME}}_type() {";
+        ForAllUnionVariantsBesidesNone(*field.value.type.enum_def,
+                                       [&](const EnumVal &unused){
+          (void) unused;
+          code_ += "        {{U_ELEMENT_ENUM_TYPE}} => {";
+          code_ += "          if let Some(x) = self.{{FIELD_TYPE_FIELD_NAME}}_as_"
+                   "{{U_ELEMENT_NAME}}() {";
+          code_ += "            ds.field(\"{{FIELD_NAME}}\", &x)";
+          code_ += "          } else {";
+          code_ += "            ds.field(\"{{FIELD_NAME}}\", {{UNION_ERR}})";
+          code_ += "          }";
+          code_ += "        },";
+        });
+        code_ += "        _ => { ";
+        code_ += "          let x: Option<()> = None;";
+        code_ += "          ds.field(\"{{FIELD_NAME}}\", &x)";
+        code_ += "        },";
+        code_ += "      };";
+      } else {
+        // Most fields.
+        code_ += "      ds.field(\"{{FIELD_NAME}}\", &self.{{FIELD_NAME}}());";
+      }
+    });
+    code_ += "      ds.finish()";
+    code_ += "  }";
+    code_ += "}";
   }
 
   // Generate functions to compare tables and structs by key. This function
@@ -1466,14 +1511,16 @@
     code_.SetValue("KEY_TYPE", GenTableAccessorFuncReturnType(field, ""));
 
     code_ += "  #[inline]";
-    code_ += "  pub fn key_compare_less_than(&self, o: &{{STRUCT_NAME}}) -> "
-             " bool {";
+    code_ +=
+        "  pub fn key_compare_less_than(&self, o: &{{STRUCT_NAME}}) -> "
+        " bool {";
     code_ += "    self.{{FIELD_NAME}}() < o.{{FIELD_NAME}}()";
     code_ += "  }";
     code_ += "";
     code_ += "  #[inline]";
-    code_ += "  pub fn key_compare_with_value(&self, val: {{KEY_TYPE}}) -> "
-             " ::std::cmp::Ordering {";
+    code_ +=
+        "  pub fn key_compare_with_value(&self, val: {{KEY_TYPE}}) -> "
+        " ::std::cmp::Ordering {";
     code_ += "    let key = self.{{FIELD_NAME}}();";
     code_ += "    key.cmp(&val)";
     code_ += "  }";
@@ -1499,16 +1546,19 @@
     code_ += "";
 
     code_ += "#[inline]";
-    code_ += "pub fn get_size_prefixed_root_as_{{STRUCT_NAME_SNAKECASE}}"
-             "<'a>(buf: &'a [u8]) -> {{STRUCT_NAME}}<'a> {";
-    code_ += "  flatbuffers::get_size_prefixed_root::<{{STRUCT_NAME}}<'a>>"
-             "(buf)";
+    code_ +=
+        "pub fn get_size_prefixed_root_as_{{STRUCT_NAME_SNAKECASE}}"
+        "<'a>(buf: &'a [u8]) -> {{STRUCT_NAME}}<'a> {";
+    code_ +=
+        "  flatbuffers::get_size_prefixed_root::<{{STRUCT_NAME}}<'a>>"
+        "(buf)";
     code_ += "}";
     code_ += "";
 
     if (parser_.file_identifier_.length()) {
       // Declare the identifier
-      code_ += "pub const {{STRUCT_NAME_CAPS}}_IDENTIFIER: &'static str\\";
+      // (no lifetime needed as constants have static lifetimes by default)
+      code_ += "pub const {{STRUCT_NAME_CAPS}}_IDENTIFIER: &str\\";
       code_ += " = \"" + parser_.file_identifier_ + "\";";
       code_ += "";
 
@@ -1516,22 +1566,22 @@
       code_ += "#[inline]";
       code_ += "pub fn {{STRUCT_NAME_SNAKECASE}}_buffer_has_identifier\\";
       code_ += "(buf: &[u8]) -> bool {";
-      code_ += "  return flatbuffers::buffer_has_identifier(buf, \\";
-      code_ += "{{STRUCT_NAME_CAPS}}_IDENTIFIER, false);";
+      code_ += "  flatbuffers::buffer_has_identifier(buf, \\";
+      code_ += "{{STRUCT_NAME_CAPS}}_IDENTIFIER, false)";
       code_ += "}";
       code_ += "";
       code_ += "#[inline]";
       code_ += "pub fn {{STRUCT_NAME_SNAKECASE}}_size_prefixed\\";
       code_ += "_buffer_has_identifier(buf: &[u8]) -> bool {";
-      code_ += "  return flatbuffers::buffer_has_identifier(buf, \\";
-      code_ += "{{STRUCT_NAME_CAPS}}_IDENTIFIER, true);";
+      code_ += "  flatbuffers::buffer_has_identifier(buf, \\";
+      code_ += "{{STRUCT_NAME_CAPS}}_IDENTIFIER, true)";
       code_ += "}";
       code_ += "";
     }
 
     if (parser_.file_extension_.length()) {
       // Return the extension
-      code_ += "pub const {{STRUCT_NAME_CAPS}}_EXTENSION: &'static str = \\";
+      code_ += "pub const {{STRUCT_NAME_CAPS}}_EXTENSION: &str = \\";
       code_ += "\"" + parser_.file_extension_ + "\";";
       code_ += "";
     }
@@ -1550,13 +1600,15 @@
     code_ += "}";
     code_ += "";
     code_ += "#[inline]";
-    code_ += "pub fn finish_size_prefixed_{{STRUCT_NAME_SNAKECASE}}_buffer"
-             "<'a, 'b>("
-             "fbb: &'b mut flatbuffers::FlatBufferBuilder<'a>, "
-             "root: flatbuffers::WIPOffset<{{STRUCT_NAME}}<'a>>) {";
+    code_ +=
+        "pub fn finish_size_prefixed_{{STRUCT_NAME_SNAKECASE}}_buffer"
+        "<'a, 'b>("
+        "fbb: &'b mut flatbuffers::FlatBufferBuilder<'a>, "
+        "root: flatbuffers::WIPOffset<{{STRUCT_NAME}}<'a>>) {";
     if (parser_.file_identifier_.length()) {
-      code_ += "  fbb.finish_size_prefixed(root, "
-               "Some({{STRUCT_NAME_CAPS}}_IDENTIFIER));";
+      code_ +=
+          "  fbb.finish_size_prefixed(root, "
+          "Some({{STRUCT_NAME_CAPS}}_IDENTIFIER));";
     } else {
       code_ += "  fbb.finish_size_prefixed(root, None);";
     }
@@ -1577,8 +1629,8 @@
   }
 
   static void PaddingDefinition(int bits, std::string *code_ptr, int *id) {
-    *code_ptr += "  padding" + NumToString((*id)++) + "__: u" + \
-                 NumToString(bits) + ",";
+    *code_ptr +=
+        "  padding" + NumToString((*id)++) + "__: u" + NumToString(bits) + ",";
   }
 
   static void PaddingInitializer(int bits, std::string *code_ptr, int *id) {
@@ -1586,6 +1638,18 @@
     *code_ptr += "padding" + NumToString((*id)++) + "__: 0,";
   }
 
+  void ForAllStructFields(
+    const StructDef &struct_def,
+    std::function<void(const FieldDef &field)> cb
+  ) {
+    for (auto it = struct_def.fields.vec.begin();
+         it != struct_def.fields.vec.end(); ++it) {
+      const auto &field = **it;
+      code_.SetValue("FIELD_TYPE", GetTypeGet(field.value.type));
+      code_.SetValue("FIELD_NAME", Name(field));
+      cb(field);
+    }
+  }
   // Generate an accessor struct with constructor for a flatbuffers struct.
   void GenStruct(const StructDef &struct_def) {
     // Generates manual padding and alignment.
@@ -1601,26 +1665,35 @@
     // PartialEq is useful to derive because we can correctly compare structs
     // for equality by just comparing their underlying byte data. This doesn't
     // hold for PartialOrd/Ord.
-    code_ += "#[derive(Clone, Copy, Debug, PartialEq)]";
+    code_ += "#[derive(Clone, Copy, PartialEq)]";
     code_ += "pub struct {{STRUCT_NAME}} {";
 
     int padding_id = 0;
-    for (auto it = struct_def.fields.vec.begin();
-         it != struct_def.fields.vec.end(); ++it) {
-      const auto &field = **it;
-      code_.SetValue("FIELD_TYPE", GetTypeGet(field.value.type));
-      code_.SetValue("FIELD_NAME", Name(field));
+    ForAllStructFields(struct_def, [&](const FieldDef &field) {
       code_ += "  {{FIELD_NAME}}_: {{FIELD_TYPE}},";
-
       if (field.padding) {
         std::string padding;
         GenPadding(field, &padding, &padding_id, PaddingDefinition);
         code_ += padding;
       }
-    }
-
+    });
     code_ += "} // pub struct {{STRUCT_NAME}}";
 
+    // Debug for structs.
+    code_ += "impl std::fmt::Debug for {{STRUCT_NAME}} {";
+    code_ += "  fn fmt(&self, f: &mut std::fmt::Formatter"
+             ") -> std::fmt::Result {";
+    code_ += "    f.debug_struct(\"{{STRUCT_NAME}}\")";
+    ForAllStructFields(struct_def, [&](const FieldDef &unused) {
+      (void) unused;
+      code_ += "      .field(\"{{FIELD_NAME}}\", &self.{{FIELD_NAME}}())";
+    });
+    code_ += "      .finish()";
+    code_ += "  }";
+    code_ += "}";
+    code_ += "";
+
+
     // Generate impls for SafeSliceAccess (because all structs are endian-safe),
     // Follow for the value type, Follow for the reference type, Push for the
     // value type, and Push for the reference type.
@@ -1644,8 +1717,9 @@
     code_ += "    #[inline]";
     code_ += "    fn push(&self, dst: &mut [u8], _rest: &[u8]) {";
     code_ += "        let src = unsafe {";
-    code_ += "            ::std::slice::from_raw_parts("
-             "self as *const {{STRUCT_NAME}} as *const u8, Self::size())";
+    code_ +=
+        "            ::std::slice::from_raw_parts("
+        "self as *const {{STRUCT_NAME}} as *const u8, Self::size())";
     code_ += "        };";
     code_ += "        dst.copy_from_slice(src);";
     code_ += "    }";
@@ -1656,8 +1730,9 @@
     code_ += "    #[inline]";
     code_ += "    fn push(&self, dst: &mut [u8], _rest: &[u8]) {";
     code_ += "        let src = unsafe {";
-    code_ += "            ::std::slice::from_raw_parts("
-             "*self as *const {{STRUCT_NAME}} as *const u8, Self::size())";
+    code_ +=
+        "            ::std::slice::from_raw_parts("
+        "*self as *const {{STRUCT_NAME}} as *const u8, Self::size())";
     code_ += "        };";
     code_ += "        dst.copy_from_slice(src);";
     code_ += "    }";
@@ -1667,86 +1742,81 @@
 
     // Generate a constructor that takes all fields as arguments.
     code_ += "impl {{STRUCT_NAME}} {";
-    std::string arg_list;
-    std::string init_list;
-    padding_id = 0;
-    for (auto it = struct_def.fields.vec.begin();
-         it != struct_def.fields.vec.end(); ++it) {
-      const auto &field = **it;
-      const auto member_name = Name(field) + "_";
-      const auto reference = StructMemberAccessNeedsCopy(field.value.type)
-                             ? "" : "&'a ";
-      const auto arg_name = "_" + Name(field);
-      const auto arg_type = reference + GetTypeGet(field.value.type);
-
-      if (it != struct_def.fields.vec.begin()) {
-        arg_list += ", ";
-      }
-      arg_list += arg_name + ": ";
-      arg_list += arg_type;
-      init_list += "      " + member_name;
-      if (StructMemberAccessNeedsCopy(field.value.type)) {
-        init_list += ": " + arg_name + ".to_little_endian(),\n";
-      } else {
-        init_list += ": *" + arg_name + ",\n";
-      }
-    }
-
-    code_.SetValue("ARG_LIST", arg_list);
-    code_.SetValue("INIT_LIST", init_list);
-    code_ += "  pub fn new<'a>({{ARG_LIST}}) -> Self {";
+    // TODO(cneo): Stop generating args on one line. Make it simpler.
+    bool first_arg = true;
+    code_ += "  pub fn new(\\";
+    ForAllStructFields(struct_def, [&](const FieldDef &field) {
+      if (first_arg) first_arg = false; else code_ += ", \\";
+      code_.SetValue("REF", IsStruct(field.value.type) ? "&" : "");
+      code_ += "_{{FIELD_NAME}}: {{REF}}{{FIELD_TYPE}}\\";
+    });
+    code_ += ") -> Self {";
     code_ += "    {{STRUCT_NAME}} {";
-    code_ += "{{INIT_LIST}}";
+
+    ForAllStructFields(struct_def, [&](const FieldDef &field) {
+      const bool is_struct = IsStruct(field.value.type);
+      code_.SetValue("DEREF", is_struct ? "*" : "");
+      code_.SetValue("TO_LE", is_struct ? "" : ".to_little_endian()");
+      code_ += "      {{FIELD_NAME}}_: {{DEREF}}_{{FIELD_NAME}}{{TO_LE}},";
+    });
+    code_ += "";
+
+    // TODO(cneo): Does this padding even work? Why after all the fields?
     padding_id = 0;
-    for (auto it = struct_def.fields.vec.begin();
-         it != struct_def.fields.vec.end(); ++it) {
-      const auto &field = **it;
+    ForAllStructFields(struct_def, [&](const FieldDef &field) {
       if (field.padding) {
         std::string padding;
         GenPadding(field, &padding, &padding_id, PaddingInitializer);
         code_ += "      " + padding;
       }
-    }
+    });
     code_ += "    }";
     code_ += "  }";
 
+    if (parser_.opts.generate_name_strings) {
+      GenFullyQualifiedNameGetter(struct_def, struct_def.name);
+    }
+
     // Generate accessor methods for the struct.
-    for (auto it = struct_def.fields.vec.begin();
-         it != struct_def.fields.vec.end(); ++it) {
-      const auto &field = **it;
+    ForAllStructFields(struct_def, [&](const FieldDef &field) {
+      const bool is_struct = IsStruct(field.value.type);
+      code_.SetValue("REF", is_struct ? "&" : "");
+      code_.SetValue("FROM_LE", is_struct ? "" : ".from_little_endian()");
 
-      auto field_type = TableBuilderArgsAddFuncType(field, "'a");
-      auto member = "self." + Name(field) + "_";
-      auto value = StructMemberAccessNeedsCopy(field.value.type) ?
-        member + ".from_little_endian()" : member;
-
-      code_.SetValue("FIELD_NAME", Name(field));
-      code_.SetValue("FIELD_TYPE", field_type);
-      code_.SetValue("FIELD_VALUE", value);
-      code_.SetValue("REF", IsStruct(field.value.type) ? "&" : "");
-
-      GenComment(field.doc_comment, "  ");
-      code_ += "  pub fn {{FIELD_NAME}}<'a>(&'a self) -> {{FIELD_TYPE}} {";
-      code_ += "    {{REF}}{{FIELD_VALUE}}";
+      this->GenComment(field.doc_comment, "  ");
+      code_ += "  pub fn {{FIELD_NAME}}(&self) -> {{REF}}{{FIELD_TYPE}} {";
+      code_ += "    {{REF}}self.{{FIELD_NAME}}_{{FROM_LE}}";
       code_ += "  }";
 
       // Generate a comparison function for this field if it is a key.
-      if (field.key) {
-        GenKeyFieldMethods(field);
-      }
-    }
+      if (field.key) { GenKeyFieldMethods(field); }
+    });
     code_ += "}";
     code_ += "";
   }
 
   void GenNamespaceImports(const int white_spaces) {
-      std::string indent = std::string(white_spaces, ' ');
-      code_ += "";
-      code_ += indent + "use std::mem;";
-      code_ += indent + "use std::cmp::Ordering;";
-      code_ += "";
-      code_ += indent + "extern crate flatbuffers;";
-      code_ += indent + "use self::flatbuffers::EndianScalar;";
+    if (white_spaces == 0) {
+      code_ += "#![allow(unused_imports, dead_code)]";
+    }
+    std::string indent = std::string(white_spaces, ' ');
+    code_ += "";
+    if (!parser_.opts.generate_all) {
+      for (auto it = parser_.included_files_.begin();
+           it != parser_.included_files_.end(); ++it) {
+        if (it->second.empty()) continue;
+        auto noext = flatbuffers::StripExtension(it->second);
+        auto basename = flatbuffers::StripPath(noext);
+
+        code_ += indent + "use crate::" + basename + "_generated::*;";
+      }
+    }
+
+    code_ += indent + "use std::mem;";
+    code_ += indent + "use std::cmp::Ordering;";
+    code_ += "";
+    code_ += indent + "extern crate flatbuffers;";
+    code_ += indent + "use self::flatbuffers::EndianScalar;";
   }
 
   // Set up the correct namespace. This opens a namespace if the current
@@ -1805,7 +1875,9 @@
                          const std::string &file_name) {
   std::string filebase =
       flatbuffers::StripPath(flatbuffers::StripExtension(file_name));
-  std::string make_rule = GeneratedFileName(path, filebase) + ": ";
+  rust::RustGenerator generator(parser, path, file_name);
+  std::string make_rule =
+      generator.GeneratedFileName(path, filebase, parser.opts) + ": ";
 
   auto included_files = parser.GetIncludedFilesRecursive(file_name);
   for (auto it = included_files.begin(); it != included_files.end(); ++it) {
@@ -1823,3 +1895,10 @@
 // TODO(rw): Generated code should generate endian-safe Debug impls.
 // TODO(rw): Generated code could use a Rust-only enum type to access unions,
 //           instead of making the user use _type() to manually switch.
+// TODO(maxburke): There should be test schemas added that use language
+//           keywords as fields of structs, tables, unions, enums, to make sure
+//           that internal code generated references escaped names correctly.
+// TODO(maxburke): We should see if there is a more flexible way of resolving
+//           module paths for use declarations. Right now if schemas refer to
+//           other flatbuffer files, the include paths in emitted Rust bindings
+//           are crate-relative which may undesirable.