Fix Rust keyword inconsistency (#6794)

* Make Rust keyword escaping more consistent

* fix comment

* git clang format

Co-authored-by: Casper Neo <cneo@google.com>

src/idl_gen_rust.cpp

@@ -51,6 +51,10 @@ std::string MakeUpper(const std::string &in) {
   return s;
 }
 
+std::string UnionTypeFieldName(const FieldDef &field) {
+  return MakeSnakeCase(field.name + "_type");
+}
+
 // Encapsulate all logical field types in this enum. This allows us to write
 // field logic based on type switches, instead of branches on the properties
 // set on the Type.
@@ -407,7 +411,7 @@ class RustGenerator : public BaseGenerator {
       gen_symbol(symbol);
       std::stringstream file_path;
       file_path << path_;
-      // DO NOT SUBMIT: CASPER: Refactor out common path name generation.
+      // Create filepath.
       if (symbol.defined_namespace)
         for (auto i = symbol.defined_namespace->components.begin();
              i != symbol.defined_namespace->components.end(); i++) {
@@ -1634,6 +1638,7 @@ class RustGenerator : public BaseGenerator {
       code_.SetValue("OFFSET_VALUE", NumToString(field.value.offset));
       code_.SetValue("FIELD_NAME", Name(field));
       code_.SetValue("BLDR_DEF_VAL", GetDefaultValue(field, kBuilder));
+      code_.SetValue("DISCRIMINANT", UnionTypeFieldName(field));
       cb(field);
     };
     const auto &fields = struct_def.fields.vec;
@@ -1905,7 +1910,6 @@ class RustGenerator : public BaseGenerator {
     // Explicit specializations for union accessors
     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;
@@ -1926,8 +1930,7 @@ class RustGenerator : public BaseGenerator {
             //
             // To avoid this problem the type field name is used unescaped here:
             code_ +=
-                "    if self.{{FIELD_TYPE_FIELD_NAME}}_type() == "
-                "{{U_ELEMENT_ENUM_TYPE}} {";
+                "    if self.{{DISCRIMINANT}}() == {{U_ELEMENT_ENUM_TYPE}} {";
 
             // The following logic is not tested in the integration test,
             // as of April 10, 2020
@@ -1973,11 +1976,16 @@ class RustGenerator : public BaseGenerator {
         return;
       }
       // Unions.
-      EnumDef &union_def = *field.value.type.enum_def;
+      const EnumDef &union_def = *field.value.type.enum_def;
       code_.SetValue("UNION_TYPE", WrapInNameSpace(union_def));
+      // TODO: Use the same function that generates the _type field for
+      // consistency. We do not call Name() because it inconsistently
+      // escapes keywords.
+      code_.SetValue("UNION_TYPE_OFFSET_NAME",
+                     "VT_" + MakeUpper(field.name + "_type"));
       code_ +=
           "\n     .visit_union::<{{UNION_TYPE}}, _>("
-          "\"{{FIELD_NAME}}_type\", Self::{{OFFSET_NAME}}_TYPE, "
+          "\"{{FIELD_NAME}}_type\", Self::{{UNION_TYPE_OFFSET_NAME}}, "
           "\"{{FIELD_NAME}}\", Self::{{OFFSET_NAME}}, {{IS_REQ}}, "
           "|key, v, pos| {";
       code_ += "        match key {";
@@ -2101,19 +2109,18 @@ class RustGenerator : public BaseGenerator {
       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() {";
+        code_ += "      match self.{{DISCRIMINANT}}() {";
         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_"
+                  "self.{{FIELD_NAME}}_as_"
                   "{{U_ELEMENT_NAME}}() {";
               code_ += "            ds.field(\"{{FIELD_NAME}}\", &x)";
               code_ += "          } else {";

tests/generate_code.sh

@@ -75,6 +75,7 @@ $TEST_NOINCL_FLAGS $TEST_CPP_FLAGS $TEST_CS_FLAGS $TEST_TS_FLAGS -o namespace_te
 
 # Generate the keywords tests
 ../flatc --csharp $TEST_BASE_FLAGS $TEST_CS_FLAGS -o keyword_test ./keyword_test.fbs
+../flatc --rust $TEST_RUST_FLAGS -o keyword_test ./keyword_test.fbs
 
 working_dir=`pwd`
 cd FlatBuffers.Test.Swift/Tests/FlatBuffers.Test.SwiftTests

tests/keyword_test.fbs

@@ -6,9 +6,10 @@ enum public: int { }
 table KeywordsInTable {
   is: ABC = void;
   private: public;
+  type: int;
 }
 
 union KeywordsInUnion {
   static: KeywordsInTable,
-  internal: string
+  internal: KeywordsInTable,
 }

tests/keyword_test/KeywordsInTable.cs

@@ -20,19 +20,24 @@ public struct KeywordsInTable : IFlatbufferObject
   public bool MutateIs(ABC is_) { int o = __p.__offset(4); if (o != 0) { __p.bb.PutInt(o + __p.bb_pos, (int)is_); return true; } else { return false; } }
   public public_ Private { get { int o = __p.__offset(6); return o != 0 ? (public_)__p.bb.GetInt(o + __p.bb_pos) : public_.NONE; } }
   public bool MutatePrivate(public_ private_) { int o = __p.__offset(6); if (o != 0) { __p.bb.PutInt(o + __p.bb_pos, (int)private_); return true; } else { return false; } }
+  public int Type { get { int o = __p.__offset(8); return o != 0 ? __p.bb.GetInt(o + __p.bb_pos) : (int)0; } }
+  public bool MutateType(int type) { int o = __p.__offset(8); if (o != 0) { __p.bb.PutInt(o + __p.bb_pos, type); return true; } else { return false; } }
 
   public static Offset<KeywordsInTable> CreateKeywordsInTable(FlatBufferBuilder builder,
       ABC is_ = ABC.void_,
-      public_ private_ = public_.NONE) {
-    builder.StartTable(2);
+      public_ private_ = public_.NONE,
+      int type = 0) {
+    builder.StartTable(3);
+    KeywordsInTable.AddType(builder, type);
     KeywordsInTable.AddPrivate(builder, private_);
     KeywordsInTable.AddIs(builder, is_);
     return KeywordsInTable.EndKeywordsInTable(builder);
   }
 
-  public static void StartKeywordsInTable(FlatBufferBuilder builder) { builder.StartTable(2); }
+  public static void StartKeywordsInTable(FlatBufferBuilder builder) { builder.StartTable(3); }
   public static void AddIs(FlatBufferBuilder builder, ABC is_) { builder.AddInt(0, (int)is_, 0); }
   public static void AddPrivate(FlatBufferBuilder builder, public_ private_) { builder.AddInt(1, (int)private_, 0); }
+  public static void AddType(FlatBufferBuilder builder, int type) { builder.AddInt(2, type, 0); }
   public static Offset<KeywordsInTable> EndKeywordsInTable(FlatBufferBuilder builder) {
     int o = builder.EndTable();
     return new Offset<KeywordsInTable>(o);
@@ -45,13 +50,15 @@ public struct KeywordsInTable : IFlatbufferObject
   public void UnPackTo(KeywordsInTableT _o) {
     _o.Is = this.Is;
     _o.Private = this.Private;
+    _o.Type = this.Type;
   }
   public static Offset<KeywordsInTable> Pack(FlatBufferBuilder builder, KeywordsInTableT _o) {
     if (_o == null) return default(Offset<KeywordsInTable>);
     return CreateKeywordsInTable(
       builder,
       _o.Is,
-      _o.Private);
+      _o.Private,
+      _o.Type);
   }
 }
 
@@ -61,10 +68,13 @@ public class KeywordsInTableT
   public ABC Is { get; set; }
   [Newtonsoft.Json.JsonProperty("private")]
   public public_ Private { get; set; }
+  [Newtonsoft.Json.JsonProperty("type")]
+  public int Type { get; set; }
 
   public KeywordsInTableT() {
     this.Is = ABC.void_;
     this.Private = public_.NONE;
+    this.Type = 0;
   }
 }
 

tests/keyword_test/KeywordsInUnion.cs

@@ -22,14 +22,14 @@ public class KeywordsInUnionUnion {
   public T As<T>() where T : class { return this.Value as T; }
   public KeywordsInTableT Asstatic() { return this.As<KeywordsInTableT>(); }
   public static KeywordsInUnionUnion Fromstatic(KeywordsInTableT _static) { return new KeywordsInUnionUnion{ Type = KeywordsInUnion.static_, Value = _static }; }
-  public string Asinternal() { return this.As<string>(); }
-  public static KeywordsInUnionUnion Frominternal(string _internal) { return new KeywordsInUnionUnion{ Type = KeywordsInUnion.internal_, Value = _internal }; }
+  public KeywordsInTableT Asinternal() { return this.As<KeywordsInTableT>(); }
+  public static KeywordsInUnionUnion Frominternal(KeywordsInTableT _internal) { return new KeywordsInUnionUnion{ Type = KeywordsInUnion.internal_, Value = _internal }; }
 
   public static int Pack(FlatBuffers.FlatBufferBuilder builder, KeywordsInUnionUnion _o) {
     switch (_o.Type) {
       default: return 0;
       case KeywordsInUnion.static_: return KeywordsInTable.Pack(builder, _o.Asstatic()).Value;
-      case KeywordsInUnion.internal_: return builder.CreateString(_o.Asinternal()).Value;
+      case KeywordsInUnion.internal_: return KeywordsInTable.Pack(builder, _o.Asinternal()).Value;
     }
   }
 }
@@ -70,7 +70,7 @@ public class KeywordsInUnionUnion_JsonConverter : Newtonsoft.Json.JsonConverter
     switch (_o.Type) {
       default: break;
       case KeywordsInUnion.static_: _o.Value = serializer.Deserialize<KeywordsInTableT>(reader); break;
-      case KeywordsInUnion.internal_: _o.Value = serializer.Deserialize<string>(reader); break;
+      case KeywordsInUnion.internal_: _o.Value = serializer.Deserialize<KeywordsInTableT>(reader); break;
     }
     return _o;
   }

tests/keyword_test/abc_generated.rs

@@ -0,0 +1,97 @@
+// automatically generated by the FlatBuffers compiler, do not modify
+extern crate flatbuffers;
+use std::mem;
+use std::cmp::Ordering;
+use self::flatbuffers::{EndianScalar, Follow};
+use super::*;
+#[deprecated(since = "2.0.0", note = "Use associated constants instead. This will no longer be generated in 2021.")]
+pub const ENUM_MIN_ABC: i32 = 0;
+#[deprecated(since = "2.0.0", note = "Use associated constants instead. This will no longer be generated in 2021.")]
+pub const ENUM_MAX_ABC: i32 = 2;
+#[deprecated(since = "2.0.0", note = "Use associated constants instead. This will no longer be generated in 2021.")]
+#[allow(non_camel_case_types)]
+pub const ENUM_VALUES_ABC: [ABC; 3] = [
+  ABC::void,
+  ABC::where_,
+  ABC::stackalloc,
+];
+
+#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Default)]
+#[repr(transparent)]
+pub struct ABC(pub i32);
+#[allow(non_upper_case_globals)]
+impl ABC {
+  pub const void: Self = Self(0);
+  pub const where_: Self = Self(1);
+  pub const stackalloc: Self = Self(2);
+
+  pub const ENUM_MIN: i32 = 0;
+  pub const ENUM_MAX: i32 = 2;
+  pub const ENUM_VALUES: &'static [Self] = &[
+    Self::void,
+    Self::where_,
+    Self::stackalloc,
+  ];
+  /// Returns the variant's name or "" if unknown.
+  pub fn variant_name(self) -> Option<&'static str> {
+    match self {
+      Self::void => Some("void"),
+      Self::where_ => Some("where_"),
+      Self::stackalloc => Some("stackalloc"),
+      _ => None,
+    }
+  }
+}
+impl std::fmt::Debug for ABC {
+  fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+    if let Some(name) = self.variant_name() {
+      f.write_str(name)
+    } else {
+      f.write_fmt(format_args!("<UNKNOWN {:?}>", self.0))
+    }
+  }
+}
+impl<'a> flatbuffers::Follow<'a> for ABC {
+  type Inner = Self;
+  #[inline]
+  fn follow(buf: &'a [u8], loc: usize) -> Self::Inner {
+    let b = unsafe {
+      flatbuffers::read_scalar_at::<i32>(buf, loc)
+    };
+    Self(b)
+  }
+}
+
+impl flatbuffers::Push for ABC {
+    type Output = ABC;
+    #[inline]
+    fn push(&self, dst: &mut [u8], _rest: &[u8]) {
+        unsafe { flatbuffers::emplace_scalar::<i32>(dst, self.0); }
+    }
+}
+
+impl flatbuffers::EndianScalar for ABC {
+  #[inline]
+  fn to_little_endian(self) -> Self {
+    let b = i32::to_le(self.0);
+    Self(b)
+  }
+  #[inline]
+  #[allow(clippy::wrong_self_convention)]
+  fn from_little_endian(self) -> Self {
+    let b = i32::from_le(self.0);
+    Self(b)
+  }
+}
+
+impl<'a> flatbuffers::Verifiable for ABC {
+  #[inline]
+  fn run_verifier(
+    v: &mut flatbuffers::Verifier, pos: usize
+  ) -> Result<(), flatbuffers::InvalidFlatbuffer> {
+    use self::flatbuffers::Verifiable;
+    i32::run_verifier(v, pos)
+  }
+}
+
+impl flatbuffers::SimpleToVerifyInSlice for ABC {}

tests/keyword_test/keywords_in_table_generated.rs

@@ -0,0 +1,170 @@
+// automatically generated by the FlatBuffers compiler, do not modify
+extern crate flatbuffers;
+use std::mem;
+use std::cmp::Ordering;
+use self::flatbuffers::{EndianScalar, Follow};
+use super::*;
+pub enum KeywordsInTableOffset {}
+#[derive(Copy, Clone, PartialEq)]
+
+pub struct KeywordsInTable<'a> {
+  pub _tab: flatbuffers::Table<'a>,
+}
+
+impl<'a> flatbuffers::Follow<'a> for KeywordsInTable<'a> {
+    type Inner = KeywordsInTable<'a>;
+    #[inline]
+    fn follow(buf: &'a [u8], loc: usize) -> Self::Inner {
+        Self { _tab: flatbuffers::Table { buf, loc } }
+    }
+}
+
+impl<'a> KeywordsInTable<'a> {
+    pub const fn get_fully_qualified_name() -> &'static str {
+        "KeywordsInTable"
+    }
+
+    #[inline]
+    pub fn init_from_table(table: flatbuffers::Table<'a>) -> Self {
+        KeywordsInTable { _tab: table }
+    }
+    #[allow(unused_mut)]
+    pub fn create<'bldr: 'args, 'args: 'mut_bldr, 'mut_bldr>(
+        _fbb: &'mut_bldr mut flatbuffers::FlatBufferBuilder<'bldr>,
+        args: &'args KeywordsInTableArgs) -> flatbuffers::WIPOffset<KeywordsInTable<'bldr>> {
+      let mut builder = KeywordsInTableBuilder::new(_fbb);
+      builder.add_type_(args.type_);
+      builder.add_private(args.private);
+      builder.add_is(args.is);
+      builder.finish()
+    }
+
+    pub fn unpack(&self) -> KeywordsInTableT {
+      let is = self.is();
+      let private = self.private();
+      let type_ = self.type_();
+      KeywordsInTableT {
+        is,
+        private,
+        type_,
+      }
+    }
+    pub const VT_IS: flatbuffers::VOffsetT = 4;
+    pub const VT_PRIVATE: flatbuffers::VOffsetT = 6;
+    pub const VT_TYPE_: flatbuffers::VOffsetT = 8;
+
+  #[inline]
+  pub fn is(&self) -> ABC {
+    self._tab.get::<ABC>(KeywordsInTable::VT_IS, Some(ABC::void)).unwrap()
+  }
+  #[inline]
+  pub fn private(&self) -> public {
+    self._tab.get::<public>(KeywordsInTable::VT_PRIVATE, Some(public::NONE)).unwrap()
+  }
+  #[inline]
+  pub fn type_(&self) -> i32 {
+    self._tab.get::<i32>(KeywordsInTable::VT_TYPE_, Some(0)).unwrap()
+  }
+}
+
+impl flatbuffers::Verifiable for KeywordsInTable<'_> {
+  #[inline]
+  fn run_verifier(
+    v: &mut flatbuffers::Verifier, pos: usize
+  ) -> Result<(), flatbuffers::InvalidFlatbuffer> {
+    use self::flatbuffers::Verifiable;
+    v.visit_table(pos)?
+     .visit_field::<ABC>("is", Self::VT_IS, false)?
+     .visit_field::<public>("private", Self::VT_PRIVATE, false)?
+     .visit_field::<i32>("type_", Self::VT_TYPE_, false)?
+     .finish();
+    Ok(())
+  }
+}
+pub struct KeywordsInTableArgs {
+    pub is: ABC,
+    pub private: public,
+    pub type_: i32,
+}
+impl<'a> Default for KeywordsInTableArgs {
+    #[inline]
+    fn default() -> Self {
+        KeywordsInTableArgs {
+            is: ABC::void,
+            private: public::NONE,
+            type_: 0,
+        }
+    }
+}
+pub struct KeywordsInTableBuilder<'a: 'b, 'b> {
+  fbb_: &'b mut flatbuffers::FlatBufferBuilder<'a>,
+  start_: flatbuffers::WIPOffset<flatbuffers::TableUnfinishedWIPOffset>,
+}
+impl<'a: 'b, 'b> KeywordsInTableBuilder<'a, 'b> {
+  #[inline]
+  pub fn add_is(&mut self, is: ABC) {
+    self.fbb_.push_slot::<ABC>(KeywordsInTable::VT_IS, is, ABC::void);
+  }
+  #[inline]
+  pub fn add_private(&mut self, private: public) {
+    self.fbb_.push_slot::<public>(KeywordsInTable::VT_PRIVATE, private, public::NONE);
+  }
+  #[inline]
+  pub fn add_type_(&mut self, type_: i32) {
+    self.fbb_.push_slot::<i32>(KeywordsInTable::VT_TYPE_, type_, 0);
+  }
+  #[inline]
+  pub fn new(_fbb: &'b mut flatbuffers::FlatBufferBuilder<'a>) -> KeywordsInTableBuilder<'a, 'b> {
+    let start = _fbb.start_table();
+    KeywordsInTableBuilder {
+      fbb_: _fbb,
+      start_: start,
+    }
+  }
+  #[inline]
+  pub fn finish(self) -> flatbuffers::WIPOffset<KeywordsInTable<'a>> {
+    let o = self.fbb_.end_table(self.start_);
+    flatbuffers::WIPOffset::new(o.value())
+  }
+}
+
+impl std::fmt::Debug for KeywordsInTable<'_> {
+  fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+    let mut ds = f.debug_struct("KeywordsInTable");
+      ds.field("is", &self.is());
+      ds.field("private", &self.private());
+      ds.field("type_", &self.type_());
+      ds.finish()
+  }
+}
+#[non_exhaustive]
+#[derive(Debug, Clone, PartialEq)]
+pub struct KeywordsInTableT {
+  pub is: ABC,
+  pub private: public,
+  pub type_: i32,
+}
+impl Default for KeywordsInTableT {
+  fn default() -> Self {
+    Self {
+      is: ABC::void,
+      private: public::NONE,
+      type_: 0,
+    }
+  }
+}
+impl KeywordsInTableT {
+  pub fn pack<'b>(
+    &self,
+    _fbb: &mut flatbuffers::FlatBufferBuilder<'b>
+  ) -> flatbuffers::WIPOffset<KeywordsInTable<'b>> {
+    let is = self.is;
+    let private = self.private;
+    let type_ = self.type_;
+    KeywordsInTable::create(_fbb, &KeywordsInTableArgs{
+      is,
+      private,
+      type_,
+    })
+  }
+}

tests/keyword_test/keywords_in_union_generated.rs

@@ -0,0 +1,170 @@
+// automatically generated by the FlatBuffers compiler, do not modify
+extern crate flatbuffers;
+use std::mem;
+use std::cmp::Ordering;
+use self::flatbuffers::{EndianScalar, Follow};
+use super::*;
+#[deprecated(since = "2.0.0", note = "Use associated constants instead. This will no longer be generated in 2021.")]
+pub const ENUM_MIN_KEYWORDS_IN_UNION: u8 = 0;
+#[deprecated(since = "2.0.0", note = "Use associated constants instead. This will no longer be generated in 2021.")]
+pub const ENUM_MAX_KEYWORDS_IN_UNION: u8 = 2;
+#[deprecated(since = "2.0.0", note = "Use associated constants instead. This will no longer be generated in 2021.")]
+#[allow(non_camel_case_types)]
+pub const ENUM_VALUES_KEYWORDS_IN_UNION: [KeywordsInUnion; 3] = [
+  KeywordsInUnion::NONE,
+  KeywordsInUnion::static_,
+  KeywordsInUnion::internal,
+];
+
+#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Default)]
+#[repr(transparent)]
+pub struct KeywordsInUnion(pub u8);
+#[allow(non_upper_case_globals)]
+impl KeywordsInUnion {
+  pub const NONE: Self = Self(0);
+  pub const static_: Self = Self(1);
+  pub const internal: Self = Self(2);
+
+  pub const ENUM_MIN: u8 = 0;
+  pub const ENUM_MAX: u8 = 2;
+  pub const ENUM_VALUES: &'static [Self] = &[
+    Self::NONE,
+    Self::static_,
+    Self::internal,
+  ];
+  /// Returns the variant's name or "" if unknown.
+  pub fn variant_name(self) -> Option<&'static str> {
+    match self {
+      Self::NONE => Some("NONE"),
+      Self::static_ => Some("static_"),
+      Self::internal => Some("internal"),
+      _ => None,
+    }
+  }
+}
+impl std::fmt::Debug for KeywordsInUnion {
+  fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+    if let Some(name) = self.variant_name() {
+      f.write_str(name)
+    } else {
+      f.write_fmt(format_args!("<UNKNOWN {:?}>", self.0))
+    }
+  }
+}
+impl<'a> flatbuffers::Follow<'a> for KeywordsInUnion {
+  type Inner = Self;
+  #[inline]
+  fn follow(buf: &'a [u8], loc: usize) -> Self::Inner {
+    let b = unsafe {
+      flatbuffers::read_scalar_at::<u8>(buf, loc)
+    };
+    Self(b)
+  }
+}
+
+impl flatbuffers::Push for KeywordsInUnion {
+    type Output = KeywordsInUnion;
+    #[inline]
+    fn push(&self, dst: &mut [u8], _rest: &[u8]) {
+        unsafe { flatbuffers::emplace_scalar::<u8>(dst, self.0); }
+    }
+}
+
+impl flatbuffers::EndianScalar for KeywordsInUnion {
+  #[inline]
+  fn to_little_endian(self) -> Self {
+    let b = u8::to_le(self.0);
+    Self(b)
+  }
+  #[inline]
+  #[allow(clippy::wrong_self_convention)]
+  fn from_little_endian(self) -> Self {
+    let b = u8::from_le(self.0);
+    Self(b)
+  }
+}
+
+impl<'a> flatbuffers::Verifiable for KeywordsInUnion {
+  #[inline]
+  fn run_verifier(
+    v: &mut flatbuffers::Verifier, pos: usize
+  ) -> Result<(), flatbuffers::InvalidFlatbuffer> {
+    use self::flatbuffers::Verifiable;
+    u8::run_verifier(v, pos)
+  }
+}
+
+impl flatbuffers::SimpleToVerifyInSlice for KeywordsInUnion {}
+pub struct KeywordsInUnionUnionTableOffset {}
+
+#[allow(clippy::upper_case_acronyms)]
+#[non_exhaustive]
+#[derive(Debug, Clone, PartialEq)]
+pub enum KeywordsInUnionT {
+  NONE,
+  Static_(Box<KeywordsInTableT>),
+  Internal(Box<KeywordsInTableT>),
+}
+impl Default for KeywordsInUnionT {
+  fn default() -> Self {
+    Self::NONE
+  }
+}
+impl KeywordsInUnionT {
+  pub fn keywords_in_union_type(&self) -> KeywordsInUnion {
+    match self {
+      Self::NONE => KeywordsInUnion::NONE,
+      Self::Static_(_) => KeywordsInUnion::static_,
+      Self::Internal(_) => KeywordsInUnion::internal,
+    }
+  }
+  pub fn pack(&self, fbb: &mut flatbuffers::FlatBufferBuilder) -> Option<flatbuffers::WIPOffset<flatbuffers::UnionWIPOffset>> {
+    match self {
+      Self::NONE => None,
+      Self::Static_(v) => Some(v.pack(fbb).as_union_value()),
+      Self::Internal(v) => Some(v.pack(fbb).as_union_value()),
+    }
+  }
+  /// If the union variant matches, return the owned KeywordsInTableT, setting the union to NONE.
+  pub fn take_static_(&mut self) -> Option<Box<KeywordsInTableT>> {
+    if let Self::Static_(_) = self {
+      let v = std::mem::replace(self, Self::NONE);
+      if let Self::Static_(w) = v {
+        Some(w)
+      } else {
+        unreachable!()
+      }
+    } else {
+      None
+    }
+  }
+  /// If the union variant matches, return a reference to the KeywordsInTableT.
+  pub fn as_static_(&self) -> Option<&KeywordsInTableT> {
+    if let Self::Static_(v) = self { Some(v.as_ref()) } else { None }
+  }
+  /// If the union variant matches, return a mutable reference to the KeywordsInTableT.
+  pub fn as_static__mut(&mut self) -> Option<&mut KeywordsInTableT> {
+    if let Self::Static_(v) = self { Some(v.as_mut()) } else { None }
+  }
+  /// If the union variant matches, return the owned KeywordsInTableT, setting the union to NONE.
+  pub fn take_internal(&mut self) -> Option<Box<KeywordsInTableT>> {
+    if let Self::Internal(_) = self {
+      let v = std::mem::replace(self, Self::NONE);
+      if let Self::Internal(w) = v {
+        Some(w)
+      } else {
+        unreachable!()
+      }
+    } else {
+      None
+    }
+  }
+  /// If the union variant matches, return a reference to the KeywordsInTableT.
+  pub fn as_internal(&self) -> Option<&KeywordsInTableT> {
+    if let Self::Internal(v) = self { Some(v.as_ref()) } else { None }
+  }
+  /// If the union variant matches, return a mutable reference to the KeywordsInTableT.
+  pub fn as_internal_mut(&mut self) -> Option<&mut KeywordsInTableT> {
+    if let Self::Internal(v) = self { Some(v.as_mut()) } else { None }
+  }
+}

tests/keyword_test/mod.rs

@@ -0,0 +1,9 @@
+// Automatically generated by the Flatbuffers compiler. Do not modify.
+mod abc_generated;
+pub use self::abc_generated::*;
+mod public_generated;
+pub use self::public_generated::*;
+mod keywords_in_union_generated;
+pub use self::keywords_in_union_generated::*;
+mod keywords_in_table_generated;
+pub use self::keywords_in_table_generated::*;

tests/keyword_test/public_generated.rs

@@ -0,0 +1,89 @@
+// automatically generated by the FlatBuffers compiler, do not modify
+extern crate flatbuffers;
+use std::mem;
+use std::cmp::Ordering;
+use self::flatbuffers::{EndianScalar, Follow};
+use super::*;
+#[deprecated(since = "2.0.0", note = "Use associated constants instead. This will no longer be generated in 2021.")]
+pub const ENUM_MIN_PUBLIC: i32 = 0;
+#[deprecated(since = "2.0.0", note = "Use associated constants instead. This will no longer be generated in 2021.")]
+pub const ENUM_MAX_PUBLIC: i32 = 0;
+#[deprecated(since = "2.0.0", note = "Use associated constants instead. This will no longer be generated in 2021.")]
+#[allow(non_camel_case_types)]
+pub const ENUM_VALUES_PUBLIC: [public; 1] = [
+  public::NONE,
+];
+
+#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Default)]
+#[repr(transparent)]
+pub struct public(pub i32);
+#[allow(non_upper_case_globals)]
+impl public {
+  pub const NONE: Self = Self(0);
+
+  pub const ENUM_MIN: i32 = 0;
+  pub const ENUM_MAX: i32 = 0;
+  pub const ENUM_VALUES: &'static [Self] = &[
+    Self::NONE,
+  ];
+  /// Returns the variant's name or "" if unknown.
+  pub fn variant_name(self) -> Option<&'static str> {
+    match self {
+      Self::NONE => Some("NONE"),
+      _ => None,
+    }
+  }
+}
+impl std::fmt::Debug for public {
+  fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+    if let Some(name) = self.variant_name() {
+      f.write_str(name)
+    } else {
+      f.write_fmt(format_args!("<UNKNOWN {:?}>", self.0))
+    }
+  }
+}
+impl<'a> flatbuffers::Follow<'a> for public {
+  type Inner = Self;
+  #[inline]
+  fn follow(buf: &'a [u8], loc: usize) -> Self::Inner {
+    let b = unsafe {
+      flatbuffers::read_scalar_at::<i32>(buf, loc)
+    };
+    Self(b)
+  }
+}
+
+impl flatbuffers::Push for public {
+    type Output = public;
+    #[inline]
+    fn push(&self, dst: &mut [u8], _rest: &[u8]) {
+        unsafe { flatbuffers::emplace_scalar::<i32>(dst, self.0); }
+    }
+}
+
+impl flatbuffers::EndianScalar for public {
+  #[inline]
+  fn to_little_endian(self) -> Self {
+    let b = i32::to_le(self.0);
+    Self(b)
+  }
+  #[inline]
+  #[allow(clippy::wrong_self_convention)]
+  fn from_little_endian(self) -> Self {
+    let b = i32::from_le(self.0);
+    Self(b)
+  }
+}
+
+impl<'a> flatbuffers::Verifiable for public {
+  #[inline]
+  fn run_verifier(
+    v: &mut flatbuffers::Verifier, pos: usize
+  ) -> Result<(), flatbuffers::InvalidFlatbuffer> {
+    use self::flatbuffers::Verifiable;
+    i32::run_verifier(v, pos)
+  }
+}
+
+impl flatbuffers::SimpleToVerifyInSlice for public {}

tests/keyword_test/type.cs

@@ -0,0 +1,10 @@
+// <auto-generated>
+//  automatically generated by the FlatBuffers compiler, do not modify
+// </auto-generated>
+
+[Newtonsoft.Json.JsonConverter(typeof(Newtonsoft.Json.Converters.StringEnumConverter))]
+public enum type : sbyte
+{
+  NONE = 0,
+};
+

tests/keyword_test/type_generated.rs

@@ -0,0 +1,89 @@
+// automatically generated by the FlatBuffers compiler, do not modify
+extern crate flatbuffers;
+use std::mem;
+use std::cmp::Ordering;
+use self::flatbuffers::{EndianScalar, Follow};
+use super::*;
+#[deprecated(since = "2.0.0", note = "Use associated constants instead. This will no longer be generated in 2021.")]
+pub const ENUM_MIN_TYPE_: i8 = 0;
+#[deprecated(since = "2.0.0", note = "Use associated constants instead. This will no longer be generated in 2021.")]
+pub const ENUM_MAX_TYPE_: i8 = 0;
+#[deprecated(since = "2.0.0", note = "Use associated constants instead. This will no longer be generated in 2021.")]
+#[allow(non_camel_case_types)]
+pub const ENUM_VALUES_TYPE_: [type_; 1] = [
+  type_::NONE,
+];
+
+#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Default)]
+#[repr(transparent)]
+pub struct type_(pub i8);
+#[allow(non_upper_case_globals)]
+impl type_ {
+  pub const NONE: Self = Self(0);
+
+  pub const ENUM_MIN: i8 = 0;
+  pub const ENUM_MAX: i8 = 0;
+  pub const ENUM_VALUES: &'static [Self] = &[
+    Self::NONE,
+  ];
+  /// Returns the variant's name or "" if unknown.
+  pub fn variant_name(self) -> Option<&'static str> {
+    match self {
+      Self::NONE => Some("NONE"),
+      _ => None,
+    }
+  }
+}
+impl std::fmt::Debug for type_ {
+  fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+    if let Some(name) = self.variant_name() {
+      f.write_str(name)
+    } else {
+      f.write_fmt(format_args!("<UNKNOWN {:?}>", self.0))
+    }
+  }
+}
+impl<'a> flatbuffers::Follow<'a> for type_ {
+  type Inner = Self;
+  #[inline]
+  fn follow(buf: &'a [u8], loc: usize) -> Self::Inner {
+    let b = unsafe {
+      flatbuffers::read_scalar_at::<i8>(buf, loc)
+    };
+    Self(b)
+  }
+}
+
+impl flatbuffers::Push for type_ {
+    type Output = type_;
+    #[inline]
+    fn push(&self, dst: &mut [u8], _rest: &[u8]) {
+        unsafe { flatbuffers::emplace_scalar::<i8>(dst, self.0); }
+    }
+}
+
+impl flatbuffers::EndianScalar for type_ {
+  #[inline]
+  fn to_little_endian(self) -> Self {
+    let b = i8::to_le(self.0);
+    Self(b)
+  }
+  #[inline]
+  #[allow(clippy::wrong_self_convention)]
+  fn from_little_endian(self) -> Self {
+    let b = i8::from_le(self.0);
+    Self(b)
+  }
+}
+
+impl<'a> flatbuffers::Verifiable for type_ {
+  #[inline]
+  fn run_verifier(
+    v: &mut flatbuffers::Verifier, pos: usize
+  ) -> Result<(), flatbuffers::InvalidFlatbuffer> {
+    use self::flatbuffers::Verifiable;
+    i8::run_verifier(v, pos)
+  }
+}
+
+impl flatbuffers::SimpleToVerifyInSlice for type_ {}

tests/rust_usage_test/tests/integration_test.rs

@@ -57,6 +57,10 @@ mod optional_scalars_generated;
 #[path = "../../arrays_test/mod.rs"]
 mod arrays_test_generated;
 
+#[allow(dead_code, unused_imports)]
+#[path = "../../keyword_test/mod.rs"]
+mod keyword_test_generated;
+
 #[rustfmt::skip] // TODO: Use standard rust formatting and remove dead code.
 #[allow(dead_code)]
 mod flatbuffers_tests {