       1
       2
       3
       4
       5
       6
       7
       8
       9
      10
      11
      12
      13
      14
      15
      16
      17
      18
      19
      20
      21
      22
      23
      24
      25
      26
      27
      28
      29
      30
      31
      32
      33
      34
      35
      36
      37
      38
      39
      40
      41
      42
      43
      44
      45
      46
      47
      48
      49
      50
      51
      52
      53
      54
      55
      56
      57
      58
      59
      60
      61
      62
      63
      64
      65
      66
      67
      68
      69
      70
      71
      72
      73
      74
      75
      76
      77
      78
      79
      80
      81
      82
      83
      84
      85
      86
      87
      88
      89
      90
      91
      92
      93
      94
      95
      96
      97
      98
      99
     100
     101
     102
     103
     104
     105
     106
     107
     108
     109
     110
     111
     112
     113
     114
     115
     116
     117
     118
     119
     120
     121
     122
     123
     124
     125
     126
     127
     128
     129
     130
     131
     132
     133
     134
     135
     136
     137
     138
     139
     140
     141
     142
     143
     144
     145
     146
     147
     148
     149
     150
     151
     152
     153
     154
     155
     156
     157
     158
     159
     160
     161
     162
     163
     164
     165
     166
     167
     168
     169
     170
     171
     172
     173
     174
     175
     176
     177
     178
     179
     180
     181
     182
     183
     184
     185
     186
     187
     188
     189
     190
     191
     192
     193
     194
     195
     196
     197
     198
     199
     200
     201
     202
     203
     204
     205
     206
     207
     208
     209
     210
     211
     212
     213
     214
     215
     216
     217
     218
     219
     220
     221
     222
     223
     224
     225
     226
     227
     228
     229
     230
     231
     232
     233
     234
     235
     236
     237
     238
     239
     240
     241
     242
     243
     244
     245
     246
     247
     248
     249
     250
     251
     252
     253
     254
     255
     256
     257
     258
     259
     260
     261
     262
     263
     264
     265
     266
     267
     268
     269
     270
     271
     272
     273
     274
     275
     276
     277
     278
     279
     280
     281
     282
     283
     284
     285
     286
     287
     288
     289
     290
     291
     292
     293
     294
     295
     296
     297
     298
     299
     300
     301
     302
     303
     304
     305
     306
     307
     308
     309
     310
     311
     312
     313
     314
     315
     316
     317
     318
     319
     320
     321
     322
     323
     324
     325
     326
     327
     328
     329
     330
     331
     332
     333
     334
     335
     336
     337
     338
     339
     340
     341
     342
     343
     344
     345
     346
     347
     348
     349
     350
     351
     352
     353
     354
     355
     356
     357
     358
     359
     360
     361
     362
     363
     364
     365
     366
     367
     368
     369
     370
     371
     372
     373
     374
     375
     376
     377
     378
     379
     380
     381
     382
     383
     384
     385
     386
     387
     388
     389
     390
     391
     392
     393
     394
     395
     396
     397
     398
     399
     400
     401
     402
     403
     404
     405
     406
     407
     408
     409
     410
     411
     412
     413
     414
     415
     416
     417
     418
     419
     420
     421
     422
     423
     424
     425
     426
     427
     428
     429
     430
     431
     432
     433
     434
     435
     436
     437
     438
     439
     440
     441
     442
     443
     444
     445
     446
     447
     448
     449
     450
     451
     452
     453
     454
     455
     456
     457
     458
     459
     460
     461
     462
     463
     464
     465
     466
     467
     468
     469
     470
     471
     472
     473
     474
     475
     476
     477
     478
     479
     480
     481
     482
     483
     484
     485
     486
     487
     488
     489
     490
     491
     492
     493
     494
     495
     496
     497
     498
     499
     500
     501
     502
     503
     504
     505
     506
     507
     508
     509
     510
     511
     512
     513
     514
     515
     516
     517
     518
     519
     520
     521
     522
     523
     524
     525
     526
     527
     528
     529
     530
     531
     532
     533
     534
     535
     536
     537
     538
     539
     540
     541
     542
     543
     544
     545
     546
     547
     548
     549
     550
     551
     552
     553
     554
     555
     556
     557
     558
     559
     560
     561
     562
     563
     564
     565
     566
     567
     568
     569
     570
     571
     572
     573
     574
     575
     576
     577
     578
     579
     580
     581
     582
     583
     584
     585
     586
     587
     588
     589
     590
     591
     592
     593
     594
     595
     596
     597
     598
     599
     600
     601
     602
     603
     604
     605
     606
     607
     608
     609
     610
     611
     612
     613
     614
     615
     616
     617
     618
     619
     620
     621
     622
     623
     624
     625
     626
     627
     628
     629
     630
     631
     632
     633
     634
     635
     636
     637
     638
     639
     640
     641
     642
     643
     644
     645
     646
     647
     648
     649
     650
     651
     652
     653
     654
     655
     656
     657
     658
     659
     660
     661
     662
     663
     664
     665
     666
     667
     668
     669
     670
     671
     672
     673
     674
     675
     676
     677
     678
     679
     680
     681
     682
     683
     684
     685
     686
     687
     688
     689
     690
     691
     692
     693
     694
     695
     696
     697
     698
     699
     700
     701
     702
     703
     704
     705
     706
     707
     708
     709
     710
     711
     712
     713
     714
     715
     716
     717
     718
     719
     720
     721
     722
     723
     724
     725
     726
     727
     728
     729
     730
     731
     732
     733
     734
     735
     736
     737
     738
     739
     740
     741
     742
     743
     744
     745
     746
     747
     748
     749
     750
     751
     752
     753
     754
     755
     756
     757
     758
     759
     760
     761
     762
     763
     764
     765
     766
     767
     768
     769
     770
     771
     772
     773
     774
     775
     776
     777
     778
     779
     780
     781
     782
     783
     784
     785
     786
     787
     788
     789
     790
     791
     792
     793
     794
     795
     796
     797
     798
     799
     800
     801
     802
     803
     804
     805
     806
     807
     808
     809
     810
     811
     812
     813
     814
     815
     816
     817
     818
     819
     820
     821
     822
     823
     824
     825
     826
     827
     828
     829
     830
     831
     832
     833
     834
     835
     836
     837
     838
     839
     840
     841
     842
     843
     844
     845
     846
     847
     848
     849
     850
     851
     852
     853
     854
     855
     856
     857
     858
     859
     860
     861
     862
     863
     864
     865
     866
     867
     868
     869
     870
     871
     872
     873
     874
     875
     876
     877
     878
     879
     880
     881
     882
     883
     884
     885
     886
     887
     888
     889
     890
     891
     892
     893
     894
     895
     896
     897
     898
     899
     900
     901
     902
     903
     904
     905
     906
     907
     908
     909
     910
     911
     912
     913
     914
     915
     916
     917
     918
     919
     920
     921
     922
     923
     924
     925
     926
     927
     928
     929
     930
     931
     932
     933
     934
     935
     936
     937
     938
     939
     940
     941
     942
     943
     944
     945
     946
     947
     948
     949
     950
     951
     952
     953
     954
     955
     956
     957
     958
     959
     960
     961
     962
     963
     964
     965
     966
     967
     968
     969
     970
     971
     972
     973
     974
     975
     976
     977
     978
     979
     980
     981
     982
     983
     984
     985
     986
     987
     988
     989
     990
     991
     992
     993
     994
     995
     996
     997
     998
     999
    1000
    1001
    1002
    1003
    1004
    1005
    1006
    1007
    1008
    1009
    1010
    1011
    1012
    1013
    1014
    1015
    1016
    1017
    1018
    1019
    1020
    1021
    1022
    1023
    1024
    1025
    1026
    1027
    1028
    1029
    1030
    1031
    1032
    1033
    1034
    1035
    1036
    1037
    1038
    1039
    1040
    1041
    1042
    1043
    1044
    1045
    1046
    1047
    1048
    1049
    1050
    1051
    1052
    1053
    1054
    1055
    1056
    1057
    1058
    1059
    1060
    1061
    1062
    1063
    1064
    1065
    1066
    1067
    1068
    1069
    1070
    1071
    1072
    1073
    1074
    1075
    1076
    1077
    1078
    1079
    1080
    1081
    1082
    1083
    1084
    1085
    1086
    1087
    1088
    1089
    1090
    1091
    1092
    1093
    1094
    1095
    1096
    1097
    1098
    1099
    1100
    1101
    1102
    1103
    1104
    1105
    1106
    1107
    1108
    1109
    1110
    1111
    1112
    1113
    1114
    1115
    1116
    1117
    1118
    1119
    1120
    1121
    1122
    1123
    1124
    1125
    1126
    1127
    1128
    1129
    1130
    1131
    1132
    1133
    1134
    1135
    1136
    1137
    1138
    1139
    1140
    1141
    1142
    1143
    1144
    1145
    1146
    1147
    1148
    1149
    1150
    1151
    1152
    1153
    1154
    1155
    1156
    1157
    1158
    1159
    1160
    1161
    1162
    1163
    1164
    1165
    1166
    1167
    1168
    1169
    1170
    1171
    1172
    1173
    1174
    1175
    1176
    1177
    1178
    1179
    1180
    1181
    1182
    1183
    1184
    1185
    1186
    1187
    1188
    1189
    1190
    1191
    1192
    1193
    1194
    1195
    1196
    1197
    1198
    1199
    1200
    1201
    1202
    1203
    1204
    1205
    1206
    1207
    1208
    1209
    1210
    1211
    1212
    1213
    1214
    1215
    1216
    1217
    1218
    1219
    1220
    1221
    1222
    1223
    1224
    1225
    1226
    1227
    1228
    1229
    1230
    1231
    1232
    1233
    1234

    //! A wrapper around the procedural macro API of the compiler's [`proc_macro`]
    //! crate. This library serves two purposes:
    //!
    //! [`proc_macro`]: https://doc.rust-lang.org/proc_macro/
    //!
    //! - **Bring proc-macro-like functionality to other contexts like build.rs and
    //!   main.rs.** Types from `proc_macro` are entirely specific to procedural
    //!   macros and cannot ever exist in code outside of a procedural macro.
    //!   Meanwhile `proc_macro2` types may exist anywhere including non-macro code.
    //!   By developing foundational libraries like [syn] and [quote] against
    //!   `proc_macro2` rather than `proc_macro`, the procedural macro ecosystem
    //!   becomes easily applicable to many other use cases and we avoid
    //!   reimplementing non-macro equivalents of those libraries.
    //!
    //! - **Make procedural macros unit testable.** As a consequence of being
    //!   specific to procedural macros, nothing that uses `proc_macro` can be
    //!   executed from a unit test. In order for helper libraries or components of
    //!   a macro to be testable in isolation, they must be implemented using
    //!   `proc_macro2`.
    //!
    //! [syn]: https://github.com/dtolnay/syn
    //! [quote]: https://github.com/dtolnay/quote
    //!
    //! # Usage
    //!
    //! The skeleton of a typical procedural macro typically looks like this:
    //!
    //! ```
    //! extern crate proc_macro;
    //!
    //! # const IGNORE: &str = stringify! {
    //! #[proc_macro_derive(MyDerive)]
    //! # };
    //! # #[cfg(wrap_proc_macro)]
    //! pub fn my_derive(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
    //!     let input = proc_macro2::TokenStream::from(input);
    //!
    //!     let output: proc_macro2::TokenStream = {
    //!         /* transform input */
    //!         # input
    //!     };
    //!
    //!     proc_macro::TokenStream::from(output)
    //! }
    //! ```
    //!
    //! If parsing with [Syn], you'll use [`parse_macro_input!`] instead to
    //! propagate parse errors correctly back to the compiler when parsing fails.
    //!
    //! [`parse_macro_input!`]: https://docs.rs/syn/1.0/syn/macro.parse_macro_input.html
    //!
    //! # Unstable features
    //!
    //! The default feature set of proc-macro2 tracks the most recent stable
    //! compiler API. Functionality in `proc_macro` that is not yet stable is not
    //! exposed by proc-macro2 by default.
    //!
    //! To opt into the additional APIs available in the most recent nightly
    //! compiler, the `procmacro2_semver_exempt` config flag must be passed to
    //! rustc. We will polyfill those nightly-only APIs back to Rust 1.31.0. As
    //! these are unstable APIs that track the nightly compiler, minor versions of
    //! proc-macro2 may make breaking changes to them at any time.
    //!
    //! ```sh
    //! RUSTFLAGS='--cfg procmacro2_semver_exempt' cargo build
    //! ```
    //!
    //! Note that this must not only be done for your crate, but for any crate that
    //! depends on your crate. This infectious nature is intentional, as it serves
    //! as a reminder that you are outside of the normal semver guarantees.
    //!
    //! Semver exempt methods are marked as such in the proc-macro2 documentation.
    //!
    //! # Thread-Safety
    //!
    //! Most types in this crate are `!Sync` because the underlying compiler
    //! types make use of thread-local memory, meaning they cannot be accessed from
    //! a different thread.

    // Proc-macro2 types in rustdoc of other crates get linked to here.
    #![doc(html_root_url = "https://docs.rs/proc-macro2/1.0.24")]
    #![cfg_attr(any(proc_macro_span, super_unstable), feature(proc_macro_span))]
    #![cfg_attr(super_unstable, feature(proc_macro_raw_ident, proc_macro_def_site))]
    #![allow(clippy::needless_doctest_main)]

    #[cfg(use_proc_macro)]
    extern crate proc_macro;

    mod marker;
    mod parse;

    #[cfg(wrap_proc_macro)]
    mod detection;

    // Public for proc_macro2::fallback::force() and unforce(), but those are quite
    // a niche use case so we omit it from rustdoc.
    #[doc(hidden)]
    pub mod fallback;

    #[cfg(not(wrap_proc_macro))]
    use crate::fallback as imp;
    #[path = "wrapper.rs"]
    #[cfg(wrap_proc_macro)]
    mod imp;

    use crate::marker::Marker;
    use std::cmp::Ordering;
    use std::error::Error;
    use std::fmt::{self, Debug, Display};
    use std::hash::{Hash, Hasher};
    use std::iter::FromIterator;
    use std::ops::RangeBounds;
    #[cfg(procmacro2_semver_exempt)]
    use std::path::PathBuf;
    use std::str::FromStr;

    /// An abstract stream of tokens, or more concretely a sequence of token trees.
    ///
    /// This type provides interfaces for iterating over token trees and for
    /// collecting token trees into one stream.
    ///
    /// Token stream is both the input and output of `#[proc_macro]`,
    /// `#[proc_macro_attribute]` and `#[proc_macro_derive]` definitions.
    #[derive(Clone)]
    pub struct TokenStream {
        inner: imp::TokenStream,
        _marker: Marker,
    }

    /// Error returned from `TokenStream::from_str`.
    pub struct LexError {
        inner: imp::LexError,
        _marker: Marker,
    }

    impl TokenStream {
        fn _new(inner: imp::TokenStream) -> TokenStream {
            TokenStream {
                inner,
                _marker: Marker,
            }
        }

        fn _new_stable(inner: fallback::TokenStream) -> TokenStream {
            TokenStream {
                inner: inner.into(),
                _marker: Marker,
            }
        }

        /// Returns an empty `TokenStream` containing no token trees.
        pub fn new() -> TokenStream {
            TokenStream::_new(imp::TokenStream::new())
        }

        /// Checks if this `TokenStream` is empty.
        pub fn is_empty(&self) -> bool {
            self.inner.is_empty()
        }
    }

    /// `TokenStream::default()` returns an empty stream,
    /// i.e. this is equivalent with `TokenStream::new()`.
    impl Default for TokenStream {
        fn default() -> Self {
            TokenStream::new()
        }
    }

    /// Attempts to break the string into tokens and parse those tokens into a token
    /// stream.
    ///
    /// May fail for a number of reasons, for example, if the string contains
    /// unbalanced delimiters or characters not existing in the language.
    ///
    /// NOTE: Some errors may cause panics instead of returning `LexError`. We
    /// reserve the right to change these errors into `LexError`s later.
    impl FromStr for TokenStream {
        type Err = LexError;

        fn from_str(src: &str) -> Result<TokenStream, LexError> {
            let e = src.parse().map_err(|e| LexError {
                inner: e,
                _marker: Marker,
            })?;
            Ok(TokenStream::_new(e))
        }
    }

    #[cfg(use_proc_macro)]
    impl From<proc_macro::TokenStream> for TokenStream {
        fn from(inner: proc_macro::TokenStream) -> TokenStream {
            TokenStream::_new(inner.into())
        }
    }

    #[cfg(use_proc_macro)]
    impl From<TokenStream> for proc_macro::TokenStream {
        fn from(inner: TokenStream) -> proc_macro::TokenStream {
            inner.inner.into()
        }
    }

    impl From<TokenTree> for TokenStream {
        fn from(token: TokenTree) -> Self {
            TokenStream::_new(imp::TokenStream::from(token))
        }
    }

    impl Extend<TokenTree> for TokenStream {
        fn extend<I: IntoIterator<Item = TokenTree>>(&mut self, streams: I) {
            self.inner.extend(streams)
        }
    }

    impl Extend<TokenStream> for TokenStream {
        fn extend<I: IntoIterator<Item = TokenStream>>(&mut self, streams: I) {
            self.inner
                .extend(streams.into_iter().map(|stream| stream.inner))
        }
    }

    /// Collects a number of token trees into a single stream.
    impl FromIterator<TokenTree> for TokenStream {
        fn from_iter<I: IntoIterator<Item = TokenTree>>(streams: I) -> Self {
            TokenStream::_new(streams.into_iter().collect())
        }
    }
    impl FromIterator<TokenStream> for TokenStream {
        fn from_iter<I: IntoIterator<Item = TokenStream>>(streams: I) -> Self {
            TokenStream::_new(streams.into_iter().map(|i| i.inner).collect())
        }
    }

    /// Prints the token stream as a string that is supposed to be losslessly
    /// convertible back into the same token stream (modulo spans), except for
    /// possibly `TokenTree::Group`s with `Delimiter::None` delimiters and negative
    /// numeric literals.
    impl Display for TokenStream {
        fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
            Display::fmt(&self.inner, f)
        }
    }

    /// Prints token in a form convenient for debugging.
    impl Debug for TokenStream {
        fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
            Debug::fmt(&self.inner, f)
        }
    }

    impl Debug for LexError {
        fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
            Debug::fmt(&self.inner, f)
        }
    }

    impl Display for LexError {
        fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
            Display::fmt(&self.inner, f)
        }
    }

    impl Error for LexError {}

    /// The source file of a given `Span`.
    ///
    /// This type is semver exempt and not exposed by default.
    #[cfg(procmacro2_semver_exempt)]
    #[derive(Clone, PartialEq, Eq)]
    pub struct SourceFile {
        inner: imp::SourceFile,
        _marker: Marker,
    }

    #[cfg(procmacro2_semver_exempt)]
    impl SourceFile {
        fn _new(inner: imp::SourceFile) -> Self {
            SourceFile {
                inner,
                _marker: Marker,
            }
        }

        /// Get the path to this source file.
        ///
        /// ### Note
        ///
        /// If the code span associated with this `SourceFile` was generated by an
        /// external macro, this may not be an actual path on the filesystem. Use
        /// [`is_real`] to check.
        ///
        /// Also note that even if `is_real` returns `true`, if
        /// `--remap-path-prefix` was passed on the command line, the path as given
        /// may not actually be valid.
        ///
        /// [`is_real`]: #method.is_real
        pub fn path(&self) -> PathBuf {
            self.inner.path()
        }

        /// Returns `true` if this source file is a real source file, and not
        /// generated by an external macro's expansion.
        pub fn is_real(&self) -> bool {
            self.inner.is_real()
        }
    }

    #[cfg(procmacro2_semver_exempt)]
    impl Debug for SourceFile {
        fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
            Debug::fmt(&self.inner, f)
        }
    }

    /// A line-column pair representing the start or end of a `Span`.
    ///
    /// This type is semver exempt and not exposed by default.
    #[cfg(span_locations)]
    #[derive(Copy, Clone, Debug, PartialEq, Eq)]
    pub struct LineColumn {
        /// The 1-indexed line in the source file on which the span starts or ends
        /// (inclusive).
        pub line: usize,
        /// The 0-indexed column (in UTF-8 characters) in the source file on which
        /// the span starts or ends (inclusive).
        pub column: usize,
    }

    #[cfg(span_locations)]
    impl Ord for LineColumn {
        fn cmp(&self, other: &Self) -> Ordering {
            self.line
                .cmp(&other.line)
                .then(self.column.cmp(&other.column))
        }
    }

    #[cfg(span_locations)]
    impl PartialOrd for LineColumn {
        fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
            Some(self.cmp(other))
        }
    }

    /// A region of source code, along with macro expansion information.
    #[derive(Copy, Clone)]
    pub struct Span {
        inner: imp::Span,
        _marker: Marker,
    }

    impl Span {
        fn _new(inner: imp::Span) -> Span {
            Span {
                inner,
                _marker: Marker,
            }
        }

        fn _new_stable(inner: fallback::Span) -> Span {
            Span {
                inner: inner.into(),
                _marker: Marker,
            }
        }

        /// The span of the invocation of the current procedural macro.
        ///
        /// Identifiers created with this span will be resolved as if they were
        /// written directly at the macro call location (call-site hygiene) and
        /// other code at the macro call site will be able to refer to them as well.
        pub fn call_site() -> Span {
            Span::_new(imp::Span::call_site())
        }

        /// The span located at the invocation of the procedural macro, but with
        /// local variables, labels, and `$crate` resolved at the definition site
        /// of the macro. This is the same hygiene behavior as `macro_rules`.
        ///
        /// This function requires Rust 1.45 or later.
        #[cfg(hygiene)]
        pub fn mixed_site() -> Span {
            Span::_new(imp::Span::mixed_site())
        }

        /// A span that resolves at the macro definition site.
        ///
        /// This method is semver exempt and not exposed by default.
        #[cfg(procmacro2_semver_exempt)]
        pub fn def_site() -> Span {
            Span::_new(imp::Span::def_site())
        }

        /// Creates a new span with the same line/column information as `self` but
        /// that resolves symbols as though it were at `other`.
        pub fn resolved_at(&self, other: Span) -> Span {
            Span::_new(self.inner.resolved_at(other.inner))
        }

        /// Creates a new span with the same name resolution behavior as `self` but
        /// with the line/column information of `other`.
        pub fn located_at(&self, other: Span) -> Span {
            Span::_new(self.inner.located_at(other.inner))
        }

        /// Convert `proc_macro2::Span` to `proc_macro::Span`.
        ///
        /// This method is available when building with a nightly compiler, or when
        /// building with rustc 1.29+ *without* semver exempt features.
        ///
        /// # Panics
        ///
        /// Panics if called from outside of a procedural macro. Unlike
        /// `proc_macro2::Span`, the `proc_macro::Span` type can only exist within
        /// the context of a procedural macro invocation.
        #[cfg(wrap_proc_macro)]
        pub fn unwrap(self) -> proc_macro::Span {
            self.inner.unwrap()
        }

        // Soft deprecated. Please use Span::unwrap.
        #[cfg(wrap_proc_macro)]
        #[doc(hidden)]
        pub fn unstable(self) -> proc_macro::Span {
            self.unwrap()
        }

        /// The original source file into which this span points.
        ///
        /// This method is semver exempt and not exposed by default.
        #[cfg(procmacro2_semver_exempt)]
        pub fn source_file(&self) -> SourceFile {
            SourceFile::_new(self.inner.source_file())
        }

        /// Get the starting line/column in the source file for this span.
        ///
        /// This method requires the `"span-locations"` feature to be enabled.
        #[cfg(span_locations)]
        pub fn start(&self) -> LineColumn {
            let imp::LineColumn { line, column } = self.inner.start();
            LineColumn { line, column }
        }

        /// Get the ending line/column in the source file for this span.
        ///
        /// This method requires the `"span-locations"` feature to be enabled.
        #[cfg(span_locations)]
        pub fn end(&self) -> LineColumn {
            let imp::LineColumn { line, column } = self.inner.end();
            LineColumn { line, column }
        }

        /// Create a new span encompassing `self` and `other`.
        ///
        /// Returns `None` if `self` and `other` are from different files.
        ///
        /// Warning: the underlying [`proc_macro::Span::join`] method is
        /// nightly-only. When called from within a procedural macro not using a
        /// nightly compiler, this method will always return `None`.
        ///
        /// [`proc_macro::Span::join`]: https://doc.rust-lang.org/proc_macro/struct.Span.html#method.join
        pub fn join(&self, other: Span) -> Option<Span> {
            self.inner.join(other.inner).map(Span::_new)
        }

        /// Compares two spans to see if they're equal.
        ///
        /// This method is semver exempt and not exposed by default.
        #[cfg(procmacro2_semver_exempt)]
        pub fn eq(&self, other: &Span) -> bool {
            self.inner.eq(&other.inner)
        }
    }

    /// Prints a span in a form convenient for debugging.
    impl Debug for Span {
        fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
            Debug::fmt(&self.inner, f)
        }
    }

    /// A single token or a delimited sequence of token trees (e.g. `[1, (), ..]`).
    #[derive(Clone)]
    pub enum TokenTree {
        /// A token stream surrounded by bracket delimiters.
        Group(Group),
        /// An identifier.
        Ident(Ident),
        /// A single punctuation character (`+`, `,`, `$`, etc.).
        Punct(Punct),
        /// A literal character (`'a'`), string (`"hello"`), number (`2.3`), etc.
        Literal(Literal),
    }

    impl TokenTree {
        /// Returns the span of this tree, delegating to the `span` method of
        /// the contained token or a delimited stream.
        pub fn span(&self) -> Span {
            match self {
                TokenTree::Group(t) => t.span(),
                TokenTree::Ident(t) => t.span(),
                TokenTree::Punct(t) => t.span(),
                TokenTree::Literal(t) => t.span(),
            }
        }

        /// Configures the span for *only this token*.
        ///
        /// Note that if this token is a `Group` then this method will not configure
        /// the span of each of the internal tokens, this will simply delegate to
        /// the `set_span` method of each variant.
        pub fn set_span(&mut self, span: Span) {
            match self {
                TokenTree::Group(t) => t.set_span(span),
                TokenTree::Ident(t) => t.set_span(span),
                TokenTree::Punct(t) => t.set_span(span),
                TokenTree::Literal(t) => t.set_span(span),
            }
        }
    }

    impl From<Group> for TokenTree {
        fn from(g: Group) -> TokenTree {
            TokenTree::Group(g)
        }
    }

    impl From<Ident> for TokenTree {
        fn from(g: Ident) -> TokenTree {
            TokenTree::Ident(g)
        }
    }

    impl From<Punct> for TokenTree {
        fn from(g: Punct) -> TokenTree {
            TokenTree::Punct(g)
        }
    }

    impl From<Literal> for TokenTree {
        fn from(g: Literal) -> TokenTree {
            TokenTree::Literal(g)
        }
    }

    /// Prints the token tree as a string that is supposed to be losslessly
    /// convertible back into the same token tree (modulo spans), except for
    /// possibly `TokenTree::Group`s with `Delimiter::None` delimiters and negative
    /// numeric literals.
    impl Display for TokenTree {
        fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
            match self {
                TokenTree::Group(t) => Display::fmt(t, f),
                TokenTree::Ident(t) => Display::fmt(t, f),
                TokenTree::Punct(t) => Display::fmt(t, f),
                TokenTree::Literal(t) => Display::fmt(t, f),
            }
        }
    }

    /// Prints token tree in a form convenient for debugging.
    impl Debug for TokenTree {
        fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
            // Each of these has the name in the struct type in the derived debug,
            // so don't bother with an extra layer of indirection
            match self {
                TokenTree::Group(t) => Debug::fmt(t, f),
                TokenTree::Ident(t) => {
                    let mut debug = f.debug_struct("Ident");
                    debug.field("sym", &format_args!("{}", t));
                    imp::debug_span_field_if_nontrivial(&mut debug, t.span().inner);
                    debug.finish()
                }
                TokenTree::Punct(t) => Debug::fmt(t, f),
                TokenTree::Literal(t) => Debug::fmt(t, f),
            }
        }
    }

    /// A delimited token stream.
    ///
    /// A `Group` internally contains a `TokenStream` which is surrounded by
    /// `Delimiter`s.
    #[derive(Clone)]
    pub struct Group {
        inner: imp::Group,
    }

    /// Describes how a sequence of token trees is delimited.
    #[derive(Copy, Clone, Debug, Eq, PartialEq)]
    pub enum Delimiter {
        /// `( ... )`
        Parenthesis,
        /// `{ ... }`
        Brace,
        /// `[ ... ]`
        Bracket,
        /// `Ø ... Ø`
        ///
        /// An implicit delimiter, that may, for example, appear around tokens
        /// coming from a "macro variable" `$var`. It is important to preserve
        /// operator priorities in cases like `$var * 3` where `$var` is `1 + 2`.
        /// Implicit delimiters may not survive roundtrip of a token stream through
        /// a string.
        None,
    }

    impl Group {
        fn _new(inner: imp::Group) -> Self {
            Group { inner }
        }

        fn _new_stable(inner: fallback::Group) -> Self {
            Group {
                inner: inner.into(),
            }
        }

        /// Creates a new `Group` with the given delimiter and token stream.
        ///
        /// This constructor will set the span for this group to
        /// `Span::call_site()`. To change the span you can use the `set_span`
        /// method below.
        pub fn new(delimiter: Delimiter, stream: TokenStream) -> Group {
            Group {
                inner: imp::Group::new(delimiter, stream.inner),
            }
        }

        /// Returns the delimiter of this `Group`
        pub fn delimiter(&self) -> Delimiter {
            self.inner.delimiter()
        }

        /// Returns the `TokenStream` of tokens that are delimited in this `Group`.
        ///
        /// Note that the returned token stream does not include the delimiter
        /// returned above.
        pub fn stream(&self) -> TokenStream {
            TokenStream::_new(self.inner.stream())
        }

        /// Returns the span for the delimiters of this token stream, spanning the
        /// entire `Group`.
        ///
        /// ```text
        /// pub fn span(&self) -> Span {
        ///            ^^^^^^^
        /// ```
        pub fn span(&self) -> Span {
            Span::_new(self.inner.span())
        }

        /// Returns the span pointing to the opening delimiter of this group.
        ///
        /// ```text
        /// pub fn span_open(&self) -> Span {
        ///                 ^
        /// ```
        pub fn span_open(&self) -> Span {
            Span::_new(self.inner.span_open())
        }

        /// Returns the span pointing to the closing delimiter of this group.
        ///
        /// ```text
        /// pub fn span_close(&self) -> Span {
        ///                        ^
        /// ```
        pub fn span_close(&self) -> Span {
            Span::_new(self.inner.span_close())
        }

        /// Configures the span for this `Group`'s delimiters, but not its internal
        /// tokens.
        ///
        /// This method will **not** set the span of all the internal tokens spanned
        /// by this group, but rather it will only set the span of the delimiter
        /// tokens at the level of the `Group`.
        pub fn set_span(&mut self, span: Span) {
            self.inner.set_span(span.inner)
        }
    }

    /// Prints the group as a string that should be losslessly convertible back
    /// into the same group (modulo spans), except for possibly `TokenTree::Group`s
    /// with `Delimiter::None` delimiters.
    impl Display for Group {
        fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
            Display::fmt(&self.inner, formatter)
        }
    }

    impl Debug for Group {
        fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
            Debug::fmt(&self.inner, formatter)
        }
    }

    /// An `Punct` is an single punctuation character like `+`, `-` or `#`.
    ///
    /// Multicharacter operators like `+=` are represented as two instances of
    /// `Punct` with different forms of `Spacing` returned.
    #[derive(Clone)]
    pub struct Punct {
        ch: char,
        spacing: Spacing,
        span: Span,
    }

    /// Whether an `Punct` is followed immediately by another `Punct` or followed by
    /// another token or whitespace.
    #[derive(Copy, Clone, Debug, Eq, PartialEq)]
    pub enum Spacing {
        /// E.g. `+` is `Alone` in `+ =`, `+ident` or `+()`.
        Alone,
        /// E.g. `+` is `Joint` in `+=` or `'` is `Joint` in `'#`.
        ///
        /// Additionally, single quote `'` can join with identifiers to form
        /// lifetimes `'ident`.
        Joint,
    }

    impl Punct {
        /// Creates a new `Punct` from the given character and spacing.
        ///
        /// The `ch` argument must be a valid punctuation character permitted by the
        /// language, otherwise the function will panic.
        ///
        /// The returned `Punct` will have the default span of `Span::call_site()`
        /// which can be further configured with the `set_span` method below.
        pub fn new(ch: char, spacing: Spacing) -> Punct {
            Punct {
                ch,
                spacing,
                span: Span::call_site(),
            }
        }

        /// Returns the value of this punctuation character as `char`.
        pub fn as_char(&self) -> char {
            self.ch
        }

        /// Returns the spacing of this punctuation character, indicating whether
        /// it's immediately followed by another `Punct` in the token stream, so
        /// they can potentially be combined into a multicharacter operator
        /// (`Joint`), or it's followed by some other token or whitespace (`Alone`)
        /// so the operator has certainly ended.
        pub fn spacing(&self) -> Spacing {
            self.spacing
        }

        /// Returns the span for this punctuation character.
        pub fn span(&self) -> Span {
            self.span
        }

        /// Configure the span for this punctuation character.
        pub fn set_span(&mut self, span: Span) {
            self.span = span;
        }
    }

    /// Prints the punctuation character as a string that should be losslessly
    /// convertible back into the same character.
    impl Display for Punct {
        fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
            Display::fmt(&self.ch, f)
        }
    }

    impl Debug for Punct {
        fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
            let mut debug = fmt.debug_struct("Punct");
            debug.field("char", &self.ch);
            debug.field("spacing", &self.spacing);
            imp::debug_span_field_if_nontrivial(&mut debug, self.span.inner);
            debug.finish()
        }
    }

    /// A word of Rust code, which may be a keyword or legal variable name.
    ///
    /// An identifier consists of at least one Unicode code point, the first of
    /// which has the XID_Start property and the rest of which have the XID_Continue
    /// property.
    ///
    /// - The empty string is not an identifier. Use `Option<Ident>`.
    /// - A lifetime is not an identifier. Use `syn::Lifetime` instead.
    ///
    /// An identifier constructed with `Ident::new` is permitted to be a Rust
    /// keyword, though parsing one through its [`Parse`] implementation rejects
    /// Rust keywords. Use `input.call(Ident::parse_any)` when parsing to match the
    /// behaviour of `Ident::new`.
    ///
    /// [`Parse`]: https://docs.rs/syn/1.0/syn/parse/trait.Parse.html
    ///
    /// # Examples
    ///
    /// A new ident can be created from a string using the `Ident::new` function.
    /// A span must be provided explicitly which governs the name resolution
    /// behavior of the resulting identifier.
    ///
    /// ```
    /// use proc_macro2::{Ident, Span};
    ///
    /// fn main() {
    ///     let call_ident = Ident::new("calligraphy", Span::call_site());
    ///
    ///     println!("{}", call_ident);
    /// }
    /// ```
    ///
    /// An ident can be interpolated into a token stream using the `quote!` macro.
    ///
    /// ```
    /// use proc_macro2::{Ident, Span};
    /// use quote::quote;
    ///
    /// fn main() {
    ///     let ident = Ident::new("demo", Span::call_site());
    ///
    ///     // Create a variable binding whose name is this ident.
    ///     let expanded = quote! { let #ident = 10; };
    ///
    ///     // Create a variable binding with a slightly different name.
    ///     let temp_ident = Ident::new(&format!("new_{}", ident), Span::call_site());
    ///     let expanded = quote! { let #temp_ident = 10; };
    /// }
    /// ```
    ///
    /// A string representation of the ident is available through the `to_string()`
    /// method.
    ///
    /// ```
    /// # use proc_macro2::{Ident, Span};
    /// #
    /// # let ident = Ident::new("another_identifier", Span::call_site());
    /// #
    /// // Examine the ident as a string.
    /// let ident_string = ident.to_string();
    /// if ident_string.len() > 60 {
    ///     println!("Very long identifier: {}", ident_string)
    /// }
    /// ```
    #[derive(Clone)]
    pub struct Ident {
        inner: imp::Ident,
        _marker: Marker,
    }

    impl Ident {
        fn _new(inner: imp::Ident) -> Ident {
            Ident {
                inner,
                _marker: Marker,
            }
        }

        /// Creates a new `Ident` with the given `string` as well as the specified
        /// `span`.
        ///
        /// The `string` argument must be a valid identifier permitted by the
        /// language, otherwise the function will panic.
        ///
        /// Note that `span`, currently in rustc, configures the hygiene information
        /// for this identifier.
        ///
        /// As of this time `Span::call_site()` explicitly opts-in to "call-site"
        /// hygiene meaning that identifiers created with this span will be resolved
        /// as if they were written directly at the location of the macro call, and
        /// other code at the macro call site will be able to refer to them as well.
        ///
        /// Later spans like `Span::def_site()` will allow to opt-in to
        /// "definition-site" hygiene meaning that identifiers created with this
        /// span will be resolved at the location of the macro definition and other
        /// code at the macro call site will not be able to refer to them.
        ///
        /// Due to the current importance of hygiene this constructor, unlike other
        /// tokens, requires a `Span` to be specified at construction.
        ///
        /// # Panics
        ///
        /// Panics if the input string is neither a keyword nor a legal variable
        /// name. If you are not sure whether the string contains an identifier and
        /// need to handle an error case, use
        /// <a href="https://docs.rs/syn/1.0/syn/fn.parse_str.html"><code
        ///   style="padding-right:0;">syn::parse_str</code></a><code
        ///   style="padding-left:0;">::&lt;Ident&gt;</code>
        /// rather than `Ident::new`.
        pub fn new(string: &str, span: Span) -> Ident {
            Ident::_new(imp::Ident::new(string, span.inner))
        }

        /// Same as `Ident::new`, but creates a raw identifier (`r#ident`).
        ///
        /// This method is semver exempt and not exposed by default.
        #[cfg(procmacro2_semver_exempt)]
        pub fn new_raw(string: &str, span: Span) -> Ident {
            Ident::_new_raw(string, span)
        }

        fn _new_raw(string: &str, span: Span) -> Ident {
            Ident::_new(imp::Ident::new_raw(string, span.inner))
        }

        /// Returns the span of this `Ident`.
        pub fn span(&self) -> Span {
            Span::_new(self.inner.span())
        }

        /// Configures the span of this `Ident`, possibly changing its hygiene
        /// context.
        pub fn set_span(&mut self, span: Span) {
            self.inner.set_span(span.inner);
        }
    }

    impl PartialEq for Ident {
        fn eq(&self, other: &Ident) -> bool {
            self.inner == other.inner
        }
    }

    impl<T> PartialEq<T> for Ident
    where
        T: ?Sized + AsRef<str>,
    {
        fn eq(&self, other: &T) -> bool {
            self.inner == other
        }
    }

    impl Eq for Ident {}

    impl PartialOrd for Ident {
        fn partial_cmp(&self, other: &Ident) -> Option<Ordering> {
            Some(self.cmp(other))
        }
    }

    impl Ord for Ident {
        fn cmp(&self, other: &Ident) -> Ordering {
            self.to_string().cmp(&other.to_string())
        }
    }

    impl Hash for Ident {
        fn hash<H: Hasher>(&self, hasher: &mut H) {
            self.to_string().hash(hasher)
        }
    }

    /// Prints the identifier as a string that should be losslessly convertible back
    /// into the same identifier.
    impl Display for Ident {
        fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
            Display::fmt(&self.inner, f)
        }
    }

    impl Debug for Ident {
        fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
            Debug::fmt(&self.inner, f)
        }
    }

    /// A literal string (`"hello"`), byte string (`b"hello"`), character (`'a'`),
    /// byte character (`b'a'`), an integer or floating point number with or without
    /// a suffix (`1`, `1u8`, `2.3`, `2.3f32`).
    ///
    /// Boolean literals like `true` and `false` do not belong here, they are
    /// `Ident`s.
    #[derive(Clone)]
    pub struct Literal {
        inner: imp::Literal,
        _marker: Marker,
    }

    macro_rules! suffixed_int_literals {
        ($($name:ident => $kind:ident,)*) => ($(
            /// Creates a new suffixed integer literal with the specified value.
            ///
            /// This function will create an integer like `1u32` where the integer
            /// value specified is the first part of the token and the integral is
            /// also suffixed at the end. Literals created from negative numbers may
            /// not survive rountrips through `TokenStream` or strings and may be
            /// broken into two tokens (`-` and positive literal).
            ///
            /// Literals created through this method have the `Span::call_site()`
            /// span by default, which can be configured with the `set_span` method
            /// below.
            pub fn $name(n: $kind) -> Literal {
                Literal::_new(imp::Literal::$name(n))
            }
        )*)
    }

    macro_rules! unsuffixed_int_literals {
        ($($name:ident => $kind:ident,)*) => ($(
            /// Creates a new unsuffixed integer literal with the specified value.
            ///
            /// This function will create an integer like `1` where the integer
            /// value specified is the first part of the token. No suffix is
            /// specified on this token, meaning that invocations like
            /// `Literal::i8_unsuffixed(1)` are equivalent to
            /// `Literal::u32_unsuffixed(1)`. Literals created from negative numbers
            /// may not survive rountrips through `TokenStream` or strings and may
            /// be broken into two tokens (`-` and positive literal).
            ///
            /// Literals created through this method have the `Span::call_site()`
            /// span by default, which can be configured with the `set_span` method
            /// below.
            pub fn $name(n: $kind) -> Literal {
                Literal::_new(imp::Literal::$name(n))
            }
        )*)
    }

    impl Literal {
        fn _new(inner: imp::Literal) -> Literal {
            Literal {
                inner,
                _marker: Marker,
            }
        }

        fn _new_stable(inner: fallback::Literal) -> Literal {
            Literal {
                inner: inner.into(),
                _marker: Marker,
            }
        }

        suffixed_int_literals! {
            u8_suffixed => u8,
            u16_suffixed => u16,
            u32_suffixed => u32,
            u64_suffixed => u64,
            u128_suffixed => u128,
            usize_suffixed => usize,
            i8_suffixed => i8,
            i16_suffixed => i16,
            i32_suffixed => i32,
            i64_suffixed => i64,
            i128_suffixed => i128,
            isize_suffixed => isize,
        }

        unsuffixed_int_literals! {
            u8_unsuffixed => u8,
            u16_unsuffixed => u16,
            u32_unsuffixed => u32,
            u64_unsuffixed => u64,
            u128_unsuffixed => u128,
            usize_unsuffixed => usize,
            i8_unsuffixed => i8,
            i16_unsuffixed => i16,
            i32_unsuffixed => i32,
            i64_unsuffixed => i64,
            i128_unsuffixed => i128,
            isize_unsuffixed => isize,
        }

        /// Creates a new unsuffixed floating-point literal.
        ///
        /// This constructor is similar to those like `Literal::i8_unsuffixed` where
        /// the float's value is emitted directly into the token but no suffix is
        /// used, so it may be inferred to be a `f64` later in the compiler.
        /// Literals created from negative numbers may not survive rountrips through
        /// `TokenStream` or strings and may be broken into two tokens (`-` and
        /// positive literal).
        ///
        /// # Panics
        ///
        /// This function requires that the specified float is finite, for example
        /// if it is infinity or NaN this function will panic.
        pub fn f64_unsuffixed(f: f64) -> Literal {
            assert!(f.is_finite());
            Literal::_new(imp::Literal::f64_unsuffixed(f))
        }

        /// Creates a new suffixed floating-point literal.
        ///
        /// This constructor will create a literal like `1.0f64` where the value
        /// specified is the preceding part of the token and `f64` is the suffix of
        /// the token. This token will always be inferred to be an `f64` in the
        /// compiler. Literals created from negative numbers may not survive
        /// rountrips through `TokenStream` or strings and may be broken into two
        /// tokens (`-` and positive literal).
        ///
        /// # Panics
        ///
        /// This function requires that the specified float is finite, for example
        /// if it is infinity or NaN this function will panic.
        pub fn f64_suffixed(f: f64) -> Literal {
            assert!(f.is_finite());
            Literal::_new(imp::Literal::f64_suffixed(f))
        }

        /// Creates a new unsuffixed floating-point literal.
        ///
        /// This constructor is similar to those like `Literal::i8_unsuffixed` where
        /// the float's value is emitted directly into the token but no suffix is
        /// used, so it may be inferred to be a `f64` later in the compiler.
        /// Literals created from negative numbers may not survive rountrips through
        /// `TokenStream` or strings and may be broken into two tokens (`-` and
        /// positive literal).
        ///
        /// # Panics
        ///
        /// This function requires that the specified float is finite, for example
        /// if it is infinity or NaN this function will panic.
        pub fn f32_unsuffixed(f: f32) -> Literal {
            assert!(f.is_finite());
            Literal::_new(imp::Literal::f32_unsuffixed(f))
        }

        /// Creates a new suffixed floating-point literal.
        ///
        /// This constructor will create a literal like `1.0f32` where the value
        /// specified is the preceding part of the token and `f32` is the suffix of
        /// the token. This token will always be inferred to be an `f32` in the
        /// compiler. Literals created from negative numbers may not survive
        /// rountrips through `TokenStream` or strings and may be broken into two
        /// tokens (`-` and positive literal).
        ///
        /// # Panics
        ///
        /// This function requires that the specified float is finite, for example
        /// if it is infinity or NaN this function will panic.
        pub fn f32_suffixed(f: f32) -> Literal {
            assert!(f.is_finite());
            Literal::_new(imp::Literal::f32_suffixed(f))
        }

        /// String literal.
        pub fn string(string: &str) -> Literal {
            Literal::_new(imp::Literal::string(string))
        }

        /// Character literal.
        pub fn character(ch: char) -> Literal {
            Literal::_new(imp::Literal::character(ch))
        }

        /// Byte string literal.
        pub fn byte_string(s: &[u8]) -> Literal {
            Literal::_new(imp::Literal::byte_string(s))
        }

        /// Returns the span encompassing this literal.
        pub fn span(&self) -> Span {
            Span::_new(self.inner.span())
        }

        /// Configures the span associated for this literal.
        pub fn set_span(&mut self, span: Span) {
            self.inner.set_span(span.inner);
        }

        /// Returns a `Span` that is a subset of `self.span()` containing only
        /// the source bytes in range `range`. Returns `None` if the would-be
        /// trimmed span is outside the bounds of `self`.
        ///
        /// Warning: the underlying [`proc_macro::Literal::subspan`] method is
        /// nightly-only. When called from within a procedural macro not using a
        /// nightly compiler, this method will always return `None`.
        ///
        /// [`proc_macro::Literal::subspan`]: https://doc.rust-lang.org/proc_macro/struct.Literal.html#method.subspan
        pub fn subspan<R: RangeBounds<usize>>(&self, range: R) -> Option<Span> {
            self.inner.subspan(range).map(Span::_new)
        }
    }

    impl Debug for Literal {
        fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
            Debug::fmt(&self.inner, f)
        }
    }

    impl Display for Literal {
        fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
            Display::fmt(&self.inner, f)
        }
    }

    /// Public implementation details for the `TokenStream` type, such as iterators.
    pub mod token_stream {
        use crate::marker::Marker;
        use crate::{imp, TokenTree};
        use std::fmt::{self, Debug};

        pub use crate::TokenStream;

        /// An iterator over `TokenStream`'s `TokenTree`s.
        ///
        /// The iteration is "shallow", e.g. the iterator doesn't recurse into
        /// delimited groups, and returns whole groups as token trees.
        #[derive(Clone)]
        pub struct IntoIter {
            inner: imp::TokenTreeIter,
            _marker: Marker,
        }

        impl Iterator for IntoIter {
            type Item = TokenTree;

            fn next(&mut self) -> Option<TokenTree> {
                self.inner.next()
            }
        }

        impl Debug for IntoIter {
            fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
                Debug::fmt(&self.inner, f)
            }
        }

        impl IntoIterator for TokenStream {
            type Item = TokenTree;
            type IntoIter = IntoIter;

            fn into_iter(self) -> IntoIter {
                IntoIter {
                    inner: self.inner.into_iter(),
                    _marker: Marker,
                }
            }
        }
    }