[PATCH 15/18] rust: syn: add SPDX License Identifiers

[Miguel Ojeda <ojeda@kernel.org>]

Originally, when the Rust upstream `alloc` standard library crate was
vendored in commit 057b8d257107 ("rust: adapt `alloc` crate to the
kernel"), the SPDX License Identifiers were added to every file so that
the license on those was clear.

Thus do the same for the `syn` crate.

This makes `scripts/spdxcheck.py` pass.

Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
---
 rust/syn/attr.rs               | 2 ++
 rust/syn/bigint.rs             | 2 ++
 rust/syn/buffer.rs             | 2 ++
 rust/syn/classify.rs           | 2 ++
 rust/syn/custom_keyword.rs     | 2 ++
 rust/syn/custom_punctuation.rs | 2 ++
 rust/syn/data.rs               | 2 ++
 rust/syn/derive.rs             | 2 ++
 rust/syn/discouraged.rs        | 2 ++
 rust/syn/drops.rs              | 2 ++
 rust/syn/error.rs              | 2 ++
 rust/syn/export.rs             | 2 ++
 rust/syn/expr.rs               | 2 ++
 rust/syn/ext.rs                | 2 ++
 rust/syn/file.rs               | 2 ++
 rust/syn/fixup.rs              | 2 ++
 rust/syn/gen/clone.rs          | 2 ++
 rust/syn/gen/debug.rs          | 2 ++
 rust/syn/gen/eq.rs             | 2 ++
 rust/syn/gen/fold.rs           | 2 ++
 rust/syn/gen/hash.rs           | 2 ++
 rust/syn/gen/visit.rs          | 2 ++
 rust/syn/gen/visit_mut.rs      | 2 ++
 rust/syn/generics.rs           | 2 ++
 rust/syn/group.rs              | 2 ++
 rust/syn/ident.rs              | 2 ++
 rust/syn/item.rs               | 2 ++
 rust/syn/lib.rs                | 2 ++
 rust/syn/lifetime.rs           | 2 ++
 rust/syn/lit.rs                | 2 ++
 rust/syn/lookahead.rs          | 2 ++
 rust/syn/mac.rs                | 2 ++
 rust/syn/macros.rs             | 2 ++
 rust/syn/meta.rs               | 2 ++
 rust/syn/op.rs                 | 2 ++
 rust/syn/parse.rs              | 2 ++
 rust/syn/parse_macro_input.rs  | 2 ++
 rust/syn/parse_quote.rs        | 2 ++
 rust/syn/pat.rs                | 2 ++
 rust/syn/path.rs               | 2 ++
 rust/syn/precedence.rs         | 2 ++
 rust/syn/print.rs              | 2 ++
 rust/syn/punctuated.rs         | 2 ++
 rust/syn/restriction.rs        | 2 ++
 rust/syn/scan_expr.rs          | 2 ++
 rust/syn/sealed.rs             | 2 ++
 rust/syn/span.rs               | 2 ++
 rust/syn/spanned.rs            | 2 ++
 rust/syn/stmt.rs               | 2 ++
 rust/syn/thread.rs             | 2 ++
 rust/syn/token.rs              | 2 ++
 rust/syn/tt.rs                 | 2 ++
 rust/syn/ty.rs                 | 2 ++
 rust/syn/verbatim.rs           | 2 ++
 rust/syn/whitespace.rs         | 2 ++
 55 files changed, 110 insertions(+)

diff --git a/rust/syn/attr.rs b/rust/syn/attr.rs
index 2bdf96ee7fa9..020b31f9de22 100644
--- a/rust/syn/attr.rs
+++ b/rust/syn/attr.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 #[cfg(feature = "parsing")]
 use crate::error::Error;
 #[cfg(feature = "parsing")]
diff --git a/rust/syn/bigint.rs b/rust/syn/bigint.rs
index 66aaa9372540..d706f9f515e9 100644
--- a/rust/syn/bigint.rs
+++ b/rust/syn/bigint.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 use std::ops::{AddAssign, MulAssign};
 
 // For implementing base10_digits() accessor on LitInt.
diff --git a/rust/syn/buffer.rs b/rust/syn/buffer.rs
index 7b6a504eeb7c..406f70db323c 100644
--- a/rust/syn/buffer.rs
+++ b/rust/syn/buffer.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 //! A stably addressed token buffer supporting efficient traversal based on a
 //! cheaply copyable cursor.
 
diff --git a/rust/syn/classify.rs b/rust/syn/classify.rs
index 8eab19dbc37c..92a975bfe4aa 100644
--- a/rust/syn/classify.rs
+++ b/rust/syn/classify.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 #[cfg(feature = "full")]
 use crate::expr::Expr;
 #[cfg(any(feature = "printing", feature = "full"))]
diff --git a/rust/syn/custom_keyword.rs b/rust/syn/custom_keyword.rs
index cc4f632c981a..ff2c415f1aab 100644
--- a/rust/syn/custom_keyword.rs
+++ b/rust/syn/custom_keyword.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 /// Define a type that supports parsing and printing a given identifier as if it
 /// were a keyword.
 ///
diff --git a/rust/syn/custom_punctuation.rs b/rust/syn/custom_punctuation.rs
index eef5f5458459..d37c0e9c3a1e 100644
--- a/rust/syn/custom_punctuation.rs
+++ b/rust/syn/custom_punctuation.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 /// Define a type that supports parsing and printing a multi-character symbol
 /// as if it were a punctuation token.
 ///
diff --git a/rust/syn/data.rs b/rust/syn/data.rs
index 96db2a0b7c6f..c32c1366c1db 100644
--- a/rust/syn/data.rs
+++ b/rust/syn/data.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 use crate::attr::Attribute;
 use crate::expr::{Expr, Index, Member};
 use crate::ident::Ident;
diff --git a/rust/syn/derive.rs b/rust/syn/derive.rs
index 3443ecfc05cb..27fd9f12c88c 100644
--- a/rust/syn/derive.rs
+++ b/rust/syn/derive.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 use crate::attr::Attribute;
 use crate::data::{Fields, FieldsNamed, Variant};
 use crate::generics::Generics;
diff --git a/rust/syn/discouraged.rs b/rust/syn/discouraged.rs
index c8d6bfe89a14..2acd631ece84 100644
--- a/rust/syn/discouraged.rs
+++ b/rust/syn/discouraged.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 //! Extensions to the parsing API with niche applicability.
 
 use crate::buffer::Cursor;
diff --git a/rust/syn/drops.rs b/rust/syn/drops.rs
index c54308f02c13..2c4ae333dad8 100644
--- a/rust/syn/drops.rs
+++ b/rust/syn/drops.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 use std::iter;
 use std::mem::ManuallyDrop;
 use std::ops::{Deref, DerefMut};
diff --git a/rust/syn/error.rs b/rust/syn/error.rs
index 63310543a3b4..6fa0faf7f4e4 100644
--- a/rust/syn/error.rs
+++ b/rust/syn/error.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 #[cfg(feature = "parsing")]
 use crate::buffer::Cursor;
 use crate::thread::ThreadBound;
diff --git a/rust/syn/export.rs b/rust/syn/export.rs
index b9ea5c747b75..05dad324ba51 100644
--- a/rust/syn/export.rs
+++ b/rust/syn/export.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 #[doc(hidden)]
 pub use std::clone::Clone;
 #[doc(hidden)]
diff --git a/rust/syn/expr.rs b/rust/syn/expr.rs
index 1e49d9a6633e..deb918436604 100644
--- a/rust/syn/expr.rs
+++ b/rust/syn/expr.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 use crate::attr::Attribute;
 #[cfg(all(feature = "parsing", feature = "full"))]
 use crate::error::Result;
diff --git a/rust/syn/ext.rs b/rust/syn/ext.rs
index 5cd79e863a9d..a9be9af42787 100644
--- a/rust/syn/ext.rs
+++ b/rust/syn/ext.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 //! Extension traits to provide parsing methods on foreign types.
 
 use crate::buffer::Cursor;
diff --git a/rust/syn/file.rs b/rust/syn/file.rs
index 8956d82eee93..ce2d2680ca9a 100644
--- a/rust/syn/file.rs
+++ b/rust/syn/file.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 use crate::attr::Attribute;
 use crate::item::Item;
 
diff --git a/rust/syn/fixup.rs b/rust/syn/fixup.rs
index 6d2c3092d548..79b6d7618bb7 100644
--- a/rust/syn/fixup.rs
+++ b/rust/syn/fixup.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 use crate::classify;
 use crate::expr::Expr;
 #[cfg(feature = "full")]
diff --git a/rust/syn/gen/clone.rs b/rust/syn/gen/clone.rs
index be2b698422da..dfb53182e378 100644
--- a/rust/syn/gen/clone.rs
+++ b/rust/syn/gen/clone.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 // This file is @generated by syn-internal-codegen.
 // It is not intended for manual editing.
 
diff --git a/rust/syn/gen/debug.rs b/rust/syn/gen/debug.rs
index aa42e32c60ed..d594e57fcf21 100644
--- a/rust/syn/gen/debug.rs
+++ b/rust/syn/gen/debug.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 // This file is @generated by syn-internal-codegen.
 // It is not intended for manual editing.
 
diff --git a/rust/syn/gen/eq.rs b/rust/syn/gen/eq.rs
index 128e8991eecc..79e9691b8c67 100644
--- a/rust/syn/gen/eq.rs
+++ b/rust/syn/gen/eq.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 // This file is @generated by syn-internal-codegen.
 // It is not intended for manual editing.
 
diff --git a/rust/syn/gen/fold.rs b/rust/syn/gen/fold.rs
index 1f0afd31919d..0643a72f87ca 100644
--- a/rust/syn/gen/fold.rs
+++ b/rust/syn/gen/fold.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 // This file is @generated by syn-internal-codegen.
 // It is not intended for manual editing.
 
diff --git a/rust/syn/gen/hash.rs b/rust/syn/gen/hash.rs
index 04f23453a117..fae2197a5610 100644
--- a/rust/syn/gen/hash.rs
+++ b/rust/syn/gen/hash.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 // This file is @generated by syn-internal-codegen.
 // It is not intended for manual editing.
 
diff --git a/rust/syn/gen/visit.rs b/rust/syn/gen/visit.rs
index cd258fcde120..a82293c053d6 100644
--- a/rust/syn/gen/visit.rs
+++ b/rust/syn/gen/visit.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 // This file is @generated by syn-internal-codegen.
 // It is not intended for manual editing.
 
diff --git a/rust/syn/gen/visit_mut.rs b/rust/syn/gen/visit_mut.rs
index 2bbd6895db75..08e134b43a92 100644
--- a/rust/syn/gen/visit_mut.rs
+++ b/rust/syn/gen/visit_mut.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 // This file is @generated by syn-internal-codegen.
 // It is not intended for manual editing.
 
diff --git a/rust/syn/generics.rs b/rust/syn/generics.rs
index 0c77193da043..9f8df8a155e1 100644
--- a/rust/syn/generics.rs
+++ b/rust/syn/generics.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 use crate::attr::Attribute;
 use crate::expr::Expr;
 use crate::ident::Ident;
diff --git a/rust/syn/group.rs b/rust/syn/group.rs
index 1534ae995dd5..57586c58fd92 100644
--- a/rust/syn/group.rs
+++ b/rust/syn/group.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 use crate::error::Result;
 use crate::parse::ParseBuffer;
 use crate::token;
diff --git a/rust/syn/ident.rs b/rust/syn/ident.rs
index 8a8e8a50d9b0..2c4b56505bec 100644
--- a/rust/syn/ident.rs
+++ b/rust/syn/ident.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 #[cfg(feature = "parsing")]
 use crate::lookahead;
 
diff --git a/rust/syn/item.rs b/rust/syn/item.rs
index 1716f5137afb..1ab10cf218a6 100644
--- a/rust/syn/item.rs
+++ b/rust/syn/item.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 use crate::attr::Attribute;
 use crate::data::{Fields, FieldsNamed, Variant};
 use crate::derive::{Data, DataEnum, DataStruct, DataUnion, DeriveInput};
diff --git a/rust/syn/lib.rs b/rust/syn/lib.rs
index 79dc9e7c3324..b0006fd30b08 100644
--- a/rust/syn/lib.rs
+++ b/rust/syn/lib.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 //! [![github]](https://github.com/dtolnay/syn)&ensp;[![crates-io]](https://crates.io/crates/syn)&ensp;[![docs-rs]](crate)
 //!
 //! [github]: https://img.shields.io/badge/github-8da0cb?style=for-the-badge&labelColor=555555&logo=github
diff --git a/rust/syn/lifetime.rs b/rust/syn/lifetime.rs
index cc189d1ac91f..24bec7fe969d 100644
--- a/rust/syn/lifetime.rs
+++ b/rust/syn/lifetime.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 #[cfg(feature = "parsing")]
 use crate::lookahead;
 use proc_macro2::{Ident, Span};
diff --git a/rust/syn/lit.rs b/rust/syn/lit.rs
index 45c26d56fed3..1d2d8bdccfb1 100644
--- a/rust/syn/lit.rs
+++ b/rust/syn/lit.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 #[cfg(feature = "parsing")]
 use crate::lookahead;
 #[cfg(feature = "parsing")]
diff --git a/rust/syn/lookahead.rs b/rust/syn/lookahead.rs
index da13ffc47a7a..a7994cb6ae88 100644
--- a/rust/syn/lookahead.rs
+++ b/rust/syn/lookahead.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 use crate::buffer::Cursor;
 use crate::error::{self, Error};
 use crate::sealed::lookahead::Sealed;
diff --git a/rust/syn/mac.rs b/rust/syn/mac.rs
index 15107801cfee..ce4b022b4d14 100644
--- a/rust/syn/mac.rs
+++ b/rust/syn/mac.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 #[cfg(feature = "parsing")]
 use crate::error::Result;
 #[cfg(feature = "parsing")]
diff --git a/rust/syn/macros.rs b/rust/syn/macros.rs
index 167f2cf260a7..8676f6492a9c 100644
--- a/rust/syn/macros.rs
+++ b/rust/syn/macros.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 #[cfg_attr(
     not(any(feature = "full", feature = "derive")),
     allow(unknown_lints, unused_macro_rules)
diff --git a/rust/syn/meta.rs b/rust/syn/meta.rs
index ffeeb2629f4f..2dd138e6dd55 100644
--- a/rust/syn/meta.rs
+++ b/rust/syn/meta.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 //! Facility for interpreting structured content inside of an `Attribute`.
 
 use crate::error::{Error, Result};
diff --git a/rust/syn/op.rs b/rust/syn/op.rs
index 575d9faa1273..73dada3fae2d 100644
--- a/rust/syn/op.rs
+++ b/rust/syn/op.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 ast_enum! {
     /// A binary operator: `+`, `+=`, `&`.
     #[cfg_attr(docsrs, doc(cfg(any(feature = "full", feature = "derive"))))]
diff --git a/rust/syn/parse.rs b/rust/syn/parse.rs
index 57531005ac4e..c6f6c0eece02 100644
--- a/rust/syn/parse.rs
+++ b/rust/syn/parse.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 //! Parsing interface for parsing a token stream into a syntax tree node.
 //!
 //! Parsing in Syn is built on parser functions that take in a [`ParseStream`]
diff --git a/rust/syn/parse_macro_input.rs b/rust/syn/parse_macro_input.rs
index f0660aedd7df..2f977754d41c 100644
--- a/rust/syn/parse_macro_input.rs
+++ b/rust/syn/parse_macro_input.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 /// Parse the input TokenStream of a macro, triggering a compile error if the
 /// tokens fail to parse.
 ///
diff --git a/rust/syn/parse_quote.rs b/rust/syn/parse_quote.rs
index 2db20597c436..7cc7b9b8fd75 100644
--- a/rust/syn/parse_quote.rs
+++ b/rust/syn/parse_quote.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 /// Quasi-quotation macro that accepts input like the [`quote!`] macro but uses
 /// type inference to figure out a return type for those tokens.
 ///
diff --git a/rust/syn/pat.rs b/rust/syn/pat.rs
index 81a2f183f6b9..46edd63d5ed8 100644
--- a/rust/syn/pat.rs
+++ b/rust/syn/pat.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 use crate::attr::Attribute;
 use crate::expr::Member;
 use crate::ident::Ident;
diff --git a/rust/syn/path.rs b/rust/syn/path.rs
index d2fcb9bc5d28..f2453bea4a3c 100644
--- a/rust/syn/path.rs
+++ b/rust/syn/path.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 #[cfg(feature = "parsing")]
 use crate::error::Result;
 use crate::expr::Expr;
diff --git a/rust/syn/precedence.rs b/rust/syn/precedence.rs
index 1891bfc202fd..cc4dba24a433 100644
--- a/rust/syn/precedence.rs
+++ b/rust/syn/precedence.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 #[cfg(all(feature = "printing", feature = "full"))]
 use crate::attr::{AttrStyle, Attribute};
 #[cfg(feature = "printing")]
diff --git a/rust/syn/print.rs b/rust/syn/print.rs
index 07409932677b..d73262cda060 100644
--- a/rust/syn/print.rs
+++ b/rust/syn/print.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 use proc_macro2::TokenStream;
 use quote::ToTokens;
 
diff --git a/rust/syn/punctuated.rs b/rust/syn/punctuated.rs
index ebaaa94f9a26..f79152940db6 100644
--- a/rust/syn/punctuated.rs
+++ b/rust/syn/punctuated.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 //! A punctuated sequence of syntax tree nodes separated by punctuation.
 //!
 //! Lots of things in Rust are punctuated sequences.
diff --git a/rust/syn/restriction.rs b/rust/syn/restriction.rs
index 6e6758f3cd73..b844f64c3a73 100644
--- a/rust/syn/restriction.rs
+++ b/rust/syn/restriction.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 use crate::path::Path;
 use crate::token;
 
diff --git a/rust/syn/scan_expr.rs b/rust/syn/scan_expr.rs
index 3d88cf06acea..a5fd1ddc1501 100644
--- a/rust/syn/scan_expr.rs
+++ b/rust/syn/scan_expr.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 use self::{Action::*, Input::*};
 use proc_macro2::{Delimiter, Ident, Spacing, TokenTree};
 use syn::parse::{ParseStream, Result};
diff --git a/rust/syn/sealed.rs b/rust/syn/sealed.rs
index dc804742d12d..541df9623755 100644
--- a/rust/syn/sealed.rs
+++ b/rust/syn/sealed.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 #[cfg(feature = "parsing")]
 pub(crate) mod lookahead {
     pub trait Sealed: Copy {}
diff --git a/rust/syn/span.rs b/rust/syn/span.rs
index eb2779479aaa..e6d55b3ccd03 100644
--- a/rust/syn/span.rs
+++ b/rust/syn/span.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 use proc_macro2::extra::DelimSpan;
 use proc_macro2::{Delimiter, Group, Span, TokenStream};
 
diff --git a/rust/syn/spanned.rs b/rust/syn/spanned.rs
index 17b69e9f5b28..fcc93699f742 100644
--- a/rust/syn/spanned.rs
+++ b/rust/syn/spanned.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 //! A trait that can provide the `Span` of the complete contents of a syntax
 //! tree node.
 //!
diff --git a/rust/syn/stmt.rs b/rust/syn/stmt.rs
index 8ea0077f63df..029171a98dca 100644
--- a/rust/syn/stmt.rs
+++ b/rust/syn/stmt.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 use crate::attr::Attribute;
 use crate::expr::Expr;
 use crate::item::Item;
diff --git a/rust/syn/thread.rs b/rust/syn/thread.rs
index b33d248afc60..4165a173d9e1 100644
--- a/rust/syn/thread.rs
+++ b/rust/syn/thread.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 use std::fmt::{self, Debug};
 use std::thread::{self, ThreadId};
 
diff --git a/rust/syn/token.rs b/rust/syn/token.rs
index 752c188883cb..18345cc5831a 100644
--- a/rust/syn/token.rs
+++ b/rust/syn/token.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 //! Tokens representing Rust punctuation, keywords, and delimiters.
 //!
 //! The type names in this module can be difficult to keep straight, so we
diff --git a/rust/syn/tt.rs b/rust/syn/tt.rs
index 7d5d6a1ac326..fc7adec3da90 100644
--- a/rust/syn/tt.rs
+++ b/rust/syn/tt.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 use proc_macro2::{Delimiter, TokenStream, TokenTree};
 use std::hash::{Hash, Hasher};
 
diff --git a/rust/syn/ty.rs b/rust/syn/ty.rs
index c093f5877b3c..ae660d2d2e74 100644
--- a/rust/syn/ty.rs
+++ b/rust/syn/ty.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 use crate::attr::Attribute;
 use crate::expr::Expr;
 use crate::generics::{BoundLifetimes, TypeParamBound};
diff --git a/rust/syn/verbatim.rs b/rust/syn/verbatim.rs
index 54dc1cfa0d82..97bc08f70afe 100644
--- a/rust/syn/verbatim.rs
+++ b/rust/syn/verbatim.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 use crate::parse::ParseStream;
 use proc_macro2::{Delimiter, TokenStream};
 use std::cmp::Ordering;
diff --git a/rust/syn/whitespace.rs b/rust/syn/whitespace.rs
index a50b5069a68b..b7319bd7af18 100644
--- a/rust/syn/whitespace.rs
+++ b/rust/syn/whitespace.rs
@@ -1,3 +1,5 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
 pub(crate) fn skip(mut s: &str) -> &str {
     'skip: while !s.is_empty() {
         let byte = s.as_bytes()[0];
-- 
2.51.2