build(rust): vendor googletest crate

third_party/crates/syn-2.0.119/src/span.rs

@@ -0,0 +1,63 @@
+use proc_macro2::extra::DelimSpan;
+use proc_macro2::{Delimiter, Group, Span, TokenStream};
+
+#[doc(hidden)]
+pub trait IntoSpans<S> {
+    fn into_spans(self) -> S;
+}
+
+impl IntoSpans<Span> for Span {
+    fn into_spans(self) -> Span {
+        self
+    }
+}
+
+impl IntoSpans<[Span; 1]> for Span {
+    fn into_spans(self) -> [Span; 1] {
+        [self]
+    }
+}
+
+impl IntoSpans<[Span; 2]> for Span {
+    fn into_spans(self) -> [Span; 2] {
+        [self, self]
+    }
+}
+
+impl IntoSpans<[Span; 3]> for Span {
+    fn into_spans(self) -> [Span; 3] {
+        [self, self, self]
+    }
+}
+
+impl IntoSpans<[Span; 1]> for [Span; 1] {
+    fn into_spans(self) -> [Span; 1] {
+        self
+    }
+}
+
+impl IntoSpans<[Span; 2]> for [Span; 2] {
+    fn into_spans(self) -> [Span; 2] {
+        self
+    }
+}
+
+impl IntoSpans<[Span; 3]> for [Span; 3] {
+    fn into_spans(self) -> [Span; 3] {
+        self
+    }
+}
+
+impl IntoSpans<DelimSpan> for Span {
+    fn into_spans(self) -> DelimSpan {
+        let mut group = Group::new(Delimiter::None, TokenStream::new());
+        group.set_span(self);
+        group.delim_span()
+    }
+}
+
+impl IntoSpans<DelimSpan> for DelimSpan {
+    fn into_spans(self) -> DelimSpan {
+        self
+    }
+}