1 files changed, 67 insertions, 0 deletions
diff --git a/third_party/rust/syn/src/span.rs b/third_party/rust/syn/src/span.rs
new file mode 100644
index 0000000000..27a7fe846d
--- /dev/null
+++ b/third_party/rust/syn/src/span.rs
@@ -0,0 +1,67 @@
+use proc_macro2::Span;
+
+pub trait IntoSpans<S> {
+    fn into_spans(self) -> S;
+}
+
+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
+    }
+}
+
+#[cfg(feature = "parsing")]
+pub trait FromSpans: Sized {
+    fn from_spans(spans: &[Span]) -> Self;
+}
+
+#[cfg(feature = "parsing")]
+impl FromSpans for [Span; 1] {
+    fn from_spans(spans: &[Span]) -> Self {
+        [spans[0]]
+    }
+}
+
+#[cfg(feature = "parsing")]
+impl FromSpans for [Span; 2] {
+    fn from_spans(spans: &[Span]) -> Self {
+        [spans[0], spans[1]]
+    }
+}
+
+#[cfg(feature = "parsing")]
+impl FromSpans for [Span; 3] {
+    fn from_spans(spans: &[Span]) -> Self {
+        [spans[0], spans[1], spans[2]]
+    }
+}