1 files changed, 18 insertions, 0 deletions
diff --git a/crates/typst-library/src/diag.rs b/crates/typst-library/src/diag.rs
index bd4c90a1..49cbd02c 100644
--- a/crates/typst-library/src/diag.rs
+++ b/crates/typst-library/src/diag.rs
@@ -11,6 +11,7 @@ use ecow::{eco_vec, EcoVec};
 use typst_syntax::package::{PackageSpec, PackageVersion};
 use typst_syntax::{Span, Spanned, SyntaxError};
 
+use crate::engine::Engine;
 use crate::{World, WorldExt};
 
 /// Early-return with a [`StrResult`] or [`SourceResult`].
@@ -228,6 +229,23 @@ impl From<SyntaxError> for SourceDiagnostic {
     }
 }
 
+/// Destination for a deprecation message when accessing a deprecated value.
+pub trait DeprecationSink {
+    /// Emits the given deprecation message into this sink.
+    fn emit(self, message: &str);
+}
+
+impl DeprecationSink for () {
+    fn emit(self, _: &str) {}
+}
+
+impl DeprecationSink for (&mut Engine<'_>, Span) {
+    /// Emits the deprecation message as a warning.
+    fn emit(self, message: &str) {
+        self.0.sink.warn(SourceDiagnostic::warning(self.1, message));
+    }
+}
+
 /// A part of a diagnostic's [trace](SourceDiagnostic::trace).
 #[derive(Debug, Clone, Eq, PartialEq, Ord, PartialOrd, Hash)]
 pub enum Tracepoint {