1 files changed, 14 insertions, 0 deletions
diff --git a/compiler/rustc_query_system/src/values.rs b/compiler/rustc_query_system/src/values.rs
new file mode 100644
index 000000000..aeef66f86
--- /dev/null
+++ b/compiler/rustc_query_system/src/values.rs
@@ -0,0 +1,14 @@
+use crate::dep_graph::DepContext;
+
+pub trait Value<CTX: DepContext>: Sized {
+    fn from_cycle_error(tcx: CTX) -> Self;
+}
+
+impl<CTX: DepContext, T> Value<CTX> for T {
+    default fn from_cycle_error(tcx: CTX) -> T {
+        tcx.sess().abort_if_errors();
+        // Ideally we would use `bug!` here. But bug! is only defined in rustc_middle, and it's
+        // non-trivial to define it earlier.
+        panic!("Value::from_cycle_error called without errors");
+    }
+}