Show rules with type ascribed object

1 files changed, 13 insertions, 0 deletions

diff --git a/src/eval/capture.rs b/src/eval/capture.rs
index 4e8d7604..8e54122f 100644
--- a/src/eval/capture.rs
+++ b/src/eval/capture.rs
@@ -88,6 +88,14 @@ impl<'a> CapturesVisitor<'a> {
                 self.bind(expr.binding());
             }
 
+            // A show rule contains a binding, but that binding is only active
+            // after the target has been evaluated.
+            Some(Expr::Show(show)) => {
+                self.visit(show.target().as_red());
+                self.bind(show.binding());
+                self.visit(show.body().as_red());
+            }
+
             // A for loop contains one or two bindings in its pattern. These are
             // active after the iterable is evaluated but before the body is
             // evaluated.
@@ -162,6 +170,11 @@ mod tests {
         test("{(..x) => x + y}", &["y"]);
         test("{(x, y: x + z) => x + y}", &["x", "z"]);
 
+        // Show rule.
+        test("#show x: y as x", &["y"]);
+        test("#show x: y as x + z", &["y", "z"]);
+        test("#show x: x as x", &["x"]);
+
         // For loop.
         test("#for x in y { x + z }", &["y", "z"]);
         test("#for x, y in y { x + y }", &["y"]);