fix: closure captures can also be constants (#11493)

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When evaluating a closure (in
`EvalRuntime::eval_row_condition_or_closure()`), we try to resolve the
closure's block's captures, but we only check if they're variables on
the stack. We need to also check if they are constants (see the logic in
`Stack::gather_captures()`).

fixes #10701
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crates/nu-engine/src/eval.rs

@@ -1102,7 +1102,18 @@ impl Eval for EvalRuntime {
             .get_block(block_id)
             .captures
             .iter()
-            .map(|&id| stack.get_var(id, span).map(|var| (id, var)))
+            .map(|&id| {
+                stack
+                    .get_var(id, span)
+                    .or_else(|_| {
+                        engine_state
+                            .get_var(id)
+                            .const_val
+                            .clone()
+                            .ok_or(ShellError::VariableNotFoundAtRuntime { span })
+                    })
+                    .map(|var| (id, var))
+            })
             .collect::<Result<_, _>>()?;
 
         Ok(Value::closure(Closure { block_id, captures }, span))

tests/const_/mod.rs

@@ -304,6 +304,19 @@ fn const_captures_work() {
     assert_eq!(actual.out, "xy");
 }
 
+#[test]
+fn const_captures_in_closures_work() {
+    let module = "module foo {
+        const a = 'world'
+        export def bar [] {
+            'hello ' + $a
+        }
+    }";
+    let inp = &[module, "use foo", "do { foo bar }"];
+    let actual = nu!(&inp.join("; "));
+    assert_eq!(actual.out, "hello world");
+}
+
 #[ignore = "TODO: Need to fix `overlay hide` to hide the constants brough by `overlay use`"]
 #[test]
 fn complex_const_overlay_use_hide() {