Show error when trying to export at non-top-level (#7110)

rust/kcl-lib/src/execution/exec_ast.rs

@@ -281,7 +281,14 @@ impl ExecutorContext {
 
                     // Track exports.
                     if let ItemVisibility::Export = variable_declaration.visibility {
-                        exec_state.mod_local.module_exports.push(var_name);
+                        if matches!(body_type, BodyType::Root) {
+                            exec_state.mod_local.module_exports.push(var_name);
+                        } else {
+                            exec_state.err(CompilationError::err(
+                                variable_declaration.as_source_range(),
+                                "Exports are only supported at the top-level of a file. Remove `export` or move it to the top-level.",
+                            ));
+                        }
                     }
                     // Variable declaration can be the return value of a module.
                     last_expr = matches!(body_type, BodyType::Root).then_some(value);

rust/kcl-lib/src/simulation_tests.rs

@@ -1185,6 +1185,27 @@ mod import_foreign {
         super::execute(TEST_NAME, false).await
     }
 }
+mod export_var_only_at_top_level {
+    const TEST_NAME: &str = "export_var_only_at_top_level";
+
+    /// Test parsing KCL.
+    #[test]
+    fn parse() {
+        super::parse(TEST_NAME)
+    }
+
+    /// Test that parsing and unparsing KCL produces the original KCL input.
+    #[tokio::test(flavor = "multi_thread")]
+    async fn unparse() {
+        super::unparse(TEST_NAME).await
+    }
+
+    /// Test that KCL is executed correctly.
+    #[tokio::test(flavor = "multi_thread")]
+    async fn kcl_test_execute() {
+        super::execute(TEST_NAME, false).await
+    }
+}
 mod assembly_non_default_units {
     const TEST_NAME: &str = "assembly_non_default_units";