From fc976172e761db42e8102ba4dd63258e8198a673 Mon Sep 17 00:00:00 2001
From: Stephen Chung <schungx@live.com>
Date: Fri, 29 Jul 2022 09:43:40 +0800
Subject: [PATCH] Fix bug with capturing undefined variable.

---
 CHANGELOG.md      |  1 +
 src/eval/stmt.rs  |  6 +++---
 tests/closures.rs | 22 ++++++++++++++++++----
 3 files changed, 22 insertions(+), 7 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3063db23..10d05cbd 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,6 +11,7 @@ Bug fixes
 
 * `switch` cases with conditions that evaluate to constant `()` no longer optimize to `false` (should raise a type error during runtime).
 * Fixes concatenation of BLOB's and strings, where the BLOB's should be interpreted as UTF-8 encoded strings.
+* Capturing an unknown variable in a closure no longer panics.
 
 New features
 ------------
diff --git a/src/eval/stmt.rs b/src/eval/stmt.rs
index 9154a92e..bb7ac905 100644
--- a/src/eval/stmt.rs
+++ b/src/eval/stmt.rs
@@ -1016,7 +1016,7 @@ impl Engine {
 
             // Share statement
             #[cfg(not(feature = "no_closure"))]
-            Stmt::Share(name, ..) => {
+            Stmt::Share(name, pos) => {
                 if let Some((index, ..)) = scope.get_index(name) {
                     let val = scope.get_mut_by_index(index);
 
@@ -1024,10 +1024,10 @@ impl Engine {
                         // Replace the variable with a shared value.
                         *val = std::mem::take(val).into_shared();
                     }
+                    Ok(Dynamic::UNIT)
                 } else {
-                    unreachable!("variable {} not found for sharing", name);
+                    Err(ERR::ErrorVariableNotFound(name.to_string(), *pos).into())
                 }
-                Ok(Dynamic::UNIT)
             }
 
             _ => unreachable!("statement cannot be evaluated: {:?}", stmt),
diff --git a/tests/closures.rs b/tests/closures.rs
index f7c1b291..392e8e94 100644
--- a/tests/closures.rs
+++ b/tests/closures.rs
@@ -42,21 +42,35 @@ fn test_fn_ptr_curry_call() -> Result<(), Box<EvalAltResult>> {
 #[cfg(not(feature = "no_object"))]
 fn test_closures() -> Result<(), Box<EvalAltResult>> {
     let mut engine = Engine::new();
+    let mut scope = Scope::new();
+
+    scope.push("x", 42 as INT);
 
     assert!(matches!(
-        *engine
-            .compile_expression("let f = |x| {};")
+        engine
+            .compile_expression("|x| {}")
             .expect_err("should error")
-            .0,
+            .err_type(),
         ParseErrorType::BadInput(..)
     ));
 
+    assert_eq!(
+        engine.eval_with_scope::<INT>(
+            &mut scope,
+            "
+                let f = || { x };
+                f.call()
+            ",
+        )?,
+        42
+    );
+
     assert_eq!(
         engine.eval::<INT>(
             "
                 let foo = #{ x: 42 };
                 let f = || { this.x };
-                foo.call(f)                
+                foo.call(f)
             ",
         )?,
         42