diff --git a/src/api/optimize.rs b/src/api/optimize.rs
index 7589c2fd..fca162f2 100644
--- a/src/api/optimize.rs
+++ b/src/api/optimize.rs
@@ -56,12 +56,7 @@ impl Engine {
             .shared_lib()
             .iter_fn()
             .filter(|f| f.func.is_script())
-            .map(|f| {
-                f.func
-                    .get_script_fn_def()
-                    .expect("script-defined function")
-                    .clone()
-            })
+            .map(|f| f.func.get_script_fn_def().unwrap().clone())
             .collect();
 
         crate::optimizer::optimize_into_ast(
diff --git a/src/eval/stmt.rs b/src/eval/stmt.rs
index b05a01a3..b5171d8e 100644
--- a/src/eval/stmt.rs
+++ b/src/eval/stmt.rs
@@ -146,7 +146,7 @@ impl Engine {
             let target_is_shared = false;
 
             if target_is_shared {
-                lock_guard = target.write_lock::<Dynamic>().expect("`Dynamic`");
+                lock_guard = target.write_lock::<Dynamic>().unwrap();
                 lhs_ptr_inner = &mut *lock_guard;
             } else {
                 lhs_ptr_inner = &mut *target;
@@ -181,7 +181,20 @@ impl Engine {
             }
         } else {
             // Normal assignment
-            *target.as_mut() = new_val;
+
+            #[cfg(not(feature = "no_closure"))]
+            if target.is_shared() {
+                // Handle case where target is a `Dynamic` shared value
+                // (returned by a variable resolver, for example)
+                *target.write_lock::<Dynamic>().unwrap() = new_val;
+            } else {
+                *target.as_mut() = new_val;
+            }
+
+            #[cfg(feature = "no_closure")]
+            {
+                *target.as_mut() = new_val;
+            }
         }
 
         target.propagate_changed_value(op_info.pos)
@@ -251,8 +264,8 @@ impl Engine {
                         let var_name = lhs.get_variable_name(false).expect("`Expr::Variable`");
 
                         #[cfg(not(feature = "no_closure"))]
-                        // Temp results from expressions are flattened so should never be shared.
-                        // A shared value may be provided by a variable resolver, however.
+                        // Also handle case where target is a `Dynamic` shared value
+                        // (returned by a variable resolver, for example)
                         let is_temp_result = !lhs_ptr.is_ref() && !lhs_ptr.is_shared();
                         #[cfg(feature = "no_closure")]
                         let is_temp_result = !lhs_ptr.is_ref();
diff --git a/src/optimizer.rs b/src/optimizer.rs
index 7d4498af..89fae709 100644
--- a/src/optimizer.rs
+++ b/src/optimizer.rs
@@ -578,7 +578,7 @@ fn optimize_stmt(stmt: &mut Stmt, state: &mut OptimizerState, preserve_result: b
 
             // Then check ranges
             if value.is::<INT>() && !ranges.is_empty() {
-                let value = value.as_int().expect("`INT`");
+                let value = value.as_int().unwrap();
 
                 // Only one range or all ranges without conditions
                 if ranges.len() == 1
diff --git a/src/tokenizer.rs b/src/tokenizer.rs
index bce10ea4..59a63bb5 100644
--- a/src/tokenizer.rs
+++ b/src/tokenizer.rs
@@ -1520,7 +1520,7 @@ fn get_next_token_inner(
                         }
                         #[cfg(any(not(feature = "no_float"), feature = "decimal"))]
                         '.' => {
-                            stream.get_next().expect("`.`");
+                            stream.get_next().unwrap();
 
                             // Check if followed by digits or something that cannot start a property name
                             match stream.peek_next().unwrap_or('\0') {
@@ -1567,7 +1567,7 @@ fn get_next_token_inner(
                                 '+' | '-' => {
                                     result.push(next_char);
                                     pos.advance();
-                                    result.push(stream.get_next().expect("`+` or `-`"));
+                                    result.push(stream.get_next().unwrap());
                                     pos.advance();
                                 }
                                 // Not a floating-point number
diff --git a/tests/var_scope.rs b/tests/var_scope.rs
index 5c6cc29c..fdf256d3 100644
--- a/tests/var_scope.rs
+++ b/tests/var_scope.rs
@@ -196,13 +196,14 @@ fn test_var_resolver() -> Result<(), Box<EvalAltResult>> {
 
     #[cfg(not(feature = "no_closure"))]
     {
-        assert_eq!(engine.eval_with_scope::<INT>(&mut scope, "HELLO")?, 1);
+        assert_eq!(engine.eval::<INT>("HELLO")?, 1);
         *base.write_lock::<INT>().unwrap() = 42;
-        assert_eq!(engine.eval_with_scope::<INT>(&mut scope, "HELLO")?, 42);
-        assert_eq!(
-            engine.eval_with_scope::<INT>(&mut scope, "HELLO = HELLO * 2; HELLO")?,
-            84
-        );
+        assert_eq!(engine.eval::<INT>("HELLO")?, 42);
+        engine.run("HELLO = 123")?;
+        assert_eq!(base.as_int().unwrap(), 123);
+        assert_eq!(engine.eval::<INT>("HELLO = HELLO + 1; HELLO")?, 124);
+        assert_eq!(engine.eval::<INT>("HELLO = HELLO * 2; HELLO")?, 248);
+        assert_eq!(base.as_int().unwrap(), 248);
     }
 
     assert_eq!(engine.eval_with_scope::<INT>(&mut scope, "chameleon")?, 1);