Merge pull request #28 from Eliah-Lakhin/closure-bugs

False-positive capturing prevention bug fix

src/parser.rs

@@ -414,7 +414,8 @@ struct ParseState<'e> {
     /// Tracks a list of external variables (variables that are not explicitly declared in the scope).
     #[cfg(not(feature = "no_closure"))]
     externals: HashMap<String, Position>,
-    /// An indicator that disables variable capturing into externals one single time.
+    /// An indicator that disables variable capturing into externals one single time
+    /// up until the nearest consumed Identifier token.
     /// If set to false the next call to `access_var` will not capture the variable.
     /// All consequent calls to `access_var` will not be affected
     #[cfg(not(feature = "no_closure"))]
@@ -1637,6 +1638,10 @@ fn parse_primary(
 
         // Function call
         Token::Identifier(s) if *next_token == Token::LeftParen || *next_token == Token::Bang => {
+            // Once the identifier consumed we must enable next variables capturing
+            #[cfg(not(feature = "no_closure"))] {
+                state.allow_capture = true;
+            }
             Expr::Variable(Box::new(((s, settings.pos), None, 0, None)))
         }
         // Normal variable access

tests/closures.rs

@@ -1,6 +1,7 @@
 #![cfg(not(feature = "no_function"))]
 use rhai::{Dynamic, Engine, EvalAltResult, FnPtr, Module, RegisterFn, INT};
 use std::any::TypeId;
+use std::mem::take;
 
 #[test]
 fn test_fn_ptr_curry_call() -> Result<(), Box<EvalAltResult>> {
@@ -88,6 +89,29 @@ fn test_closures() -> Result<(), Box<EvalAltResult>> {
         42
     );
 
+    engine.register_raw_fn(
+        "custom_call",
+        &[TypeId::of::<INT>(), TypeId::of::<FnPtr>()],
+        |engine: &Engine, module: &Module, args: &mut [&mut Dynamic]| {
+            let func = take(args[1]).cast::<FnPtr>();
+
+            func.call_dynamic(engine, module, None, [])
+        },
+    );
+
+    assert_eq!(
+        engine.eval::<INT>(
+            r#"
+                let a = 41;
+                let b = 0;
+                let f = || b.custom_call(|| a + 1);
+                
+                f.call()
+            "#
+        )?,
+        42
+    );
+
     Ok(())
 }