Fix Void callability

src/compiler/ast.rs

@@ -1120,7 +1120,7 @@ fn traverse_node(scope: &Scope, node: &Dict) -> ImlOp {
                     scope.error(
                         traverse_node_offset(node),
                         format!(
-                            "Cannot assign constant '{}' as consumable. Use an identifier starting in upper-case, e.g. '{}{}'",
+                            "Cannot assign to constant '{}' as consumable. Use an identifier starting in upper-case, e.g. '{}{}'",
                             ident, &ident[0..1].to_uppercase(), &ident[1..]
                         )
                     );

src/compiler/iml/imlvalue.rs

@@ -294,7 +294,7 @@ impl ImlValue {
     pub fn is_callable(&self, without_arguments: bool) -> bool {
         match self {
             Self::Shared(value) => value.borrow().is_callable(without_arguments),
-            Self::SelfValue | Self::SelfToken => true, // fixme?
+            Self::SelfValue | Self::SelfToken | Self::VoidToken => true,
             Self::Value(value) => value.is_callable(without_arguments),
             Self::Parselet(parselet) => {
                 let parselet = parselet.borrow();

tests/compiler_identifiers.tok

@@ -19,6 +19,6 @@ _ : "abc"
 
 #---
 #ERR:Line 1, column 1: Cannot assign to constant 'Pi', because it must be consumable. Use an identifier starting in lower-case, e.g. 'pi'
-#ERR:Line 5, column 1: Cannot assign constant 'cident' as consumable. Use an identifier starting in upper-case, e.g. 'Cident'
+#ERR:Line 5, column 1: Cannot assign to constant 'cident' as consumable. Use an identifier starting in upper-case, e.g. 'Cident'
 #ERR:Line 12, column 1: Cannot assign to constant 'Factorial', because it must be consumable. Use an identifier starting in lower-case, e.g. 'factorial'
 #ERR:Line 18, column 1: Cannot assign to constant '_', because it must be consumable. Use an identifier not starting with '_'.