FIX: TRUE and FALSE can also be functions

Previously the engine was internally transforming TRUE() to TRUE

Note that the friendly giant implements this only for
compatibility reasons

base/src/functions/logical.rs

@@ -7,6 +7,22 @@ use crate::{
 use super::util::compare_values;
 
 impl Model {
+    pub(crate) fn fn_true(&mut self, args: &[Node], cell: CellReferenceIndex) -> CalcResult {
+        if args.is_empty() {
+            CalcResult::Boolean(true)
+        } else {
+            CalcResult::new_args_number_error(cell)
+        }
+    }
+
+    pub(crate) fn fn_false(&mut self, args: &[Node], cell: CellReferenceIndex) -> CalcResult {
+        if args.is_empty() {
+            CalcResult::Boolean(false)
+        } else {
+            CalcResult::new_args_number_error(cell)
+        }
+    }
+
     pub(crate) fn fn_if(&mut self, args: &[Node], cell: CellReferenceIndex) -> CalcResult {
         if args.len() == 2 || args.len() == 3 {
             let cond_result = self.get_boolean(&args[0], cell);

base/src/functions/mod.rs

@@ -949,7 +949,7 @@ impl Model {
         match kind {
             // Logical
             Function::And => self.fn_and(args, cell),
-            Function::False => CalcResult::Boolean(false),
+            Function::False => self.fn_false(args, cell),
             Function::If => self.fn_if(args, cell),
             Function::Iferror => self.fn_iferror(args, cell),
             Function::Ifna => self.fn_ifna(args, cell),
@@ -957,7 +957,7 @@ impl Model {
             Function::Not => self.fn_not(args, cell),
             Function::Or => self.fn_or(args, cell),
             Function::Switch => self.fn_switch(args, cell),
-            Function::True => CalcResult::Boolean(true),
+            Function::True => self.fn_true(args, cell),
             Function::Xor => self.fn_xor(args, cell),
             // Math and trigonometry
             Function::Sin => self.fn_sin(args, cell),