added type_checks method

Author: Theomat

synth/syntax/program.py

@@ -124,6 +124,9 @@ def __contains__(self, other: "Program") -> bool:
     def __pickle__(o: "Program") -> Tuple:
         pass
 
+    def type_checks(self) -> bool:
+        return True
+
 
 class Variable(Program):
     """
@@ -271,6 +274,12 @@ def __str__(self) -> str:
                 s += " " + format(arg)
             return s + ")"
 
+    def type_checks(self) -> bool:
+        return all(
+            arg.type.is_instance(f_arg_t)
+            for arg, f_arg_t in zip(self.arguments, self.function.type.arguments())
+        )
+
     def __pretty_print__(
         self,
         defined: Dict["Program", Tuple[int, str, str]],