Rework generate_raw to avoid need to intern in prop tests

Also, this commit makes `apply_term` automatically re-intern the
  program since it isn't safe to apply any term onto a UPLC program. In
  particular, terms that introduce new let-bindings (via lambdas) will
  mess with the already generated DeBruijn indices.

  The problem doesn't occur for pure constant terms like Data. So we
  still have a safe and fast version 'apply_data' when needed.

crates/uplc/src/ast.rs

@@ -7,6 +7,7 @@ use crate::{
         eval_result::EvalResult,
         Machine,
     },
+    parser::interner::Interner,
 };
 use num_bigint::BigInt;
 use num_traits::ToPrimitive;
@@ -18,7 +19,6 @@ use pallas::ledger::{
     },
     traverse::ComputeHash,
 };
-
 use serde::{
     self,
     de::{self, Deserialize, Deserializer, MapAccess, Visitor},
@@ -58,21 +58,8 @@ where
         }
     }
 
-    /// We use this to apply the validator to Datum,
-    /// then redeemer, then ScriptContext. If datum is
-    /// even necessary (i.e. minting policy).
-    pub fn apply_term(&self, term: &Term<T>) -> Self {
-        let applied_term = Term::Apply {
-            function: Rc::new(self.term.clone()),
-            argument: Rc::new(term.clone()),
-        };
-
-        Program {
-            version: self.version,
-            term: applied_term,
-        }
-    }
-
+    /// A convenient and faster version that `apply_term` since the program doesn't need to be
+    /// re-interned (constant Data do not introduce new bindings).
     pub fn apply_data(&self, plutus_data: PlutusData) -> Self {
         let applied_term = Term::Apply {
             function: Rc::new(self.term.clone()),
@@ -86,6 +73,27 @@ where
     }
 }
 
+impl Program<Name> {
+    /// We use this to apply the validator to Datum,
+    /// then redeemer, then ScriptContext. If datum is
+    /// even necessary (i.e. minting policy).
+    pub fn apply_term(&self, term: &Term<Name>) -> Self {
+        let applied_term = Term::Apply {
+            function: Rc::new(self.term.clone()),
+            argument: Rc::new(term.clone()),
+        };
+
+        let mut program = Program {
+            version: self.version,
+            term: applied_term,
+        };
+
+        Interner::new().program(&mut program);
+
+        program
+    }
+}
+
 impl<'a, T> Display for Program<T>
 where
     T: Binder<'a>,