feat: new Error not a constant

crates/uplc/src/machine/error.rs

@@ -12,13 +12,13 @@ pub enum Error {
     OutOfExError(ExBudget),
     #[error("Invalid Stepkind: {0}")]
     InvalidStepKind(u8),
-    #[error("Cannot evaluate an open term: {0:#?}")]
+    #[error("Cannot evaluate an open term:\n\n{0:#?}")]
     OpenTermEvaluated(Term<NamedDeBruijn>),
     #[error("The provided Plutus code called 'error'.")]
     EvaluationFailure,
-    #[error("Attempted to instantiate a non-polymorphic term: {0:#?}")]
+    #[error("Attempted to instantiate a non-polymorphic term:\n\n{0:#?}")]
     NonPolymorphicInstantiation(Value),
-    #[error("Attempted to apply a non-function: {0:#?}")]
+    #[error("Attempted to apply a non-function:\n\n{0:#?}")]
     NonFunctionalApplication(Value),
     #[error("Type mismatch expected '{0}' got '{1}'")]
     TypeMismatch(Type, Type),
@@ -26,9 +26,11 @@ pub enum Error {
     UnexpectedBuiltinTermArgument(Term<NamedDeBruijn>),
     #[error("A builtin expected a term argument, but something else was received:\n\n{}\n\nYou probably have an extra force wrapped around a builtin", .0.to_pretty())]
     BuiltinTermArgumentExpected(Term<NamedDeBruijn>),
+    #[error("Unable to unlift value because it is not a constant:\n\n{0:#?}")]
+    NotAConstant(Value),
 }
 
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, PartialEq)]
 pub enum Type {
     Bool,
     Integer,