feat: error if validators have wrong arity

crates/project/src/error.rs

@@ -57,6 +57,15 @@ pub enum Error {
         src: String,
         location: Span,
     },
+
+    #[error("{name} requires at least {at_least} arguments")]
+    WrongValidatorArity {
+        name: String,
+        at_least: u8,
+        location: Span,
+        path: PathBuf,
+        src: String,
+    },
 }
 
 impl Error {
@@ -151,19 +160,20 @@ impl Diagnostic for Error {
             Error::StandardIo(_) => None,
             Error::Format { .. } => None,
             Error::ValidatorMustReturnBool { .. } => Some(Box::new("aiken::scripts")),
+            Error::WrongValidatorArity { .. } => Some(Box::new("aiken::validators")),
         }
     }
 
     fn help<'a>(&'a self) -> Option<Box<dyn Display + 'a>> {
         match self {
             Error::DuplicateModule { first, second, .. } => Some(Box::new(format!(
-                "rename either {} or {}",
+                "Rename either {} or {}",
                 first.display(),
                 second.display()
             ))),
             Error::FileIo { .. } => None,
             Error::ImportCycle { modules } => Some(Box::new(format!(
-                "try moving the shared code to a separate module that the others can depend on\n- {}",
+                "Try moving the shared code to a separate module that the others can depend on\n- {}",
                 modules.join("\n- ")
             ))),
             Error::List(_) => None,
@@ -171,7 +181,8 @@ impl Diagnostic for Error {
             Error::Type { error, .. } => error.help(),
             Error::StandardIo(_) => None,
             Error::Format { .. } => None,
-            Error::ValidatorMustReturnBool { .. } => Some(Box::new("try annotating the validator's return type with Bool")),
+            Error::ValidatorMustReturnBool { .. } => Some(Box::new("Try annotating the validator's return type with Bool")),
+            Error::WrongValidatorArity { .. } => Some(Box::new("Validators require a minimum number of arguments please add the missing arguments.\nIf you don't need one of the required arguments use an underscore `_datum`.")),
         }
     }
 
@@ -188,6 +199,9 @@ impl Diagnostic for Error {
             Error::ValidatorMustReturnBool { location, .. } => Some(Box::new(
                 vec![LabeledSpan::new_with_span(None, *location)].into_iter(),
             )),
+            Error::WrongValidatorArity { location, .. } => Some(Box::new(
+                vec![LabeledSpan::new_with_span(None, *location)].into_iter(),
+            )),
         }
     }
 
@@ -202,6 +216,7 @@ impl Diagnostic for Error {
             Error::StandardIo(_) => None,
             Error::Format { .. } => None,
             Error::ValidatorMustReturnBool { src, .. } => Some(src),
+            Error::WrongValidatorArity { src, .. } => Some(src),
         }
     }
 }

crates/project/src/lib.rs

@@ -12,7 +12,7 @@ pub mod module;
 use aiken_lang::{
     ast::{Definition, ModuleKind},
     builtins,
-    tipo::{Type, TypeInfo},
+    tipo::TypeInfo,
     IdGenerator,
 };
 
@@ -83,7 +83,7 @@ impl Project {
 
         let mut checked_modules = self.type_check(parsed_modules, processing_sequence)?;
 
-        let scripts = self.validate_scripts(&mut checked_modules)?;
+        let _scripts = self.validate_scripts(&mut checked_modules)?;
 
         Ok(())
     }
@@ -260,6 +260,25 @@ impl Project {
 
                         // depending on name, validate the minimum number of arguments
                         // if too low, push a new error on to errors
+                        if [MINT, CERT, WITHDRAWL].contains(&name.as_str()) && arguments.len() < 2 {
+                            errors.push(Error::WrongValidatorArity {
+                                location: *location,
+                                src: module.code.clone(),
+                                path: module.input_path.clone(),
+                                name: name.clone(),
+                                at_least: 2,
+                            })
+                        }
+
+                        if SPEND == name && arguments.len() < 3 {
+                            errors.push(Error::WrongValidatorArity {
+                                location: *location,
+                                src: module.code.clone(),
+                                path: module.input_path.clone(),
+                                name: name.clone(),
+                                at_least: 3,
+                            })
+                        }
                     }
                 }
             }