Add support for multiple integer types.

src/repl.rs

@@ -1,6 +1,6 @@
 use crate::backend::{Backend, BackendError};
 use crate::ir::Program as IR;
-use crate::syntax::{Location, ParserError, Statement};
+use crate::syntax::{ConstantType, Location, ParserError, Statement};
 use codespan_reporting::diagnostic::Diagnostic;
 use codespan_reporting::files::SimpleFiles;
 use codespan_reporting::term::{self, Config};
@@ -135,7 +135,8 @@ impl REPL {
         if let Statement::Binding(_, ref name, _) = syntax {
             if !self.variable_binding_sites.contains_key(name.as_str()) {
                 self.jitter.define_string(name)?;
-                self.jitter.define_variable(name.clone())?;
+                self.jitter
+                    .define_variable(name.clone(), ConstantType::U64)?;
             }
         };