Start messing around with cranelift.

src/errors.rs

@@ -21,6 +21,9 @@ pub enum Error {
 
     #[error("Unbound variable '{0}'")]
     UnboundVariable(Location, String),
+
+    #[error("Internal error: {0}")]
+    InternalError(Location, String),
 }
 
 fn locations_to_labels(start: &Location, end: &Location) -> Vec<Label<usize>> {
@@ -168,6 +171,17 @@ impl From<Error> for Diagnostic<usize> {
                     ])
                     .with_message(format!("Unbound variable '{}'", name)),
             },
+
+            Error::InternalError(location, string) => match location {
+                Location::Manufactured => {
+                    Diagnostic::error().with_message(format!("Internal error: {}", string))
+                }
+                Location::InFile(file_id, offset) => Diagnostic::error()
+                    .with_labels(vec![
+                        Label::primary(*file_id, *offset..*offset).with_message("this is related")
+                    ])
+                    .with_message(format!("Internal error: {}", string)),
+            }
         }
     }
 }