bug fixes and performance improvements

src/pipeline/error/visibility_mismatch.rs

@@ -0,0 +1,25 @@
+use std::rc::Rc;
+use crate::representations::location::Location;
+use crate::utils::{BoxedIter, iter::box_once};
+
+use super::project_error::{ProjectError, ErrorPosition};
+
+#[derive(Debug)]
+pub struct VisibilityMismatch{
+  pub namespace: Vec<String>,
+  pub file: Rc<Vec<String>>
+}
+impl ProjectError for VisibilityMismatch {
+  fn description(&self) -> &str {
+    "Some occurences of a namespace are exported but others are not"
+  }
+  fn positions(&self) -> BoxedIter<ErrorPosition> {
+    box_once(ErrorPosition {
+      location: Location::File(self.file.clone()),
+      message: Some(format!(
+        "{} is opened multiple times with different visibilities",
+        self.namespace.join("::")
+      ))
+    })
+  }
+}