fix: lsp hover wasn't always working (#5515)

# Description

## Problem

Resolves #5516

## Summary

It seems hover broke in 70dabfa .
However, our tests still pass. I still don't understand why it only
breaks when the request comes from an actual VS Code instance and not in
tests... but for now I'd rather revert the commit that broke it and
eventually try to do the refactor again, because having hover is pretty
nice :-)

## Additional Context

None.

## Documentation\*

Check one:
- [x] No documentation needed.
- [ ] Documentation included in this PR.
- [ ] **[For Experimental Features]** Documentation to be submitted in a
separate PR.

# PR Checklist\*

- [x] I have tested the changes locally.
- [x] I have formatted the changes with [Prettier](https://prettier.io/)
and/or `cargo fmt` on default settings.

Co-authored-by: Tom French <[email protected]>

compiler/noirc_frontend/src/hir/def_collector/dc_mod.rs

@@ -732,7 +732,11 @@ impl<'a> ModCollector<'a> {
 
             context.def_interner.add_module_attributes(
                 mod_id,
-                ModuleAttributes { name: mod_name.0.contents.clone(), location: mod_location },
+                ModuleAttributes {
+                    name: mod_name.0.contents.clone(),
+                    location: mod_location,
+                    parent: self.module_id,
+                },
             );
         }
 

compiler/noirc_frontend/src/node_interner.rs

@@ -48,6 +48,7 @@ const IMPL_SEARCH_RECURSION_LIMIT: u32 = 10;
 pub struct ModuleAttributes {
     pub name: String,
     pub location: Location,
+    pub parent: LocalModuleId,
 }
 
 type StructAttributes = Vec<SecondaryAttribute>;
@@ -1016,6 +1017,10 @@ impl NodeInterner {
         self.module_attributes.get(module_id)
     }
 
+    pub fn try_module_parent(&self, module_id: &ModuleId) -> Option<LocalModuleId> {
+        self.try_module_attributes(module_id).map(|attrs| attrs.parent)
+    }
+
     pub fn global_attributes(&self, global_id: &GlobalId) -> &[SecondaryAttribute] {
         &self.global_attributes[global_id]
     }

tooling/lsp/src/requests/hover.rs

@@ -56,17 +56,14 @@ fn format_reference(reference: ReferenceId, args: &ProcessRequestCallbackArgs) -
 }
 fn format_module(id: ModuleId, args: &ProcessRequestCallbackArgs) -> String {
     let module_attributes = args.interner.module_attributes(&id);
-    let parent_module_id = args.def_maps[&id.krate].modules()[id.local_id.0].parent;
 
     let mut string = String::new();
-    if let Some(parent_module_id) = parent_module_id {
-        if format_parent_module_from_module_id(
-            &ModuleId { krate: id.krate, local_id: parent_module_id },
-            args,
-            &mut string,
-        ) {
-            string.push('\n');
-        }
+    if format_parent_module_from_module_id(
+        &ModuleId { krate: id.krate, local_id: module_attributes.parent },
+        args,
+        &mut string,
+    ) {
+        string.push('\n');
     }
     string.push_str("    ");
     string.push_str("mod ");
@@ -319,6 +316,7 @@ fn format_parent_module_from_module_id(
         CrateId::Stdlib(_) => Some("std".to_string()),
         CrateId::Dummy => None,
     };
+
     let wrote_crate = if let Some(crate_name) = crate_name {
         string.push_str("    ");
         string.push_str(&crate_name);
@@ -331,27 +329,20 @@ fn format_parent_module_from_module_id(
         return wrote_crate;
     };
 
-    let modules = args.def_maps[&module.krate].modules();
-    let module_data = &modules[module.local_id.0];
-
     if wrote_crate {
         string.push_str("::");
     } else {
         string.push_str("    ");
     }
 
     let mut segments = Vec::new();
-    let mut current_parent = module_data.parent;
-    while let Some(parent) = current_parent {
-        let parent_attributes = args
-            .interner
-            .try_module_attributes(&ModuleId { krate: module.krate, local_id: parent });
-        if let Some(parent_attributes) = parent_attributes {
-            segments.push(&parent_attributes.name);
-            current_parent = modules[module.local_id.0].parent;
-        } else {
-            break;
-        }
+    let mut current_attributes = module_attributes;
+    while let Some(parent_attributes) = args.interner.try_module_attributes(&ModuleId {
+        krate: module.krate,
+        local_id: current_attributes.parent,
+    }) {
+        segments.push(&parent_attributes.name);
+        current_attributes = parent_attributes;
     }
 
     for segment in segments.iter().rev() {

tooling/lsp/src/requests/mod.rs

@@ -1,7 +1,4 @@
-use std::{
-    collections::{BTreeMap, HashMap},
-    future::Future,
-};
+use std::{collections::HashMap, future::Future};
 
 use crate::{
     parse_diff, resolve_workspace_for_source_path,
@@ -17,11 +14,7 @@ use lsp_types::{
 use nargo::insert_all_files_for_workspace_into_file_manager;
 use nargo_fmt::Config;
 use noirc_driver::file_manager_with_stdlib;
-use noirc_frontend::{
-    graph::{CrateId, Dependency},
-    hir::def_map::CrateDefMap,
-    macros_api::NodeInterner,
-};
+use noirc_frontend::{graph::Dependency, macros_api::NodeInterner};
 use serde::{Deserialize, Serialize};
 
 use crate::{
@@ -285,7 +278,6 @@ pub(crate) struct ProcessRequestCallbackArgs<'a> {
     interners: &'a HashMap<String, NodeInterner>,
     root_crate_name: String,
     root_crate_dependencies: &'a Vec<Dependency>,
-    def_maps: &'a BTreeMap<CrateId, CrateDefMap>,
 }
 
 pub(crate) fn process_request<F, T>(
@@ -340,7 +332,6 @@ where
         interners: &state.cached_definitions,
         root_crate_name: package.name.to_string(),
         root_crate_dependencies: &context.crate_graph[context.root_crate_id()].dependencies,
-        def_maps: &context.def_maps,
     }))
 }
 pub(crate) fn find_all_references_in_workspace(