feat: user super:: in LSP autocompletion if possible (#5751)

# Description

## Problem

Part of #1577

## Summary

We recently added `super::` to `use` so I thought it would be nice if
the auto-importer used that if possible.


![lsp-use-super](https://github.com/user-attachments/assets/4f8cbf37-f844-4293-832e-bc9685295837)

## Additional Context

This PR also includes a small refactor in the hover code because the
code to format a module path exists there too (but the two are different
enough that I didn't reuse them).

## 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 <15848336+TomAFrench@users.noreply.github.com>

tooling/lsp/src/requests/completion.rs

@@ -1185,9 +1185,15 @@ fn name_matches(name: &str, prefix: &str) -> bool {
 
     let mut last_index: i32 = -1;
     for prefix_part in prefix.split('_') {
-        if let Some(name_part_index) =
-            name_parts.iter().position(|name_part| name_part.starts_with(prefix_part))
+        // Look past parts we already matched
+        let offset = if last_index >= 0 { last_index as usize + 1 } else { 0 };
+
+        if let Some(mut name_part_index) =
+            name_parts.iter().skip(offset).position(|name_part| name_part.starts_with(prefix_part))
         {
+            // Need to adjust the index if we skipped some segments
+            name_part_index += offset;
+
             if last_index >= name_part_index as i32 {
                 return false;
             }
@@ -1225,6 +1231,7 @@ mod completion_name_matches_tests {
         assert!(name_matches("FooBar", "foo"));
         assert!(name_matches("FooBar", "bar"));
         assert!(name_matches("FooBar", "foo_bar"));
+        assert!(name_matches("bar_baz", "bar_b"));
 
         assert!(!name_matches("foo_bar", "o_b"));
     }

tooling/lsp/src/requests/completion/auto_import.rs

@@ -1,8 +1,10 @@
+use std::collections::BTreeMap;
+
 use lsp_types::{Position, Range, TextEdit};
 use noirc_frontend::{
     ast::ItemVisibility,
     graph::{CrateId, Dependency},
-    hir::def_map::ModuleId,
+    hir::def_map::{CrateDefMap, ModuleId},
     macros_api::{ModuleDefId, NodeInterner},
     node_interner::ReferenceId,
 };
@@ -16,6 +18,8 @@ use super::{
 
 impl<'a> NodeFinder<'a> {
     pub(super) fn complete_auto_imports(&mut self, prefix: &str, requested_items: RequestedItems) {
+        let current_module_parent_id = get_parent_module_id(self.def_maps, self.module_id);
+
         for (name, entries) in self.interner.get_auto_import_names() {
             if !name_matches(name, prefix) {
                 continue;
@@ -39,8 +43,9 @@ impl<'a> NodeFinder<'a> {
                 let module_full_path;
                 if let ModuleDefId::ModuleId(module_id) = module_def_id {
                     module_full_path = module_id_path(
-                        module_id,
+                        *module_id,
                         &self.module_id,
+                        current_module_parent_id,
                         self.interner,
                         self.dependencies,
                     );
@@ -67,6 +72,7 @@ impl<'a> NodeFinder<'a> {
                     module_full_path = module_id_path(
                         parent_module,
                         &self.module_id,
+                        current_module_parent_id,
                         self.interner,
                         self.dependencies,
                     );
@@ -111,9 +117,18 @@ impl<'a> NodeFinder<'a> {
     }
 }
 
-fn get_parent_module(interner: &NodeInterner, module_def_id: ModuleDefId) -> Option<&ModuleId> {
+fn get_parent_module(interner: &NodeInterner, module_def_id: ModuleDefId) -> Option<ModuleId> {
     let reference_id = module_def_id_to_reference_id(module_def_id);
-    interner.reference_module(reference_id)
+    interner.reference_module(reference_id).copied()
+}
+
+fn get_parent_module_id(
+    def_maps: &BTreeMap<CrateId, CrateDefMap>,
+    module_id: ModuleId,
+) -> Option<ModuleId> {
+    let crate_def_map = &def_maps[&module_id.krate];
+    let module_data = &crate_def_map.modules()[module_id.local_id.0];
+    module_data.parent.map(|parent| ModuleId { krate: module_id.krate, local_id: parent })
 }
 
 fn module_def_id_to_reference_id(module_def_id: ModuleDefId) -> ReferenceId {
@@ -127,69 +142,69 @@ fn module_def_id_to_reference_id(module_def_id: ModuleDefId) -> ReferenceId {
     }
 }
 
-/// Computes the path of `module_id` relative to `current_module_id`.
-/// If it's not relative, the full path is returned.
+/// Returns the path to reach an item inside `target_module_id` from inside `current_module_id`.
+/// Returns a relative path if possible.
 fn module_id_path(
-    module_id: &ModuleId,
+    target_module_id: ModuleId,
     current_module_id: &ModuleId,
+    current_module_parent_id: Option<ModuleId>,
     interner: &NodeInterner,
     dependencies: &[Dependency],
 ) -> String {
-    let mut string = String::new();
-
-    let crate_id = module_id.krate;
-    let crate_name = match crate_id {
-        CrateId::Root(_) => Some("crate".to_string()),
-        CrateId::Crate(_) => dependencies
-            .iter()
-            .find(|dep| dep.crate_id == crate_id)
-            .map(|dep| format!("{}", dep.name)),
-        CrateId::Stdlib(_) => Some("std".to_string()),
-        CrateId::Dummy => None,
-    };
+    if Some(target_module_id) == current_module_parent_id {
+        return "super".to_string();
+    }
 
-    let wrote_crate = if let Some(crate_name) = crate_name {
-        string.push_str(&crate_name);
-        true
-    } else {
-        false
-    };
+    let mut segments: Vec<&str> = Vec::new();
+    let mut is_relative = false;
 
-    let Some(module_attributes) = interner.try_module_attributes(module_id) else {
-        return string;
-    };
+    if let Some(module_attributes) = interner.try_module_attributes(&target_module_id) {
+        segments.push(&module_attributes.name);
 
-    if wrote_crate {
-        string.push_str("::");
-    }
+        let mut current_attributes = module_attributes;
+        loop {
+            let parent_module_id =
+                &ModuleId { krate: target_module_id.krate, local_id: current_attributes.parent };
 
-    let mut segments = Vec::new();
-    let mut current_attributes = module_attributes;
-    loop {
-        let parent_module_id =
-            &ModuleId { krate: module_id.krate, local_id: current_attributes.parent };
-
-        // If the parent module is the current module we stop because we want a relative path to the module
-        if current_module_id == parent_module_id {
-            // When the path is relative we don't want the "crate::" prefix anymore
-            string = string.strip_prefix("crate::").unwrap_or(&string).to_string();
-            break;
-        }
+            if current_module_id == parent_module_id {
+                is_relative = true;
+                break;
+            }
 
-        let Some(parent_attributes) = interner.try_module_attributes(parent_module_id) else {
-            break;
-        };
+            if current_module_parent_id == Some(*parent_module_id) {
+                segments.push("super");
+                is_relative = true;
+                break;
+            }
 
-        segments.push(&parent_attributes.name);
-        current_attributes = parent_attributes;
-    }
+            let Some(parent_attributes) = interner.try_module_attributes(parent_module_id) else {
+                break;
+            };
 
-    for segment in segments.iter().rev() {
-        string.push_str(segment);
-        string.push_str("::");
+            segments.push(&parent_attributes.name);
+            current_attributes = parent_attributes;
+        }
     }
 
-    string.push_str(&module_attributes.name);
+    let crate_id = target_module_id.krate;
+    let crate_name = if is_relative {
+        None
+    } else {
+        match crate_id {
+            CrateId::Root(_) => Some("crate".to_string()),
+            CrateId::Stdlib(_) => Some("std".to_string()),
+            CrateId::Crate(_) => dependencies
+                .iter()
+                .find(|dep| dep.crate_id == crate_id)
+                .map(|dep| dep.name.to_string()),
+            CrateId::Dummy => unreachable!("ICE: A dummy CrateId should not be accessible"),
+        }
+    };
+
+    if let Some(crate_name) = &crate_name {
+        segments.push(crate_name);
+    };
 
-    string
+    segments.reverse();
+    segments.join("::")
 }

tooling/lsp/src/requests/completion/tests.rs

@@ -1446,7 +1446,7 @@ mod completion_tests {
         assert_eq!(
             item.label_details,
             Some(CompletionItemLabelDetails {
-                detail: Some("(use crate::foo::bar::hello_world)".to_string()),
+                detail: Some("(use super::bar::hello_world)".to_string()),
                 description: Some("fn()".to_string())
             })
         );
@@ -1458,7 +1458,7 @@ mod completion_tests {
                     start: Position { line: 7, character: 8 },
                     end: Position { line: 7, character: 8 },
                 },
-                new_text: "use crate::foo::bar::hello_world;\n\n        ".to_string(),
+                new_text: "use super::bar::hello_world;\n\n        ".to_string(),
             }])
         );
     }
@@ -1613,4 +1613,29 @@ mod completion_tests {
         )
         .await;
     }
+
+    #[test]
+    async fn test_auto_import_with_super() {
+        let src = r#"
+            pub fn bar_baz() {}
+
+            mod tests {
+                fn foo() {
+                    bar_b>|<
+                }
+            }
+        "#;
+        let items = get_completions(src).await;
+        assert_eq!(items.len(), 1);
+
+        let item = &items[0];
+        assert_eq!(item.label, "bar_baz()");
+        assert_eq!(
+            item.label_details,
+            Some(CompletionItemLabelDetails {
+                detail: Some("(use super::bar_baz)".to_string()),
+                description: Some("fn()".to_string())
+            })
+        );
+    }
 }

tooling/lsp/src/requests/hover.rs

@@ -319,6 +319,21 @@ fn format_parent_module_from_module_id(
     args: &ProcessRequestCallbackArgs,
     string: &mut String,
 ) -> bool {
+    let mut segments: Vec<&str> = Vec::new();
+
+    if let Some(module_attributes) = args.interner.try_module_attributes(module) {
+        segments.push(&module_attributes.name);
+
+        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;
+        }
+    }
+
     let crate_id = module.krate;
     let crate_name = match crate_id {
         CrateId::Root(_) => Some(args.crate_name.clone()),
@@ -328,44 +343,21 @@ fn format_parent_module_from_module_id(
             .find(|dep| dep.crate_id == crate_id)
             .map(|dep| format!("{}", dep.name)),
         CrateId::Stdlib(_) => Some("std".to_string()),
-        CrateId::Dummy => None,
+        CrateId::Dummy => unreachable!("ICE: A dummy CrateId should not be accessible"),
     };
 
-    let wrote_crate = if let Some(crate_name) = crate_name {
-        string.push_str("    ");
-        string.push_str(&crate_name);
-        true
-    } else {
-        false
-    };
-
-    let Some(module_attributes) = args.interner.try_module_attributes(module) else {
-        return wrote_crate;
+    if let Some(crate_name) = &crate_name {
+        segments.push(crate_name);
     };
 
-    if wrote_crate {
-        string.push_str("::");
-    } else {
-        string.push_str("    ");
-    }
-
-    let mut segments = Vec::new();
-    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() {
-        string.push_str(segment);
-        string.push_str("::");
+    if segments.is_empty() {
+        return false;
     }
 
-    string.push_str(&module_attributes.name);
+    segments.reverse();
 
+    string.push_str("    ");
+    string.push_str(&segments.join("::"));
     true
 }