From 90b135c44bdf91603f2e2cdf0ab6f168087bab36 Mon Sep 17 00:00:00 2001
From: Ary Borenszweig <asterite@gmail.com>
Date: Wed, 3 Jul 2024 10:06:07 -0300
Subject: [PATCH] fix: go to definition from aliased use (#5396)

# Description

## Problem

Resolves
https://github.com/noir-lang/noir/pull/5390#issuecomment-2205880047

## Summary

Go to definition didn't work in this case:

```rust
use some::name as aliased_name;
//        ~~~~ click here
```



https://github.com/noir-lang/noir/assets/209371/e35ca028-69e0-4e74-8fce-9c63a1376232



Also adds a test that clicking "aliased_name" also works the same way.

## Additional Context



## 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.
- [ ] I have formatted the changes with [Prettier](https://prettier.io/)
and/or `cargo fmt` on default settings.
---
 .../src/hir/def_collector/dc_crate.rs         |  7 +++-
 tooling/lsp/src/requests/goto_definition.rs   | 34 +++++++++++++++++++
 .../go_to_definition/src/main.nr              |  1 +
 3 files changed, 41 insertions(+), 1 deletion(-)

diff --git a/compiler/noirc_frontend/src/hir/def_collector/dc_crate.rs b/compiler/noirc_frontend/src/hir/def_collector/dc_crate.rs
index 5f860e971c9..cd670167d2c 100644
--- a/compiler/noirc_frontend/src/hir/def_collector/dc_crate.rs
+++ b/compiler/noirc_frontend/src/hir/def_collector/dc_crate.rs
@@ -348,7 +348,12 @@ impl DefCollector {
                             .import(name.clone(), ns, resolved_import.is_prelude);
 
                         let file_id = current_def_map.file_id(module_id);
-                        add_import_reference(ns, &name, &mut context.def_interner, file_id);
+                        let last_segment = collected_import.path.last_segment();
+
+                        add_import_reference(ns, &last_segment, &mut context.def_interner, file_id);
+                        if let Some(ref alias) = collected_import.alias {
+                            add_import_reference(ns, alias, &mut context.def_interner, file_id);
+                        }
 
                         if let Err((first_def, second_def)) = result {
                             let err = DefCollectorErrorKind::Duplicate {
diff --git a/tooling/lsp/src/requests/goto_definition.rs b/tooling/lsp/src/requests/goto_definition.rs
index 158b8a1dc35..d52211c08f9 100644
--- a/tooling/lsp/src/requests/goto_definition.rs
+++ b/tooling/lsp/src/requests/goto_definition.rs
@@ -46,6 +46,7 @@ mod goto_definition_tests {
     use std::panic;
 
     use crate::test_utils::{self, search_in_file};
+    use lsp_types::{Position, Range};
     use tokio::test;
 
     use super::*;
@@ -93,4 +94,37 @@ mod goto_definition_tests {
     async fn goto_from_function_location_to_declaration() {
         expect_goto("go_to_definition", "another_function", 0).await;
     }
+
+    #[test]
+    async fn goto_from_use_as() {
+        let (mut state, noir_text_document) = test_utils::init_lsp_server("go_to_definition").await;
+
+        let params = GotoDefinitionParams {
+            text_document_position_params: lsp_types::TextDocumentPositionParams {
+                text_document: lsp_types::TextDocumentIdentifier {
+                    uri: noir_text_document.clone(),
+                },
+                position: Position { line: 7, character: 29 }, // The word after `as`
+            },
+            work_done_progress_params: Default::default(),
+            partial_result_params: Default::default(),
+        };
+
+        let response = on_goto_definition_request(&mut state, params)
+            .await
+            .expect("Could execute on_goto_definition_request")
+            .unwrap_or_else(|| panic!("Didn't get a goto definition response"));
+
+        if let GotoDefinitionResponse::Scalar(location) = response {
+            assert_eq!(
+                location.range,
+                Range {
+                    start: Position { line: 1, character: 11 },
+                    end: Position { line: 1, character: 27 }
+                }
+            );
+        } else {
+            panic!("Expected a scalar response");
+        };
+    }
 }
diff --git a/tooling/lsp/test_programs/go_to_definition/src/main.nr b/tooling/lsp/test_programs/go_to_definition/src/main.nr
index 01ea5a3eadf..c62abb257f2 100644
--- a/tooling/lsp/test_programs/go_to_definition/src/main.nr
+++ b/tooling/lsp/test_programs/go_to_definition/src/main.nr
@@ -5,6 +5,7 @@ mod foo {
 }
 
 use foo::another_function;
+use foo::another_function as aliased_function;
 
 fn some_function() -> Field {
     1 + 2