LS: Add hovers for path segments

crates/cairo-lang-language-server/src/ide/hover/render/definition.rs

@@ -32,6 +32,17 @@ pub fn definition(
             md
         }
 
+        SymbolDef::Module(module) => {
+            let mut md = String::new();
+            md += &fenced_code_block(&module.definition_path());
+            md += &fenced_code_block(&module.signature());
+            if let Some(doc) = module.documentation(db) {
+                md += RULE;
+                md += &doc;
+            }
+            md
+        }
+
         SymbolDef::Variable(var) => fenced_code_block(&var.signature(db)),
         SymbolDef::ExprInlineMacro(macro_name) => {
             let mut md = fenced_code_block(macro_name);

crates/cairo-lang-language-server/src/lang/inspect/defs.rs

@@ -7,6 +7,7 @@ use cairo_lang_defs::ids::{
 };
 use cairo_lang_diagnostics::ToOption;
 use cairo_lang_doc::db::DocGroup;
+use cairo_lang_doc::documentable_item::DocumentableItemId;
 use cairo_lang_parser::db::ParserGroup;
 use cairo_lang_semantic::db::SemanticGroup;
 use cairo_lang_semantic::expr::pattern::QueryPatternVariablesFromDb;
@@ -38,6 +39,7 @@ pub enum SymbolDef {
     Variable(VariableDef),
     ExprInlineMacro(String),
     Member(MemberDef),
+    Module(ModuleDef),
 }
 
 /// Information about a struct member.
@@ -78,7 +80,6 @@ impl SymbolDef {
 
         match definition_item {
             ResolvedItem::Generic(ResolvedGenericItem::GenericConstant(_))
-            | ResolvedItem::Generic(ResolvedGenericItem::Module(_))
             | ResolvedItem::Generic(ResolvedGenericItem::GenericFunction(_))
             | ResolvedItem::Generic(ResolvedGenericItem::TraitFunction(_))
             | ResolvedItem::Generic(ResolvedGenericItem::GenericType(_))
@@ -88,7 +89,6 @@ impl SymbolDef {
             | ResolvedItem::Generic(ResolvedGenericItem::Trait(_))
             | ResolvedItem::Generic(ResolvedGenericItem::Impl(_))
             | ResolvedItem::Concrete(ResolvedConcreteItem::Constant(_))
-            | ResolvedItem::Concrete(ResolvedConcreteItem::Module(_))
             | ResolvedItem::Concrete(ResolvedConcreteItem::Function(_))
             | ResolvedItem::Concrete(ResolvedConcreteItem::TraitFunction(_))
             | ResolvedItem::Concrete(ResolvedConcreteItem::Type(_))
@@ -98,6 +98,14 @@ impl SymbolDef {
                 ItemDef::new(db, &definition_node).map(Self::Item)
             }
 
+            ResolvedItem::Generic(ResolvedGenericItem::Module(id)) => {
+                Some(Self::Module(ModuleDef::new(db, id)))
+            }
+
+            ResolvedItem::Concrete(ResolvedConcreteItem::Module(id)) => {
+                Some(Self::Module(ModuleDef::new(db, id)))
+            }
+
             ResolvedItem::Generic(ResolvedGenericItem::Variable(_)) => {
                 VariableDef::new(db, definition_node).map(Self::Variable)
             }
@@ -290,6 +298,54 @@ impl VariableDef {
     }
 }
 
+/// Information about the definition of a module.
+pub struct ModuleDef {
+    id: ModuleId,
+    name: SmolStr,
+    /// A full path to the parent module if [`ModuleId`] points to a submodule,
+    /// None otherwise (i.e. for a crate root).
+    parent_full_path: Option<String>,
+}
+
+impl ModuleDef {
+    /// Constructs new [`ModuleDef`] instance.
+    pub fn new(db: &AnalysisDatabase, id: ModuleId) -> Self {
+        let name = id.name(db);
+        let parent_full_path = id
+            .full_path(db)
+            .strip_suffix(name.as_str())
+            .unwrap()
+            .strip_suffix("::")  // Fails when path lacks `::`, i.e. when we import from a crate root.
+            .map(String::from);
+
+        ModuleDef { id, name, parent_full_path }
+    }
+
+    /// Gets the module signature: a name preceded by a qualifier: "mod" for submodule
+    /// and "crate" for crate root.
+    pub fn signature(&self) -> String {
+        let prefix = if self.parent_full_path.is_some() { "mod" } else { "crate" };
+        format!("{prefix} {}", self.name)
+    }
+
+    /// Gets the full path of a parent module of the current module.
+    pub fn definition_path(&self) -> String {
+        self.parent_full_path.clone().unwrap_or_default()
+    }
+
+    /// Gets the module's documentation if it's available.
+    pub fn documentation(&self, db: &AnalysisDatabase) -> Option<String> {
+        let doc_id = match self.id {
+            ModuleId::CrateRoot(id) => DocumentableItemId::Crate(id),
+            ModuleId::Submodule(id) => DocumentableItemId::LookupItem(LookupItemId::ModuleItem(
+                ModuleItemId::Submodule(id),
+            )),
+        };
+
+        db.get_item_documentation(doc_id)
+    }
+}
+
 // TODO(mkaput): make private.
 pub fn find_definition(
     db: &AnalysisDatabase,

crates/cairo-lang-language-server/tests/e2e/hover.rs

@@ -17,7 +17,8 @@ cairo_lang_test_utils::test_file_test!(
         partial: "partial.txt",
         starknet: "starknet.txt",
         literals: "literals.txt",
-        structs: "structs.txt"
+        structs: "structs.txt",
+        paths: "paths.txt",
     },
     test_hover
 );

crates/cairo-lang-language-server/tests/test_data/hover/basic.txt

@@ -170,21 +170,31 @@ fn add_two(x: u32) -> u32
 // = source context
     front<caret>_of_house::hosting::add_to_waitlist();
 // = highlight
-No highlight information.
+    <sel>front_of_house</sel>::hosting::add_to_waitlist();
 // = popover
 ```cairo
-fn add_to_waitlist() -> ()
+hello
 ```
+```cairo
+mod front_of_house
+```
+---
+Front of house module.
 
 //! > hover #7
 // = source context
     front_of_house::ho<caret>sting::add_to_waitlist();
 // = highlight
-No highlight information.
+    front_of_house::<sel>hosting</sel>::add_to_waitlist();
 // = popover
 ```cairo
-fn add_to_waitlist() -> ()
+hello::front_of_house
+```
+```cairo
+mod hosting
 ```
+---
+Hosting module.
 
 //! > hover #8
 // = source context