LS: Fix hover on definition (#6255)

crates/cairo-lang-language-server/src/lib.rs

@@ -51,8 +51,9 @@ use cairo_lang_compiler::project::{setup_project, update_crate_roots_from_projec
 use cairo_lang_defs::db::DefsGroup;
 use cairo_lang_defs::ids::{
     FunctionTitleId, LanguageElementId, LookupItemId, MemberId, ModuleId, SubmoduleLongId,
+    TraitItemId,
 };
-use cairo_lang_diagnostics::Diagnostics;
+use cairo_lang_diagnostics::{Diagnostics, ToOption};
 use cairo_lang_filesystem::db::{
     get_originating_location, AsFilesGroupMut, FilesGroup, FilesGroupEx, PrivRawFileContentQuery,
 };
@@ -1045,7 +1046,29 @@ fn find_definition(
             return Some((ResolvedItem::Concrete(item), stable_ptr));
         }
     }
-    None
+
+    // Skip variable definition, otherwise we would get parent ModuleItem for variable.
+    if db.first_ancestor_of_kind(identifier.as_syntax_node(), SyntaxKind::StatementLet).is_none() {
+        let item = match lookup_items.first().copied()? {
+            LookupItemId::ModuleItem(item) => {
+                ResolvedGenericItem::from_module_item(db, item).to_option()?
+            }
+            LookupItemId::TraitItem(trait_item) => {
+                if let TraitItemId::Function(trait_fn) = trait_item {
+                    ResolvedGenericItem::TraitFunction(trait_fn)
+                } else {
+                    ResolvedGenericItem::Trait(trait_item.trait_id(db))
+                }
+            }
+            LookupItemId::ImplItem(impl_item) => {
+                ResolvedGenericItem::Impl(impl_item.impl_def_id(db))
+            }
+        };
+
+        Some((ResolvedItem::Generic(item.clone()), resolved_generic_item_def(db, item)?))
+    } else {
+        None
+    }
 }
 
 #[tracing::instrument(level = "trace", skip_all)]

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

@@ -264,15 +264,32 @@ Calculate the area of the rectangle.
 // = source context
 fn add_t<caret>wo(x: u32) -> u32 { x + 2 }
 // = highlight
-No highlight information.
+fn <sel>add_two</sel>(x: u32) -> u32 { x + 2 }
 // = popover
+```cairo
+hello
+```
+```cairo
+fn add_two(x: u32) -> u32
+```
+---
+`add_two` documentation.
 
 //! > hover #15
 // = source context
     fn area(sel<caret>f: @Rectangle) -> u64;
 // = highlight
-No highlight information.
+    fn area(<sel>self</sel>: @Rectangle) -> u64;
 // = popover
+```cairo
+hello::RectangleTrait
+```
+```cairo
+trait RectangleTrait
+fn area(self: @Rectangle) -> u64
+```
+---
+Calculate the area of the rectangle.
 
 //! > hover #16
 // = source context
@@ -298,8 +315,16 @@ Rectangle struct.
 // = source context
     fn area(se<caret>lf: @Rectangle) -> u64 {
 // = highlight
-No highlight information.
+    fn area(<sel>self</sel>: @Rectangle) -> u64 {
 // = popover
+```cairo
+hello
+```
+```cairo
+impl RectangleImpl of RectangleTrait
+```
+---
+Implementing the `RectangleTrait` for the `Rectangle` struct.
 
 //! > hover #18
 // = source context
@@ -445,31 +470,57 @@ Width of the rectangle.
 // = source context
 enum Co<caret>in {
 // = highlight
-No highlight information.
+enum <sel>Coin</sel> {
 // = popover
-No hover information.
+```cairo
+hello
+```
+```cairo
+enum Coin {
+    Penny,
+}
+```
 
 //! > hover #27
 // = source context
     Pen<caret>ny,
 // = highlight
-No highlight information.
+    <sel>Penny</sel>,
 // = popover
-No hover information.
+```cairo
+hello
+```
+```cairo
+enum Coin {
+    Penny,
+}
+```
 
 //! > hover #28
 // = source context
 fn value_i<caret>n_cents(coin: Coin) -> felt252 {
 // = highlight
-No highlight information.
+fn <sel>value_in_cents</sel>(coin: Coin) -> felt252 {
 // = popover
+```cairo
+hello
+```
+```cairo
+fn value_in_cents(coin: Coin) -> felt252
+```
 
 //! > hover #29
 // = source context
 fn value_in_cents(co<caret>in: Coin) -> felt252 {
 // = highlight
-No highlight information.
+fn value_in_cents(<sel>coin</sel>: Coin) -> felt252 {
 // = popover
+```cairo
+hello
+```
+```cairo
+fn value_in_cents(coin: Coin) -> felt252
+```
 
 //! > hover #30
 // = source context

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

@@ -52,8 +52,14 @@ let mut xyz: <missing>
 // = source context
 fn f(ab<caret>c) -> felt252 {
 // = highlight
-No highlight information.
+fn f(<sel>abc</sel>) -> felt252 {
 // = popover
+```cairo
+hello
+```
+```cairo
+fn f(abc) -> felt252
+```
 
 //! > hover #4
 // = source context

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

@@ -66,8 +66,14 @@ pub fn contract_state_for_testing() -> ContractState
 // = source context
     fn constructor(ref se<caret>lf: ContractState, value_: u128) {
 // = highlight
-No highlight information.
+    fn constructor(ref <sel>self</sel>: ContractState, value_: u128) {
 // = popover
+```cairo
+hello::Balance
+```
+```cairo
+fn constructor(ref self: ContractState, value_: u128)
+```
 
 //! > hover #2
 // = source context