fix trait function generic params in doc signature

crates/cairo-lang-doc/src/documentable_formatter.rs

@@ -463,8 +463,8 @@ impl<'db> HirDisplay<'db> for ImplConstantDefId<'db> {
 
 impl<'db> HirDisplay<'db> for TraitFunctionId<'db> {
     fn hir_fmt(&self, f: &mut HirFormatter<'db>) -> Result<(), SignatureError> {
-        let free_function_full_signature = get_trait_function_signature_data(f.db, *self)?;
-        write_function_signature(f, free_function_full_signature, "".to_string())
+        let trait_function_full_signature = get_trait_function_signature_data(f.db, *self)?;
+        write_function_signature(f, trait_function_full_signature, "".to_string())
             .map_err(|_| SignatureError::FailedWritingSignature(self.full_path(f.db)))?;
         f.format();
         Ok(())

crates/cairo-lang-doc/src/signature_data.rs

@@ -1,3 +1,5 @@
+use std::collections::HashSet;
+
 use cairo_lang_defs::ids::TraitItemId::Function;
 use cairo_lang_defs::ids::{
     ConstantId, EnumId, ExternFunctionId, ExternTypeId, FreeFunctionId, GenericParamId,
@@ -18,8 +20,10 @@ use cairo_lang_semantic::items::module_type_alias::ModuleTypeAliasSemantic;
 use cairo_lang_semantic::items::structure::StructSemantic;
 use cairo_lang_semantic::items::trt::TraitSemantic;
 use cairo_lang_semantic::items::visibility::Visibility;
+use cairo_lang_semantic::lookup_item::HasResolverData;
 use cairo_lang_semantic::{Expr, GenericArgumentId, GenericParam, Parameter, TypeId};
 use cairo_lang_syntax::attribute::structured::Attribute;
+use itertools::Itertools;
 use salsa::Database;
 
 use crate::documentable_item::DocumentableItemId;
@@ -226,6 +230,21 @@ pub(crate) fn get_trait_function_signature_data<'db>(
         .trait_function_resolver_data(item_id)
         .map_err(|_| SignatureError::FailedRetrievingSemanticData(item_id.full_path(db)))?;
 
+    // trait function resolver data contains both: its own and the traits generic params,
+    // to get a signature relevant subset, the trait ones need to be filtered out
+    let trait_id = item_id.trait_id(db);
+    let trait_resolver_data = trait_id
+        .resolver_data(db)
+        .map_err(|_| SignatureError::FailedRetrievingSemanticData(item_id.full_path(db)))?;
+    let trait_params_set: HashSet<_> = trait_resolver_data.generic_params.iter().collect();
+
+    let function_generic_params: Vec<GenericParamId<'_>> = resolver_data
+        .generic_params
+        .iter()
+        .filter(|param| !trait_params_set.contains(param))
+        .cloned()
+        .collect_vec();
+
     Ok(DocumentableItemSignatureData {
         item_id: DocumentableItemId::from(LookupItemId::TraitItem(Function(item_id))),
         name: item_id.name(db),
@@ -237,7 +256,7 @@ pub(crate) fn get_trait_function_signature_data<'db>(
         return_type: Some(signature.return_type),
         attributes: None,
         params: Some(signature.params.clone()),
-        resolver_generic_params: Some(resolver_data.generic_params.clone()),
+        resolver_generic_params: Some(function_generic_params),
         return_value_expr: None,
         full_path: item_id.full_path(db),
     })

crates/cairo-lang-doc/src/tests/test-data/basic.txt

@@ -107,6 +107,10 @@ struct Glass {}
 /// When it's dropped, it shatters.
 struct Cup {}
 
+pub trait TryInto<T, S> {
+    fn try_into(self: T) -> Option<S>;
+}
+
 //! > Item signature #1
 
 //! > Item documentation #1
@@ -364,3 +368,17 @@ When it's dropped, it shatters.
 Content("This cup is droppable.")
 Content("\n")
 Content("When it's dropped, it shatters.")
+
+//! > Item signature #19
+pub trait TryInto<T, S>
+
+//! > Item documentation #19
+
+//! > Item documentation tokens #19
+
+//! > Item signature #20
+fn try_into(self: T) -> Option<S>
+
+//! > Item documentation #20
+
+//! > Item documentation tokens #20

crates/cairo-lang-doc/src/tests/test-data/signature.txt

@@ -195,7 +195,7 @@ type ShapePair;
 //! > Item documentation tokens #12
 
 //! > Item signature #13
-fn area<T, T>(self: T) -> u32
+fn area(self: T) -> u32
 
 //! > Item documentation #13