use std::{ borrow::BorrowMut, collections::{HashMap, HashSet}, iter::FromIterator, ops::{Deref, DerefMut}, sync::Arc, }; use super::typecheck::type_inferencer::PrimitiveStore; use super::typecheck::typedef::{FunSignature, FuncArg, SharedUnifier, Type, TypeEnum, Unifier}; use crate::{ symbol_resolver::SymbolResolver, typecheck::{type_inferencer::CodeLocation, typedef::CallId}, }; use itertools::{izip, Itertools}; use parking_lot::RwLock; use rustpython_parser::ast::{self, Stmt}; #[derive(PartialEq, Eq, PartialOrd, Ord, Clone, Copy, Hash)] pub struct DefinitionId(pub usize); mod type_annotation; use type_annotation::*; mod helper; #[derive(Clone)] pub struct FunInstance { pub body: Vec>>, pub calls: HashMap, pub subst: HashMap, pub unifier_id: usize, } pub enum TopLevelDef { Class { // name for error messages and symbols name: String, // object ID used for TypeEnum object_id: DefinitionId, /// type variables bounded to the class. type_vars: Vec, // class fields fields: Vec<(String, Type)>, // class methods, pointing to the corresponding function definition. methods: Vec<(String, Type, DefinitionId)>, // ancestor classes, including itself. ancestors: Vec, // symbol resolver of the module defined the class, none if it is built-in type resolver: Option>>, }, Function { // prefix for symbol, should be unique globally, and not ending with numbers name: String, // function signature. signature: Type, // instantiated type variable IDs var_id: Vec, /// Function instance to symbol mapping /// Key: string representation of type variable values, sorted by variable ID in ascending /// order, including type variables associated with the class. /// Value: function symbol name. instance_to_symbol: HashMap, /// Function instances to annotated AST mapping /// Key: string representation of type variable values, sorted by variable ID in ascending /// order, including type variables associated with the class. Excluding rigid type /// variables. /// rigid type variables that would be substituted when the function is instantiated. instance_to_stmt: HashMap, // symbol resolver of the module defined the class resolver: Option>>, }, Initializer { class_id: DefinitionId, }, } pub struct TopLevelContext { pub definitions: Arc>>>>, pub unifiers: Arc>>, } pub struct TopLevelComposer { // list of top level definitions, same as top level context pub definition_ast_list: Vec<(Arc>, Option>)>, // start as a primitive unifier, will add more top_level defs inside pub unifier: Unifier, // primitive store pub primitives_ty: PrimitiveStore, // keyword list to prevent same user-defined name pub keyword_list: HashSet, } impl Default for TopLevelComposer { fn default() -> Self { Self::new() } } impl TopLevelComposer { /// return a composer and things to make a "primitive" symbol resolver, so that the symbol /// resolver can later figure out primitive type definitions when passed a primitive type name pub fn new() -> Self { let primitives = Self::make_primitives(); let top_level_def_list = vec![ Arc::new(RwLock::new(Self::make_top_level_class_def(0, None, "int32"))), Arc::new(RwLock::new(Self::make_top_level_class_def(1, None, "int64"))), Arc::new(RwLock::new(Self::make_top_level_class_def(2, None, "float"))), Arc::new(RwLock::new(Self::make_top_level_class_def(3, None, "bool"))), Arc::new(RwLock::new(Self::make_top_level_class_def(4, None, "none"))), ]; let ast_list: Vec>> = vec![None, None, None, None, None]; TopLevelComposer { definition_ast_list: izip!(top_level_def_list, ast_list).collect_vec(), primitives_ty: primitives.0, unifier: primitives.1, // class_method_to_def_id: Default::default(), // to_be_analyzed_class: Default::default(), keyword_list: HashSet::from_iter(vec![ "Generic".into(), "virtual".into(), "list".into(), "tuple".into(), "int32".into(), "int64".into(), "float".into(), "bool".into(), "none".into(), "None".into(), ]), } } pub fn make_top_level_context(self) -> TopLevelContext { TopLevelContext { definitions: RwLock::new( self.definition_ast_list.into_iter().map(|(x, ..)| x).collect::>(), ) .into(), // FIXME: all the big unifier or? unifiers: Default::default(), } } fn extract_def_list(&self) -> Vec>> { self.definition_ast_list.iter().map(|(def, ..)| def.clone()).collect_vec() } /// step 0, register, just remeber the names of top level classes/function /// and check duplicate class/method/function definition pub fn register_top_level( &mut self, ast: ast::Stmt<()>, resolver: Option>>, ) -> Result<(String, DefinitionId), String> { let mut defined_class_name: HashSet = HashSet::new(); let mut defined_class_method_name: HashSet = HashSet::new(); let mut defined_function_name: HashSet = HashSet::new(); match &ast.node { ast::StmtKind::ClassDef { name, body, .. } => { if self.keyword_list.contains(name) { return Err("cannot use keyword as a class name".into()); } if !defined_class_name.insert(name.clone()) { return Err("duplicate definition of class".into()); } let class_name = name.to_string(); let class_def_id = self.definition_ast_list.len(); // since later when registering class method, ast will still be used, // here push None temporarly, later will move the ast inside let mut class_def_ast = ( Arc::new(RwLock::new(Self::make_top_level_class_def( class_def_id, resolver.clone(), name.as_str(), ))), None, ); // parse class def body and register class methods into the def list. // module's symbol resolver would not know the name of the class methods, // thus cannot return their definition_id let mut class_method_name_def_ids: Vec<( // the simple method name without class name String, // in this top level def, method name is prefixed with the class name Arc>, DefinitionId, Type, )> = Vec::new(); // we do not push anything to the def list, so we keep track of the index // and then push in the correct order after the for loop let mut class_method_index_offset = 0; for b in body { if let ast::StmtKind::FunctionDef { name: method_name, .. } = &b.node { if self.keyword_list.contains(name) { return Err("cannot use keyword as a method name".into()); } let global_class_method_name = Self::make_class_method_name(class_name.clone(), method_name); if !defined_class_method_name.insert(global_class_method_name.clone()) { return Err("duplicate class method definition".into()); } let method_def_id = self.definition_ast_list.len() + { // plus 1 here since we already have the class def class_method_index_offset += 1; class_method_index_offset }; // dummy method define here let dummy_method_type = self.unifier.get_fresh_var(); class_method_name_def_ids.push(( method_name.clone(), RwLock::new(Self::make_top_level_function_def( global_class_method_name, // later unify with parsed type dummy_method_type.0, resolver.clone(), )) .into(), DefinitionId(method_def_id), dummy_method_type.0, )); } else { // do nothing continue; } } // move the ast to the entry of the class in the ast_list class_def_ast.1 = Some(ast); // get the methods into the class_def for (name, _, id, ty) in &class_method_name_def_ids { let mut class_def = class_def_ast.0.write(); if let TopLevelDef::Class { methods, .. } = class_def.deref_mut() { methods.push((name.clone(), *ty, *id)) } else { unreachable!() } } // now class_def_ast and class_method_def_ast_ids are ok, put them into actual def list in correct order self.definition_ast_list.push(class_def_ast); for (_, def, ..) in class_method_name_def_ids { self.definition_ast_list.push((def, None)); } // put the constructor into the def_list self.definition_ast_list.push(( RwLock::new(TopLevelDef::Initializer { class_id: DefinitionId(class_def_id) }) .into(), None, )); Ok((class_name, DefinitionId(class_def_id))) } ast::StmtKind::FunctionDef { name, .. } => { if self.keyword_list.contains(name) { return Err("cannot use keyword as a top level function name".into()); } let fun_name = name.to_string(); if !defined_function_name.insert(name.to_string()) { return Err("duplicate top level function define".into()); } // add to the definition list self.definition_ast_list.push(( RwLock::new(Self::make_top_level_function_def( name.into(), // unify with correct type later self.unifier.get_fresh_var().0, resolver, )) .into(), Some(ast), )); // return Ok((fun_name, DefinitionId(self.definition_ast_list.len() - 1))) } _ => Err("only registrations of top level classes/functions are supprted".into()), } } /// step 1, analyze the type vars associated with top level class fn analyze_top_level_class_type_var(&mut self) -> Result<(), String> { let def_list = &self.definition_ast_list; let temp_def_list = self.extract_def_list(); let unifier = self.unifier.borrow_mut(); let primitives_store = &self.primitives_ty; for (class_def, class_ast) in def_list { // only deal with class def here let mut class_def = class_def.write(); let (class_bases_ast, class_def_type_vars, class_resolver) = { if let TopLevelDef::Class { type_vars, resolver, .. } = class_def.deref_mut() { if let Some(ast::Located { node: ast::StmtKind::ClassDef { bases, .. }, .. }) = class_ast { (bases, type_vars, resolver) } else { unreachable!("must be both class") } } else { continue; } }; let class_resolver = class_resolver.as_ref().unwrap(); let class_resolver = class_resolver.deref(); let mut is_generic = false; for b in class_bases_ast { match &b.node { // analyze typevars bounded to the class, // only support things like `class A(Generic[T, V])`, // things like `class A(Generic[T, V, ImportedModule.T])` is not supported // i.e. only simple names are allowed in the subscript // should update the TopLevelDef::Class.typevars and the TypeEnum::TObj.params ast::ExprKind::Subscript { value, slice, .. } if { matches!( &value.node, ast::ExprKind::Name { id, .. } if id == "Generic" ) } => { if !is_generic { is_generic = true; } else { return Err("Only single Generic[...] can be in bases".into()); } let mut type_var_list: Vec<&ast::Expr<()>> = vec![]; // if `class A(Generic[T, V, G])` if let ast::ExprKind::Tuple { elts, .. } = &slice.node { type_var_list.extend(elts.iter()); // `class A(Generic[T])` } else { type_var_list.push(slice.deref()); } // parse the type vars let type_vars = type_var_list .into_iter() .map(|e| { class_resolver.parse_type_annotation( &temp_def_list, unifier, primitives_store, e, ) }) .collect::, _>>()?; // check if all are unique type vars let all_unique_type_var = { let mut occured_type_var_id: HashSet = HashSet::new(); type_vars.iter().all(|x| { let ty = unifier.get_ty(*x); if let TypeEnum::TVar { id, .. } = ty.as_ref() { occured_type_var_id.insert(*id) } else { false } }) }; if !all_unique_type_var { return Err("expect unique type variables".into()); } // add to TopLevelDef class_def_type_vars.extend(type_vars); } // if others, do nothing in this function _ => continue, } } } Ok(()) } /// step 2, base classes. /// now that the type vars of all classes are done, handle base classes and /// put Self class into the ancestors list. We only allow single inheritance fn analyze_top_level_class_bases(&mut self) -> Result<(), String> { let temp_def_list = self.extract_def_list(); let unifier = self.unifier.borrow_mut(); // first, only push direct parent into the list for (class_def, class_ast) in self.definition_ast_list.iter_mut() { let mut class_def = class_def.write(); let (class_bases, class_ancestors, class_resolver) = { if let TopLevelDef::Class { ancestors, resolver, .. } = class_def.deref_mut() { if let Some(ast::Located { node: ast::StmtKind::ClassDef { bases, .. }, .. }) = class_ast { (bases, ancestors, resolver) } else { unreachable!("must be both class") } } else { continue; } }; let class_resolver = class_resolver.as_ref().unwrap(); let class_resolver = class_resolver.deref(); let mut has_base = false; for b in class_bases { // type vars have already been handled, so skip on `Generic[...]` if matches!( &b.node, ast::ExprKind::Subscript { value, .. } if matches!( &value.node, ast::ExprKind::Name { id, .. } if id == "Generic" ) ) { continue; } if has_base { return Err("a class def can only have at most one base class \ declaration and one generic declaration" .into()); } has_base = true; // the function parse_ast_to make sure that no type var occured in // bast_ty if it is a CustomClassKind let base_ty = parse_ast_to_type_annotation_kinds( class_resolver, &temp_def_list, unifier, &self.primitives_ty, b, )?; if let TypeAnnotation::CustomClassKind { .. } = &base_ty { class_ancestors.push(base_ty); } else { return Err("class base declaration can only be custom class".into()); } } } // second, get all ancestors let mut ancestors_store: HashMap> = Default::default(); for (class_def, class_ast) in self.definition_ast_list.iter_mut() { let mut class_def = class_def.write(); let (class_ancestors, class_id) = { if let TopLevelDef::Class { ancestors, object_id, .. } = class_def.deref_mut() { if let Some(ast::Located { node: ast::StmtKind::ClassDef { .. }, .. }) = class_ast { (ancestors, *object_id) } else { unreachable!("must be both class") } } else { continue; } }; ancestors_store.insert( class_id, Self::get_all_ancestors_helper(&class_ancestors[0], temp_def_list.as_slice()), ); } // insert the ancestors to the def list for (class_def, class_ast) in self.definition_ast_list.iter_mut() { let mut class_def = class_def.write(); let (class_ancestors, class_id) = { if let TopLevelDef::Class { ancestors, object_id, .. } = class_def.deref_mut() { if let Some(ast::Located { node: ast::StmtKind::ClassDef { .. }, .. }) = class_ast { (ancestors, *object_id) } else { unreachable!("must be both class") } } else { continue; } }; let ans = ancestors_store.get_mut(&class_id).unwrap(); class_ancestors.append(ans); // insert self type annotation class_ancestors .insert(0, make_self_type_annotation(temp_def_list.as_slice(), class_id)?); } Ok(()) } /// step 3, class fields and methods fn analyze_top_level_class_fields_methods(&mut self) -> Result<(), String> { let temp_def_list = self.extract_def_list(); let unifier = self.unifier.borrow_mut(); let primitives = &self.primitives_ty; let def_ast_list = &self.definition_ast_list; let mut type_var_to_concrete_def: HashMap = HashMap::new(); for (class_def, class_ast) in def_ast_list { Self::analyze_single_class_methods_fields( class_def.clone(), &class_ast.as_ref().unwrap().node, &temp_def_list, unifier, primitives, &mut type_var_to_concrete_def, &self.keyword_list, )? } // unification of previously assigned typevar for (ty, def) in type_var_to_concrete_def { let target_ty = get_type_from_type_annotation_kinds(&temp_def_list, unifier, primitives, &def)?; unifier.unify(ty, target_ty)?; } // handle the inheritanced methods and fields for (class_def, _) in def_ast_list { Self::analyze_single_class_ancestors( class_def.clone(), &temp_def_list, unifier, primitives, )?; } Ok(()) } /// step 4, after class methods are done, top level functions have nothing unknown fn analyze_top_level_function(&mut self) -> Result<(), String> { let def_list = &self.definition_ast_list; let keyword_list = &self.keyword_list; let temp_def_list = self.extract_def_list(); let unifier = self.unifier.borrow_mut(); let primitives_store = &self.primitives_ty; for (function_def, function_ast) in def_list { let function_def = function_def.read(); let function_def = function_def.deref(); let function_ast = if let Some(function_ast) = function_ast { function_ast } else { // no ast, class method, continue continue; }; if let TopLevelDef::Function { signature: dummy_ty, resolver, .. } = function_def { if let ast::StmtKind::FunctionDef { args, returns, .. } = &function_ast.node { let resolver = resolver.as_ref(); let resolver = resolver.unwrap(); let resolver = resolver.deref(); let mut function_var_map: HashMap = HashMap::new(); let arg_types = { // make sure no duplicate parameter let mut defined_paramter_name: HashSet = HashSet::new(); let have_unique_fuction_parameter_name = args.args.iter().all(|x| { defined_paramter_name.insert(x.node.arg.clone()) && keyword_list.contains(&x.node.arg) && "self" != x.node.arg }); if !have_unique_fuction_parameter_name { return Err("top level function must have unique parameter names \ and names thould not be the same as the keywords" .into()); } args.args .iter() .map(|x| -> Result { let annotation = x .node .annotation .as_ref() .ok_or_else(|| { "function parameter type annotation needed".to_string() })? .as_ref(); let type_annotation = parse_ast_to_type_annotation_kinds( resolver, temp_def_list.as_slice(), unifier, primitives_store, annotation, )?; // if there are same type variables appears, we only need to copy them once let type_vars_within = get_type_var_contained_in_type_annotation(&type_annotation) .into_iter() .map(|x| -> Result<(u32, Type), String> { if let TypeAnnotation::TypeVarKind(ty) = x { Ok((get_var_id(ty, unifier)?, ty)) } else { unreachable!("must be type var annotation kind") } }) .collect::, _>>()?; for (id, ty) in type_vars_within { if let Some(prev_ty) = function_var_map.insert(id, ty) { // if already have the type inserted, make sure they are the same thing assert_eq!(prev_ty, ty); } } let ty = get_type_from_type_annotation_kinds( temp_def_list.as_ref(), unifier, primitives_store, &type_annotation, )?; Ok(FuncArg { name: x.node.arg.clone(), ty, default_value: Default::default(), }) }) .collect::, _>>()? }; let return_ty_annotation = { let return_annotation = returns .as_ref() .ok_or_else(|| "function return type needed".to_string())? .as_ref(); parse_ast_to_type_annotation_kinds( resolver, &temp_def_list, unifier, primitives_store, return_annotation, )? }; let type_vars_within = get_type_var_contained_in_type_annotation(&return_ty_annotation) .into_iter() .map(|x| -> Result<(u32, Type), String> { if let TypeAnnotation::TypeVarKind(ty) = x { Ok((get_var_id(ty, unifier)?, ty)) } else { unreachable!("must be type var here") } }) .collect::, _>>()?; for (id, ty) in type_vars_within { if let Some(prev_ty) = function_var_map.insert(id, ty) { // if already have the type inserted, make sure they are the same thing assert_eq!(prev_ty, ty); } } let return_ty = get_type_from_type_annotation_kinds( &temp_def_list, unifier, primitives_store, &return_ty_annotation, )?; let function_ty = unifier.add_ty(TypeEnum::TFunc( FunSignature { args: arg_types, ret: return_ty, vars: function_var_map } .into(), )); unifier.unify(*dummy_ty, function_ty)?; } else { unreachable!("must be both function"); } } else { continue; } } Ok(()) } fn analyze_single_class_methods_fields( class_def: Arc>, class_ast: &ast::StmtKind<()>, temp_def_list: &[Arc>], unifier: &mut Unifier, primitives: &PrimitiveStore, type_var_to_concrete_def: &mut HashMap, keyword_list: &HashSet, ) -> Result<(), String> { let mut class_def = class_def.write(); let ( class_id, _class_name, _class_bases_ast, class_body_ast, _class_ancestor_def, class_fields_def, class_methods_def, class_type_vars_def, class_resolver, ) = if let TopLevelDef::Class { object_id, ancestors, fields, methods, resolver, type_vars, .. } = class_def.deref_mut() { if let ast::StmtKind::ClassDef { name, bases, body, .. } = &class_ast { ( *object_id, name.clone(), bases, body, ancestors, fields, methods, type_vars, resolver, ) } else { unreachable!("here must be class def ast"); } } else { unreachable!("here must be class def ast"); }; let class_resolver = class_resolver.as_ref().unwrap(); let class_resolver = class_resolver.as_ref(); for b in class_body_ast { if let ast::StmtKind::FunctionDef { args, returns, name, body, .. } = &b.node { let (method_dummy_ty, ..) = Self::get_class_method_def_info(class_methods_def, name)?; // the method var map can surely include the class's generic parameters let mut method_var_map: HashMap = class_type_vars_def .iter() .map(|ty| { if let TypeEnum::TVar { id, .. } = unifier.get_ty(*ty).as_ref() { (*id, *ty) } else { unreachable!("must be type var here") } }) .collect(); let arg_types: Vec = { // check method parameters cannot have same name let mut defined_paramter_name: HashSet = HashSet::new(); let have_unique_fuction_parameter_name = args.args.iter().all(|x| { defined_paramter_name.insert(x.node.arg.clone()) && !keyword_list.contains(&x.node.arg) }); if !have_unique_fuction_parameter_name { return Err("class method must have unique parameter names \ and names thould not be the same as the keywords" .into()); } let mut result = Vec::new(); for x in &args.args { let name = x.node.arg.clone(); if name != "self" { let type_ann = { let annotation_expr = x .node .annotation .as_ref() .ok_or_else(|| "type annotation needed".to_string())? .as_ref(); parse_ast_to_type_annotation_kinds( class_resolver, temp_def_list, unifier, primitives, annotation_expr, )? }; // find type vars within this method parameter type annotation let type_vars_within = get_type_var_contained_in_type_annotation(&type_ann); // handle the class type var and the method type var for type_var_within in type_vars_within { if let TypeAnnotation::TypeVarKind(ty) = type_var_within { let id = get_var_id(ty, unifier)?; if let Some(prev_ty) = method_var_map.insert(id, ty) { // if already in the list, make sure they are the same? assert_eq!(prev_ty, ty); } } else { unreachable!("must be type var annotation"); } } // finish handling type vars let dummy_func_arg = FuncArg { name, ty: unifier.get_fresh_var().0, // TODO: symbol default value? default_value: None, }; // push the dummy type and the type annotation // into the list for later unification type_var_to_concrete_def.insert(dummy_func_arg.ty, type_ann.clone()); result.push(dummy_func_arg) } else { // if the parameter name is self // python does not seem to enforce the name // representing the self class object to be // `self`??, but we do it here let dummy_func_arg = FuncArg { name: "self".into(), ty: unifier.get_fresh_var().0, default_value: None, }; type_var_to_concrete_def.insert( dummy_func_arg.ty, make_self_type_annotation(temp_def_list, class_id)?, ); result.push(dummy_func_arg); } } result }; let ret_type = { if name != "__init__" { let result = returns .as_ref() .ok_or_else(|| "method return type annotation needed".to_string())? .as_ref(); let annotation = parse_ast_to_type_annotation_kinds( class_resolver, temp_def_list, unifier, primitives, result, )?; // find type vars within this return type annotation let type_vars_within = get_type_var_contained_in_type_annotation(&annotation); // handle the class type var and the method type var for type_var_within in type_vars_within { if let TypeAnnotation::TypeVarKind(ty) = type_var_within { let id = get_var_id(ty, unifier)?; if let Some(prev_ty) = method_var_map.insert(id, ty) { // if already in the list, make sure they are the same? assert_eq!(prev_ty, ty); } } else { unreachable!("must be type var annotation"); } } let dummy_return_type = unifier.get_fresh_var().0; type_var_to_concrete_def.insert(dummy_return_type, annotation.clone()); dummy_return_type } else { // if is the "__init__" function, the return type is self let dummy_return_type = unifier.get_fresh_var().0; type_var_to_concrete_def.insert( dummy_return_type, make_self_type_annotation(temp_def_list, class_id)?, ); dummy_return_type } }; let method_type = unifier.add_ty(TypeEnum::TFunc( FunSignature { args: arg_types, ret: ret_type, vars: method_var_map }.into(), )); // NOTE: unify now since function type is not in type annotation define // which is fine since type within method_type will be subst later unifier.unify(method_dummy_ty, method_type)?; // class fields if name == "__init__" { for b in body { let mut defined_fields: HashSet = HashSet::new(); // TODO: check the type of value, field instantiation check? if let ast::StmtKind::AnnAssign { annotation, target, value: _, .. } = &b.node { if let ast::ExprKind::Attribute { value, attr, .. } = &target.node { if matches!(&value.node, ast::ExprKind::Name { id, .. } if id == "self") { if defined_fields.insert(attr.to_string()) { let dummy_field_type = unifier.get_fresh_var().0; class_fields_def.push((attr.to_string(), dummy_field_type)); let annotation = parse_ast_to_type_annotation_kinds( class_resolver, &temp_def_list, unifier, primitives, annotation.as_ref(), )?; // find type vars within this return type annotation let type_vars_within = get_type_var_contained_in_type_annotation(&annotation); // handle the class type var and the method type var for type_var_within in type_vars_within { if let TypeAnnotation::TypeVarKind(t) = type_var_within { if !class_type_vars_def.contains(&t) { return Err("class fields can only use type \ vars declared as class generic type vars" .into()); } } else { unreachable!("must be type var annotation"); } } type_var_to_concrete_def .insert(dummy_field_type, annotation); } else { return Err("same class fields defined twice".into()); } } } } } } } else { continue; } } Ok(()) } fn analyze_single_class_ancestors( class_def: Arc>, temp_def_list: &[Arc>], unifier: &mut Unifier, primitives: &PrimitiveStore, ) -> Result<(), String> { let mut class_def = class_def.write(); let ( _class_id, class_ancestor_def, _class_fields_def, class_methods_def, _class_type_vars_def, _class_resolver, ) = if let TopLevelDef::Class { object_id, ancestors, fields, methods, resolver, type_vars, .. } = class_def.deref_mut() { (*object_id, ancestors, fields, methods, type_vars, resolver) } else { unreachable!("here must be class def ast"); }; for (method_name, method_ty, ..) in class_methods_def { if method_name == "__init__" { continue; } // search the ancestors from the nearest to the deepest to find overload and check 'search_for_overload: for anc in class_ancestor_def.iter().skip(1) { if let TypeAnnotation::CustomClassKind { id, params } = anc { let anc_class_def = temp_def_list.get(id.0).unwrap().read(); let anc_class_def = anc_class_def.deref(); if let TopLevelDef::Class { methods, type_vars, .. } = anc_class_def { for (anc_method_name, anc_method_ty, ..) in methods { // if same name, then is overload, needs check if anc_method_name == method_name { let param_ty = params .iter() .map(|x| { get_type_from_type_annotation_kinds( temp_def_list, unifier, primitives, x, ) }) .collect::, _>>()?; let subst = type_vars .iter() .map(|x| { if let TypeEnum::TVar { id, .. } = unifier.get_ty(*x).as_ref() { *id } else { unreachable!() } }) .zip(param_ty.into_iter()) .collect::>(); let anc_method_ty = unifier.subst(*anc_method_ty, &subst).unwrap(); if let ( TypeEnum::TFunc(child_method_sig), TypeEnum::TFunc(parent_method_sig), ) = ( unifier.get_ty(*method_ty).as_ref(), unifier.get_ty(anc_method_ty).as_ref(), ) { let ( FunSignature { args: c_as, ret: c_r, .. }, FunSignature { args: p_as, ret: p_r, .. }, ) = (&*child_method_sig.borrow(), &*parent_method_sig.borrow()); // arguments for ( FuncArg { name: c_name, ty: c_ty, .. }, FuncArg { name: p_name, ty: p_ty, .. }, ) in c_as.iter().zip(p_as) { if c_name == "self" { continue; } if c_name != p_name || !Self::check_overload_type_compatible( unifier, *c_ty, *p_ty, ) { return Err("incompatible parameter".into()); } } // check the compatibility of c_r and p_r if !Self::check_overload_type_compatible(unifier, *c_r, *p_r) { return Err("incompatible parameter".into()); } } else { unreachable!("must be function type") } break 'search_for_overload; } } } } } } Ok(()) } }