//! Contains basic data about various HIR declarations.

pub mod adt;

use base_db::CrateId;
use hir_expand::{
    name::Name, AstId, ExpandResult, HirFileId, InFile, MacroCallId, MacroCallKind, MacroDefKind,
};
use intern::Interned;
use smallvec::SmallVec;
use syntax::{ast, Parse};
use triomphe::Arc;

use crate::{
    attr::Attrs,
    db::DefDatabase,
    expander::{Expander, Mark},
    item_tree::{
        self, AssocItem, FnFlags, ItemTree, ItemTreeId, MacroCall, ModItem, Param, TreeId,
    },
    macro_call_as_call_id, macro_id_to_def_id,
    nameres::{
        attr_resolution::ResolvedAttr,
        diagnostics::DefDiagnostic,
        proc_macro::{parse_macro_name_and_helper_attrs, ProcMacroKind},
        DefMap, MacroSubNs,
    },
    path::ImportAlias,
    type_ref::{TraitRef, TypeBound, TypeRef},
    visibility::RawVisibility,
    AssocItemId, AstIdWithPath, ConstId, ConstLoc, ExternCrateId, FunctionId, FunctionLoc,
    HasModule, ImplId, Intern, ItemContainerId, ItemLoc, Lookup, Macro2Id, MacroRulesId, ModuleId,
    ProcMacroId, StaticId, TraitAliasId, TraitId, TypeAliasId, TypeAliasLoc,
};

#[derive(Debug, Clone, PartialEq, Eq)]
pub struct FunctionData {
    pub name: Name,
    pub params: Vec<Interned<TypeRef>>,
    pub ret_type: Interned<TypeRef>,
    pub attrs: Attrs,
    pub visibility: RawVisibility,
    pub abi: Option<Interned<str>>,
    pub legacy_const_generics_indices: Box<[u32]>,
    pub rustc_allow_incoherent_impl: bool,
    flags: FnFlags,
}

impl FunctionData {
    pub(crate) fn fn_data_query(db: &dyn DefDatabase, func: FunctionId) -> Arc<FunctionData> {
        let loc = func.lookup(db);
        let krate = loc.container.module(db).krate;
        let item_tree = loc.id.item_tree(db);
        let func = &item_tree[loc.id.value];
        let visibility = if let ItemContainerId::TraitId(trait_id) = loc.container {
            trait_vis(db, trait_id)
        } else {
            item_tree[func.visibility].clone()
        };

        let crate_graph = db.crate_graph();
        let cfg_options = &crate_graph[krate].cfg_options;
        let enabled_params = func
            .params
            .clone()
            .filter(|&param| item_tree.attrs(db, krate, param.into()).is_cfg_enabled(cfg_options));

        // If last cfg-enabled param is a `...` param, it's a varargs function.
        let is_varargs = enabled_params
            .clone()
            .next_back()
            .map_or(false, |param| matches!(item_tree[param], Param::Varargs));

        let mut flags = func.flags;
        if is_varargs {
            flags |= FnFlags::IS_VARARGS;
        }
        if flags.contains(FnFlags::HAS_SELF_PARAM) {
            // If there's a self param in the syntax, but it is cfg'd out, remove the flag.
            let is_cfgd_out = match func.params.clone().next() {
                Some(param) => {
                    !item_tree.attrs(db, krate, param.into()).is_cfg_enabled(cfg_options)
                }
                None => {
                    stdx::never!("fn HAS_SELF_PARAM but no parameters allocated");
                    true
                }
            };
            if is_cfgd_out {
                cov_mark::hit!(cfgd_out_self_param);
                flags.remove(FnFlags::HAS_SELF_PARAM);
            }
        }

        let attrs = item_tree.attrs(db, krate, ModItem::from(loc.id.value).into());
        let legacy_const_generics_indices = attrs
            .by_key("rustc_legacy_const_generics")
            .tt_values()
            .next()
            .map(parse_rustc_legacy_const_generics)
            .unwrap_or_default();
        let rustc_allow_incoherent_impl = attrs.by_key("rustc_allow_incoherent_impl").exists();

        Arc::new(FunctionData {
            name: func.name.clone(),
            params: enabled_params
                .clone()
                .filter_map(|id| match &item_tree[id] {
                    Param::Normal(ty) => Some(ty.clone()),
                    Param::Varargs => None,
                })
                .collect(),
            ret_type: func.ret_type.clone(),
            attrs: item_tree.attrs(db, krate, ModItem::from(loc.id.value).into()),
            visibility,
            abi: func.abi.clone(),
            legacy_const_generics_indices,
            flags,
            rustc_allow_incoherent_impl,
        })
    }

    pub fn has_body(&self) -> bool {
        self.flags.contains(FnFlags::HAS_BODY)
    }

    /// True if the first param is `self`. This is relevant to decide whether this
    /// can be called as a method.
    pub fn has_self_param(&self) -> bool {
        self.flags.contains(FnFlags::HAS_SELF_PARAM)
    }

    pub fn has_default_kw(&self) -> bool {
        self.flags.contains(FnFlags::HAS_DEFAULT_KW)
    }

    pub fn has_const_kw(&self) -> bool {
        self.flags.contains(FnFlags::HAS_CONST_KW)
    }

    pub fn has_async_kw(&self) -> bool {
        self.flags.contains(FnFlags::HAS_ASYNC_KW)
    }

    pub fn has_unsafe_kw(&self) -> bool {
        self.flags.contains(FnFlags::HAS_UNSAFE_KW)
    }

    pub fn is_varargs(&self) -> bool {
        self.flags.contains(FnFlags::IS_VARARGS)
    }
}

fn parse_rustc_legacy_const_generics(tt: &crate::tt::Subtree) -> Box<[u32]> {
    let mut indices = Vec::new();
    for args in tt.token_trees.chunks(2) {
        match &args[0] {
            tt::TokenTree::Leaf(tt::Leaf::Literal(lit)) => match lit.text.parse() {
                Ok(index) => indices.push(index),
                Err(_) => break,
            },
            _ => break,
        }

        if let Some(comma) = args.get(1) {
            match comma {
                tt::TokenTree::Leaf(tt::Leaf::Punct(punct)) if punct.char == ',' => {}
                _ => break,
            }
        }
    }

    indices.into_boxed_slice()
}

#[derive(Debug, Clone, PartialEq, Eq)]
pub struct TypeAliasData {
    pub name: Name,
    pub type_ref: Option<Interned<TypeRef>>,
    pub visibility: RawVisibility,
    pub is_extern: bool,
    pub rustc_has_incoherent_inherent_impls: bool,
    pub rustc_allow_incoherent_impl: bool,
    /// Bounds restricting the type alias itself (eg. `type Ty: Bound;` in a trait or impl).
    pub bounds: Vec<Interned<TypeBound>>,
}

impl TypeAliasData {
    pub(crate) fn type_alias_data_query(
        db: &dyn DefDatabase,
        typ: TypeAliasId,
    ) -> Arc<TypeAliasData> {
        let loc = typ.lookup(db);
        let item_tree = loc.id.item_tree(db);
        let typ = &item_tree[loc.id.value];
        let visibility = if let ItemContainerId::TraitId(trait_id) = loc.container {
            trait_vis(db, trait_id)
        } else {
            item_tree[typ.visibility].clone()
        };

        let attrs = item_tree.attrs(
            db,
            loc.container.module(db).krate(),
            ModItem::from(loc.id.value).into(),
        );
        let rustc_has_incoherent_inherent_impls =
            attrs.by_key("rustc_has_incoherent_inherent_impls").exists();
        let rustc_allow_incoherent_impl = attrs.by_key("rustc_allow_incoherent_impl").exists();

        Arc::new(TypeAliasData {
            name: typ.name.clone(),
            type_ref: typ.type_ref.clone(),
            visibility,
            is_extern: matches!(loc.container, ItemContainerId::ExternBlockId(_)),
            rustc_has_incoherent_inherent_impls,
            rustc_allow_incoherent_impl,
            bounds: typ.bounds.to_vec(),
        })
    }
}

#[derive(Debug, Clone, PartialEq, Eq)]
pub struct TraitData {
    pub name: Name,
    pub items: Vec<(Name, AssocItemId)>,
    pub is_auto: bool,
    pub is_unsafe: bool,
    pub rustc_has_incoherent_inherent_impls: bool,
    pub skip_array_during_method_dispatch: bool,
    pub fundamental: bool,
    pub visibility: RawVisibility,
    /// Whether the trait has `#[rust_skip_array_during_method_dispatch]`. `hir_ty` will ignore
    /// method calls to this trait's methods when the receiver is an array and the crate edition is
    /// 2015 or 2018.
    // box it as the vec is usually empty anyways
    pub attribute_calls: Option<Box<Vec<(AstId<ast::Item>, MacroCallId)>>>,
}

impl TraitData {
    pub(crate) fn trait_data_query(db: &dyn DefDatabase, tr: TraitId) -> Arc<TraitData> {
        db.trait_data_with_diagnostics(tr).0
    }

    pub(crate) fn trait_data_with_diagnostics_query(
        db: &dyn DefDatabase,
        tr: TraitId,
    ) -> (Arc<TraitData>, Arc<[DefDiagnostic]>) {
        let tr_loc @ ItemLoc { container: module_id, id: tree_id } = tr.lookup(db);
        let item_tree = tree_id.item_tree(db);
        let tr_def = &item_tree[tree_id.value];
        let _cx = stdx::panic_context::enter(format!(
            "trait_data_query({tr:?} -> {tr_loc:?} -> {tr_def:?})"
        ));
        let name = tr_def.name.clone();
        let is_auto = tr_def.is_auto;
        let is_unsafe = tr_def.is_unsafe;
        let visibility = item_tree[tr_def.visibility].clone();
        let attrs = item_tree.attrs(db, module_id.krate(), ModItem::from(tree_id.value).into());
        let skip_array_during_method_dispatch =
            attrs.by_key("rustc_skip_array_during_method_dispatch").exists();
        let rustc_has_incoherent_inherent_impls =
            attrs.by_key("rustc_has_incoherent_inherent_impls").exists();
        let fundamental = attrs.by_key("fundamental").exists();
        let mut collector =
            AssocItemCollector::new(db, module_id, tree_id.file_id(), ItemContainerId::TraitId(tr));
        collector.collect(&item_tree, tree_id.tree_id(), &tr_def.items);
        let (items, attribute_calls, diagnostics) = collector.finish();

        (
            Arc::new(TraitData {
                name,
                attribute_calls,
                items,
                is_auto,
                is_unsafe,
                visibility,
                skip_array_during_method_dispatch,
                rustc_has_incoherent_inherent_impls,
                fundamental,
            }),
            diagnostics.into(),
        )
    }

    pub fn associated_types(&self) -> impl Iterator<Item = TypeAliasId> + '_ {
        self.items.iter().filter_map(|(_name, item)| match item {
            AssocItemId::TypeAliasId(t) => Some(*t),
            _ => None,
        })
    }

    pub fn associated_type_by_name(&self, name: &Name) -> Option<TypeAliasId> {
        self.items.iter().find_map(|(item_name, item)| match item {
            AssocItemId::TypeAliasId(t) if item_name == name => Some(*t),
            _ => None,
        })
    }

    pub fn method_by_name(&self, name: &Name) -> Option<FunctionId> {
        self.items.iter().find_map(|(item_name, item)| match item {
            AssocItemId::FunctionId(t) if item_name == name => Some(*t),
            _ => None,
        })
    }

    pub fn attribute_calls(&self) -> impl Iterator<Item = (AstId<ast::Item>, MacroCallId)> + '_ {
        self.attribute_calls.iter().flat_map(|it| it.iter()).copied()
    }
}

#[derive(Debug, Clone, PartialEq, Eq)]
pub struct TraitAliasData {
    pub name: Name,
    pub visibility: RawVisibility,
}

impl TraitAliasData {
    pub(crate) fn trait_alias_query(db: &dyn DefDatabase, id: TraitAliasId) -> Arc<TraitAliasData> {
        let loc = id.lookup(db);
        let item_tree = loc.id.item_tree(db);
        let alias = &item_tree[loc.id.value];
        let visibility = item_tree[alias.visibility].clone();

        Arc::new(TraitAliasData { name: alias.name.clone(), visibility })
    }
}

#[derive(Debug, Clone, PartialEq, Eq)]
pub struct ImplData {
    pub target_trait: Option<Interned<TraitRef>>,
    pub self_ty: Interned<TypeRef>,
    pub items: Vec<AssocItemId>,
    pub is_negative: bool,
    // box it as the vec is usually empty anyways
    pub attribute_calls: Option<Box<Vec<(AstId<ast::Item>, MacroCallId)>>>,
}

impl ImplData {
    pub(crate) fn impl_data_query(db: &dyn DefDatabase, id: ImplId) -> Arc<ImplData> {
        db.impl_data_with_diagnostics(id).0
    }

    pub(crate) fn impl_data_with_diagnostics_query(
        db: &dyn DefDatabase,
        id: ImplId,
    ) -> (Arc<ImplData>, Arc<[DefDiagnostic]>) {
        let _p = profile::span("impl_data_with_diagnostics_query");
        let ItemLoc { container: module_id, id: tree_id } = id.lookup(db);

        let item_tree = tree_id.item_tree(db);
        let impl_def = &item_tree[tree_id.value];
        let target_trait = impl_def.target_trait.clone();
        let self_ty = impl_def.self_ty.clone();
        let is_negative = impl_def.is_negative;

        let mut collector =
            AssocItemCollector::new(db, module_id, tree_id.file_id(), ItemContainerId::ImplId(id));
        collector.collect(&item_tree, tree_id.tree_id(), &impl_def.items);

        let (items, attribute_calls, diagnostics) = collector.finish();
        let items = items.into_iter().map(|(_, item)| item).collect();

        (
            Arc::new(ImplData { target_trait, self_ty, items, is_negative, attribute_calls }),
            diagnostics.into(),
        )
    }

    pub fn attribute_calls(&self) -> impl Iterator<Item = (AstId<ast::Item>, MacroCallId)> + '_ {
        self.attribute_calls.iter().flat_map(|it| it.iter()).copied()
    }
}

#[derive(Debug, Clone, PartialEq, Eq)]
pub struct Macro2Data {
    pub name: Name,
    pub visibility: RawVisibility,
    // It's a bit wasteful as currently this is only for builtin `Default` derive macro, but macro2
    // are rarely used in practice so I think it's okay for now.
    /// Derive helpers, if this is a derive rustc_builtin_macro
    pub helpers: Option<Box<[Name]>>,
}

impl Macro2Data {
    pub(crate) fn macro2_data_query(db: &dyn DefDatabase, makro: Macro2Id) -> Arc<Macro2Data> {
        let loc = makro.lookup(db);
        let item_tree = loc.id.item_tree(db);
        let makro = &item_tree[loc.id.value];

        let helpers = item_tree
            .attrs(db, loc.container.krate(), ModItem::from(loc.id.value).into())
            .by_key("rustc_builtin_macro")
            .tt_values()
            .next()
            .and_then(|attr| parse_macro_name_and_helper_attrs(&attr.token_trees))
            .map(|(_, helpers)| helpers);

        Arc::new(Macro2Data {
            name: makro.name.clone(),
            visibility: item_tree[makro.visibility].clone(),
            helpers,
        })
    }
}
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct MacroRulesData {
    pub name: Name,
    pub macro_export: bool,
}

impl MacroRulesData {
    pub(crate) fn macro_rules_data_query(
        db: &dyn DefDatabase,
        makro: MacroRulesId,
    ) -> Arc<MacroRulesData> {
        let loc = makro.lookup(db);
        let item_tree = loc.id.item_tree(db);
        let makro = &item_tree[loc.id.value];

        let macro_export = item_tree
            .attrs(db, loc.container.krate(), ModItem::from(loc.id.value).into())
            .by_key("macro_export")
            .exists();

        Arc::new(MacroRulesData { name: makro.name.clone(), macro_export })
    }
}

#[derive(Debug, Clone, PartialEq, Eq)]
pub struct ProcMacroData {
    pub name: Name,
    /// Derive helpers, if this is a derive
    pub helpers: Option<Box<[Name]>>,
}

impl ProcMacroData {
    pub(crate) fn proc_macro_data_query(
        db: &dyn DefDatabase,
        makro: ProcMacroId,
    ) -> Arc<ProcMacroData> {
        let loc = makro.lookup(db);
        let item_tree = loc.id.item_tree(db);
        let makro = &item_tree[loc.id.value];

        let (name, helpers) = if let Some(def) = item_tree
            .attrs(db, loc.container.krate(), ModItem::from(loc.id.value).into())
            .parse_proc_macro_decl(&makro.name)
        {
            (
                def.name,
                match def.kind {
                    ProcMacroKind::CustomDerive { helpers } => Some(helpers),
                    ProcMacroKind::FnLike | ProcMacroKind::Attr => None,
                },
            )
        } else {
            // eeeh...
            stdx::never!("proc macro declaration is not a proc macro");
            (makro.name.clone(), None)
        };
        Arc::new(ProcMacroData { name, helpers })
    }
}

#[derive(Debug, Clone, PartialEq, Eq)]
pub struct ExternCrateDeclData {
    pub name: Name,
    pub alias: Option<ImportAlias>,
    pub visibility: RawVisibility,
    pub crate_id: Option<CrateId>,
}

impl ExternCrateDeclData {
    pub(crate) fn extern_crate_decl_data_query(
        db: &dyn DefDatabase,
        extern_crate: ExternCrateId,
    ) -> Arc<ExternCrateDeclData> {
        let loc = extern_crate.lookup(db);
        let item_tree = loc.id.item_tree(db);
        let extern_crate = &item_tree[loc.id.value];

        let name = extern_crate.name.clone();
        let crate_id = if name == hir_expand::name![self] {
            Some(loc.container.krate())
        } else {
            db.crate_def_map(loc.container.krate())
                .extern_prelude()
                .find(|&(prelude_name, ..)| *prelude_name == name)
                .map(|(_, (root, _))| root.krate())
        };

        Arc::new(Self {
            name: extern_crate.name.clone(),
            visibility: item_tree[extern_crate.visibility].clone(),
            alias: extern_crate.alias.clone(),
            crate_id,
        })
    }
}

#[derive(Debug, Clone, PartialEq, Eq)]
pub struct ConstData {
    /// `None` for `const _: () = ();`
    pub name: Option<Name>,
    pub type_ref: Interned<TypeRef>,
    pub visibility: RawVisibility,
    pub rustc_allow_incoherent_impl: bool,
}

impl ConstData {
    pub(crate) fn const_data_query(db: &dyn DefDatabase, konst: ConstId) -> Arc<ConstData> {
        let loc = konst.lookup(db);
        let item_tree = loc.id.item_tree(db);
        let konst = &item_tree[loc.id.value];
        let visibility = if let ItemContainerId::TraitId(trait_id) = loc.container {
            trait_vis(db, trait_id)
        } else {
            item_tree[konst.visibility].clone()
        };

        let rustc_allow_incoherent_impl = item_tree
            .attrs(db, loc.container.module(db).krate(), ModItem::from(loc.id.value).into())
            .by_key("rustc_allow_incoherent_impl")
            .exists();

        Arc::new(ConstData {
            name: konst.name.clone(),
            type_ref: konst.type_ref.clone(),
            visibility,
            rustc_allow_incoherent_impl,
        })
    }
}

#[derive(Debug, Clone, PartialEq, Eq)]
pub struct StaticData {
    pub name: Name,
    pub type_ref: Interned<TypeRef>,
    pub visibility: RawVisibility,
    pub mutable: bool,
    pub is_extern: bool,
}

impl StaticData {
    pub(crate) fn static_data_query(db: &dyn DefDatabase, konst: StaticId) -> Arc<StaticData> {
        let loc = konst.lookup(db);
        let item_tree = loc.id.item_tree(db);
        let statik = &item_tree[loc.id.value];

        Arc::new(StaticData {
            name: statik.name.clone(),
            type_ref: statik.type_ref.clone(),
            visibility: item_tree[statik.visibility].clone(),
            mutable: statik.mutable,
            is_extern: matches!(loc.container, ItemContainerId::ExternBlockId(_)),
        })
    }
}

struct AssocItemCollector<'a> {
    db: &'a dyn DefDatabase,
    module_id: ModuleId,
    def_map: Arc<DefMap>,
    diagnostics: Vec<DefDiagnostic>,
    container: ItemContainerId,
    expander: Expander,

    items: Vec<(Name, AssocItemId)>,
    attr_calls: Vec<(AstId<ast::Item>, MacroCallId)>,
}

impl<'a> AssocItemCollector<'a> {
    fn new(
        db: &'a dyn DefDatabase,
        module_id: ModuleId,
        file_id: HirFileId,
        container: ItemContainerId,
    ) -> Self {
        Self {
            db,
            module_id,
            def_map: module_id.def_map(db),
            container,
            expander: Expander::new(db, file_id, module_id),
            items: Vec::new(),
            attr_calls: Vec::new(),
            diagnostics: Vec::new(),
        }
    }

    fn finish(
        self,
    ) -> (
        Vec<(Name, AssocItemId)>,
        Option<Box<Vec<(AstId<ast::Item>, MacroCallId)>>>,
        Vec<DefDiagnostic>,
    ) {
        (
            self.items,
            if self.attr_calls.is_empty() { None } else { Some(Box::new(self.attr_calls)) },
            self.diagnostics,
        )
    }

    fn collect(&mut self, item_tree: &ItemTree, tree_id: TreeId, assoc_items: &[AssocItem]) {
        let container = self.container;
        self.items.reserve(assoc_items.len());

        'items: for &item in assoc_items {
            let attrs = item_tree.attrs(self.db, self.module_id.krate, ModItem::from(item).into());
            if !attrs.is_cfg_enabled(self.expander.cfg_options()) {
                self.diagnostics.push(DefDiagnostic::unconfigured_code(
                    self.module_id.local_id,
                    InFile::new(self.expander.current_file_id(), item.ast_id(item_tree).erase()),
                    attrs.cfg().unwrap(),
                    self.expander.cfg_options().clone(),
                ));
                continue;
            }

            'attrs: for attr in &*attrs {
                let ast_id =
                    AstId::new(self.expander.current_file_id(), item.ast_id(item_tree).upcast());
                let ast_id_with_path = AstIdWithPath { path: (*attr.path).clone(), ast_id };

                match self.def_map.resolve_attr_macro(
                    self.db,
                    self.module_id.local_id,
                    ast_id_with_path,
                    attr,
                ) {
                    Ok(ResolvedAttr::Macro(call_id)) => {
                        self.attr_calls.push((ast_id, call_id));
                        // If proc attribute macro expansion is disabled, skip expanding it here
                        if !self.db.expand_proc_attr_macros() {
                            continue 'attrs;
                        }
                        let loc = self.db.lookup_intern_macro_call(call_id);
                        if let MacroDefKind::ProcMacro(exp, ..) = loc.def.kind {
                            // If there's no expander for the proc macro (e.g. the
                            // proc macro is ignored, or building the proc macro
                            // crate failed), skip expansion like we would if it was
                            // disabled. This is analogous to the handling in
                            // `DefCollector::collect_macros`.
                            if exp.is_dummy() {
                                continue 'attrs;
                            }
                        }

                        let res =
                            self.expander.enter_expand_id::<ast::MacroItems>(self.db, call_id);
                        self.collect_macro_items(res, &|| loc.kind.clone());
                        continue 'items;
                    }
                    Ok(_) => (),
                    Err(_) => {
                        self.diagnostics.push(DefDiagnostic::unresolved_macro_call(
                            self.module_id.local_id,
                            MacroCallKind::Attr {
                                ast_id,
                                attr_args: Arc::new((tt::Subtree::empty(), Default::default())),
                                invoc_attr_index: attr.id,
                            },
                            attr.path().clone(),
                        ));
                    }
                }
            }

            self.collect_item(item_tree, tree_id, container, item);
        }
    }

    fn collect_item(
        &mut self,
        item_tree: &ItemTree,
        tree_id: TreeId,
        container: ItemContainerId,
        item: AssocItem,
    ) {
        match item {
            AssocItem::Function(id) => {
                let item = &item_tree[id];

                let def =
                    FunctionLoc { container, id: ItemTreeId::new(tree_id, id) }.intern(self.db);
                self.items.push((item.name.clone(), def.into()));
            }
            AssocItem::Const(id) => {
                let item = &item_tree[id];
                let Some(name) = item.name.clone() else { return };
                let def = ConstLoc { container, id: ItemTreeId::new(tree_id, id) }.intern(self.db);
                self.items.push((name, def.into()));
            }
            AssocItem::TypeAlias(id) => {
                let item = &item_tree[id];

                let def =
                    TypeAliasLoc { container, id: ItemTreeId::new(tree_id, id) }.intern(self.db);
                self.items.push((item.name.clone(), def.into()));
            }
            AssocItem::MacroCall(call) => {
                let file_id = self.expander.current_file_id();
                let MacroCall { ast_id, expand_to, ref path } = item_tree[call];
                let module = self.expander.module.local_id;

                let resolver = |path| {
                    self.def_map
                        .resolve_path(
                            self.db,
                            module,
                            &path,
                            crate::item_scope::BuiltinShadowMode::Other,
                            Some(MacroSubNs::Bang),
                        )
                        .0
                        .take_macros()
                        .map(|it| macro_id_to_def_id(self.db, it))
                };
                match macro_call_as_call_id(
                    self.db.upcast(),
                    &AstIdWithPath::new(file_id, ast_id, Clone::clone(path)),
                    expand_to,
                    self.expander.module.krate(),
                    resolver,
                ) {
                    Ok(Some(call_id)) => {
                        let res =
                            self.expander.enter_expand_id::<ast::MacroItems>(self.db, call_id);
                        self.collect_macro_items(res, &|| hir_expand::MacroCallKind::FnLike {
                            ast_id: InFile::new(file_id, ast_id),
                            expand_to: hir_expand::ExpandTo::Items,
                        });
                    }
                    Ok(None) => (),
                    Err(_) => {
                        self.diagnostics.push(DefDiagnostic::unresolved_macro_call(
                            self.module_id.local_id,
                            MacroCallKind::FnLike {
                                ast_id: InFile::new(file_id, ast_id),
                                expand_to,
                            },
                            Clone::clone(path),
                        ));
                    }
                }
            }
        }
    }

    fn collect_macro_items(
        &mut self,
        ExpandResult { value, err }: ExpandResult<Option<(Mark, Parse<ast::MacroItems>)>>,
        error_call_kind: &dyn Fn() -> hir_expand::MacroCallKind,
    ) {
        let Some((mark, parse)) = value else { return };

        if let Some(err) = err {
            let diag = match err {
                // why is this reported here?
                hir_expand::ExpandError::UnresolvedProcMacro(krate) => {
                    DefDiagnostic::unresolved_proc_macro(
                        self.module_id.local_id,
                        error_call_kind(),
                        krate,
                    )
                }
                _ => DefDiagnostic::macro_error(
                    self.module_id.local_id,
                    error_call_kind(),
                    err.to_string(),
                ),
            };
            self.diagnostics.push(diag);
        }
        if let errors @ [_, ..] = parse.errors() {
            self.diagnostics.push(DefDiagnostic::macro_expansion_parse_error(
                self.module_id.local_id,
                error_call_kind(),
                errors.into(),
            ));
        }

        let tree_id = item_tree::TreeId::new(self.expander.current_file_id(), None);
        let item_tree = tree_id.item_tree(self.db);
        let iter: SmallVec<[_; 2]> =
            item_tree.top_level_items().iter().filter_map(ModItem::as_assoc_item).collect();

        self.collect(&item_tree, tree_id, &iter);

        self.expander.exit(self.db, mark);
    }
}

fn trait_vis(db: &dyn DefDatabase, trait_id: TraitId) -> RawVisibility {
    let ItemLoc { id: tree_id, .. } = trait_id.lookup(db);
    let item_tree = tree_id.item_tree(db);
    let tr_def = &item_tree[tree_id.value];
    item_tree[tr_def.visibility].clone()
}