331 lines
10 KiB
Rust
331 lines
10 KiB
Rust
//! Builtin derives.
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use base_db::{CrateOrigin, LangCrateOrigin};
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use std::collections::HashSet;
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use tracing::debug;
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use crate::tt::{self, TokenId};
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use syntax::{
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ast::{self, AstNode, HasGenericParams, HasModuleItem, HasName, HasTypeBounds, PathType},
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match_ast,
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};
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use crate::{db::ExpandDatabase, name, quote, ExpandError, ExpandResult, MacroCallId};
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macro_rules! register_builtin {
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( $($trait:ident => $expand:ident),* ) => {
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#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
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pub enum BuiltinDeriveExpander {
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$($trait),*
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}
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impl BuiltinDeriveExpander {
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pub fn expand(
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&self,
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db: &dyn ExpandDatabase,
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id: MacroCallId,
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tt: &tt::Subtree,
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) -> ExpandResult<tt::Subtree> {
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let expander = match *self {
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$( BuiltinDeriveExpander::$trait => $expand, )*
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};
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expander(db, id, tt)
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}
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fn find_by_name(name: &name::Name) -> Option<Self> {
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match name {
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$( id if id == &name::name![$trait] => Some(BuiltinDeriveExpander::$trait), )*
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_ => None,
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}
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}
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}
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};
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}
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register_builtin! {
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Copy => copy_expand,
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Clone => clone_expand,
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Default => default_expand,
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Debug => debug_expand,
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Hash => hash_expand,
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Ord => ord_expand,
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PartialOrd => partial_ord_expand,
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Eq => eq_expand,
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PartialEq => partial_eq_expand
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}
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pub fn find_builtin_derive(ident: &name::Name) -> Option<BuiltinDeriveExpander> {
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BuiltinDeriveExpander::find_by_name(ident)
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}
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struct BasicAdtInfo {
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name: tt::Ident,
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/// first field is the name, and
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/// second field is `Some(ty)` if it's a const param of type `ty`, `None` if it's a type param.
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/// third fields is where bounds, if any
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param_types: Vec<(tt::Subtree, Option<tt::Subtree>, Option<tt::Subtree>)>,
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associated_types: Vec<tt::Subtree>,
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}
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fn parse_adt(tt: &tt::Subtree) -> Result<BasicAdtInfo, ExpandError> {
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let (parsed, token_map) = mbe::token_tree_to_syntax_node(tt, mbe::TopEntryPoint::MacroItems);
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let macro_items = ast::MacroItems::cast(parsed.syntax_node()).ok_or_else(|| {
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debug!("derive node didn't parse");
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ExpandError::Other("invalid item definition".into())
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})?;
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let item = macro_items.items().next().ok_or_else(|| {
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debug!("no module item parsed");
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ExpandError::Other("no item found".into())
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})?;
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let node = item.syntax();
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let (name, params) = match_ast! {
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match node {
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ast::Struct(it) => (it.name(), it.generic_param_list()),
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ast::Enum(it) => (it.name(), it.generic_param_list()),
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ast::Union(it) => (it.name(), it.generic_param_list()),
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_ => {
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debug!("unexpected node is {:?}", node);
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return Err(ExpandError::Other("expected struct, enum or union".into()))
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},
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}
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};
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let mut param_type_set: HashSet<String> = HashSet::new();
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let param_types = params
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.into_iter()
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.flat_map(|param_list| param_list.type_or_const_params())
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.map(|param| {
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let name = {
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let this = param.name();
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match this {
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Some(x) => {
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param_type_set.insert(x.to_string());
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mbe::syntax_node_to_token_tree(x.syntax()).0
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}
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None => tt::Subtree::empty(),
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}
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};
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let bounds = match ¶m {
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ast::TypeOrConstParam::Type(x) => {
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x.type_bound_list().map(|x| mbe::syntax_node_to_token_tree(x.syntax()).0)
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}
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ast::TypeOrConstParam::Const(_) => None,
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};
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let ty = if let ast::TypeOrConstParam::Const(param) = param {
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let ty = param
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.ty()
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.map(|ty| mbe::syntax_node_to_token_tree(ty.syntax()).0)
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.unwrap_or_else(tt::Subtree::empty);
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Some(ty)
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} else {
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None
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};
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(name, ty, bounds)
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})
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.collect();
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let is_associated_type = |p: &PathType| {
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if let Some(p) = p.path() {
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if let Some(parent) = p.qualifier() {
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if let Some(x) = parent.segment() {
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if let Some(x) = x.path_type() {
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if let Some(x) = x.path() {
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if let Some(pname) = x.as_single_name_ref() {
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if param_type_set.contains(&pname.to_string()) {
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// <T as Trait>::Assoc
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return true;
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}
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}
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}
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}
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}
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if let Some(pname) = parent.as_single_name_ref() {
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if param_type_set.contains(&pname.to_string()) {
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// T::Assoc
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return true;
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}
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}
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}
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}
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false
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};
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let associated_types = node
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.descendants()
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.filter_map(PathType::cast)
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.filter(is_associated_type)
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.map(|x| mbe::syntax_node_to_token_tree(x.syntax()).0)
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.collect::<Vec<_>>();
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let name = name.ok_or_else(|| {
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debug!("parsed item has no name");
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ExpandError::Other("missing name".into())
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})?;
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let name_token_id =
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token_map.token_by_range(name.syntax().text_range()).unwrap_or_else(TokenId::unspecified);
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let name_token = tt::Ident { span: name_token_id, text: name.text().into() };
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Ok(BasicAdtInfo { name: name_token, param_types, associated_types })
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}
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/// Given that we are deriving a trait `DerivedTrait` for a type like:
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///
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/// ```ignore (only-for-syntax-highlight)
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/// struct Struct<'a, ..., 'z, A, B: DeclaredTrait, C, ..., Z> where C: WhereTrait {
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/// a: A,
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/// b: B::Item,
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/// b1: <B as DeclaredTrait>::Item,
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/// c1: <C as WhereTrait>::Item,
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/// c2: Option<<C as WhereTrait>::Item>,
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/// ...
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/// }
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/// ```
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///
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/// create an impl like:
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///
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/// ```ignore (only-for-syntax-highlight)
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/// impl<'a, ..., 'z, A, B: DeclaredTrait, C, ... Z> where
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/// C: WhereTrait,
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/// A: DerivedTrait + B1 + ... + BN,
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/// B: DerivedTrait + B1 + ... + BN,
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/// C: DerivedTrait + B1 + ... + BN,
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/// B::Item: DerivedTrait + B1 + ... + BN,
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/// <C as WhereTrait>::Item: DerivedTrait + B1 + ... + BN,
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/// ...
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/// {
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/// ...
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/// }
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/// ```
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///
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/// where B1, ..., BN are the bounds given by `bounds_paths`.'. Z is a phantom type, and
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/// therefore does not get bound by the derived trait.
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fn expand_simple_derive(tt: &tt::Subtree, trait_path: tt::Subtree) -> ExpandResult<tt::Subtree> {
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let info = match parse_adt(tt) {
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Ok(info) => info,
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Err(e) => return ExpandResult::with_err(tt::Subtree::empty(), e),
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};
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let mut where_block = vec![];
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let (params, args): (Vec<_>, Vec<_>) = info
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.param_types
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.into_iter()
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.map(|(ident, param_ty, bound)| {
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let ident_ = ident.clone();
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if let Some(b) = bound {
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let ident = ident.clone();
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where_block.push(quote! { #ident : #b , });
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}
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if let Some(ty) = param_ty {
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(quote! { const #ident : #ty , }, quote! { #ident_ , })
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} else {
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let bound = trait_path.clone();
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(quote! { #ident : #bound , }, quote! { #ident_ , })
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}
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})
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.unzip();
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where_block.extend(info.associated_types.iter().map(|x| {
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let x = x.clone();
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let bound = trait_path.clone();
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quote! { #x : #bound , }
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}));
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let name = info.name;
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let expanded = quote! {
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impl < ##params > #trait_path for #name < ##args > where ##where_block {}
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};
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ExpandResult::ok(expanded)
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}
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fn find_builtin_crate(db: &dyn ExpandDatabase, id: MacroCallId) -> tt::TokenTree {
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// FIXME: make hygiene works for builtin derive macro
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// such that $crate can be used here.
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let cg = db.crate_graph();
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let krate = db.lookup_intern_macro_call(id).krate;
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let tt = if matches!(cg[krate].origin, CrateOrigin::Lang(LangCrateOrigin::Core)) {
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cov_mark::hit!(test_copy_expand_in_core);
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quote! { crate }
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} else {
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quote! { core }
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};
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tt.token_trees[0].clone()
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}
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fn copy_expand(
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db: &dyn ExpandDatabase,
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id: MacroCallId,
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tt: &tt::Subtree,
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) -> ExpandResult<tt::Subtree> {
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let krate = find_builtin_crate(db, id);
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expand_simple_derive(tt, quote! { #krate::marker::Copy })
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}
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fn clone_expand(
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db: &dyn ExpandDatabase,
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id: MacroCallId,
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tt: &tt::Subtree,
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) -> ExpandResult<tt::Subtree> {
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let krate = find_builtin_crate(db, id);
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expand_simple_derive(tt, quote! { #krate::clone::Clone })
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}
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fn default_expand(
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db: &dyn ExpandDatabase,
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id: MacroCallId,
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tt: &tt::Subtree,
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) -> ExpandResult<tt::Subtree> {
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let krate = find_builtin_crate(db, id);
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expand_simple_derive(tt, quote! { #krate::default::Default })
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}
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fn debug_expand(
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db: &dyn ExpandDatabase,
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id: MacroCallId,
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tt: &tt::Subtree,
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) -> ExpandResult<tt::Subtree> {
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let krate = find_builtin_crate(db, id);
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expand_simple_derive(tt, quote! { #krate::fmt::Debug })
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}
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fn hash_expand(
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db: &dyn ExpandDatabase,
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id: MacroCallId,
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tt: &tt::Subtree,
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) -> ExpandResult<tt::Subtree> {
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let krate = find_builtin_crate(db, id);
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expand_simple_derive(tt, quote! { #krate::hash::Hash })
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}
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fn eq_expand(
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db: &dyn ExpandDatabase,
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id: MacroCallId,
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tt: &tt::Subtree,
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) -> ExpandResult<tt::Subtree> {
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let krate = find_builtin_crate(db, id);
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expand_simple_derive(tt, quote! { #krate::cmp::Eq })
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}
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fn partial_eq_expand(
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db: &dyn ExpandDatabase,
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id: MacroCallId,
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tt: &tt::Subtree,
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) -> ExpandResult<tt::Subtree> {
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let krate = find_builtin_crate(db, id);
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expand_simple_derive(tt, quote! { #krate::cmp::PartialEq })
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}
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fn ord_expand(
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db: &dyn ExpandDatabase,
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id: MacroCallId,
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tt: &tt::Subtree,
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) -> ExpandResult<tt::Subtree> {
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let krate = find_builtin_crate(db, id);
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expand_simple_derive(tt, quote! { #krate::cmp::Ord })
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}
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fn partial_ord_expand(
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db: &dyn ExpandDatabase,
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id: MacroCallId,
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tt: &tt::Subtree,
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) -> ExpandResult<tt::Subtree> {
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let krate = find_builtin_crate(db, id);
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expand_simple_derive(tt, quote! { #krate::cmp::PartialOrd })
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}
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