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expand: Support helper attributes for built-in derive macros

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This commit is contained in:
Vadim Petrochenkov 2021-07-10 17:16:53 +03:00
parent 3e1c75c6e2
commit 6c9ea1e8a9
6 changed files with 144 additions and 81 deletions
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83
compiler/rustc_builtin_macros/src/proc_macro_harness.rs
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@ -5,7 +5,7 @@ use rustc_ast::ptr::P;
use rustc_ast::visit::{self, Visitor};
use rustc_ast::{self as ast, NodeId};
use rustc_ast_pretty::pprust;
use rustc_expand::base::{ExtCtxt, ResolverExpand};
use rustc_expand::base::{parse_macro_name_and_helper_attrs, ExtCtxt, ResolverExpand};
use rustc_expand::expand::{AstFragment, ExpansionConfig};
use rustc_session::Session;
use rustc_span::hygiene::AstPass;
@ -109,86 +109,17 @@ impl<'a> CollectProcMacros<'a> {
}
fn collect_custom_derive(&mut self, item: &'a ast::Item, attr: &'a ast::Attribute) {
// Once we've located the `#[proc_macro_derive]` attribute, verify
// that it's of the form `#[proc_macro_derive(Foo)]` or
// `#[proc_macro_derive(Foo, attributes(A, ..))]`
let list = match attr.meta_item_list() {
Some(list) => list,
None => return,
};
if list.len() != 1 && list.len() != 2 {
self.handler.span_err(attr.span, "attribute must have either one or two arguments");
return;
}
let trait_attr = match list[0].meta_item() {
Some(meta_item) => meta_item,
_ => {
self.handler.span_err(list[0].span(), "not a meta item");
return;
}
};
let trait_ident = match trait_attr.ident() {
Some(trait_ident) if trait_attr.is_word() => trait_ident,
_ => {
self.handler.span_err(trait_attr.span, "must only be one word");
return;
}
};
if !trait_ident.name.can_be_raw() {
self.handler.span_err(
trait_attr.span,
&format!("`{}` cannot be a name of derive macro", trait_ident),
);
}
let attributes_attr = list.get(1);
let proc_attrs: Vec<_> = if let Some(attr) = attributes_attr {
if !attr.has_name(sym::attributes) {
self.handler.span_err(attr.span(), "second argument must be `attributes`")
}
attr.meta_item_list()
.unwrap_or_else(|| {
self.handler
.span_err(attr.span(), "attribute must be of form: `attributes(foo, bar)`");
&[]
})
.iter()
.filter_map(|attr| {
let attr = match attr.meta_item() {
Some(meta_item) => meta_item,
_ => {
self.handler.span_err(attr.span(), "not a meta item");
return None;
}
};
let ident = match attr.ident() {
Some(ident) if attr.is_word() => ident,
_ => {
self.handler.span_err(attr.span, "must only be one word");
return None;
}
};
if !ident.name.can_be_raw() {
self.handler.span_err(
attr.span,
&format!("`{}` cannot be a name of derive helper attribute", ident),
);
}
Some(ident.name)
})
.collect()
} else {
Vec::new()
};
let (trait_name, proc_attrs) =
match parse_macro_name_and_helper_attrs(self.handler, attr, "derive") {
Some(name_and_attrs) => name_and_attrs,
None => return,
};
if self.in_root && item.vis.kind.is_pub() {
self.macros.push(ProcMacro::Derive(ProcMacroDerive {
id: item.id,
span: item.span,
trait_name: trait_ident.name,
trait_name,
function_name: item.ident,
attrs: proc_attrs,
}));