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//! FIXME: write short doc here
use super::*;
pub(super) const PATH_FIRST: TokenSet =
TokenSet::new(&[IDENT, T![self], T![super], T![crate], T![:], T![<]]);
pub(super) fn is_path_start(p: &Parser) -> bool {
is_use_path_start(p) || p.at(T![<])
}
pub(super) fn is_use_path_start(p: &Parser) -> bool {
match p.current() {
IDENT | T![self] | T![super] | T![crate] => true,
T![:] if p.at(T![::]) => true,
_ => false,
}
}
pub(super) fn use_path(p: &mut Parser) {
path(p, Mode::Use)
}
pub(crate) fn type_path(p: &mut Parser) {
path(p, Mode::Type)
}
pub(super) fn expr_path(p: &mut Parser) {
path(p, Mode::Expr)
}
#[derive(Clone, Copy, Eq, PartialEq)]
enum Mode {
Use,
Type,
Expr,
}
fn path(p: &mut Parser, mode: Mode) {
let path = p.start();
path_segment(p, mode, true);
let mut qual = path.complete(p, PATH);
loop {
let use_tree = matches!(p.nth(2), T![*] | T!['{']);
if p.at(T![::]) && !use_tree {
let path = qual.precede(p);
p.bump(T![::]);
path_segment(p, mode, false);
let path = path.complete(p, PATH);
qual = path;
} else {
break;
}
}
}
fn path_segment(p: &mut Parser, mode: Mode, first: bool) {
let m = p.start();
// test qual_paths
// type X = <A as B>::Output;
// fn foo() { <usize as Default>::default(); }
if first && p.eat(T![<]) {
types::type_(p);
if p.eat(T![as]) {
if is_use_path_start(p) {
types::path_type(p);
} else {
p.error("expected a trait");
}
}
p.expect(T![>]);
} else {
let mut empty = true;
if first {
p.eat(T![::]);
empty = false;
}
match p.current() {
IDENT => {
name_ref(p);
opt_path_type_args(p, mode);
}
// test crate_path
// use crate::foo;
T![self] | T![super] | T![crate] => p.bump_any(),
_ => {
p.err_recover("expected identifier", items::ITEM_RECOVERY_SET);
if empty {
// test_err empty_segment
// use crate::;
m.abandon(p);
return;
}
}
};
}
m.complete(p, PATH_SEGMENT);
}
fn opt_path_type_args(p: &mut Parser, mode: Mode) {
match mode {
Mode::Use => {}
Mode::Type => {
// test path_fn_trait_args
// type F = Box<Fn(i32) -> ()>;
if p.at(T!['(']) {
params::param_list_fn_trait(p);
opt_ret_type(p);
} else {
type_args::opt_generic_arg_list(p, false)
}
}
Mode::Expr => type_args::opt_generic_arg_list(p, true),
}
}
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