Rename ra_parser -> parser

This commit is contained in:
Aleksey Kladov 2020-08-12 17:06:49 +02:00
parent 6dafc13f5f
commit 50a02eb359
47 changed files with 65 additions and 65 deletions

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//! FIXME: write short doc here
use super::*;
pub(super) fn inner_attributes(p: &mut Parser) {
while p.at(T![#]) && p.nth(1) == T![!] {
attribute(p, true)
}
}
pub(super) fn outer_attributes(p: &mut Parser) {
while p.at(T![#]) {
attribute(p, false)
}
}
fn attribute(p: &mut Parser, inner: bool) {
let attr = p.start();
assert!(p.at(T![#]));
p.bump(T![#]);
if inner {
assert!(p.at(T![!]));
p.bump(T![!]);
}
if p.eat(T!['[']) {
paths::use_path(p);
match p.current() {
T![=] => {
p.bump(T![=]);
if expressions::literal(p).is_none() {
p.error("expected literal");
}
}
T!['('] | T!['['] | T!['{'] => items::token_tree(p),
_ => {}
}
if !p.eat(T![']']) {
p.error("expected `]`");
}
} else {
p.error("expected `[`");
}
attr.complete(p, ATTR);
}

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//! FIXME: write short doc here
mod atom;
pub(crate) use self::atom::{block_expr, match_arm_list};
pub(super) use self::atom::{literal, LITERAL_FIRST};
use super::*;
pub(super) enum StmtWithSemi {
Yes,
No,
Optional,
}
const EXPR_FIRST: TokenSet = LHS_FIRST;
pub(super) fn expr(p: &mut Parser) -> (Option<CompletedMarker>, BlockLike) {
let r = Restrictions { forbid_structs: false, prefer_stmt: false };
expr_bp(p, r, 1)
}
pub(super) fn expr_with_attrs(p: &mut Parser) -> bool {
let m = p.start();
let has_attrs = p.at(T![#]);
attributes::outer_attributes(p);
let (cm, _block_like) = expr(p);
let success = cm.is_some();
match (has_attrs, cm) {
(true, Some(cm)) => {
let kind = cm.kind();
cm.undo_completion(p).abandon(p);
m.complete(p, kind);
}
_ => m.abandon(p),
}
success
}
pub(super) fn expr_stmt(p: &mut Parser) -> (Option<CompletedMarker>, BlockLike) {
let r = Restrictions { forbid_structs: false, prefer_stmt: true };
expr_bp(p, r, 1)
}
fn expr_no_struct(p: &mut Parser) {
let r = Restrictions { forbid_structs: true, prefer_stmt: false };
expr_bp(p, r, 1);
}
fn is_expr_stmt_attr_allowed(kind: SyntaxKind) -> bool {
let forbid = matches!(kind, BIN_EXPR | RANGE_EXPR);
!forbid
}
pub(super) fn stmt(p: &mut Parser, with_semi: StmtWithSemi) {
let m = p.start();
// test attr_on_expr_stmt
// fn foo() {
// #[A] foo();
// #[B] bar!{}
// #[C] #[D] {}
// #[D] return ();
// }
let has_attrs = p.at(T![#]);
attributes::outer_attributes(p);
if p.at(T![let]) {
let_stmt(p, m, with_semi);
return;
}
// test block_items
// fn a() { fn b() {} }
let m = match items::maybe_item(p, m) {
Ok(()) => return,
Err(m) => m,
};
let (cm, blocklike) = expr_stmt(p);
let kind = cm.as_ref().map(|cm| cm.kind()).unwrap_or(ERROR);
if has_attrs && !is_expr_stmt_attr_allowed(kind) {
// test_err attr_on_expr_not_allowed
// fn foo() {
// #[A] 1 + 2;
// #[B] if true {};
// }
p.error(format!("attributes are not allowed on {:?}", kind));
}
if p.at(T!['}']) {
// test attr_on_last_expr_in_block
// fn foo() {
// { #[A] bar!()? }
// #[B] &()
// }
if let Some(cm) = cm {
cm.undo_completion(p).abandon(p);
m.complete(p, kind);
} else {
m.abandon(p);
}
} else {
// test no_semi_after_block
// fn foo() {
// if true {}
// loop {}
// match () {}
// while true {}
// for _ in () {}
// {}
// {}
// macro_rules! test {
// () => {}
// }
// test!{}
// }
match with_semi {
StmtWithSemi::Yes => {
if blocklike.is_block() {
p.eat(T![;]);
} else {
p.expect(T![;]);
}
}
StmtWithSemi::No => {}
StmtWithSemi::Optional => {
if p.at(T![;]) {
p.eat(T![;]);
}
}
}
m.complete(p, EXPR_STMT);
}
// test let_stmt
// fn foo() {
// let a;
// let b: i32;
// let c = 92;
// let d: i32 = 92;
// let e: !;
// let _: ! = {};
// let f = #[attr]||{};
// }
fn let_stmt(p: &mut Parser, m: Marker, with_semi: StmtWithSemi) {
assert!(p.at(T![let]));
p.bump(T![let]);
patterns::pattern(p);
if p.at(T![:]) {
types::ascription(p);
}
if p.eat(T![=]) {
expressions::expr_with_attrs(p);
}
match with_semi {
StmtWithSemi::Yes => {
p.expect(T![;]);
}
StmtWithSemi::No => {}
StmtWithSemi::Optional => {
if p.at(T![;]) {
p.eat(T![;]);
}
}
}
m.complete(p, LET_STMT);
}
}
pub(super) fn expr_block_contents(p: &mut Parser) {
// This is checked by a validator
attributes::inner_attributes(p);
while !p.at(EOF) && !p.at(T!['}']) {
// test nocontentexpr
// fn foo(){
// ;;;some_expr();;;;{;;;};;;;Ok(())
// }
// test nocontentexpr_after_item
// fn simple_function() {
// enum LocalEnum {
// One,
// Two,
// };
// fn f() {};
// struct S {};
// }
if p.at(T![;]) {
p.bump(T![;]);
continue;
}
stmt(p, StmtWithSemi::Yes)
}
}
#[derive(Clone, Copy)]
struct Restrictions {
forbid_structs: bool,
prefer_stmt: bool,
}
/// Binding powers of operators for a Pratt parser.
///
/// See https://www.oilshell.org/blog/2016/11/03.html
#[rustfmt::skip]
fn current_op(p: &Parser) -> (u8, SyntaxKind) {
const NOT_AN_OP: (u8, SyntaxKind) = (0, T![@]);
match p.current() {
T![|] if p.at(T![||]) => (3, T![||]),
T![|] if p.at(T![|=]) => (1, T![|=]),
T![|] => (6, T![|]),
T![>] if p.at(T![>>=]) => (1, T![>>=]),
T![>] if p.at(T![>>]) => (9, T![>>]),
T![>] if p.at(T![>=]) => (5, T![>=]),
T![>] => (5, T![>]),
T![=] if p.at(T![=>]) => NOT_AN_OP,
T![=] if p.at(T![==]) => (5, T![==]),
T![=] => (1, T![=]),
T![<] if p.at(T![<=]) => (5, T![<=]),
T![<] if p.at(T![<<=]) => (1, T![<<=]),
T![<] if p.at(T![<<]) => (9, T![<<]),
T![<] => (5, T![<]),
T![+] if p.at(T![+=]) => (1, T![+=]),
T![+] => (10, T![+]),
T![^] if p.at(T![^=]) => (1, T![^=]),
T![^] => (7, T![^]),
T![%] if p.at(T![%=]) => (1, T![%=]),
T![%] => (11, T![%]),
T![&] if p.at(T![&=]) => (1, T![&=]),
T![&] if p.at(T![&&]) => (4, T![&&]),
T![&] => (8, T![&]),
T![/] if p.at(T![/=]) => (1, T![/=]),
T![/] => (11, T![/]),
T![*] if p.at(T![*=]) => (1, T![*=]),
T![*] => (11, T![*]),
T![.] if p.at(T![..=]) => (2, T![..=]),
T![.] if p.at(T![..]) => (2, T![..]),
T![!] if p.at(T![!=]) => (5, T![!=]),
T![-] if p.at(T![-=]) => (1, T![-=]),
T![-] => (10, T![-]),
T![as] => (12, T![as]),
_ => NOT_AN_OP
}
}
// Parses expression with binding power of at least bp.
fn expr_bp(p: &mut Parser, mut r: Restrictions, bp: u8) -> (Option<CompletedMarker>, BlockLike) {
let mut lhs = match lhs(p, r) {
Some((lhs, blocklike)) => {
// test stmt_bin_expr_ambiguity
// fn foo() {
// let _ = {1} & 2;
// {1} &2;
// }
if r.prefer_stmt && blocklike.is_block() {
return (Some(lhs), BlockLike::Block);
}
lhs
}
None => return (None, BlockLike::NotBlock),
};
loop {
let is_range = p.at(T![..]) || p.at(T![..=]);
let (op_bp, op) = current_op(p);
if op_bp < bp {
break;
}
// test as_precedence
// fn foo() {
// let _ = &1 as *const i32;
// }
if p.at(T![as]) {
lhs = cast_expr(p, lhs);
continue;
}
let m = lhs.precede(p);
p.bump(op);
// test binop_resets_statementness
// fn foo() {
// v = {1}&2;
// }
r = Restrictions { prefer_stmt: false, ..r };
if is_range {
// test postfix_range
// fn foo() {
// let x = 1..;
// match 1.. { _ => () };
// match a.b()..S { _ => () };
// }
let has_trailing_expression =
p.at_ts(EXPR_FIRST) && !(r.forbid_structs && p.at(T!['{']));
if !has_trailing_expression {
// no RHS
lhs = m.complete(p, RANGE_EXPR);
break;
}
}
expr_bp(p, Restrictions { prefer_stmt: false, ..r }, op_bp + 1);
lhs = m.complete(p, if is_range { RANGE_EXPR } else { BIN_EXPR });
}
(Some(lhs), BlockLike::NotBlock)
}
const LHS_FIRST: TokenSet =
atom::ATOM_EXPR_FIRST.union(token_set![T![&], T![*], T![!], T![.], T![-]]);
fn lhs(p: &mut Parser, r: Restrictions) -> Option<(CompletedMarker, BlockLike)> {
let m;
let kind = match p.current() {
// test ref_expr
// fn foo() {
// // reference operator
// let _ = &1;
// let _ = &mut &f();
// let _ = &raw;
// let _ = &raw.0;
// // raw reference operator
// let _ = &raw mut foo;
// let _ = &raw const foo;
// }
T![&] => {
m = p.start();
p.bump(T![&]);
if p.at(IDENT)
&& p.at_contextual_kw("raw")
&& (p.nth_at(1, T![mut]) || p.nth_at(1, T![const]))
{
p.bump_remap(T![raw]);
p.bump_any();
} else {
p.eat(T![mut]);
}
REF_EXPR
}
// test unary_expr
// fn foo() {
// **&1;
// !!true;
// --1;
// }
T![*] | T![!] | T![-] => {
m = p.start();
p.bump_any();
PREFIX_EXPR
}
_ => {
// test full_range_expr
// fn foo() { xs[..]; }
for &op in [T![..=], T![..]].iter() {
if p.at(op) {
m = p.start();
p.bump(op);
if p.at_ts(EXPR_FIRST) && !(r.forbid_structs && p.at(T!['{'])) {
expr_bp(p, r, 2);
}
return Some((m.complete(p, RANGE_EXPR), BlockLike::NotBlock));
}
}
// test expression_after_block
// fn foo() {
// let mut p = F{x: 5};
// {p}.x = 10;
// }
//
let (lhs, blocklike) = atom::atom_expr(p, r)?;
return Some(postfix_expr(p, lhs, blocklike, !(r.prefer_stmt && blocklike.is_block())));
}
};
// parse the interior of the unary expression
expr_bp(p, r, 255);
Some((m.complete(p, kind), BlockLike::NotBlock))
}
fn postfix_expr(
p: &mut Parser,
mut lhs: CompletedMarker,
// Calls are disallowed if the type is a block and we prefer statements because the call cannot be disambiguated from a tuple
// E.g. `while true {break}();` is parsed as
// `while true {break}; ();`
mut block_like: BlockLike,
mut allow_calls: bool,
) -> (CompletedMarker, BlockLike) {
loop {
lhs = match p.current() {
// test stmt_postfix_expr_ambiguity
// fn foo() {
// match () {
// _ => {}
// () => {}
// [] => {}
// }
// }
T!['('] if allow_calls => call_expr(p, lhs),
T!['['] if allow_calls => index_expr(p, lhs),
T![.] => match postfix_dot_expr(p, lhs) {
Ok(it) => it,
Err(it) => {
lhs = it;
break;
}
},
T![?] => try_expr(p, lhs),
_ => break,
};
allow_calls = true;
block_like = BlockLike::NotBlock;
}
return (lhs, block_like);
fn postfix_dot_expr(
p: &mut Parser,
lhs: CompletedMarker,
) -> Result<CompletedMarker, CompletedMarker> {
assert!(p.at(T![.]));
if p.nth(1) == IDENT && (p.nth(2) == T!['('] || p.nth_at(2, T![::])) {
return Ok(method_call_expr(p, lhs));
}
// test await_expr
// fn foo() {
// x.await;
// x.0.await;
// x.0().await?.hello();
// }
if p.nth(1) == T![await] {
let m = lhs.precede(p);
p.bump(T![.]);
p.bump(T![await]);
return Ok(m.complete(p, AWAIT_EXPR));
}
if p.at(T![..=]) || p.at(T![..]) {
return Err(lhs);
}
Ok(field_expr(p, lhs))
}
}
// test call_expr
// fn foo() {
// let _ = f();
// let _ = f()(1)(1, 2,);
// let _ = f(<Foo>::func());
// f(<Foo as Trait>::func());
// }
fn call_expr(p: &mut Parser, lhs: CompletedMarker) -> CompletedMarker {
assert!(p.at(T!['(']));
let m = lhs.precede(p);
arg_list(p);
m.complete(p, CALL_EXPR)
}
// test index_expr
// fn foo() {
// x[1][2];
// }
fn index_expr(p: &mut Parser, lhs: CompletedMarker) -> CompletedMarker {
assert!(p.at(T!['[']));
let m = lhs.precede(p);
p.bump(T!['[']);
expr(p);
p.expect(T![']']);
m.complete(p, INDEX_EXPR)
}
// test method_call_expr
// fn foo() {
// x.foo();
// y.bar::<T>(1, 2,);
// }
fn method_call_expr(p: &mut Parser, lhs: CompletedMarker) -> CompletedMarker {
assert!(p.at(T![.]) && p.nth(1) == IDENT && (p.nth(2) == T!['('] || p.nth_at(2, T![::])));
let m = lhs.precede(p);
p.bump_any();
name_ref(p);
type_args::opt_type_arg_list(p, true);
if p.at(T!['(']) {
arg_list(p);
}
m.complete(p, METHOD_CALL_EXPR)
}
// test field_expr
// fn foo() {
// x.foo;
// x.0.bar;
// x.0();
// }
// test_err bad_tuple_index_expr
// fn foo() {
// x.0.;
// x.1i32;
// x.0x01;
// }
fn field_expr(p: &mut Parser, lhs: CompletedMarker) -> CompletedMarker {
assert!(p.at(T![.]));
let m = lhs.precede(p);
p.bump(T![.]);
if p.at(IDENT) || p.at(INT_NUMBER) {
name_ref_or_index(p)
} else if p.at(FLOAT_NUMBER) {
// FIXME: How to recover and instead parse INT + T![.]?
p.bump_any();
} else {
p.error("expected field name or number")
}
m.complete(p, FIELD_EXPR)
}
// test try_expr
// fn foo() {
// x?;
// }
fn try_expr(p: &mut Parser, lhs: CompletedMarker) -> CompletedMarker {
assert!(p.at(T![?]));
let m = lhs.precede(p);
p.bump(T![?]);
m.complete(p, TRY_EXPR)
}
// test cast_expr
// fn foo() {
// 82 as i32;
// 81 as i8 + 1;
// 79 as i16 - 1;
// 0x36 as u8 <= 0x37;
// }
fn cast_expr(p: &mut Parser, lhs: CompletedMarker) -> CompletedMarker {
assert!(p.at(T![as]));
let m = lhs.precede(p);
p.bump(T![as]);
// Use type_no_bounds(), because cast expressions are not
// allowed to have bounds.
types::type_no_bounds(p);
m.complete(p, CAST_EXPR)
}
fn arg_list(p: &mut Parser) {
assert!(p.at(T!['(']));
let m = p.start();
p.bump(T!['(']);
while !p.at(T![')']) && !p.at(EOF) {
// test arg_with_attr
// fn main() {
// foo(#[attr] 92)
// }
if !expr_with_attrs(p) {
break;
}
if !p.at(T![')']) && !p.expect(T![,]) {
break;
}
}
p.eat(T![')']);
m.complete(p, ARG_LIST);
}
// test path_expr
// fn foo() {
// let _ = a;
// let _ = a::b;
// let _ = ::a::<b>;
// let _ = format!();
// }
fn path_expr(p: &mut Parser, r: Restrictions) -> (CompletedMarker, BlockLike) {
assert!(paths::is_path_start(p));
let m = p.start();
paths::expr_path(p);
match p.current() {
T!['{'] if !r.forbid_structs => {
record_field_list(p);
(m.complete(p, RECORD_EXPR), BlockLike::NotBlock)
}
T![!] if !p.at(T![!=]) => {
let block_like = items::macro_call_after_excl(p);
(m.complete(p, MACRO_CALL), block_like)
}
_ => (m.complete(p, PATH_EXPR), BlockLike::NotBlock),
}
}
// test record_lit
// fn foo() {
// S {};
// S { x, y: 32, };
// S { x, y: 32, ..Default::default() };
// TupleStruct { 0: 1 };
// }
pub(crate) fn record_field_list(p: &mut Parser) {
assert!(p.at(T!['{']));
let m = p.start();
p.bump(T!['{']);
while !p.at(EOF) && !p.at(T!['}']) {
let m = p.start();
// test record_literal_field_with_attr
// fn main() {
// S { #[cfg(test)] field: 1 }
// }
attributes::outer_attributes(p);
match p.current() {
IDENT | INT_NUMBER => {
// test_err record_literal_before_ellipsis_recovery
// fn main() {
// S { field ..S::default() }
// }
if p.nth_at(1, T![:]) || p.nth_at(1, T![..]) {
name_ref_or_index(p);
p.expect(T![:]);
}
expr(p);
m.complete(p, RECORD_EXPR_FIELD);
}
T![.] if p.at(T![..]) => {
m.abandon(p);
p.bump(T![..]);
expr(p);
}
T!['{'] => {
error_block(p, "expected a field");
m.abandon(p);
}
_ => {
p.err_and_bump("expected identifier");
m.abandon(p);
}
}
if !p.at(T!['}']) {
p.expect(T![,]);
}
}
p.expect(T!['}']);
m.complete(p, RECORD_EXPR_FIELD_LIST);
}

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//! FIXME: write short doc here
use super::*;
// test expr_literals
// fn foo() {
// let _ = true;
// let _ = false;
// let _ = 1;
// let _ = 2.0;
// let _ = b'a';
// let _ = 'b';
// let _ = "c";
// let _ = r"d";
// let _ = b"e";
// let _ = br"f";
// }
pub(crate) const LITERAL_FIRST: TokenSet = token_set![
TRUE_KW,
FALSE_KW,
INT_NUMBER,
FLOAT_NUMBER,
BYTE,
CHAR,
STRING,
RAW_STRING,
BYTE_STRING,
RAW_BYTE_STRING
];
pub(crate) fn literal(p: &mut Parser) -> Option<CompletedMarker> {
if !p.at_ts(LITERAL_FIRST) {
return None;
}
let m = p.start();
p.bump_any();
Some(m.complete(p, LITERAL))
}
// E.g. for after the break in `if break {}`, this should not match
pub(super) const ATOM_EXPR_FIRST: TokenSet =
LITERAL_FIRST.union(paths::PATH_FIRST).union(token_set![
T!['('],
T!['{'],
T!['['],
L_DOLLAR,
T![|],
T![move],
T![box],
T![if],
T![while],
T![match],
T![unsafe],
T![return],
T![break],
T![continue],
T![async],
T![try],
T![loop],
T![for],
LIFETIME,
]);
const EXPR_RECOVERY_SET: TokenSet = token_set![LET_KW, R_DOLLAR];
pub(super) fn atom_expr(p: &mut Parser, r: Restrictions) -> Option<(CompletedMarker, BlockLike)> {
if let Some(m) = literal(p) {
return Some((m, BlockLike::NotBlock));
}
if paths::is_path_start(p) {
return Some(path_expr(p, r));
}
let la = p.nth(1);
let done = match p.current() {
T!['('] => tuple_expr(p),
T!['['] => array_expr(p),
L_DOLLAR => meta_var_expr(p),
T![|] => lambda_expr(p),
T![move] if la == T![|] => lambda_expr(p),
T![async] if la == T![|] || (la == T![move] && p.nth(2) == T![|]) => lambda_expr(p),
T![if] => if_expr(p),
T![loop] => loop_expr(p, None),
T![box] => box_expr(p, None),
T![for] => for_expr(p, None),
T![while] => while_expr(p, None),
T![try] => try_block_expr(p, None),
LIFETIME if la == T![:] => {
let m = p.start();
label(p);
match p.current() {
T![loop] => loop_expr(p, Some(m)),
T![for] => for_expr(p, Some(m)),
T![while] => while_expr(p, Some(m)),
// test labeled_block
// fn f() { 'label: {}; }
T!['{'] => {
block_expr(p);
m.complete(p, EFFECT_EXPR)
}
_ => {
// test_err misplaced_label_err
// fn main() {
// 'loop: impl
// }
p.error("expected a loop");
m.complete(p, ERROR);
return None;
}
}
}
T![async] if la == T!['{'] || (la == T![move] && p.nth(2) == T!['{']) => {
let m = p.start();
p.bump(T![async]);
p.eat(T![move]);
block_expr(p);
m.complete(p, EFFECT_EXPR)
}
T![match] => match_expr(p),
// test unsafe_block
// fn f() { unsafe { } }
T![unsafe] if la == T!['{'] => {
let m = p.start();
p.bump(T![unsafe]);
block_expr(p);
m.complete(p, EFFECT_EXPR)
}
T!['{'] => {
// test for_range_from
// fn foo() {
// for x in 0 .. {
// break;
// }
// }
block_expr_unchecked(p)
}
T![return] => return_expr(p),
T![continue] => continue_expr(p),
T![break] => break_expr(p, r),
_ => {
p.err_recover("expected expression", EXPR_RECOVERY_SET);
return None;
}
};
let blocklike = match done.kind() {
IF_EXPR | WHILE_EXPR | FOR_EXPR | LOOP_EXPR | MATCH_EXPR | BLOCK_EXPR | EFFECT_EXPR => {
BlockLike::Block
}
_ => BlockLike::NotBlock,
};
Some((done, blocklike))
}
// test tuple_expr
// fn foo() {
// ();
// (1);
// (1,);
// }
fn tuple_expr(p: &mut Parser) -> CompletedMarker {
assert!(p.at(T!['(']));
let m = p.start();
p.expect(T!['(']);
let mut saw_comma = false;
let mut saw_expr = false;
while !p.at(EOF) && !p.at(T![')']) {
saw_expr = true;
if !p.at_ts(EXPR_FIRST) {
p.error("expected expression");
break;
}
expr(p);
if !p.at(T![')']) {
saw_comma = true;
p.expect(T![,]);
}
}
p.expect(T![')']);
m.complete(p, if saw_expr && !saw_comma { PAREN_EXPR } else { TUPLE_EXPR })
}
// test array_expr
// fn foo() {
// [];
// [1];
// [1, 2,];
// [1; 2];
// }
fn array_expr(p: &mut Parser) -> CompletedMarker {
assert!(p.at(T!['[']));
let m = p.start();
let mut n_exprs = 0u32;
let mut has_semi = false;
p.bump(T!['[']);
while !p.at(EOF) && !p.at(T![']']) {
n_exprs += 1;
// test array_attrs
// const A: &[i64] = &[1, #[cfg(test)] 2];
if !expr_with_attrs(p) {
break;
}
if n_exprs == 1 && p.eat(T![;]) {
has_semi = true;
continue;
}
if has_semi || !p.at(T![']']) && !p.expect(T![,]) {
break;
}
}
p.expect(T![']']);
m.complete(p, ARRAY_EXPR)
}
// test lambda_expr
// fn foo() {
// || ();
// || -> i32 { 92 };
// |x| x;
// move |x: i32,| x;
// async || {};
// move || {};
// async move || {};
// }
fn lambda_expr(p: &mut Parser) -> CompletedMarker {
assert!(
p.at(T![|])
|| (p.at(T![move]) && p.nth(1) == T![|])
|| (p.at(T![async]) && p.nth(1) == T![|])
|| (p.at(T![async]) && p.nth(1) == T![move] && p.nth(2) == T![|])
);
let m = p.start();
p.eat(T![async]);
p.eat(T![move]);
params::param_list_closure(p);
if opt_fn_ret_type(p) {
// test lambda_ret_block
// fn main() { || -> i32 { 92 }(); }
block_expr(p);
} else {
if p.at_ts(EXPR_FIRST) {
expr(p);
} else {
p.error("expected expression");
}
}
m.complete(p, CLOSURE_EXPR)
}
// test if_expr
// fn foo() {
// if true {};
// if true {} else {};
// if true {} else if false {} else {};
// if S {};
// if { true } { } else { };
// }
fn if_expr(p: &mut Parser) -> CompletedMarker {
assert!(p.at(T![if]));
let m = p.start();
p.bump(T![if]);
cond(p);
block_expr(p);
if p.at(T![else]) {
p.bump(T![else]);
if p.at(T![if]) {
if_expr(p);
} else {
block_expr(p);
}
}
m.complete(p, IF_EXPR)
}
// test label
// fn foo() {
// 'a: loop {}
// 'b: while true {}
// 'c: for x in () {}
// }
fn label(p: &mut Parser) {
assert!(p.at(LIFETIME) && p.nth(1) == T![:]);
let m = p.start();
p.bump(LIFETIME);
p.bump_any();
m.complete(p, LABEL);
}
// test loop_expr
// fn foo() {
// loop {};
// }
fn loop_expr(p: &mut Parser, m: Option<Marker>) -> CompletedMarker {
assert!(p.at(T![loop]));
let m = m.unwrap_or_else(|| p.start());
p.bump(T![loop]);
block_expr(p);
m.complete(p, LOOP_EXPR)
}
// test while_expr
// fn foo() {
// while true {};
// while let Some(x) = it.next() {};
// while { true } {};
// }
fn while_expr(p: &mut Parser, m: Option<Marker>) -> CompletedMarker {
assert!(p.at(T![while]));
let m = m.unwrap_or_else(|| p.start());
p.bump(T![while]);
cond(p);
block_expr(p);
m.complete(p, WHILE_EXPR)
}
// test for_expr
// fn foo() {
// for x in [] {};
// }
fn for_expr(p: &mut Parser, m: Option<Marker>) -> CompletedMarker {
assert!(p.at(T![for]));
let m = m.unwrap_or_else(|| p.start());
p.bump(T![for]);
patterns::pattern(p);
p.expect(T![in]);
expr_no_struct(p);
block_expr(p);
m.complete(p, FOR_EXPR)
}
// test cond
// fn foo() { if let Some(_) = None {} }
// fn bar() {
// if let Some(_) | Some(_) = None {}
// if let | Some(_) = None {}
// while let Some(_) | Some(_) = None {}
// while let | Some(_) = None {}
// }
fn cond(p: &mut Parser) {
let m = p.start();
if p.eat(T![let]) {
patterns::pattern_top(p);
p.expect(T![=]);
}
expr_no_struct(p);
m.complete(p, CONDITION);
}
// test match_expr
// fn foo() {
// match () { };
// match S {};
// match { } { _ => () };
// match { S {} } {};
// }
fn match_expr(p: &mut Parser) -> CompletedMarker {
assert!(p.at(T![match]));
let m = p.start();
p.bump(T![match]);
expr_no_struct(p);
if p.at(T!['{']) {
match_arm_list(p);
} else {
p.error("expected `{`")
}
m.complete(p, MATCH_EXPR)
}
pub(crate) fn match_arm_list(p: &mut Parser) {
assert!(p.at(T!['{']));
let m = p.start();
p.eat(T!['{']);
// test match_arms_inner_attribute
// fn foo() {
// match () {
// #![doc("Inner attribute")]
// #![doc("Can be")]
// #![doc("Stacked")]
// _ => (),
// }
// }
attributes::inner_attributes(p);
while !p.at(EOF) && !p.at(T!['}']) {
if p.at(T!['{']) {
error_block(p, "expected match arm");
continue;
}
// test match_arms_commas
// fn foo() {
// match () {
// _ => (),
// _ => {}
// _ => ()
// }
// }
if match_arm(p).is_block() {
p.eat(T![,]);
} else if !p.at(T!['}']) {
p.expect(T![,]);
}
}
p.expect(T!['}']);
m.complete(p, MATCH_ARM_LIST);
}
// test match_arm
// fn foo() {
// match () {
// _ => (),
// _ if Test > Test{field: 0} => (),
// X | Y if Z => (),
// | X | Y if Z => (),
// | X => (),
// };
// }
fn match_arm(p: &mut Parser) -> BlockLike {
let m = p.start();
// test match_arms_outer_attributes
// fn foo() {
// match () {
// #[cfg(feature = "some")]
// _ => (),
// #[cfg(feature = "other")]
// _ => (),
// #[cfg(feature = "many")]
// #[cfg(feature = "attributes")]
// #[cfg(feature = "before")]
// _ => (),
// }
// }
attributes::outer_attributes(p);
patterns::pattern_top_r(p, TokenSet::EMPTY);
if p.at(T![if]) {
match_guard(p);
}
p.expect(T![=>]);
let blocklike = expr_stmt(p).1;
m.complete(p, MATCH_ARM);
blocklike
}
// test match_guard
// fn foo() {
// match () {
// _ if foo => (),
// }
// }
fn match_guard(p: &mut Parser) -> CompletedMarker {
assert!(p.at(T![if]));
let m = p.start();
p.bump(T![if]);
expr(p);
m.complete(p, MATCH_GUARD)
}
// test block
// fn a() {}
// fn b() { let _ = 1; }
// fn c() { 1; 2; }
// fn d() { 1; 2 }
pub(crate) fn block_expr(p: &mut Parser) {
if !p.at(T!['{']) {
p.error("expected a block");
return;
}
block_expr_unchecked(p);
}
fn block_expr_unchecked(p: &mut Parser) -> CompletedMarker {
assert!(p.at(T!['{']));
let m = p.start();
p.bump(T!['{']);
expr_block_contents(p);
p.expect(T!['}']);
m.complete(p, BLOCK_EXPR)
}
// test return_expr
// fn foo() {
// return;
// return 92;
// }
fn return_expr(p: &mut Parser) -> CompletedMarker {
assert!(p.at(T![return]));
let m = p.start();
p.bump(T![return]);
if p.at_ts(EXPR_FIRST) {
expr(p);
}
m.complete(p, RETURN_EXPR)
}
// test continue_expr
// fn foo() {
// loop {
// continue;
// continue 'l;
// }
// }
fn continue_expr(p: &mut Parser) -> CompletedMarker {
assert!(p.at(T![continue]));
let m = p.start();
p.bump(T![continue]);
p.eat(LIFETIME);
m.complete(p, CONTINUE_EXPR)
}
// test break_expr
// fn foo() {
// loop {
// break;
// break 'l;
// break 92;
// break 'l 92;
// }
// }
fn break_expr(p: &mut Parser, r: Restrictions) -> CompletedMarker {
assert!(p.at(T![break]));
let m = p.start();
p.bump(T![break]);
p.eat(LIFETIME);
// test break_ambiguity
// fn foo(){
// if break {}
// while break {}
// for i in break {}
// match break {}
// }
if p.at_ts(EXPR_FIRST) && !(r.forbid_structs && p.at(T!['{'])) {
expr(p);
}
m.complete(p, BREAK_EXPR)
}
// test try_block_expr
// fn foo() {
// let _ = try {};
// }
fn try_block_expr(p: &mut Parser, m: Option<Marker>) -> CompletedMarker {
assert!(p.at(T![try]));
let m = m.unwrap_or_else(|| p.start());
// Special-case `try!` as macro.
// This is a hack until we do proper edition support
if p.nth_at(1, T![!]) {
// test try_macro_fallback
// fn foo() { try!(Ok(())); }
let path = p.start();
let path_segment = p.start();
let name_ref = p.start();
p.bump_remap(IDENT);
name_ref.complete(p, NAME_REF);
path_segment.complete(p, PATH_SEGMENT);
path.complete(p, PATH);
let _block_like = items::macro_call_after_excl(p);
return m.complete(p, MACRO_CALL);
}
p.bump(T![try]);
block_expr(p);
m.complete(p, EFFECT_EXPR)
}
// test box_expr
// fn foo() {
// let x = box 1i32;
// let y = (box 1i32, box 2i32);
// let z = Foo(box 1i32, box 2i32);
// }
fn box_expr(p: &mut Parser, m: Option<Marker>) -> CompletedMarker {
assert!(p.at(T![box]));
let m = m.unwrap_or_else(|| p.start());
p.bump(T![box]);
if p.at_ts(EXPR_FIRST) {
expr(p);
}
m.complete(p, BOX_EXPR)
}
/// Expression from `$var` macro expansion, wrapped in dollars
fn meta_var_expr(p: &mut Parser) -> CompletedMarker {
assert!(p.at(L_DOLLAR));
let m = p.start();
p.bump(L_DOLLAR);
let (completed, _is_block) =
expr_bp(p, Restrictions { forbid_structs: false, prefer_stmt: false }, 1);
match (completed, p.current()) {
(Some(it), R_DOLLAR) => {
p.bump(R_DOLLAR);
m.abandon(p);
it
}
_ => {
while !p.at(R_DOLLAR) {
p.bump_any()
}
p.bump(R_DOLLAR);
m.complete(p, ERROR)
}
}
}

View file

@ -0,0 +1,432 @@
//! FIXME: write short doc here
mod consts;
mod adt;
mod traits;
mod use_item;
pub(crate) use self::{
adt::{enum_variant_list, record_field_def_list},
expressions::{match_arm_list, record_field_list},
traits::{impl_item_list, trait_item_list},
use_item::use_tree_list,
};
use super::*;
// test mod_contents
// fn foo() {}
// macro_rules! foo {}
// foo::bar!();
// super::baz! {}
// struct S;
pub(super) fn mod_contents(p: &mut Parser, stop_on_r_curly: bool) {
attributes::inner_attributes(p);
while !(stop_on_r_curly && p.at(T!['}']) || p.at(EOF)) {
item_or_macro(p, stop_on_r_curly)
}
}
pub(super) const ITEM_RECOVERY_SET: TokenSet = token_set![
FN_KW, STRUCT_KW, ENUM_KW, IMPL_KW, TRAIT_KW, CONST_KW, STATIC_KW, LET_KW, MOD_KW, PUB_KW,
CRATE_KW, USE_KW, MACRO_KW
];
pub(super) fn item_or_macro(p: &mut Parser, stop_on_r_curly: bool) {
let m = p.start();
attributes::outer_attributes(p);
let m = match maybe_item(p, m) {
Ok(()) => {
if p.at(T![;]) {
p.err_and_bump(
"expected item, found `;`\n\
consider removing this semicolon",
);
}
return;
}
Err(m) => m,
};
if paths::is_use_path_start(p) {
match macro_call(p) {
BlockLike::Block => (),
BlockLike::NotBlock => {
p.expect(T![;]);
}
}
m.complete(p, MACRO_CALL);
} else {
m.abandon(p);
if p.at(T!['{']) {
error_block(p, "expected an item");
} else if p.at(T!['}']) && !stop_on_r_curly {
let e = p.start();
p.error("unmatched `}`");
p.bump(T!['}']);
e.complete(p, ERROR);
} else if !p.at(EOF) && !p.at(T!['}']) {
p.err_and_bump("expected an item");
} else {
p.error("expected an item");
}
}
}
pub(super) fn maybe_item(p: &mut Parser, m: Marker) -> Result<(), Marker> {
// test_err pub_expr
// fn foo() { pub 92; }
let has_visibility = opt_visibility(p);
let m = match items_without_modifiers(p, m) {
Ok(()) => return Ok(()),
Err(m) => m,
};
let mut has_mods = false;
// modifiers
has_mods |= p.eat(T![const]);
// test_err async_without_semicolon
// fn foo() { let _ = async {} }
if p.at(T![async]) && p.nth(1) != T!['{'] && p.nth(1) != T![move] && p.nth(1) != T![|] {
p.eat(T![async]);
has_mods = true;
}
// test_err unsafe_block_in_mod
// fn foo(){} unsafe { } fn bar(){}
if p.at(T![unsafe]) && p.nth(1) != T!['{'] {
p.eat(T![unsafe]);
has_mods = true;
}
if p.at(T![extern]) {
has_mods = true;
abi(p);
}
if p.at(IDENT) && p.at_contextual_kw("auto") && p.nth(1) == T![trait] {
p.bump_remap(T![auto]);
has_mods = true;
}
// test default_item
// default impl T for Foo {}
if p.at(IDENT) && p.at_contextual_kw("default") {
match p.nth(1) {
T![fn] | T![type] | T![const] | T![impl] => {
p.bump_remap(T![default]);
has_mods = true;
}
T![unsafe] => {
// test default_unsafe_item
// default unsafe impl T for Foo {
// default unsafe fn foo() {}
// }
if matches!(p.nth(2), T![impl] | T![fn]) {
p.bump_remap(T![default]);
p.bump(T![unsafe]);
has_mods = true;
}
}
_ => (),
}
}
// test existential_type
// existential type Foo: Fn() -> usize;
if p.at(IDENT) && p.at_contextual_kw("existential") && p.nth(1) == T![type] {
p.bump_remap(T![existential]);
has_mods = true;
}
// items
match p.current() {
// test fn
// fn foo() {}
T![fn] => {
fn_def(p);
m.complete(p, FN);
}
// test trait
// trait T {}
T![trait] => {
traits::trait_def(p);
m.complete(p, TRAIT);
}
T![const] => {
consts::const_def(p, m);
}
// test impl
// impl T for S {}
T![impl] => {
traits::impl_def(p);
m.complete(p, IMPL);
}
T![type] => {
type_def(p, m);
}
_ => {
if !has_visibility && !has_mods {
return Err(m);
} else {
if has_mods {
p.error("expected existential, fn, trait or impl");
} else {
p.error("expected an item");
}
m.complete(p, ERROR);
}
}
}
Ok(())
}
fn items_without_modifiers(p: &mut Parser, m: Marker) -> Result<(), Marker> {
let la = p.nth(1);
match p.current() {
// test extern_crate
// extern crate foo;
T![extern] if la == T![crate] => extern_crate_item(p, m),
T![type] => {
type_def(p, m);
}
T![mod] => mod_item(p, m),
T![struct] => {
// test struct_items
// struct Foo;
// struct Foo {}
// struct Foo();
// struct Foo(String, usize);
// struct Foo {
// a: i32,
// b: f32,
// }
adt::struct_def(p, m);
}
// test pub_macro_def
// pub macro m($:ident) {}
T![macro] => {
macro_def(p, m);
}
IDENT if p.at_contextual_kw("union") && p.nth(1) == IDENT => {
// test union_items
// union Foo {}
// union Foo {
// a: i32,
// b: f32,
// }
adt::union_def(p, m);
}
T![enum] => adt::enum_def(p, m),
T![use] => use_item::use_item(p, m),
T![const] if (la == IDENT || la == T![_] || la == T![mut]) => consts::const_def(p, m),
T![static] => consts::static_def(p, m),
// test extern_block
// extern {}
T![extern]
if la == T!['{'] || ((la == STRING || la == RAW_STRING) && p.nth(2) == T!['{']) =>
{
abi(p);
extern_item_list(p);
m.complete(p, EXTERN_BLOCK);
}
_ => return Err(m),
};
Ok(())
}
fn extern_crate_item(p: &mut Parser, m: Marker) {
assert!(p.at(T![extern]));
p.bump(T![extern]);
assert!(p.at(T![crate]));
p.bump(T![crate]);
if p.at(T![self]) {
p.bump(T![self]);
} else {
name_ref(p);
}
opt_alias(p);
p.expect(T![;]);
m.complete(p, EXTERN_CRATE);
}
pub(crate) fn extern_item_list(p: &mut Parser) {
assert!(p.at(T!['{']));
let m = p.start();
p.bump(T!['{']);
mod_contents(p, true);
p.expect(T!['}']);
m.complete(p, EXTERN_ITEM_LIST);
}
fn fn_def(p: &mut Parser) {
assert!(p.at(T![fn]));
p.bump(T![fn]);
name_r(p, ITEM_RECOVERY_SET);
// test function_type_params
// fn foo<T: Clone + Copy>(){}
type_params::opt_type_param_list(p);
if p.at(T!['(']) {
params::param_list_fn_def(p);
} else {
p.error("expected function arguments");
}
// test function_ret_type
// fn foo() {}
// fn bar() -> () {}
opt_fn_ret_type(p);
// test function_where_clause
// fn foo<T>() where T: Copy {}
type_params::opt_where_clause(p);
// test fn_decl
// trait T { fn foo(); }
if p.at(T![;]) {
p.bump(T![;]);
} else {
expressions::block_expr(p)
}
}
// test type_item
// type Foo = Bar;
fn type_def(p: &mut Parser, m: Marker) {
assert!(p.at(T![type]));
p.bump(T![type]);
name(p);
// test type_item_type_params
// type Result<T> = ();
type_params::opt_type_param_list(p);
if p.at(T![:]) {
type_params::bounds(p);
}
// test type_item_where_clause
// type Foo where Foo: Copy = ();
type_params::opt_where_clause(p);
if p.eat(T![=]) {
types::type_(p);
}
p.expect(T![;]);
m.complete(p, TYPE_ALIAS);
}
pub(crate) fn mod_item(p: &mut Parser, m: Marker) {
assert!(p.at(T![mod]));
p.bump(T![mod]);
name(p);
if p.at(T!['{']) {
mod_item_list(p);
} else if !p.eat(T![;]) {
p.error("expected `;` or `{`");
}
m.complete(p, MODULE);
}
pub(crate) fn mod_item_list(p: &mut Parser) {
assert!(p.at(T!['{']));
let m = p.start();
p.bump(T!['{']);
mod_contents(p, true);
p.expect(T!['}']);
m.complete(p, ITEM_LIST);
}
// test macro_def
// macro m { ($i:ident) => {} }
// macro m($i:ident) {}
fn macro_def(p: &mut Parser, m: Marker) {
p.expect(T![macro]);
name_r(p, ITEM_RECOVERY_SET);
if p.at(T!['{']) {
token_tree(p);
} else if !p.at(T!['(']) {
p.error("unmatched `(`");
} else {
let m = p.start();
token_tree(p);
match p.current() {
T!['{'] | T!['['] | T!['('] => token_tree(p),
_ => p.error("expected `{`, `[`, `(`"),
}
m.complete(p, TOKEN_TREE);
}
m.complete(p, MACRO_DEF);
}
fn macro_call(p: &mut Parser) -> BlockLike {
assert!(paths::is_use_path_start(p));
paths::use_path(p);
macro_call_after_excl(p)
}
pub(super) fn macro_call_after_excl(p: &mut Parser) -> BlockLike {
p.expect(T![!]);
if p.at(IDENT) {
name(p);
}
// Special-case `macro_rules! try`.
// This is a hack until we do proper edition support
// test try_macro_rules
// macro_rules! try { () => {} }
if p.at(T![try]) {
let m = p.start();
p.bump_remap(IDENT);
m.complete(p, NAME);
}
match p.current() {
T!['{'] => {
token_tree(p);
BlockLike::Block
}
T!['('] | T!['['] => {
token_tree(p);
BlockLike::NotBlock
}
_ => {
p.error("expected `{`, `[`, `(`");
BlockLike::NotBlock
}
}
}
pub(crate) fn token_tree(p: &mut Parser) {
let closing_paren_kind = match p.current() {
T!['{'] => T!['}'],
T!['('] => T![')'],
T!['['] => T![']'],
_ => unreachable!(),
};
let m = p.start();
p.bump_any();
while !p.at(EOF) && !p.at(closing_paren_kind) {
match p.current() {
T!['{'] | T!['('] | T!['['] => token_tree(p),
T!['}'] => {
p.error("unmatched `}`");
m.complete(p, TOKEN_TREE);
return;
}
T![')'] | T![']'] => p.err_and_bump("unmatched brace"),
_ => p.bump_any(),
}
}
p.expect(closing_paren_kind);
m.complete(p, TOKEN_TREE);
}

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//! FIXME: write short doc here
use super::*;
pub(super) fn struct_def(p: &mut Parser, m: Marker) {
assert!(p.at(T![struct]));
p.bump(T![struct]);
struct_or_union(p, m, T![struct], STRUCT);
}
pub(super) fn union_def(p: &mut Parser, m: Marker) {
assert!(p.at_contextual_kw("union"));
p.bump_remap(T![union]);
struct_or_union(p, m, T![union], UNION);
}
fn struct_or_union(p: &mut Parser, m: Marker, kw: SyntaxKind, def: SyntaxKind) {
name_r(p, ITEM_RECOVERY_SET);
type_params::opt_type_param_list(p);
match p.current() {
T![where] => {
type_params::opt_where_clause(p);
match p.current() {
T![;] => {
p.bump(T![;]);
}
T!['{'] => record_field_def_list(p),
_ => {
//FIXME: special case `(` error message
p.error("expected `;` or `{`");
}
}
}
T![;] if kw == T![struct] => {
p.bump(T![;]);
}
T!['{'] => record_field_def_list(p),
T!['('] if kw == T![struct] => {
tuple_field_def_list(p);
// test tuple_struct_where
// struct Test<T>(T) where T: Clone;
// struct Test<T>(T);
type_params::opt_where_clause(p);
p.expect(T![;]);
}
_ if kw == T![struct] => {
p.error("expected `;`, `{`, or `(`");
}
_ => {
p.error("expected `{`");
}
}
m.complete(p, def);
}
pub(super) fn enum_def(p: &mut Parser, m: Marker) {
assert!(p.at(T![enum]));
p.bump(T![enum]);
name_r(p, ITEM_RECOVERY_SET);
type_params::opt_type_param_list(p);
type_params::opt_where_clause(p);
if p.at(T!['{']) {
enum_variant_list(p);
} else {
p.error("expected `{`")
}
m.complete(p, ENUM);
}
pub(crate) fn enum_variant_list(p: &mut Parser) {
assert!(p.at(T!['{']));
let m = p.start();
p.bump(T!['{']);
while !p.at(EOF) && !p.at(T!['}']) {
if p.at(T!['{']) {
error_block(p, "expected enum variant");
continue;
}
let var = p.start();
attributes::outer_attributes(p);
if p.at(IDENT) {
name(p);
match p.current() {
T!['{'] => record_field_def_list(p),
T!['('] => tuple_field_def_list(p),
_ => (),
}
// test variant_discriminant
// enum E { X(i32) = 10 }
if p.eat(T![=]) {
expressions::expr(p);
}
var.complete(p, VARIANT);
} else {
var.abandon(p);
p.err_and_bump("expected enum variant");
}
if !p.at(T!['}']) {
p.expect(T![,]);
}
}
p.expect(T!['}']);
m.complete(p, VARIANT_LIST);
}
pub(crate) fn record_field_def_list(p: &mut Parser) {
assert!(p.at(T!['{']));
let m = p.start();
p.bump(T!['{']);
while !p.at(T!['}']) && !p.at(EOF) {
if p.at(T!['{']) {
error_block(p, "expected field");
continue;
}
record_field_def(p);
if !p.at(T!['}']) {
p.expect(T![,]);
}
}
p.expect(T!['}']);
m.complete(p, RECORD_FIELD_LIST);
fn record_field_def(p: &mut Parser) {
let m = p.start();
// test record_field_attrs
// struct S {
// #[serde(with = "url_serde")]
// pub uri: Uri,
// }
attributes::outer_attributes(p);
opt_visibility(p);
if p.at(IDENT) {
name(p);
p.expect(T![:]);
types::type_(p);
m.complete(p, RECORD_FIELD);
} else {
m.abandon(p);
p.err_and_bump("expected field declaration");
}
}
}
fn tuple_field_def_list(p: &mut Parser) {
assert!(p.at(T!['(']));
let m = p.start();
if !p.expect(T!['(']) {
return;
}
while !p.at(T![')']) && !p.at(EOF) {
let m = p.start();
// test tuple_field_attrs
// struct S (
// #[serde(with = "url_serde")]
// pub Uri,
// );
//
// enum S {
// Uri(#[serde(with = "url_serde")] Uri),
// }
attributes::outer_attributes(p);
opt_visibility(p);
if !p.at_ts(types::TYPE_FIRST) {
p.error("expected a type");
m.complete(p, ERROR);
break;
}
types::type_(p);
m.complete(p, TUPLE_FIELD);
if !p.at(T![')']) {
p.expect(T![,]);
}
}
p.expect(T![')']);
m.complete(p, TUPLE_FIELD_LIST);
}

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//! FIXME: write short doc here
use super::*;
pub(super) fn static_def(p: &mut Parser, m: Marker) {
const_or_static(p, m, T![static], STATIC)
}
pub(super) fn const_def(p: &mut Parser, m: Marker) {
const_or_static(p, m, T![const], CONST)
}
fn const_or_static(p: &mut Parser, m: Marker, kw: SyntaxKind, def: SyntaxKind) {
assert!(p.at(kw));
p.bump(kw);
p.eat(T![mut]); // FIXME: validator to forbid const mut
// Allow `_` in place of an identifier in a `const`.
let is_const_underscore = kw == T![const] && p.eat(T![_]);
if !is_const_underscore {
name(p);
}
// test_err static_underscore
// static _: i32 = 5;
types::ascription(p);
if p.eat(T![=]) {
expressions::expr(p);
}
p.expect(T![;]);
m.complete(p, def);
}

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//! FIXME: write short doc here
use super::*;
// test trait_item
// trait T<U>: Hash + Clone where U: Copy {}
// trait X<U: Debug + Display>: Hash + Clone where U: Copy {}
pub(super) fn trait_def(p: &mut Parser) {
assert!(p.at(T![trait]));
p.bump(T![trait]);
name_r(p, ITEM_RECOVERY_SET);
type_params::opt_type_param_list(p);
// test trait_alias
// trait Z<U> = T<U>;
// trait Z<U> = T<U> where U: Copy;
// trait Z<U> = where Self: T<U>;
if p.eat(T![=]) {
type_params::bounds_without_colon(p);
type_params::opt_where_clause(p);
p.expect(T![;]);
return;
}
if p.at(T![:]) {
type_params::bounds(p);
}
type_params::opt_where_clause(p);
if p.at(T!['{']) {
trait_item_list(p);
} else {
p.error("expected `{`");
}
}
// test trait_item_list
// impl F {
// type A: Clone;
// const B: i32;
// fn foo() {}
// fn bar(&self);
// }
pub(crate) fn trait_item_list(p: &mut Parser) {
assert!(p.at(T!['{']));
let m = p.start();
p.bump(T!['{']);
while !p.at(EOF) && !p.at(T!['}']) {
if p.at(T!['{']) {
error_block(p, "expected an item");
continue;
}
item_or_macro(p, true);
}
p.expect(T!['}']);
m.complete(p, ASSOC_ITEM_LIST);
}
// test impl_def
// impl Foo {}
pub(super) fn impl_def(p: &mut Parser) {
assert!(p.at(T![impl]));
p.bump(T![impl]);
if choose_type_params_over_qpath(p) {
type_params::opt_type_param_list(p);
}
// FIXME: never type
// impl ! {}
// test impl_def_neg
// impl !Send for X {}
p.eat(T![!]);
impl_type(p);
if p.eat(T![for]) {
impl_type(p);
}
type_params::opt_where_clause(p);
if p.at(T!['{']) {
impl_item_list(p);
} else {
p.error("expected `{`");
}
}
// test impl_item_list
// impl F {
// type A = i32;
// const B: i32 = 92;
// fn foo() {}
// fn bar(&self) {}
// }
pub(crate) fn impl_item_list(p: &mut Parser) {
assert!(p.at(T!['{']));
let m = p.start();
p.bump(T!['{']);
// test impl_inner_attributes
// enum F{}
// impl F {
// //! This is a doc comment
// #![doc("This is also a doc comment")]
// }
attributes::inner_attributes(p);
while !p.at(EOF) && !p.at(T!['}']) {
if p.at(T!['{']) {
error_block(p, "expected an item");
continue;
}
item_or_macro(p, true);
}
p.expect(T!['}']);
m.complete(p, ASSOC_ITEM_LIST);
}
// test impl_type_params
// impl<const N: u32> Bar<N> {}
fn choose_type_params_over_qpath(p: &Parser) -> bool {
// There's an ambiguity between generic parameters and qualified paths in impls.
// If we see `<` it may start both, so we have to inspect some following tokens.
// The following combinations can only start generics,
// but not qualified paths (with one exception):
// `<` `>` - empty generic parameters
// `<` `#` - generic parameters with attributes
// `<` `const` - const generic parameters
// `<` (LIFETIME|IDENT) `>` - single generic parameter
// `<` (LIFETIME|IDENT) `,` - first generic parameter in a list
// `<` (LIFETIME|IDENT) `:` - generic parameter with bounds
// `<` (LIFETIME|IDENT) `=` - generic parameter with a default
// The only truly ambiguous case is
// `<` IDENT `>` `::` IDENT ...
// we disambiguate it in favor of generics (`impl<T> ::absolute::Path<T> { ... }`)
// because this is what almost always expected in practice, qualified paths in impls
// (`impl <Type>::AssocTy { ... }`) aren't even allowed by type checker at the moment.
if !p.at(T![<]) {
return false;
}
if p.nth(1) == T![#] || p.nth(1) == T![>] || p.nth(1) == CONST_KW {
return true;
}
(p.nth(1) == LIFETIME || p.nth(1) == IDENT)
&& (p.nth(2) == T![>] || p.nth(2) == T![,] || p.nth(2) == T![:] || p.nth(2) == T![=])
}
// test_err impl_type
// impl Type {}
// impl Trait1 for T {}
// impl impl NotType {}
// impl Trait2 for impl NotType {}
pub(crate) fn impl_type(p: &mut Parser) {
if p.at(T![impl]) {
p.error("expected trait or type");
return;
}
types::type_(p);
}

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//! FIXME: write short doc here
use super::*;
pub(super) fn use_item(p: &mut Parser, m: Marker) {
assert!(p.at(T![use]));
p.bump(T![use]);
use_tree(p, true);
p.expect(T![;]);
m.complete(p, USE);
}
/// Parse a use 'tree', such as `some::path` in `use some::path;`
/// Note that this is called both by `use_item` and `use_tree_list`,
/// so handles both `some::path::{inner::path}` and `inner::path` in
/// `use some::path::{inner::path};`
fn use_tree(p: &mut Parser, top_level: bool) {
let m = p.start();
match p.current() {
// Finish the use_tree for cases of e.g.
// `use some::path::{self, *};` or `use *;`
// This does not handle cases such as `use some::path::*`
// N.B. in Rust 2015 `use *;` imports all from crate root
// however in Rust 2018 `use *;` errors: ('cannot glob-import all possible crates')
// FIXME: Add this error (if not out of scope)
// test use_star
// use *;
// use ::*;
// use some::path::{*};
// use some::path::{::*};
T![*] => p.bump(T![*]),
T![:] if p.at(T![::]) && p.nth(2) == T![*] => {
// Parse `use ::*;`, which imports all from the crate root in Rust 2015
// This is invalid inside a use_tree_list, (e.g. `use some::path::{::*}`)
// but still parses and errors later: ('crate root in paths can only be used in start position')
// FIXME: Add this error (if not out of scope)
// In Rust 2018, it is always invalid (see above)
p.bump(T![::]);
p.bump(T![*]);
}
// Open a use tree list
// Handles cases such as `use {some::path};` or `{inner::path}` in
// `use some::path::{{inner::path}, other::path}`
// test use_tree_list
// use {crate::path::from::root, or::path::from::crate_name}; // Rust 2018 (with a crate named `or`)
// use {path::from::root}; // Rust 2015
// use ::{some::arbritrary::path}; // Rust 2015
// use ::{{{root::export}}}; // Nonsensical but perfectly legal nesting
T!['{'] => {
use_tree_list(p);
}
T![:] if p.at(T![::]) && p.nth(2) == T!['{'] => {
p.bump(T![::]);
use_tree_list(p);
}
// Parse a 'standard' path.
// Also handles aliases (e.g. `use something as something_else`)
// test use_path
// use ::crate_name; // Rust 2018 - All flavours
// use crate_name; // Rust 2018 - Anchored paths
// use item_in_scope_or_crate_name; // Rust 2018 - Uniform Paths
//
// use self::module::Item;
// use crate::Item;
// use self::some::Struct;
// use crate_name::some_item;
_ if paths::is_use_path_start(p) => {
paths::use_path(p);
match p.current() {
T![as] => {
// test use_alias
// use some::path as some_name;
// use some::{
// other::path as some_other_name,
// different::path as different_name,
// yet::another::path,
// running::out::of::synonyms::for_::different::*
// };
// use Trait as _;
opt_alias(p);
}
T![:] if p.at(T![::]) => {
p.bump(T![::]);
match p.current() {
T![*] => {
p.bump(T![*]);
}
// test use_tree_list_after_path
// use crate::{Item};
// use self::{Item};
T!['{'] => use_tree_list(p),
_ => {
// is this unreachable?
p.error("expected `{` or `*`");
}
}
}
_ => (),
}
}
_ => {
m.abandon(p);
let msg = "expected one of `*`, `::`, `{`, `self`, `super` or an identifier";
if top_level {
p.err_recover(msg, ITEM_RECOVERY_SET);
} else {
// if we are parsing a nested tree, we have to eat a token to
// main balanced `{}`
p.err_and_bump(msg);
}
return;
}
}
m.complete(p, USE_TREE);
}
pub(crate) fn use_tree_list(p: &mut Parser) {
assert!(p.at(T!['{']));
let m = p.start();
p.bump(T!['{']);
while !p.at(EOF) && !p.at(T!['}']) {
use_tree(p, false);
if !p.at(T!['}']) {
p.expect(T![,]);
}
}
p.expect(T!['}']);
m.complete(p, USE_TREE_LIST);
}

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//! FIXME: write short doc here
use super::*;
// test param_list
// fn a() {}
// fn b(x: i32) {}
// fn c(x: i32, ) {}
// fn d(x: i32, y: ()) {}
pub(super) fn param_list_fn_def(p: &mut Parser) {
list_(p, Flavor::FnDef)
}
// test param_list_opt_patterns
// fn foo<F: FnMut(&mut Foo<'a>)>(){}
pub(super) fn param_list_fn_trait(p: &mut Parser) {
list_(p, Flavor::FnTrait)
}
pub(super) fn param_list_fn_ptr(p: &mut Parser) {
list_(p, Flavor::FnPointer)
}
pub(super) fn param_list_closure(p: &mut Parser) {
list_(p, Flavor::Closure)
}
#[derive(Debug, Clone, Copy)]
enum Flavor {
FnDef, // Includes trait fn params; omitted param idents are not supported
FnTrait, // Params for `Fn(...)`/`FnMut(...)`/`FnOnce(...)` annotations
FnPointer,
Closure,
}
fn list_(p: &mut Parser, flavor: Flavor) {
use Flavor::*;
let (bra, ket) = match flavor {
Closure => (T![|], T![|]),
FnDef | FnTrait | FnPointer => (T!['('], T![')']),
};
let m = p.start();
p.bump(bra);
if let FnDef = flavor {
// test self_param_outer_attr
// fn f(#[must_use] self) {}
attributes::outer_attributes(p);
opt_self_param(p);
}
while !p.at(EOF) && !p.at(ket) {
// test param_outer_arg
// fn f(#[attr1] pat: Type) {}
attributes::outer_attributes(p);
if !p.at_ts(VALUE_PARAMETER_FIRST) {
p.error("expected value parameter");
break;
}
let param = value_parameter(p, flavor);
if !p.at(ket) {
p.expect(T![,]);
}
if let Variadic(true) = param {
break;
}
}
p.expect(ket);
m.complete(p, PARAM_LIST);
}
const VALUE_PARAMETER_FIRST: TokenSet = patterns::PATTERN_FIRST.union(types::TYPE_FIRST);
struct Variadic(bool);
fn value_parameter(p: &mut Parser, flavor: Flavor) -> Variadic {
let mut res = Variadic(false);
let m = p.start();
match flavor {
// test param_list_vararg
// extern "C" { fn printf(format: *const i8, ...) -> i32; }
Flavor::FnDef | Flavor::FnPointer if p.eat(T![...]) => res = Variadic(true),
// test fn_def_param
// fn foo((x, y): (i32, i32)) {}
Flavor::FnDef => {
patterns::pattern(p);
if variadic_param(p) {
res = Variadic(true)
} else {
types::ascription(p);
}
}
// test value_parameters_no_patterns
// type F = Box<Fn(i32, &i32, &i32, ())>;
Flavor::FnTrait => {
types::type_(p);
}
// test fn_pointer_param_ident_path
// type Foo = fn(Bar::Baz);
// type Qux = fn(baz: Bar::Baz);
// test fn_pointer_unnamed_arg
// type Foo = fn(_: bar);
Flavor::FnPointer => {
if (p.at(IDENT) || p.at(UNDERSCORE)) && p.nth(1) == T![:] && !p.nth_at(1, T![::]) {
patterns::pattern_single(p);
if variadic_param(p) {
res = Variadic(true)
} else {
types::ascription(p);
}
} else {
types::type_(p);
}
}
// test closure_params
// fn main() {
// let foo = |bar, baz: Baz, qux: Qux::Quux| ();
// }
Flavor::Closure => {
patterns::pattern_single(p);
if p.at(T![:]) && !p.at(T![::]) {
types::ascription(p);
}
}
}
m.complete(p, PARAM);
res
}
fn variadic_param(p: &mut Parser) -> bool {
if p.at(T![:]) && p.nth_at(1, T![...]) {
p.bump(T![:]);
p.bump(T![...]);
true
} else {
false
}
}
// test self_param
// impl S {
// fn a(self) {}
// fn b(&self,) {}
// fn c(&'a self,) {}
// fn d(&'a mut self, x: i32) {}
// fn e(mut self) {}
// }
fn opt_self_param(p: &mut Parser) {
let m;
if p.at(T![self]) || p.at(T![mut]) && p.nth(1) == T![self] {
m = p.start();
p.eat(T![mut]);
p.eat(T![self]);
// test arb_self_types
// impl S {
// fn a(self: &Self) {}
// fn b(mut self: Box<Self>) {}
// }
if p.at(T![:]) {
types::ascription(p);
}
} else {
let la1 = p.nth(1);
let la2 = p.nth(2);
let la3 = p.nth(3);
let n_toks = match (p.current(), la1, la2, la3) {
(T![&], T![self], _, _) => 2,
(T![&], T![mut], T![self], _) => 3,
(T![&], LIFETIME, T![self], _) => 3,
(T![&], LIFETIME, T![mut], T![self]) => 4,
_ => return,
};
m = p.start();
for _ in 0..n_toks {
p.bump_any();
}
}
m.complete(p, SELF_PARAM);
if !p.at(T![')']) {
p.expect(T![,]);
}
}

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//! FIXME: write short doc here
use super::*;
pub(super) const PATH_FIRST: TokenSet =
token_set![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_fn_ret_type(p);
} else {
type_args::opt_type_arg_list(p, false)
}
}
Mode::Expr => type_args::opt_type_arg_list(p, true),
}
}

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@ -0,0 +1,379 @@
//! FIXME: write short doc here
use super::*;
pub(super) const PATTERN_FIRST: TokenSet = expressions::LITERAL_FIRST
.union(paths::PATH_FIRST)
.union(token_set![T![box], T![ref], T![mut], T!['('], T!['['], T![&], T![_], T![-], T![.]]);
pub(crate) fn pattern(p: &mut Parser) {
pattern_r(p, PAT_RECOVERY_SET);
}
/// Parses a pattern list separated by pipes `|`
pub(super) fn pattern_top(p: &mut Parser) {
pattern_top_r(p, PAT_RECOVERY_SET)
}
pub(crate) fn pattern_single(p: &mut Parser) {
pattern_single_r(p, PAT_RECOVERY_SET);
}
/// Parses a pattern list separated by pipes `|`
/// using the given `recovery_set`
pub(super) fn pattern_top_r(p: &mut Parser, recovery_set: TokenSet) {
p.eat(T![|]);
pattern_r(p, recovery_set);
}
/// Parses a pattern list separated by pipes `|`, with no leading `|`,using the
/// given `recovery_set`
// test or_pattern
// fn main() {
// match () {
// (_ | _) => (),
// &(_ | _) => (),
// (_ | _,) => (),
// [_ | _,] => (),
// }
// }
fn pattern_r(p: &mut Parser, recovery_set: TokenSet) {
let m = p.start();
pattern_single_r(p, recovery_set);
if !p.at(T![|]) {
m.abandon(p);
return;
}
while p.eat(T![|]) {
pattern_single_r(p, recovery_set);
}
m.complete(p, OR_PAT);
}
fn pattern_single_r(p: &mut Parser, recovery_set: TokenSet) {
if let Some(lhs) = atom_pat(p, recovery_set) {
// test range_pat
// fn main() {
// match 92 {
// 0 ... 100 => (),
// 101 ..= 200 => (),
// 200 .. 301=> (),
// }
// }
for &range_op in [T![...], T![..=], T![..]].iter() {
if p.at(range_op) {
let m = lhs.precede(p);
p.bump(range_op);
atom_pat(p, recovery_set);
m.complete(p, RANGE_PAT);
return;
}
}
}
}
const PAT_RECOVERY_SET: TokenSet =
token_set![LET_KW, IF_KW, WHILE_KW, LOOP_KW, MATCH_KW, R_PAREN, COMMA];
fn atom_pat(p: &mut Parser, recovery_set: TokenSet) -> Option<CompletedMarker> {
let m = match p.nth(0) {
T![box] => box_pat(p),
T![ref] | T![mut] => bind_pat(p, true),
IDENT => match p.nth(1) {
// Checks the token after an IDENT to see if a pattern is a path (Struct { .. }) or macro
// (T![x]).
T!['('] | T!['{'] | T![!] => path_or_macro_pat(p),
T![:] if p.nth_at(1, T![::]) => path_or_macro_pat(p),
_ => bind_pat(p, true),
},
// test type_path_in_pattern
// fn main() { let <_>::Foo = (); }
_ if paths::is_path_start(p) => path_or_macro_pat(p),
_ if is_literal_pat_start(p) => literal_pat(p),
T![.] if p.at(T![..]) => dot_dot_pat(p),
T![_] => placeholder_pat(p),
T![&] => ref_pat(p),
T!['('] => tuple_pat(p),
T!['['] => slice_pat(p),
_ => {
p.err_recover("expected pattern", recovery_set);
return None;
}
};
Some(m)
}
fn is_literal_pat_start(p: &Parser) -> bool {
p.at(T![-]) && (p.nth(1) == INT_NUMBER || p.nth(1) == FLOAT_NUMBER)
|| p.at_ts(expressions::LITERAL_FIRST)
}
// test literal_pattern
// fn main() {
// match () {
// -1 => (),
// 92 => (),
// 'c' => (),
// "hello" => (),
// }
// }
fn literal_pat(p: &mut Parser) -> CompletedMarker {
assert!(is_literal_pat_start(p));
let m = p.start();
if p.at(T![-]) {
p.bump(T![-]);
}
expressions::literal(p);
m.complete(p, LITERAL_PAT)
}
// test path_part
// fn foo() {
// let foo::Bar = ();
// let ::Bar = ();
// let Bar { .. } = ();
// let Bar(..) = ();
// }
fn path_or_macro_pat(p: &mut Parser) -> CompletedMarker {
assert!(paths::is_path_start(p));
let m = p.start();
paths::expr_path(p);
let kind = match p.current() {
T!['('] => {
tuple_pat_fields(p);
TUPLE_STRUCT_PAT
}
T!['{'] => {
record_field_pat_list(p);
RECORD_PAT
}
// test marco_pat
// fn main() {
// let m!(x) = 0;
// }
T![!] => {
items::macro_call_after_excl(p);
return m.complete(p, MACRO_CALL).precede(p).complete(p, MACRO_PAT);
}
_ => PATH_PAT,
};
m.complete(p, kind)
}
// test tuple_pat_fields
// fn foo() {
// let S() = ();
// let S(_) = ();
// let S(_,) = ();
// let S(_, .. , x) = ();
// }
fn tuple_pat_fields(p: &mut Parser) {
assert!(p.at(T!['(']));
p.bump(T!['(']);
pat_list(p, T![')']);
p.expect(T![')']);
}
// test record_field_pat_list
// fn foo() {
// let S {} = ();
// let S { f, ref mut g } = ();
// let S { h: _, ..} = ();
// let S { h: _, } = ();
// }
fn record_field_pat_list(p: &mut Parser) {
assert!(p.at(T!['{']));
let m = p.start();
p.bump(T!['{']);
while !p.at(EOF) && !p.at(T!['}']) {
match p.current() {
// A trailing `..` is *not* treated as a REST_PAT.
T![.] if p.at(T![..]) => p.bump(T![..]),
T!['{'] => error_block(p, "expected ident"),
c => {
let m = p.start();
match c {
// test record_field_pat
// fn foo() {
// let S { 0: 1 } = ();
// let S { x: 1 } = ();
// }
IDENT | INT_NUMBER if p.nth(1) == T![:] => {
name_ref_or_index(p);
p.bump(T![:]);
pattern(p);
}
T![box] => {
// FIXME: not all box patterns should be allowed
box_pat(p);
}
_ => {
bind_pat(p, false);
}
}
m.complete(p, RECORD_PAT_FIELD);
}
}
if !p.at(T!['}']) {
p.expect(T![,]);
}
}
p.expect(T!['}']);
m.complete(p, RECORD_PAT_FIELD_LIST);
}
// test placeholder_pat
// fn main() { let _ = (); }
fn placeholder_pat(p: &mut Parser) -> CompletedMarker {
assert!(p.at(T![_]));
let m = p.start();
p.bump(T![_]);
m.complete(p, WILDCARD_PAT)
}
// test dot_dot_pat
// fn main() {
// let .. = ();
// //
// // Tuples
// //
// let (a, ..) = ();
// let (a, ..,) = ();
// let Tuple(a, ..) = ();
// let Tuple(a, ..,) = ();
// let (.., ..) = ();
// let Tuple(.., ..) = ();
// let (.., a, ..) = ();
// let Tuple(.., a, ..) = ();
// //
// // Slices
// //
// let [..] = ();
// let [head, ..] = ();
// let [head, tail @ ..] = ();
// let [head, .., cons] = ();
// let [head, mid @ .., cons] = ();
// let [head, .., .., cons] = ();
// let [head, .., mid, tail @ ..] = ();
// let [head, .., mid, .., cons] = ();
// }
fn dot_dot_pat(p: &mut Parser) -> CompletedMarker {
assert!(p.at(T![..]));
let m = p.start();
p.bump(T![..]);
m.complete(p, REST_PAT)
}
// test ref_pat
// fn main() {
// let &a = ();
// let &mut b = ();
// }
fn ref_pat(p: &mut Parser) -> CompletedMarker {
assert!(p.at(T![&]));
let m = p.start();
p.bump(T![&]);
p.eat(T![mut]);
pattern_single(p);
m.complete(p, REF_PAT)
}
// test tuple_pat
// fn main() {
// let (a, b, ..) = ();
// let (a,) = ();
// let (..) = ();
// let () = ();
// }
fn tuple_pat(p: &mut Parser) -> CompletedMarker {
assert!(p.at(T!['(']));
let m = p.start();
p.bump(T!['(']);
let mut has_comma = false;
let mut has_pat = false;
let mut has_rest = false;
while !p.at(EOF) && !p.at(T![')']) {
has_pat = true;
if !p.at_ts(PATTERN_FIRST) {
p.error("expected a pattern");
break;
}
has_rest |= p.at(T![..]);
pattern(p);
if !p.at(T![')']) {
has_comma = true;
p.expect(T![,]);
}
}
p.expect(T![')']);
m.complete(p, if !has_comma && !has_rest && has_pat { PAREN_PAT } else { TUPLE_PAT })
}
// test slice_pat
// fn main() {
// let [a, b, ..] = [];
// }
fn slice_pat(p: &mut Parser) -> CompletedMarker {
assert!(p.at(T!['[']));
let m = p.start();
p.bump(T!['[']);
pat_list(p, T![']']);
p.expect(T![']']);
m.complete(p, SLICE_PAT)
}
fn pat_list(p: &mut Parser, ket: SyntaxKind) {
while !p.at(EOF) && !p.at(ket) {
if !p.at_ts(PATTERN_FIRST) {
p.error("expected a pattern");
break;
}
pattern(p);
if !p.at(ket) {
p.expect(T![,]);
}
}
}
// test bind_pat
// fn main() {
// let a = ();
// let mut b = ();
// let ref c = ();
// let ref mut d = ();
// let e @ _ = ();
// let ref mut f @ g @ _ = ();
// }
fn bind_pat(p: &mut Parser, with_at: bool) -> CompletedMarker {
let m = p.start();
p.eat(T![ref]);
p.eat(T![mut]);
name(p);
if with_at && p.eat(T![@]) {
pattern_single(p);
}
m.complete(p, IDENT_PAT)
}
// test box_pat
// fn main() {
// let box i = ();
// let box Outer { box i, j: box Inner(box &x) } = ();
// let box ref mut i = ();
// }
fn box_pat(p: &mut Parser) -> CompletedMarker {
assert!(p.at(T![box]));
let m = p.start();
p.bump(T![box]);
pattern_single(p);
m.complete(p, BOX_PAT)
}

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//! FIXME: write short doc here
use super::*;
pub(super) fn opt_type_arg_list(p: &mut Parser, colon_colon_required: bool) {
let m;
if p.at(T![::]) && p.nth(2) == T![<] {
m = p.start();
p.bump(T![::]);
p.bump(T![<]);
} else if !colon_colon_required && p.at(T![<]) && p.nth(1) != T![=] {
m = p.start();
p.bump(T![<]);
} else {
return;
}
while !p.at(EOF) && !p.at(T![>]) {
type_arg(p);
if !p.at(T![>]) && !p.expect(T![,]) {
break;
}
}
p.expect(T![>]);
m.complete(p, GENERIC_ARG_LIST);
}
// test type_arg
// type A = B<'static, i32, 1, { 2 }, Item=u64>;
fn type_arg(p: &mut Parser) {
let m = p.start();
match p.current() {
LIFETIME => {
p.bump(LIFETIME);
m.complete(p, LIFETIME_ARG);
}
// test associated_type_bounds
// fn print_all<T: Iterator<Item: Display>>(printables: T) {}
IDENT if p.nth(1) == T![:] && p.nth(2) != T![:] => {
name_ref(p);
type_params::bounds(p);
m.complete(p, ASSOC_TYPE_ARG);
}
IDENT if p.nth(1) == T![=] => {
name_ref(p);
p.bump_any();
types::type_(p);
m.complete(p, ASSOC_TYPE_ARG);
}
T!['{'] => {
expressions::block_expr(p);
m.complete(p, CONST_ARG);
}
k if k.is_literal() => {
expressions::literal(p);
m.complete(p, CONST_ARG);
}
_ => {
types::type_(p);
m.complete(p, TYPE_ARG);
}
}
}

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//! FIXME: write short doc here
use super::*;
pub(super) fn opt_type_param_list(p: &mut Parser) {
if !p.at(T![<]) {
return;
}
type_param_list(p);
}
fn type_param_list(p: &mut Parser) {
assert!(p.at(T![<]));
let m = p.start();
p.bump(T![<]);
while !p.at(EOF) && !p.at(T![>]) {
let m = p.start();
// test generic_lifetime_type_attribute
// fn foo<#[derive(Lifetime)] 'a, #[derive(Type)] T>(_: &'a T) {
// }
attributes::outer_attributes(p);
match p.current() {
LIFETIME => lifetime_param(p, m),
IDENT => type_param(p, m),
CONST_KW => type_const_param(p, m),
_ => {
m.abandon(p);
p.err_and_bump("expected type parameter")
}
}
if !p.at(T![>]) && !p.expect(T![,]) {
break;
}
}
p.expect(T![>]);
m.complete(p, GENERIC_PARAM_LIST);
}
fn lifetime_param(p: &mut Parser, m: Marker) {
assert!(p.at(LIFETIME));
p.bump(LIFETIME);
if p.at(T![:]) {
lifetime_bounds(p);
}
m.complete(p, LIFETIME_PARAM);
}
fn type_param(p: &mut Parser, m: Marker) {
assert!(p.at(IDENT));
name(p);
if p.at(T![:]) {
bounds(p);
}
// test type_param_default
// struct S<T = i32>;
if p.at(T![=]) {
p.bump(T![=]);
types::type_(p)
}
m.complete(p, TYPE_PARAM);
}
// test const_param
// struct S<const N: u32>;
fn type_const_param(p: &mut Parser, m: Marker) {
assert!(p.at(CONST_KW));
p.bump(T![const]);
name(p);
types::ascription(p);
m.complete(p, CONST_PARAM);
}
// test type_param_bounds
// struct S<T: 'a + ?Sized + (Copy)>;
pub(super) fn bounds(p: &mut Parser) {
assert!(p.at(T![:]));
p.bump(T![:]);
bounds_without_colon(p);
}
fn lifetime_bounds(p: &mut Parser) {
assert!(p.at(T![:]));
p.bump(T![:]);
while p.at(LIFETIME) {
p.bump(LIFETIME);
if !p.eat(T![+]) {
break;
}
}
}
pub(super) fn bounds_without_colon_m(p: &mut Parser, marker: Marker) -> CompletedMarker {
while type_bound(p) {
if !p.eat(T![+]) {
break;
}
}
marker.complete(p, TYPE_BOUND_LIST)
}
pub(super) fn bounds_without_colon(p: &mut Parser) {
let m = p.start();
bounds_without_colon_m(p, m);
}
fn type_bound(p: &mut Parser) -> bool {
let m = p.start();
let has_paren = p.eat(T!['(']);
p.eat(T![?]);
match p.current() {
LIFETIME => p.bump(LIFETIME),
T![for] => types::for_type(p),
_ if paths::is_use_path_start(p) => types::path_type_(p, false),
_ => {
m.abandon(p);
return false;
}
}
if has_paren {
p.expect(T![')']);
}
m.complete(p, TYPE_BOUND);
true
}
// test where_clause
// fn foo()
// where
// 'a: 'b + 'c,
// T: Clone + Copy + 'static,
// Iterator::Item: 'a,
// <T as Iterator>::Item: 'a
// {}
pub(super) fn opt_where_clause(p: &mut Parser) {
if !p.at(T![where]) {
return;
}
let m = p.start();
p.bump(T![where]);
while is_where_predicate(p) {
where_predicate(p);
let comma = p.eat(T![,]);
if is_where_clause_end(p) {
break;
}
if !comma {
p.error("expected comma");
}
}
m.complete(p, WHERE_CLAUSE);
}
fn is_where_predicate(p: &mut Parser) -> bool {
match p.current() {
LIFETIME => true,
T![impl] => false,
token => types::TYPE_FIRST.contains(token),
}
}
fn is_where_clause_end(p: &mut Parser) -> bool {
matches!(p.current(), T!['{'] | T![;] | T![=])
}
fn where_predicate(p: &mut Parser) {
let m = p.start();
match p.current() {
LIFETIME => {
p.bump(LIFETIME);
if p.at(T![:]) {
bounds(p);
} else {
p.error("expected colon");
}
}
T![impl] => {
p.error("expected lifetime or type");
}
_ => {
// test where_pred_for
// fn for_trait<F>()
// where
// for<'a> F: Fn(&'a str)
// { }
if p.at(T![for]) {
types::for_binder(p);
}
types::type_(p);
if p.at(T![:]) {
bounds(p);
} else {
p.error("expected colon");
}
}
}
m.complete(p, WHERE_PRED);
}

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//! FIXME: write short doc here
use super::*;
pub(super) const TYPE_FIRST: TokenSet = paths::PATH_FIRST.union(token_set![
T!['('],
T!['['],
T![<],
T![!],
T![*],
T![&],
T![_],
T![fn],
T![unsafe],
T![extern],
T![for],
T![impl],
T![dyn],
]);
const TYPE_RECOVERY_SET: TokenSet = token_set![R_PAREN, COMMA, L_DOLLAR];
pub(crate) fn type_(p: &mut Parser) {
type_with_bounds_cond(p, true);
}
pub(super) fn type_no_bounds(p: &mut Parser) {
type_with_bounds_cond(p, false);
}
fn type_with_bounds_cond(p: &mut Parser, allow_bounds: bool) {
match p.current() {
T!['('] => paren_or_tuple_type(p),
T![!] => never_type(p),
T![*] => pointer_type(p),
T!['['] => array_or_slice_type(p),
T![&] => reference_type(p),
T![_] => placeholder_type(p),
T![fn] | T![unsafe] | T![extern] => fn_pointer_type(p),
T![for] => for_type(p),
T![impl] => impl_trait_type(p),
T![dyn] => dyn_trait_type(p),
// Some path types are not allowed to have bounds (no plus)
T![<] => path_type_(p, allow_bounds),
_ if paths::is_use_path_start(p) => path_or_macro_type_(p, allow_bounds),
_ => {
p.err_recover("expected type", TYPE_RECOVERY_SET);
}
}
}
pub(super) fn ascription(p: &mut Parser) {
p.expect(T![:]);
type_(p)
}
fn paren_or_tuple_type(p: &mut Parser) {
assert!(p.at(T!['(']));
let m = p.start();
p.bump(T!['(']);
let mut n_types: u32 = 0;
let mut trailing_comma: bool = false;
while !p.at(EOF) && !p.at(T![')']) {
n_types += 1;
type_(p);
if p.eat(T![,]) {
trailing_comma = true;
} else {
trailing_comma = false;
break;
}
}
p.expect(T![')']);
let kind = if n_types == 1 && !trailing_comma {
// test paren_type
// type T = (i32);
PAREN_TYPE
} else {
// test unit_type
// type T = ();
// test singleton_tuple_type
// type T = (i32,);
TUPLE_TYPE
};
m.complete(p, kind);
}
// test never_type
// type Never = !;
fn never_type(p: &mut Parser) {
assert!(p.at(T![!]));
let m = p.start();
p.bump(T![!]);
m.complete(p, NEVER_TYPE);
}
fn pointer_type(p: &mut Parser) {
assert!(p.at(T![*]));
let m = p.start();
p.bump(T![*]);
match p.current() {
// test pointer_type_mut
// type M = *mut ();
// type C = *mut ();
T![mut] | T![const] => p.bump_any(),
_ => {
// test_err pointer_type_no_mutability
// type T = *();
p.error(
"expected mut or const in raw pointer type \
(use `*mut T` or `*const T` as appropriate)",
);
}
};
type_no_bounds(p);
m.complete(p, PTR_TYPE);
}
fn array_or_slice_type(p: &mut Parser) {
assert!(p.at(T!['[']));
let m = p.start();
p.bump(T!['[']);
type_(p);
let kind = match p.current() {
// test slice_type
// type T = [()];
T![']'] => {
p.bump(T![']']);
SLICE_TYPE
}
// test array_type
// type T = [(); 92];
T![;] => {
p.bump(T![;]);
expressions::expr(p);
p.expect(T![']']);
ARRAY_TYPE
}
// test_err array_type_missing_semi
// type T = [() 92];
_ => {
p.error("expected `;` or `]`");
SLICE_TYPE
}
};
m.complete(p, kind);
}
// test reference_type;
// type A = &();
// type B = &'static ();
// type C = &mut ();
fn reference_type(p: &mut Parser) {
assert!(p.at(T![&]));
let m = p.start();
p.bump(T![&]);
p.eat(LIFETIME);
p.eat(T![mut]);
type_no_bounds(p);
m.complete(p, REF_TYPE);
}
// test placeholder_type
// type Placeholder = _;
fn placeholder_type(p: &mut Parser) {
assert!(p.at(T![_]));
let m = p.start();
p.bump(T![_]);
m.complete(p, INFER_TYPE);
}
// test fn_pointer_type
// type A = fn();
// type B = unsafe fn();
// type C = unsafe extern "C" fn();
// type D = extern "C" fn ( u8 , ... ) -> u8;
fn fn_pointer_type(p: &mut Parser) {
let m = p.start();
p.eat(T![unsafe]);
if p.at(T![extern]) {
abi(p);
}
// test_err fn_pointer_type_missing_fn
// type F = unsafe ();
if !p.eat(T![fn]) {
m.abandon(p);
p.error("expected `fn`");
return;
}
if p.at(T!['(']) {
params::param_list_fn_ptr(p);
} else {
p.error("expected parameters")
}
// test fn_pointer_type_with_ret
// type F = fn() -> ();
opt_fn_ret_type(p);
m.complete(p, FN_PTR_TYPE);
}
pub(super) fn for_binder(p: &mut Parser) {
assert!(p.at(T![for]));
p.bump(T![for]);
if p.at(T![<]) {
type_params::opt_type_param_list(p);
} else {
p.error("expected `<`");
}
}
// test for_type
// type A = for<'a> fn() -> ();
// type B = for<'a> unsafe extern "C" fn(&'a ()) -> ();
// type Obj = for<'a> PartialEq<&'a i32>;
pub(super) fn for_type(p: &mut Parser) {
assert!(p.at(T![for]));
let m = p.start();
for_binder(p);
match p.current() {
T![fn] | T![unsafe] | T![extern] => {}
// OK: legacy trait object format
_ if paths::is_use_path_start(p) => {}
_ => {
p.error("expected a function pointer or path");
}
}
type_no_bounds(p);
m.complete(p, FOR_TYPE);
}
// test impl_trait_type
// type A = impl Iterator<Item=Foo<'a>> + 'a;
fn impl_trait_type(p: &mut Parser) {
assert!(p.at(T![impl]));
let m = p.start();
p.bump(T![impl]);
type_params::bounds_without_colon(p);
m.complete(p, IMPL_TRAIT_TYPE);
}
// test dyn_trait_type
// type A = dyn Iterator<Item=Foo<'a>> + 'a;
fn dyn_trait_type(p: &mut Parser) {
assert!(p.at(T![dyn]));
let m = p.start();
p.bump(T![dyn]);
type_params::bounds_without_colon(p);
m.complete(p, DYN_TRAIT_TYPE);
}
// test path_type
// type A = Foo;
// type B = ::Foo;
// type C = self::Foo;
// type D = super::Foo;
pub(super) fn path_type(p: &mut Parser) {
path_type_(p, true)
}
// test macro_call_type
// type A = foo!();
// type B = crate::foo!();
fn path_or_macro_type_(p: &mut Parser, allow_bounds: bool) {
assert!(paths::is_path_start(p));
let m = p.start();
paths::type_path(p);
let kind = if p.at(T![!]) && !p.at(T![!=]) {
items::macro_call_after_excl(p);
MACRO_CALL
} else {
PATH_TYPE
};
let path = m.complete(p, kind);
if allow_bounds {
opt_path_type_bounds_as_dyn_trait_type(p, path);
}
}
pub(super) fn path_type_(p: &mut Parser, allow_bounds: bool) {
assert!(paths::is_path_start(p));
let m = p.start();
paths::type_path(p);
// test path_type_with_bounds
// fn foo() -> Box<T + 'f> {}
// fn foo() -> Box<dyn T + 'f> {}
let path = m.complete(p, PATH_TYPE);
if allow_bounds {
opt_path_type_bounds_as_dyn_trait_type(p, path);
}
}
/// This turns a parsed PATH_TYPE optionally into a DYN_TRAIT_TYPE
/// with a TYPE_BOUND_LIST
fn opt_path_type_bounds_as_dyn_trait_type(p: &mut Parser, path_type_marker: CompletedMarker) {
if !p.at(T![+]) {
return;
}
// First create a TYPE_BOUND from the completed PATH_TYPE
let m = path_type_marker.precede(p).complete(p, TYPE_BOUND);
// Next setup a marker for the TYPE_BOUND_LIST
let m = m.precede(p);
// This gets consumed here so it gets properly set
// in the TYPE_BOUND_LIST
p.eat(T![+]);
// Parse rest of the bounds into the TYPE_BOUND_LIST
let m = type_params::bounds_without_colon_m(p, m);
// Finally precede everything with DYN_TRAIT_TYPE
m.precede(p).complete(p, DYN_TRAIT_TYPE);
}