CONST LOOPS ARE HERE

crates/parser/src/grammar/expressions.rs

@@ -316,7 +316,7 @@ fn expr_bp(p: &mut Parser, mut r: Restrictions, bp: u8) -> (Option<CompletedMark
 }
 
 const LHS_FIRST: TokenSet =
-    atom::ATOM_EXPR_FIRST.union(token_set![T![&], T![*], T![!], T![.], T![-]]);
+    atom::ATOM_EXPR_FIRST.union(TokenSet::new(&[T![&], T![*], T![!], T![.], T![-]]));
 
 fn lhs(p: &mut Parser, r: Restrictions) -> Option<(CompletedMarker, BlockLike)> {
     let m;

crates/parser/src/grammar/expressions/atom.rs

@@ -15,7 +15,7 @@ use super::*;
 //     let _ = b"e";
 //     let _ = br"f";
 // }
-pub(crate) const LITERAL_FIRST: TokenSet = token_set![
+pub(crate) const LITERAL_FIRST: TokenSet = TokenSet::new(&[
     TRUE_KW,
     FALSE_KW,
     INT_NUMBER,
@@ -25,8 +25,8 @@ pub(crate) const LITERAL_FIRST: TokenSet = token_set![
     STRING,
     RAW_STRING,
     BYTE_STRING,
-    RAW_BYTE_STRING
+    RAW_BYTE_STRING,
-];
+]);
 
 pub(crate) fn literal(p: &mut Parser) -> Option<CompletedMarker> {
     if !p.at_ts(LITERAL_FIRST) {
@@ -39,7 +39,7 @@ pub(crate) fn literal(p: &mut Parser) -> Option<CompletedMarker> {
 
 // 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![
+    LITERAL_FIRST.union(paths::PATH_FIRST).union(TokenSet::new(&[
         T!['('],
         T!['{'],
         T!['['],
@@ -59,9 +59,9 @@ pub(super) const ATOM_EXPR_FIRST: TokenSet =
         T![loop],
         T![for],
         LIFETIME,
-    ]);
+    ]));
 
-const EXPR_RECOVERY_SET: TokenSet = token_set![LET_KW, R_DOLLAR];
+const EXPR_RECOVERY_SET: TokenSet = TokenSet::new(&[LET_KW, R_DOLLAR]);
 
 pub(super) fn atom_expr(p: &mut Parser, r: Restrictions) -> Option<(CompletedMarker, BlockLike)> {
     if let Some(m) = literal(p) {

crates/parser/src/grammar/items.rs

@@ -26,7 +26,7 @@ pub(super) fn mod_contents(p: &mut Parser, stop_on_r_curly: bool) {
     }
 }
 
-pub(super) const ITEM_RECOVERY_SET: TokenSet = token_set![
+pub(super) const ITEM_RECOVERY_SET: TokenSet = TokenSet::new(&[
     FN_KW,
     STRUCT_KW,
     ENUM_KW,
@@ -41,7 +41,7 @@ pub(super) const ITEM_RECOVERY_SET: TokenSet = token_set![
     USE_KW,
     MACRO_KW,
     T![;],
-];
+]);
 
 pub(super) fn item_or_macro(p: &mut Parser, stop_on_r_curly: bool) {
     let m = p.start();

crates/parser/src/grammar/paths.rs

@@ -3,7 +3,7 @@
 use super::*;
 
 pub(super) const PATH_FIRST: TokenSet =
-    token_set![IDENT, T![self], T![super], T![crate], T![:], T![<]];
+    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![<])

crates/parser/src/grammar/patterns.rs

@@ -2,9 +2,18 @@
 
 use super::*;
 
-pub(super) const PATTERN_FIRST: TokenSet = expressions::LITERAL_FIRST
+pub(super) const PATTERN_FIRST: TokenSet =
-    .union(paths::PATH_FIRST)
+    expressions::LITERAL_FIRST.union(paths::PATH_FIRST).union(TokenSet::new(&[
-    .union(token_set![T![box], T![ref], T![mut], T!['('], T!['['], T![&], T![_], T![-], T![.]]);
+        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);
@@ -74,7 +83,7 @@ fn pattern_single_r(p: &mut Parser, recovery_set: TokenSet) {
 }
 
 const PAT_RECOVERY_SET: TokenSet =
-    token_set![LET_KW, IF_KW, WHILE_KW, LOOP_KW, MATCH_KW, R_PAREN, COMMA];
+    TokenSet::new(&[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) {

crates/parser/src/grammar/types.rs

@@ -2,7 +2,7 @@
 
 use super::*;
 
-pub(super) const TYPE_FIRST: TokenSet = paths::PATH_FIRST.union(token_set![
+pub(super) const TYPE_FIRST: TokenSet = paths::PATH_FIRST.union(TokenSet::new(&[
     T!['('],
     T!['['],
     T![<],
@@ -16,16 +16,16 @@ pub(super) const TYPE_FIRST: TokenSet = paths::PATH_FIRST.union(token_set![
     T![for],
     T![impl],
     T![dyn],
-]);
+]));
 
-const TYPE_RECOVERY_SET: TokenSet = token_set![
+const TYPE_RECOVERY_SET: TokenSet = TokenSet::new(&[
     T![')'],
     T![,],
     L_DOLLAR,
     // test_err struct_field_recover
     // struct S { f pub g: () }
     T![pub],
-];
+]);
 
 pub(crate) fn type_(p: &mut Parser) {
     type_with_bounds_cond(p, true);

crates/parser/src/token_set.rs

@@ -9,15 +9,21 @@ pub(crate) struct TokenSet(u128);
 impl TokenSet {
     pub(crate) const EMPTY: TokenSet = TokenSet(0);
 
-    pub(crate) const fn singleton(kind: SyntaxKind) -> TokenSet {
+    pub(crate) const fn new(kinds: &[SyntaxKind]) -> TokenSet {
-        TokenSet(mask(kind))
+        let mut res = 0u128;
+        let mut i = 0;
+        while i < kinds.len() {
+            res |= mask(kinds[i]);
+            i += 1
+        }
+        TokenSet(res)
     }
 
     pub(crate) const fn union(self, other: TokenSet) -> TokenSet {
         TokenSet(self.0 | other.0)
     }
 
-    pub(crate) fn contains(&self, kind: SyntaxKind) -> bool {
+    pub(crate) const fn contains(&self, kind: SyntaxKind) -> bool {
         self.0 & mask(kind) != 0
     }
 }
@@ -26,16 +32,10 @@ const fn mask(kind: SyntaxKind) -> u128 {
     1u128 << (kind as usize)
 }
 
-#[macro_export]
-macro_rules! token_set {
-    ($($t:expr),*) => { TokenSet::EMPTY$(.union(TokenSet::singleton($t)))* };
-    ($($t:expr),* ,) => { token_set!($($t),*) };
-}
-
 #[test]
 fn token_set_works_for_tokens() {
     use crate::SyntaxKind::*;
-    let ts = token_set![EOF, SHEBANG];
+    let ts = TokenSet::new(&[EOF, SHEBANG]);
     assert!(ts.contains(EOF));
     assert!(ts.contains(SHEBANG));
     assert!(!ts.contains(PLUS));

xtask/src/install.rs

@@ -7,7 +7,7 @@ use anyhow::{bail, format_err, Context, Result};
 use crate::not_bash::{pushd, run};
 
 // Latest stable, feel free to send a PR if this lags behind.
-const REQUIRED_RUST_VERSION: u32 = 43;
+const REQUIRED_RUST_VERSION: u32 = 46;
 
 pub struct InstallCmd {
     pub client: Option<ClientOpt>,