6 files changed, 67 insertions, 25 deletions

diff --git a/crates/parser/src/grammar/expressions/atom.rs b/crates/parser/src/grammar/expressions/atom.rs
index 18b63feb7..c7a3556a7 100644
--- a/crates/parser/src/grammar/expressions/atom.rs
+++ b/crates/parser/src/grammar/expressions/atom.rs
@@ -46,6 +46,7 @@ pub(super) const ATOM_EXPR_FIRST: TokenSet =
         T![continue],
         T![async],
         T![try],
+        T![const],
         T![loop],
         T![for],
         LIFETIME_IDENT,
@@ -115,6 +116,14 @@ pub(super) fn atom_expr(p: &mut Parser, r: Restrictions) -> Option<(CompletedMar
             block_expr(p);
             m.complete(p, EFFECT_EXPR)
         }
+        // test const_block
+        // fn f() { const { } }
+        T![const] if la == T!['{'] => {
+            let m = p.start();
+            p.bump(T![const]);
+            block_expr(p);
+            m.complete(p, EFFECT_EXPR)
+        }
         T!['{'] => {
             // test for_range_from
             // fn foo() {
@@ -156,11 +165,13 @@ fn tuple_expr(p: &mut Parser) -> CompletedMarker {
     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");
+
+        // test tuple_attrs
+        // const A: (i64, i64) = (1, #[cfg(test)] 2);
+        if !expr_with_attrs(p) {
             break;
         }
-        expr(p);
+
         if !p.at(T![')']) {
             saw_comma = true;
             p.expect(T![,]);
diff --git a/crates/parser/src/grammar/items.rs b/crates/parser/src/grammar/items.rs
index 8999829b4..cf4168d32 100644
--- a/crates/parser/src/grammar/items.rs
+++ b/crates/parser/src/grammar/items.rs
@@ -96,7 +96,10 @@ pub(super) fn maybe_item(p: &mut Parser, m: Marker) -> Result<(), Marker> {
     let mut has_mods = false;
 
     // modifiers
-    has_mods |= p.eat(T![const]);
+    if p.at(T![const]) && p.nth(1) != T!['{'] {
+        p.eat(T![const]);
+        has_mods = true;
+    }
 
     // test_err async_without_semicolon
     // fn foo() { let _ = async {} }
@@ -167,7 +170,7 @@ pub(super) fn maybe_item(p: &mut Parser, m: Marker) -> Result<(), Marker> {
             m.complete(p, TRAIT);
         }
 
-        T![const] => {
+        T![const] if p.nth(1) != T!['{'] => {
             consts::konst(p, m);
         }
 
@@ -386,10 +389,15 @@ fn macro_rules(p: &mut Parser, m: Marker) {
     }
 
     match p.current() {
-        T!['{'] => {
+        // test macro_rules_non_brace
+        // macro_rules! m ( ($i:ident) => {} );
+        // macro_rules! m [ ($i:ident) => {} ];
+        T!['['] | T!['('] => {
             token_tree(p);
+            p.expect(T![;]);
         }
-        _ => p.error("expected `{`"),
+        T!['{'] => token_tree(p),
+        _ => p.error("expected `{`, `[`, `(`"),
     }
     m.complete(p, MACRO_RULES);
 }
diff --git a/crates/parser/src/grammar/params.rs b/crates/parser/src/grammar/params.rs
index 3ee4e4fca..2d006a1d5 100644
--- a/crates/parser/src/grammar/params.rs
+++ b/crates/parser/src/grammar/params.rs
@@ -47,20 +47,23 @@ fn list_(p: &mut Parser, flavor: Flavor) {
     if let FnDef = flavor {
         // test self_param_outer_attr
         // fn f(#[must_use] self) {}
+        let m = p.start();
         attributes::outer_attrs(p);
-        opt_self_param(p);
+        opt_self_param(p, m);
     }
 
     while !p.at(EOF) && !p.at(ket) {
         // test param_outer_arg
         // fn f(#[attr1] pat: Type) {}
+        let m = p.start();
         attributes::outer_attrs(p);
 
         if !p.at_ts(PARAM_FIRST) {
             p.error("expected value parameter");
+            m.abandon(p);
             break;
         }
-        let param = param(p, flavor);
+        let param = param(p, m, flavor);
         if !p.at(ket) {
             p.expect(T![,]);
         }
@@ -77,9 +80,8 @@ const PARAM_FIRST: TokenSet = patterns::PATTERN_FIRST.union(types::TYPE_FIRST);
 
 struct Variadic(bool);
 
-fn param(p: &mut Parser, flavor: Flavor) -> Variadic {
+fn param(p: &mut Parser, m: Marker, 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; }
@@ -151,10 +153,8 @@ fn variadic_param(p: &mut Parser) -> bool {
 //     fn d(&'a mut self, x: i32) {}
 //     fn e(mut self) {}
 // }
-fn opt_self_param(p: &mut Parser) {
-    let m;
+fn opt_self_param(p: &mut Parser, m: Marker) {
     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
@@ -174,9 +174,8 @@ fn opt_self_param(p: &mut Parser) {
             (T![&], T![mut], T![self], _) => 3,
             (T![&], LIFETIME_IDENT, T![self], _) => 3,
             (T![&], LIFETIME_IDENT, T![mut], T![self]) => 4,
-            _ => return,
+            _ => return m.abandon(p),
         };
-        m = p.start();
         p.bump_any();
         if p.at(LIFETIME_IDENT) {
             lifetime(p);
diff --git a/crates/parser/src/grammar/patterns.rs b/crates/parser/src/grammar/patterns.rs
index 7e7f73dee..b53d5749f 100644
--- a/crates/parser/src/grammar/patterns.rs
+++ b/crates/parser/src/grammar/patterns.rs
@@ -89,6 +89,7 @@ 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] => ident_pat(p, true),
+        T![const] => const_block_pat(p),
         IDENT => match p.nth(1) {
             // Checks the token after an IDENT to see if a pattern is a path (Struct { .. }) or macro
             // (T![x]).
@@ -386,3 +387,16 @@ fn box_pat(p: &mut Parser) -> CompletedMarker {
     pattern_single(p);
     m.complete(p, BOX_PAT)
 }
+
+// test const_block_pat
+// fn main() {
+//     let const { 15 } = ();
+//     let const { foo(); bar() } = ();
+// }
+fn const_block_pat(p: &mut Parser) -> CompletedMarker {
+    assert!(p.at(T![const]));
+    let m = p.start();
+    p.bump(T![const]);
+    expressions::block_expr(p);
+    m.complete(p, CONST_BLOCK_PAT)
+}
diff --git a/crates/parser/src/grammar/type_params.rs b/crates/parser/src/grammar/type_params.rs
index 9c3f7c28a..4aeccd193 100644
--- a/crates/parser/src/grammar/type_params.rs
+++ b/crates/parser/src/grammar/type_params.rs
@@ -113,7 +113,7 @@ fn type_bound(p: &mut Parser) -> bool {
     p.eat(T![?]);
     match p.current() {
         LIFETIME_IDENT => lifetime(p),
-        T![for] => types::for_type(p),
+        T![for] => types::for_type(p, false),
         _ if paths::is_use_path_start(p) => types::path_type_(p, false),
         _ => {
             m.abandon(p);
diff --git a/crates/parser/src/grammar/types.rs b/crates/parser/src/grammar/types.rs
index 36a15eace..94cbf7d85 100644
--- a/crates/parser/src/grammar/types.rs
+++ b/crates/parser/src/grammar/types.rs
@@ -44,7 +44,7 @@ fn type_with_bounds_cond(p: &mut Parser, allow_bounds: bool) {
         T![&] => ref_type(p),
         T![_] => infer_type(p),
         T![fn] | T![unsafe] | T![extern] => fn_ptr_type(p),
-        T![for] => for_type(p),
+        T![for] => for_type(p, allow_bounds),
         T![impl] => impl_trait_type(p),
         T![dyn] => dyn_trait_type(p),
         // Some path types are not allowed to have bounds (no plus)
@@ -227,7 +227,7 @@ pub(super) fn for_binder(p: &mut Parser) {
 // 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) {
+pub(super) fn for_type(p: &mut Parser, allow_bounds: bool) {
     assert!(p.at(T![for]));
     let m = p.start();
     for_binder(p);
@@ -240,7 +240,13 @@ pub(super) fn for_type(p: &mut Parser) {
         }
     }
     type_no_bounds(p);
-    m.complete(p, FOR_TYPE);
+    let completed = m.complete(p, FOR_TYPE);
+
+    // test no_dyn_trait_leading_for
+    // type A = for<'a> Test<'a> + Send;
+    if allow_bounds {
+        opt_type_bounds_as_dyn_trait_type(p, completed);
+    }
 }
 
 // test impl_trait_type
@@ -290,7 +296,7 @@ fn path_or_macro_type_(p: &mut Parser, allow_bounds: bool) {
     let path = m.complete(p, kind);
 
     if allow_bounds {
-        opt_path_type_bounds_as_dyn_trait_type(p, path);
+        opt_type_bounds_as_dyn_trait_type(p, path);
     }
 }
 
@@ -304,19 +310,23 @@ pub(super) fn path_type_(p: &mut Parser, allow_bounds: bool) {
     // 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);
+        opt_type_bounds_as_dyn_trait_type(p, path);
     }
 }
 
-/// This turns a parsed PATH_TYPE optionally into a DYN_TRAIT_TYPE
+/// This turns a parsed PATH_TYPE or FOR_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) {
+fn opt_type_bounds_as_dyn_trait_type(p: &mut Parser, type_marker: CompletedMarker) {
+    assert!(matches!(
+        type_marker.kind(),
+        SyntaxKind::PATH_TYPE | SyntaxKind::FOR_TYPE | SyntaxKind::MACRO_CALL
+    ));
     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);
+    let m = type_marker.precede(p).complete(p, TYPE_BOUND);
 
     // Next setup a marker for the TYPE_BOUND_LIST
     let m = m.precede(p);