9 files changed, 63 insertions, 12 deletions

diff --git a/crates/ra_parser/src/grammar.rs b/crates/ra_parser/src/grammar.rs
index 6e9e212b7..22f64a9f4 100644
--- a/crates/ra_parser/src/grammar.rs
+++ b/crates/ra_parser/src/grammar.rs
@@ -264,7 +264,7 @@ fn name_r(p: &mut Parser, recovery: TokenSet) {
 }
 
 fn name(p: &mut Parser) {
-    name_r(p, TokenSet::empty())
+    name_r(p, TokenSet::EMPTY)
 }
 
 fn name_ref(p: &mut Parser) {
diff --git a/crates/ra_parser/src/grammar/expressions/atom.rs b/crates/ra_parser/src/grammar/expressions/atom.rs
index f06191963..4ac1d6334 100644
--- a/crates/ra_parser/src/grammar/expressions/atom.rs
+++ b/crates/ra_parser/src/grammar/expressions/atom.rs
@@ -43,6 +43,7 @@ pub(super) const ATOM_EXPR_FIRST: TokenSet =
         T!['('],
         T!['{'],
         T!['['],
+        L_DOLLAR,
         T![|],
         T![move],
         T![box],
@@ -248,7 +249,12 @@ fn lambda_expr(p: &mut Parser) -> CompletedMarker {
             p.error("expected `{`");
         }
     }
-    expr(p);
+
+    if p.at_ts(EXPR_FIRST) {
+        expr(p);
+    } else {
+        p.error("expected expression");
+    }
     m.complete(p, LAMBDA_EXPR)
 }
 
@@ -438,7 +444,7 @@ fn match_arm(p: &mut Parser) -> BlockLike {
     // }
     attributes::outer_attributes(p);
 
-    patterns::pattern_list_r(p, TokenSet::empty());
+    patterns::pattern_list_r(p, TokenSet::EMPTY);
     if p.at(T![if]) {
         match_guard(p);
     }
diff --git a/crates/ra_parser/src/grammar/items.rs b/crates/ra_parser/src/grammar/items.rs
index 370990e21..6e23d9b72 100644
--- a/crates/ra_parser/src/grammar/items.rs
+++ b/crates/ra_parser/src/grammar/items.rs
@@ -33,7 +33,7 @@ pub(super) enum ItemFlavor {
 
 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
+    CRATE_KW, USE_KW, MACRO_KW
 ];
 
 pub(super) fn item_or_macro(p: &mut Parser, stop_on_r_curly: bool, flavor: ItemFlavor) {
@@ -249,6 +249,11 @@ fn items_without_modifiers(p: &mut Parser, m: Marker) -> Result<(), Marker> {
             // }
             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 {}
@@ -379,6 +384,29 @@ pub(crate) fn mod_item_list(p: &mut Parser) {
     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);
diff --git a/crates/ra_parser/src/grammar/patterns.rs b/crates/ra_parser/src/grammar/patterns.rs
index f5d12278c..422a4e3dc 100644
--- a/crates/ra_parser/src/grammar/patterns.rs
+++ b/crates/ra_parser/src/grammar/patterns.rs
@@ -50,7 +50,7 @@ pub(super) fn pattern_r(p: &mut Parser, recovery_set: TokenSet) {
         //     let m!(x) = 0;
         // }
         if lhs.kind() == PATH_PAT && p.at(T![!]) {
-            let m = lhs.precede(p);
+            let m = lhs.undo_completion(p);
             items::macro_call_after_excl(p);
             m.complete(p, MACRO_CALL);
         }
diff --git a/crates/ra_parser/src/grammar/type_params.rs b/crates/ra_parser/src/grammar/type_params.rs
index 34406b5bd..50e4900c3 100644
--- a/crates/ra_parser/src/grammar/type_params.rs
+++ b/crates/ra_parser/src/grammar/type_params.rs
@@ -25,6 +25,7 @@ fn type_param_list(p: &mut Parser) {
         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")
@@ -62,6 +63,16 @@ fn type_param(p: &mut Parser, m: Marker) {
     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) {
diff --git a/crates/ra_parser/src/lib.rs b/crates/ra_parser/src/lib.rs
index 45241e566..65134277e 100644
--- a/crates/ra_parser/src/lib.rs
+++ b/crates/ra_parser/src/lib.rs
@@ -83,6 +83,7 @@ pub fn parse(token_source: &mut dyn TokenSource, tree_sink: &mut dyn TreeSink) {
     parse_from_tokens(token_source, tree_sink, grammar::root);
 }
 
+#[derive(Clone, Copy)]
 pub enum FragmentKind {
     Path,
     Expr,
diff --git a/crates/ra_parser/src/parser.rs b/crates/ra_parser/src/parser.rs
index dafd5247b..1071c46dc 100644
--- a/crates/ra_parser/src/parser.rs
+++ b/crates/ra_parser/src/parser.rs
@@ -208,7 +208,7 @@ impl<'t> Parser<'t> {
 
     /// Create an error node and consume the next token.
     pub(crate) fn err_and_bump(&mut self, message: &str) {
-        self.err_recover(message, TokenSet::empty());
+        self.err_recover(message, TokenSet::EMPTY);
     }
 
     /// Create an error node and consume the next token.
diff --git a/crates/ra_parser/src/syntax_kind/generated.rs b/crates/ra_parser/src/syntax_kind/generated.rs
index fe0fcdb33..af2945f57 100644
--- a/crates/ra_parser/src/syntax_kind/generated.rs
+++ b/crates/ra_parser/src/syntax_kind/generated.rs
@@ -100,6 +100,7 @@ pub enum SyntaxKind {
     TRY_KW,
     BOX_KW,
     AWAIT_KW,
+    MACRO_KW,
     AUTO_KW,
     DEFAULT_KW,
     EXISTENTIAL_KW,
@@ -136,6 +137,7 @@ pub enum SyntaxKind {
     TYPE_ALIAS_DEF,
     MACRO_CALL,
     TOKEN_TREE,
+    MACRO_DEF,
     PAREN_TYPE,
     TUPLE_TYPE,
     NEVER_TYPE,
@@ -227,6 +229,7 @@ pub enum SyntaxKind {
     TYPE_PARAM_LIST,
     LIFETIME_PARAM,
     TYPE_PARAM,
+    CONST_PARAM,
     TYPE_ARG_LIST,
     LIFETIME_ARG,
     TYPE_ARG,
@@ -251,7 +254,7 @@ impl SyntaxKind {
             | SUPER_KW | IN_KW | WHERE_KW | FOR_KW | LOOP_KW | WHILE_KW | CONTINUE_KW
             | BREAK_KW | IF_KW | ELSE_KW | MATCH_KW | CONST_KW | STATIC_KW | MUT_KW | UNSAFE_KW
             | TYPE_KW | REF_KW | LET_KW | MOVE_KW | RETURN_KW | TRY_KW | BOX_KW | AWAIT_KW
-            | AUTO_KW | DEFAULT_KW | EXISTENTIAL_KW | UNION_KW => true,
+            | MACRO_KW | AUTO_KW | DEFAULT_KW | EXISTENTIAL_KW | UNION_KW => true,
             _ => false,
         }
     }
@@ -314,6 +317,7 @@ impl SyntaxKind {
             "try" => TRY_KW,
             "box" => BOX_KW,
             "await" => AWAIT_KW,
+            "macro" => MACRO_KW,
             _ => return None,
         };
         Some(kw)
@@ -628,6 +632,9 @@ macro_rules! T {
     ( await ) => {
         $crate::SyntaxKind::AWAIT_KW
     };
+    ( macro ) => {
+        $crate::SyntaxKind::MACRO_KW
+    };
     ( auto ) => {
         $crate::SyntaxKind::AUTO_KW
     };
diff --git a/crates/ra_parser/src/token_set.rs b/crates/ra_parser/src/token_set.rs
index 2a6952c01..994017acf 100644
--- a/crates/ra_parser/src/token_set.rs
+++ b/crates/ra_parser/src/token_set.rs
@@ -1,4 +1,4 @@
-//! FIXME: write short doc here
+//! A bit-set of `SyntaxKind`s.
 
 use crate::SyntaxKind;
 
@@ -7,9 +7,7 @@ use crate::SyntaxKind;
 pub(crate) struct TokenSet(u128);
 
 impl TokenSet {
-    pub(crate) const fn empty() -> TokenSet {
-        TokenSet(0)
-    }
+    pub(crate) const EMPTY: TokenSet = TokenSet(0);
 
     pub(crate) const fn singleton(kind: SyntaxKind) -> TokenSet {
         TokenSet(mask(kind))
@@ -30,7 +28,7 @@ const fn mask(kind: SyntaxKind) -> u128 {
 
 #[macro_export]
 macro_rules! token_set {
-    ($($t:expr),*) => { TokenSet::empty()$(.union(TokenSet::singleton($t)))* };
+    ($($t:expr),*) => { TokenSet::EMPTY$(.union(TokenSet::singleton($t)))* };
     ($($t:expr),* ,) => { token_set!($($t),*) };
 }