10 files changed, 72 insertions, 2 deletions

diff --git a/crates/ra_parser/src/grammar/expressions/atom.rs b/crates/ra_parser/src/grammar/expressions/atom.rs
index 9f282c74d..53bb26c5f 100644
--- a/crates/ra_parser/src/grammar/expressions/atom.rs
+++ b/crates/ra_parser/src/grammar/expressions/atom.rs
@@ -93,6 +93,11 @@ pub(super) fn atom_expr(p: &mut Parser, r: Restrictions) -> Option<(CompletedMar
             }
         }
 
+        ASYNC_KW if la == L_CURLY => {
+            let m = p.start();
+            p.bump();
+            block_expr(p, Some(m))
+        }
         MATCH_KW => match_expr(p),
         UNSAFE_KW if la == L_CURLY => {
             let m = p.start();
diff --git a/crates/ra_parser/src/grammar/items.rs b/crates/ra_parser/src/grammar/items.rs
index ab9d2de90..a057c8167 100644
--- a/crates/ra_parser/src/grammar/items.rs
+++ b/crates/ra_parser/src/grammar/items.rs
@@ -86,9 +86,15 @@ pub(super) fn maybe_item(p: &mut Parser, flavor: ItemFlavor) -> MaybeItem {
     }
 
     let mut has_mods = false;
+
     // modifiers
+    // test_err async_without_semicolon
+    // fn foo() { let _ = async {} }
     has_mods |= p.eat(CONST_KW);
-
+    if p.at(ASYNC_KW) && p.nth(1) != L_CURLY {
+        p.eat(ASYNC_KW);
+        has_mods = true;
+    }
     // test_err unsafe_block_in_mod
     // fn foo(){} unsafe { } fn bar(){}
     if p.at(UNSAFE_KW) && p.nth(1) != L_CURLY {
@@ -110,6 +116,9 @@ pub(super) fn maybe_item(p: &mut Parser, flavor: ItemFlavor) -> MaybeItem {
 
     // items
     let kind = match p.current() {
+        // test async_fn
+        // async fn foo() {}
+
         // test extern_fn
         // extern fn foo() {}
 
diff --git a/crates/ra_parser/src/syntax_kind/generated.rs b/crates/ra_parser/src/syntax_kind/generated.rs
index 0eed44ecf..03247ae38 100644
--- a/crates/ra_parser/src/syntax_kind/generated.rs
+++ b/crates/ra_parser/src/syntax_kind/generated.rs
@@ -66,6 +66,7 @@ pub enum SyntaxKind {
     SHR,
     SHLEQ,
     SHREQ,
+    ASYNC_KW,
     USE_KW,
     FN_KW,
     STRUCT_KW,
@@ -233,6 +234,7 @@ use self::SyntaxKind::*;
 impl SyntaxKind {
     pub fn is_keyword(self) -> bool {
         match self {
+            | ASYNC_KW
             | USE_KW
             | FN_KW
             | STRUCT_KW
@@ -403,6 +405,7 @@ impl SyntaxKind {
             SHR => &SyntaxInfo { name: "SHR" },
             SHLEQ => &SyntaxInfo { name: "SHLEQ" },
             SHREQ => &SyntaxInfo { name: "SHREQ" },
+            ASYNC_KW => &SyntaxInfo { name: "ASYNC_KW" },
             USE_KW => &SyntaxInfo { name: "USE_KW" },
             FN_KW => &SyntaxInfo { name: "FN_KW" },
             STRUCT_KW => &SyntaxInfo { name: "STRUCT_KW" },
@@ -570,6 +573,7 @@ impl SyntaxKind {
     }
     pub fn from_keyword(ident: &str) -> Option<SyntaxKind> {
         let kw = match ident {
+            "async" => ASYNC_KW,
             "use" => USE_KW,
             "fn" => FN_KW,
             "struct" => STRUCT_KW,
diff --git a/crates/ra_syntax/src/grammar.ron b/crates/ra_syntax/src/grammar.ron
index b7a2d1c01..66f1339c1 100644
--- a/crates/ra_syntax/src/grammar.ron
+++ b/crates/ra_syntax/src/grammar.ron
@@ -59,6 +59,7 @@ Grammar(
         [">>=", "SHREQ"],
     ],
     keywords: [
+        "async",
         "use",
         "fn",
         "struct",
diff --git a/crates/ra_syntax/tests/data/lexer/0011_keywords.rs b/crates/ra_syntax/tests/data/lexer/0011_keywords.rs
index e6bf64d4d..1e91bff4e 100644
--- a/crates/ra_syntax/tests/data/lexer/0011_keywords.rs
+++ b/crates/ra_syntax/tests/data/lexer/0011_keywords.rs
@@ -1,3 +1,3 @@
-fn use struct trait enum impl true false as extern crate
+async fn use struct trait enum impl true false as extern crate
 mod pub self super in where for loop while if match const
 static mut type ref let else move return
diff --git a/crates/ra_syntax/tests/data/lexer/0011_keywords.txt b/crates/ra_syntax/tests/data/lexer/0011_keywords.txt
index d6a1abe8a..22c00eefb 100644
--- a/crates/ra_syntax/tests/data/lexer/0011_keywords.txt
+++ b/crates/ra_syntax/tests/data/lexer/0011_keywords.txt
@@ -1,3 +1,5 @@
+ASYNC_KW 5 "async"
+WHITESPACE 1 " "
 FN_KW 2 "fn"
 WHITESPACE 1 " "
 USE_KW 3 "use"
diff --git a/crates/ra_syntax/tests/data/parser/inline/err/0007_async_without_semicolon.rs b/crates/ra_syntax/tests/data/parser/inline/err/0007_async_without_semicolon.rs
new file mode 100644
index 000000000..9a423248c
--- /dev/null
+++ b/crates/ra_syntax/tests/data/parser/inline/err/0007_async_without_semicolon.rs
@@ -0,0 +1 @@
+fn foo() { let _ = async {} }
diff --git a/crates/ra_syntax/tests/data/parser/inline/err/0007_async_without_semicolon.txt b/crates/ra_syntax/tests/data/parser/inline/err/0007_async_without_semicolon.txt
new file mode 100644
index 000000000..bb9a2d029
--- /dev/null
+++ b/crates/ra_syntax/tests/data/parser/inline/err/0007_async_without_semicolon.txt
@@ -0,0 +1,31 @@
+SOURCE_FILE@[0; 30)
+  FN_DEF@[0; 29)
+    FN_KW@[0; 2)
+    WHITESPACE@[2; 3)
+    NAME@[3; 6)
+      IDENT@[3; 6) "foo"
+    PARAM_LIST@[6; 8)
+      L_PAREN@[6; 7)
+      R_PAREN@[7; 8)
+    WHITESPACE@[8; 9)
+    BLOCK@[9; 29)
+      L_CURLY@[9; 10)
+      WHITESPACE@[10; 11)
+      LET_STMT@[11; 27)
+        LET_KW@[11; 14)
+        WHITESPACE@[14; 15)
+        PLACEHOLDER_PAT@[15; 16)
+          UNDERSCORE@[15; 16)
+        WHITESPACE@[16; 17)
+        EQ@[17; 18)
+        WHITESPACE@[18; 19)
+        BLOCK_EXPR@[19; 27)
+          ASYNC_KW@[19; 24)
+          WHITESPACE@[24; 25)
+          BLOCK@[25; 27)
+            L_CURLY@[25; 26)
+            R_CURLY@[26; 27)
+            err: `expected SEMI`
+      WHITESPACE@[27; 28)
+      R_CURLY@[28; 29)
+  WHITESPACE@[29; 30)
diff --git a/crates/ra_syntax/tests/data/parser/inline/ok/0124_async_fn.rs b/crates/ra_syntax/tests/data/parser/inline/ok/0124_async_fn.rs
new file mode 100644
index 000000000..f4adcb62b
--- /dev/null
+++ b/crates/ra_syntax/tests/data/parser/inline/ok/0124_async_fn.rs
@@ -0,0 +1 @@
+async fn foo() {}
diff --git a/crates/ra_syntax/tests/data/parser/inline/ok/0124_async_fn.txt b/crates/ra_syntax/tests/data/parser/inline/ok/0124_async_fn.txt
new file mode 100644
index 000000000..d1a706ecc
--- /dev/null
+++ b/crates/ra_syntax/tests/data/parser/inline/ok/0124_async_fn.txt
@@ -0,0 +1,16 @@
+SOURCE_FILE@[0; 18)
+  FN_DEF@[0; 17)
+    ASYNC_KW@[0; 5)
+    WHITESPACE@[5; 6)
+    FN_KW@[6; 8)
+    WHITESPACE@[8; 9)
+    NAME@[9; 12)
+      IDENT@[9; 12) "foo"
+    PARAM_LIST@[12; 14)
+      L_PAREN@[12; 13)
+      R_PAREN@[13; 14)
+    WHITESPACE@[14; 15)
+    BLOCK@[15; 17)
+      L_CURLY@[15; 16)
+      R_CURLY@[16; 17)
+  WHITESPACE@[17; 18)