Merge #956

956: Add async keyword r=c410-f3r a=c410-f3r

Fixes #954.

Co-authored-by: Caio <c410.f3r@gmail.com>

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();

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
-    has_mods |= p.eat(CONST_KW);
 
+    // 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() {}
 

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,

crates/ra_syntax/src/grammar.ron

@@ -59,6 +59,7 @@ Grammar(
         [">>=", "SHREQ"],
     ],
     keywords: [
+        "async",
         "use",
         "fn",
         "struct",

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

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"

crates/ra_syntax/tests/data/parser/inline/err/0007_async_without_semicolon.rs

@@ -0,0 +1 @@
+fn foo() { let _ = async {} }

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)

crates/ra_syntax/tests/data/parser/inline/ok/0124_async_fn.rs

@@ -0,0 +1 @@
+async fn foo() {}

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)