Merge #7209

7209: Support yield keyword r=Veykril a=sasurau4

Part of #4309 
The inference of yield will be implemented at another PR.

Co-authored-by: Daiki Ihara <[email protected]>

12 files changed, 152 insertions, 52 deletions

diff --git a/Cargo.lock b/Cargo.lock
index 0d23bcc9e..9498d8bf3 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -26,9 +26,9 @@ dependencies = [
 
 [[package]]
 name = "anyhow"
-version = "1.0.38"
+version = "1.0.37"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "afddf7f520a80dbf76e6f50a35bca42a2331ef227a28b3b6dc5c2e2338d114b1"
+checksum = "ee67c11feeac938fae061b232e38e0b6d94f97a9df10e6271319325ac4c56a86"
 
 [[package]]
 name = "anymap"
@@ -118,9 +118,9 @@ checksum = "cf1de2fe8c75bc145a2f577add951f8134889b4795d47466a54a5c846d691693"
 
 [[package]]
 name = "byteorder"
-version = "1.4.2"
+version = "1.3.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ae44d1a3d5a19df61dd0c8beb138458ac2a53a7ac09eba97d55592540004306b"
+checksum = "08c48aae112d48ed9f069b33538ea9e3e90aa263cfa3d1c24309612b1f7472de"
 
 [[package]]
 name = "cargo-platform"
@@ -269,9 +269,9 @@ dependencies = [
 
 [[package]]
 name = "const_fn"
-version = "0.4.5"
+version = "0.4.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "28b9d6de7f49e22cf97ad17fc4036ece69300032f45f78f30b4a4482cdc3f4a6"
+checksum = "cd51eab21ab4fd6a3bf889e2d0958c0a6e3a61ad04260325e919e652a2a62826"
 
 [[package]]
 name = "crc32fast"
@@ -791,9 +791,9 @@ checksum = "830d08ce1d1d941e6b30645f1a0eb5643013d835ce3779a5fc208261dbe10f55"
 
 [[package]]
 name = "libc"
-version = "0.2.82"
+version = "0.2.81"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "89203f3fba0a3795506acaad8ebce3c80c0af93f994d5a1d7a0b1eeb23271929"
+checksum = "1482821306169ec4d07f6aca392a4681f66c75c9918aa49641a2595db64053cb"
 
 [[package]]
 name = "libloading"
@@ -825,9 +825,9 @@ dependencies = [
 
 [[package]]
 name = "log"
-version = "0.4.13"
+version = "0.4.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "fcf3805d4480bb5b86070dcfeb9e2cb2ebc148adb753c5cca5f884d1d65a42b2"
+checksum = "4fabed175da42fed1fa0746b0ea71f412aa9d35e76e95e59b192c64b9dc2bf8b"
 dependencies = [
  "cfg-if 0.1.10",
 ]
@@ -1151,9 +1151,9 @@ checksum = "28b9b4df73455c861d7cbf8be42f01d3b373ed7f02e378d55fa84eafc6f638b1"
 
 [[package]]
 name = "pin-project-lite"
-version = "0.2.4"
+version = "0.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "439697af366c49a6d0a010c56a0d97685bc140ce0d377b13a2ea2aa42d64a827"
+checksum = "6b063f57ec186e6140e2b8b6921e5f1bd89c7356dda5b33acc5401203ca6131c"
 
 [[package]]
 name = "proc-macro2"
@@ -1291,9 +1291,9 @@ checksum = "41cc0f7e4d5d4544e8861606a285bb08d3e70712ccc7d2b84d7c0ccfaf4b05ce"
 
 [[package]]
 name = "regex"
-version = "1.4.3"
+version = "1.4.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d9251239e129e16308e70d853559389de218ac275b515068abc96829d05b948a"
+checksum = "38cf2c13ed4745de91a5eb834e11c00bcc3709e773173b2ce4c56c9fbde04b9c"
 dependencies = [
  "regex-syntax",
 ]
@@ -1310,9 +1310,9 @@ dependencies = [
 
 [[package]]
 name = "regex-syntax"
-version = "0.6.22"
+version = "0.6.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b5eb417147ba9860a96cfe72a0b93bf88fee1744b5636ec99ab20c1aa9376581"
+checksum = "3b181ba2dcf07aaccad5448e8ead58db5b742cf85dfe035e2227f137a539a189"
 
 [[package]]
 name = "rowan"
@@ -1541,9 +1541,9 @@ checksum = "c111b5bd5695e56cffe5129854aa230b39c93a305372fdbb2668ca2394eea9f8"
 
 [[package]]
 name = "smallvec"
-version = "1.6.1"
+version = "1.6.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "fe0f37c9e8f3c5a4a66ad655a93c74daac4ad00c441533bf5c6e7990bb42604e"
+checksum = "1a55ca5f3b68e41c979bf8c46a6f1da892ca4db8f94023ce0bd32407573b1ac0"
 
 [[package]]
 name = "smol_str"
@@ -1577,9 +1577,9 @@ dependencies = [
 
 [[package]]
 name = "syn"
-version = "1.0.58"
+version = "1.0.57"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cc60a3d73ea6594cd712d830cc1f0390fd71542d8c8cd24e70cc54cdfd5e05d5"
+checksum = "4211ce9909eb971f111059df92c45640aad50a619cf55cd76476be803c4c68e6"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -1662,9 +1662,9 @@ checksum = "db3c46be180f1af9673ebb27bc1235396f61ef6965b3fe0dbb2e624deb604f0e"
 
 [[package]]
 name = "thread_local"
-version = "1.1.0"
+version = "1.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bb9bc092d0d51e76b2b19d9d85534ffc9ec2db959a2523cdae0697e2972cd447"
+checksum = "d40c6d1b69745a6ec6fb1ca717914848da4b44ae29d9b3080cbee91d72a69b14"
 dependencies = [
  "lazy_static",
 ]
@@ -1817,9 +1817,9 @@ checksum = "56dee185309b50d1f11bfedef0fe6d036842e3fb77413abef29f8f8d1c5d4c1c"
 
 [[package]]
 name = "ungrammar"
-version = "1.6.0"
+version = "1.7.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f96cc1b6938f7c548fbcc630bac5c896ae77a130909829ab18b8eab78c51b7ee"
+checksum = "7758fccf6038d5c368a17c7224abc85d6508d5ae266d5a3de25faac3cc168509"
 
 [[package]]
 name = "unicase"
diff --git a/crates/assists/src/handlers/inline_local_variable.rs b/crates/assists/src/handlers/inline_local_variable.rs
index dc798daaa..0e63a60e8 100644
--- a/crates/assists/src/handlers/inline_local_variable.rs
+++ b/crates/assists/src/handlers/inline_local_variable.rs
@@ -79,29 +79,30 @@ pub(crate) fn inline_local_variable(acc: &mut Assists, ctx: &AssistContext) -> O
                 None => return Ok(false),
             };
 
-            Ok(!matches!((&initializer_expr, usage_parent),
+            Ok(!matches!(
+                (&initializer_expr, usage_parent),
                 (ast::Expr::CallExpr(_), _)
-                | (ast::Expr::IndexExpr(_), _)
-                | (ast::Expr::MethodCallExpr(_), _)
-                | (ast::Expr::FieldExpr(_), _)
-                | (ast::Expr::TryExpr(_), _)
-                | (ast::Expr::RefExpr(_), _)
-                | (ast::Expr::Literal(_), _)
-                | (ast::Expr::TupleExpr(_), _)
-                | (ast::Expr::ArrayExpr(_), _)
-                | (ast::Expr::ParenExpr(_), _)
-                | (ast::Expr::PathExpr(_), _)
-                | (ast::Expr::BlockExpr(_), _)
-                | (ast::Expr::EffectExpr(_), _)
-                | (_, ast::Expr::CallExpr(_))
-                | (_, ast::Expr::TupleExpr(_))
-                | (_, ast::Expr::ArrayExpr(_))
-                | (_, ast::Expr::ParenExpr(_))
-                | (_, ast::Expr::ForExpr(_))
-                | (_, ast::Expr::WhileExpr(_))
-                | (_, ast::Expr::BreakExpr(_))
-                | (_, ast::Expr::ReturnExpr(_))
-                | (_, ast::Expr::MatchExpr(_))
+                    | (ast::Expr::IndexExpr(_), _)
+                    | (ast::Expr::MethodCallExpr(_), _)
+                    | (ast::Expr::FieldExpr(_), _)
+                    | (ast::Expr::TryExpr(_), _)
+                    | (ast::Expr::RefExpr(_), _)
+                    | (ast::Expr::Literal(_), _)
+                    | (ast::Expr::TupleExpr(_), _)
+                    | (ast::Expr::ArrayExpr(_), _)
+                    | (ast::Expr::ParenExpr(_), _)
+                    | (ast::Expr::PathExpr(_), _)
+                    | (ast::Expr::BlockExpr(_), _)
+                    | (ast::Expr::EffectExpr(_), _)
+                    | (_, ast::Expr::CallExpr(_))
+                    | (_, ast::Expr::TupleExpr(_))
+                    | (_, ast::Expr::ArrayExpr(_))
+                    | (_, ast::Expr::ParenExpr(_))
+                    | (_, ast::Expr::ForExpr(_))
+                    | (_, ast::Expr::WhileExpr(_))
+                    | (_, ast::Expr::BreakExpr(_))
+                    | (_, ast::Expr::ReturnExpr(_))
+                    | (_, ast::Expr::MatchExpr(_))
             ))
         })
         .collect::<Result<Vec<_>, _>>()?;
diff --git a/crates/hir_def/src/body/lower.rs b/crates/hir_def/src/body/lower.rs
index 27575c537..4ce5e5b72 100644
--- a/crates/hir_def/src/body/lower.rs
+++ b/crates/hir_def/src/body/lower.rs
@@ -386,6 +386,10 @@ impl ExprCollector<'_> {
                 let expr = e.expr().map(|e| self.collect_expr(e));
                 self.alloc_expr(Expr::Return { expr }, syntax_ptr)
             }
+            ast::Expr::YieldExpr(e) => {
+                let expr = e.expr().map(|e| self.collect_expr(e));
+                self.alloc_expr(Expr::Yield { expr }, syntax_ptr)
+            }
             ast::Expr::RecordExpr(e) => {
                 let path = e.path().and_then(|path| self.expander.parse_path(path));
                 let mut field_ptrs = Vec::new();
diff --git a/crates/hir_def/src/expr.rs b/crates/hir_def/src/expr.rs
index af01d32dc..a293df9f1 100644
--- a/crates/hir_def/src/expr.rs
+++ b/crates/hir_def/src/expr.rs
@@ -99,6 +99,9 @@ pub enum Expr {
     Return {
         expr: Option<ExprId>,
     },
+    Yield {
+        expr: Option<ExprId>,
+    },
     RecordLit {
         path: Option<Path>,
         fields: Vec<RecordLitField>,
@@ -294,7 +297,7 @@ impl Expr {
                 }
             }
             Expr::Continue { .. } => {}
-            Expr::Break { expr, .. } | Expr::Return { expr } => {
+            Expr::Break { expr, .. } | Expr::Return { expr } | Expr::Yield { expr } => {
                 if let Some(expr) = expr {
                     f(*expr);
                 }
diff --git a/crates/hir_ty/src/infer/expr.rs b/crates/hir_ty/src/infer/expr.rs
index f2fc69b2f..9bf3b51b0 100644
--- a/crates/hir_ty/src/infer/expr.rs
+++ b/crates/hir_ty/src/infer/expr.rs
@@ -367,6 +367,13 @@ impl<'a> InferenceContext<'a> {
                 }
                 Ty::simple(TypeCtor::Never)
             }
+            Expr::Yield { expr } => {
+                // FIXME: track yield type for coercion
+                if let Some(expr) = expr {
+                    self.infer_expr(*expr, &Expectation::none());
+                }
+                Ty::simple(TypeCtor::Never)
+            }
             Expr::RecordLit { path, fields, spread } => {
                 let (ty, def_id) = self.resolve_variant(path.as_ref());
                 if let Some(variant) = def_id {
diff --git a/crates/parser/src/grammar/expressions/atom.rs b/crates/parser/src/grammar/expressions/atom.rs
index d61950b96..093a9890d 100644
--- a/crates/parser/src/grammar/expressions/atom.rs
+++ b/crates/parser/src/grammar/expressions/atom.rs
@@ -50,6 +50,7 @@ pub(super) const ATOM_EXPR_FIRST: TokenSet =
         T![match],
         T![unsafe],
         T![return],
+        T![yield],
         T![break],
         T![continue],
         T![async],
@@ -142,6 +143,7 @@ pub(super) fn atom_expr(p: &mut Parser, r: Restrictions) -> Option<(CompletedMar
             block_expr_unchecked(p)
         }
         T![return] => return_expr(p),
+        T![yield] => yield_expr(p),
         T![continue] => continue_expr(p),
         T![break] => break_expr(p, r),
         _ => {
@@ -508,6 +510,20 @@ fn return_expr(p: &mut Parser) -> CompletedMarker {
     }
     m.complete(p, RETURN_EXPR)
 }
+// test yield_expr
+// fn foo() {
+//     yield;
+//     yield 1;
+// }
+fn yield_expr(p: &mut Parser) -> CompletedMarker {
+    assert!(p.at(T![yield]));
+    let m = p.start();
+    p.bump(T![yield]);
+    if p.at_ts(EXPR_FIRST) {
+        expr(p);
+    }
+    m.complete(p, YIELD_EXPR)
+}
 
 // test continue_expr
 // fn foo() {
diff --git a/crates/parser/src/syntax_kind/generated.rs b/crates/parser/src/syntax_kind/generated.rs
index f69e71bdb..7d53cc4cd 100644
--- a/crates/parser/src/syntax_kind/generated.rs
+++ b/crates/parser/src/syntax_kind/generated.rs
@@ -101,6 +101,7 @@ pub enum SyntaxKind {
     USE_KW,
     WHERE_KW,
     WHILE_KW,
+    YIELD_KW,
     AUTO_KW,
     DEFAULT_KW,
     EXISTENTIAL_KW,
@@ -186,6 +187,7 @@ pub enum SyntaxKind {
     LABEL,
     BLOCK_EXPR,
     RETURN_EXPR,
+    YIELD_EXPR,
     MATCH_EXPR,
     MATCH_ARM_LIST,
     MATCH_ARM,
@@ -263,7 +265,8 @@ impl SyntaxKind {
             | IMPL_KW | IN_KW | LET_KW | LOOP_KW | MACRO_KW | MATCH_KW | MOD_KW | MOVE_KW
             | MUT_KW | PUB_KW | REF_KW | RETURN_KW | SELF_KW | STATIC_KW | STRUCT_KW | SUPER_KW
             | TRAIT_KW | TRUE_KW | TRY_KW | TYPE_KW | UNSAFE_KW | USE_KW | WHERE_KW | WHILE_KW
-            | AUTO_KW | DEFAULT_KW | EXISTENTIAL_KW | UNION_KW | RAW_KW | MACRO_RULES_KW => true,
+            | YIELD_KW | AUTO_KW | DEFAULT_KW | EXISTENTIAL_KW | UNION_KW | RAW_KW
+            | MACRO_RULES_KW => true,
             _ => false,
         }
     }
@@ -326,6 +329,7 @@ impl SyntaxKind {
             "use" => USE_KW,
             "where" => WHERE_KW,
             "while" => WHILE_KW,
+            "yield" => YIELD_KW,
             _ => return None,
         };
         Some(kw)
@@ -366,4 +370,4 @@ impl SyntaxKind {
     }
 }
 #[macro_export]
-macro_rules ! T { [;] => { $ crate :: SyntaxKind :: SEMICOLON } ; [,] => { $ crate :: SyntaxKind :: COMMA } ; ['('] => { $ crate :: SyntaxKind :: L_PAREN } ; [')'] => { $ crate :: SyntaxKind :: R_PAREN } ; ['{'] => { $ crate :: SyntaxKind :: L_CURLY } ; ['}'] => { $ crate :: SyntaxKind :: R_CURLY } ; ['['] => { $ crate :: SyntaxKind :: L_BRACK } ; [']'] => { $ crate :: SyntaxKind :: R_BRACK } ; [<] => { $ crate :: SyntaxKind :: L_ANGLE } ; [>] => { $ crate :: SyntaxKind :: R_ANGLE } ; [@] => { $ crate :: SyntaxKind :: AT } ; [#] => { $ crate :: SyntaxKind :: POUND } ; [~] => { $ crate :: SyntaxKind :: TILDE } ; [?] => { $ crate :: SyntaxKind :: QUESTION } ; [$] => { $ crate :: SyntaxKind :: DOLLAR } ; [&] => { $ crate :: SyntaxKind :: AMP } ; [|] => { $ crate :: SyntaxKind :: PIPE } ; [+] => { $ crate :: SyntaxKind :: PLUS } ; [*] => { $ crate :: SyntaxKind :: STAR } ; [/] => { $ crate :: SyntaxKind :: SLASH } ; [^] => { $ crate :: SyntaxKind :: CARET } ; [%] => { $ crate :: SyntaxKind :: PERCENT } ; [_] => { $ crate :: SyntaxKind :: UNDERSCORE } ; [.] => { $ crate :: SyntaxKind :: DOT } ; [..] => { $ crate :: SyntaxKind :: DOT2 } ; [...] => { $ crate :: SyntaxKind :: DOT3 } ; [..=] => { $ crate :: SyntaxKind :: DOT2EQ } ; [:] => { $ crate :: SyntaxKind :: COLON } ; [::] => { $ crate :: SyntaxKind :: COLON2 } ; [=] => { $ crate :: SyntaxKind :: EQ } ; [==] => { $ crate :: SyntaxKind :: EQ2 } ; [=>] => { $ crate :: SyntaxKind :: FAT_ARROW } ; [!] => { $ crate :: SyntaxKind :: BANG } ; [!=] => { $ crate :: SyntaxKind :: NEQ } ; [-] => { $ crate :: SyntaxKind :: MINUS } ; [->] => { $ crate :: SyntaxKind :: THIN_ARROW } ; [<=] => { $ crate :: SyntaxKind :: LTEQ } ; [>=] => { $ crate :: SyntaxKind :: GTEQ } ; [+=] => { $ crate :: SyntaxKind :: PLUSEQ } ; [-=] => { $ crate :: SyntaxKind :: MINUSEQ } ; [|=] => { $ crate :: SyntaxKind :: PIPEEQ } ; [&=] => { $ crate :: SyntaxKind :: AMPEQ } ; [^=] => { $ crate :: SyntaxKind :: CARETEQ } ; [/=] => { $ crate :: SyntaxKind :: SLASHEQ } ; [*=] => { $ crate :: SyntaxKind :: STAREQ } ; [%=] => { $ crate :: SyntaxKind :: PERCENTEQ } ; [&&] => { $ crate :: SyntaxKind :: AMP2 } ; [||] => { $ crate :: SyntaxKind :: PIPE2 } ; [<<] => { $ crate :: SyntaxKind :: SHL } ; [>>] => { $ crate :: SyntaxKind :: SHR } ; [<<=] => { $ crate :: SyntaxKind :: SHLEQ } ; [>>=] => { $ crate :: SyntaxKind :: SHREQ } ; [as] => { $ crate :: SyntaxKind :: AS_KW } ; [async] => { $ crate :: SyntaxKind :: ASYNC_KW } ; [await] => { $ crate :: SyntaxKind :: AWAIT_KW } ; [box] => { $ crate :: SyntaxKind :: BOX_KW } ; [break] => { $ crate :: SyntaxKind :: BREAK_KW } ; [const] => { $ crate :: SyntaxKind :: CONST_KW } ; [continue] => { $ crate :: SyntaxKind :: CONTINUE_KW } ; [crate] => { $ crate :: SyntaxKind :: CRATE_KW } ; [dyn] => { $ crate :: SyntaxKind :: DYN_KW } ; [else] => { $ crate :: SyntaxKind :: ELSE_KW } ; [enum] => { $ crate :: SyntaxKind :: ENUM_KW } ; [extern] => { $ crate :: SyntaxKind :: EXTERN_KW } ; [false] => { $ crate :: SyntaxKind :: FALSE_KW } ; [fn] => { $ crate :: SyntaxKind :: FN_KW } ; [for] => { $ crate :: SyntaxKind :: FOR_KW } ; [if] => { $ crate :: SyntaxKind :: IF_KW } ; [impl] => { $ crate :: SyntaxKind :: IMPL_KW } ; [in] => { $ crate :: SyntaxKind :: IN_KW } ; [let] => { $ crate :: SyntaxKind :: LET_KW } ; [loop] => { $ crate :: SyntaxKind :: LOOP_KW } ; [macro] => { $ crate :: SyntaxKind :: MACRO_KW } ; [match] => { $ crate :: SyntaxKind :: MATCH_KW } ; [mod] => { $ crate :: SyntaxKind :: MOD_KW } ; [move] => { $ crate :: SyntaxKind :: MOVE_KW } ; [mut] => { $ crate :: SyntaxKind :: MUT_KW } ; [pub] => { $ crate :: SyntaxKind :: PUB_KW } ; [ref] => { $ crate :: SyntaxKind :: REF_KW } ; [return] => { $ crate :: SyntaxKind :: RETURN_KW } ; [self] => { $ crate :: SyntaxKind :: SELF_KW } ; [static] => { $ crate :: SyntaxKind :: STATIC_KW } ; [struct] => { $ crate :: SyntaxKind :: STRUCT_KW } ; [super] => { $ crate :: SyntaxKind :: SUPER_KW } ; [trait] => { $ crate :: SyntaxKind :: TRAIT_KW } ; [true] => { $ crate :: SyntaxKind :: TRUE_KW } ; [try] => { $ crate :: SyntaxKind :: TRY_KW } ; [type] => { $ crate :: SyntaxKind :: TYPE_KW } ; [unsafe] => { $ crate :: SyntaxKind :: UNSAFE_KW } ; [use] => { $ crate :: SyntaxKind :: USE_KW } ; [where] => { $ crate :: SyntaxKind :: WHERE_KW } ; [while] => { $ crate :: SyntaxKind :: WHILE_KW } ; [auto] => { $ crate :: SyntaxKind :: AUTO_KW } ; [default] => { $ crate :: SyntaxKind :: DEFAULT_KW } ; [existential] => { $ crate :: SyntaxKind :: EXISTENTIAL_KW } ; [union] => { $ crate :: SyntaxKind :: UNION_KW } ; [raw] => { $ crate :: SyntaxKind :: RAW_KW } ; [macro_rules] => { $ crate :: SyntaxKind :: MACRO_RULES_KW } ; [lifetime_ident] => { $ crate :: SyntaxKind :: LIFETIME_IDENT } ; [ident] => { $ crate :: SyntaxKind :: IDENT } ; [shebang] => { $ crate :: SyntaxKind :: SHEBANG } ; }
+macro_rules ! T { [;] => { $ crate :: SyntaxKind :: SEMICOLON } ; [,] => { $ crate :: SyntaxKind :: COMMA } ; ['('] => { $ crate :: SyntaxKind :: L_PAREN } ; [')'] => { $ crate :: SyntaxKind :: R_PAREN } ; ['{'] => { $ crate :: SyntaxKind :: L_CURLY } ; ['}'] => { $ crate :: SyntaxKind :: R_CURLY } ; ['['] => { $ crate :: SyntaxKind :: L_BRACK } ; [']'] => { $ crate :: SyntaxKind :: R_BRACK } ; [<] => { $ crate :: SyntaxKind :: L_ANGLE } ; [>] => { $ crate :: SyntaxKind :: R_ANGLE } ; [@] => { $ crate :: SyntaxKind :: AT } ; [#] => { $ crate :: SyntaxKind :: POUND } ; [~] => { $ crate :: SyntaxKind :: TILDE } ; [?] => { $ crate :: SyntaxKind :: QUESTION } ; [$] => { $ crate :: SyntaxKind :: DOLLAR } ; [&] => { $ crate :: SyntaxKind :: AMP } ; [|] => { $ crate :: SyntaxKind :: PIPE } ; [+] => { $ crate :: SyntaxKind :: PLUS } ; [*] => { $ crate :: SyntaxKind :: STAR } ; [/] => { $ crate :: SyntaxKind :: SLASH } ; [^] => { $ crate :: SyntaxKind :: CARET } ; [%] => { $ crate :: SyntaxKind :: PERCENT } ; [_] => { $ crate :: SyntaxKind :: UNDERSCORE } ; [.] => { $ crate :: SyntaxKind :: DOT } ; [..] => { $ crate :: SyntaxKind :: DOT2 } ; [...] => { $ crate :: SyntaxKind :: DOT3 } ; [..=] => { $ crate :: SyntaxKind :: DOT2EQ } ; [:] => { $ crate :: SyntaxKind :: COLON } ; [::] => { $ crate :: SyntaxKind :: COLON2 } ; [=] => { $ crate :: SyntaxKind :: EQ } ; [==] => { $ crate :: SyntaxKind :: EQ2 } ; [=>] => { $ crate :: SyntaxKind :: FAT_ARROW } ; [!] => { $ crate :: SyntaxKind :: BANG } ; [!=] => { $ crate :: SyntaxKind :: NEQ } ; [-] => { $ crate :: SyntaxKind :: MINUS } ; [->] => { $ crate :: SyntaxKind :: THIN_ARROW } ; [<=] => { $ crate :: SyntaxKind :: LTEQ } ; [>=] => { $ crate :: SyntaxKind :: GTEQ } ; [+=] => { $ crate :: SyntaxKind :: PLUSEQ } ; [-=] => { $ crate :: SyntaxKind :: MINUSEQ } ; [|=] => { $ crate :: SyntaxKind :: PIPEEQ } ; [&=] => { $ crate :: SyntaxKind :: AMPEQ } ; [^=] => { $ crate :: SyntaxKind :: CARETEQ } ; [/=] => { $ crate :: SyntaxKind :: SLASHEQ } ; [*=] => { $ crate :: SyntaxKind :: STAREQ } ; [%=] => { $ crate :: SyntaxKind :: PERCENTEQ } ; [&&] => { $ crate :: SyntaxKind :: AMP2 } ; [||] => { $ crate :: SyntaxKind :: PIPE2 } ; [<<] => { $ crate :: SyntaxKind :: SHL } ; [>>] => { $ crate :: SyntaxKind :: SHR } ; [<<=] => { $ crate :: SyntaxKind :: SHLEQ } ; [>>=] => { $ crate :: SyntaxKind :: SHREQ } ; [as] => { $ crate :: SyntaxKind :: AS_KW } ; [async] => { $ crate :: SyntaxKind :: ASYNC_KW } ; [await] => { $ crate :: SyntaxKind :: AWAIT_KW } ; [box] => { $ crate :: SyntaxKind :: BOX_KW } ; [break] => { $ crate :: SyntaxKind :: BREAK_KW } ; [const] => { $ crate :: SyntaxKind :: CONST_KW } ; [continue] => { $ crate :: SyntaxKind :: CONTINUE_KW } ; [crate] => { $ crate :: SyntaxKind :: CRATE_KW } ; [dyn] => { $ crate :: SyntaxKind :: DYN_KW } ; [else] => { $ crate :: SyntaxKind :: ELSE_KW } ; [enum] => { $ crate :: SyntaxKind :: ENUM_KW } ; [extern] => { $ crate :: SyntaxKind :: EXTERN_KW } ; [false] => { $ crate :: SyntaxKind :: FALSE_KW } ; [fn] => { $ crate :: SyntaxKind :: FN_KW } ; [for] => { $ crate :: SyntaxKind :: FOR_KW } ; [if] => { $ crate :: SyntaxKind :: IF_KW } ; [impl] => { $ crate :: SyntaxKind :: IMPL_KW } ; [in] => { $ crate :: SyntaxKind :: IN_KW } ; [let] => { $ crate :: SyntaxKind :: LET_KW } ; [loop] => { $ crate :: SyntaxKind :: LOOP_KW } ; [macro] => { $ crate :: SyntaxKind :: MACRO_KW } ; [match] => { $ crate :: SyntaxKind :: MATCH_KW } ; [mod] => { $ crate :: SyntaxKind :: MOD_KW } ; [move] => { $ crate :: SyntaxKind :: MOVE_KW } ; [mut] => { $ crate :: SyntaxKind :: MUT_KW } ; [pub] => { $ crate :: SyntaxKind :: PUB_KW } ; [ref] => { $ crate :: SyntaxKind :: REF_KW } ; [return] => { $ crate :: SyntaxKind :: RETURN_KW } ; [self] => { $ crate :: SyntaxKind :: SELF_KW } ; [static] => { $ crate :: SyntaxKind :: STATIC_KW } ; [struct] => { $ crate :: SyntaxKind :: STRUCT_KW } ; [super] => { $ crate :: SyntaxKind :: SUPER_KW } ; [trait] => { $ crate :: SyntaxKind :: TRAIT_KW } ; [true] => { $ crate :: SyntaxKind :: TRUE_KW } ; [try] => { $ crate :: SyntaxKind :: TRY_KW } ; [type] => { $ crate :: SyntaxKind :: TYPE_KW } ; [unsafe] => { $ crate :: SyntaxKind :: UNSAFE_KW } ; [use] => { $ crate :: SyntaxKind :: USE_KW } ; [where] => { $ crate :: SyntaxKind :: WHERE_KW } ; [while] => { $ crate :: SyntaxKind :: WHILE_KW } ; [yield] => { $ crate :: SyntaxKind :: YIELD_KW } ; [auto] => { $ crate :: SyntaxKind :: AUTO_KW } ; [default] => { $ crate :: SyntaxKind :: DEFAULT_KW } ; [existential] => { $ crate :: SyntaxKind :: EXISTENTIAL_KW } ; [union] => { $ crate :: SyntaxKind :: UNION_KW } ; [raw] => { $ crate :: SyntaxKind :: RAW_KW } ; [macro_rules] => { $ crate :: SyntaxKind :: MACRO_RULES_KW } ; [lifetime_ident] => { $ crate :: SyntaxKind :: LIFETIME_IDENT } ; [ident] => { $ crate :: SyntaxKind :: IDENT } ; [shebang] => { $ crate :: SyntaxKind :: SHEBANG } ; }
diff --git a/crates/syntax/src/ast/generated/nodes.rs b/crates/syntax/src/ast/generated/nodes.rs
index 92ed2ee9d..9c96d3d07 100644
--- a/crates/syntax/src/ast/generated/nodes.rs
+++ b/crates/syntax/src/ast/generated/nodes.rs
@@ -931,6 +931,15 @@ impl WhileExpr {
     pub fn condition(&self) -> Option<Condition> { support::child(&self.syntax) }
 }
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub struct YieldExpr {
+    pub(crate) syntax: SyntaxNode,
+}
+impl ast::AttrsOwner for YieldExpr {}
+impl YieldExpr {
+    pub fn yield_token(&self) -> Option<SyntaxToken> { support::token(&self.syntax, T![yield]) }
+    pub fn expr(&self) -> Option<Expr> { support::child(&self.syntax) }
+}
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub struct Label {
     pub(crate) syntax: SyntaxNode,
 }
@@ -1334,6 +1343,7 @@ pub enum Expr {
     TryExpr(TryExpr),
     TupleExpr(TupleExpr),
     WhileExpr(WhileExpr),
+    YieldExpr(YieldExpr),
 }
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub enum Item {
@@ -2386,6 +2396,17 @@ impl AstNode for WhileExpr {
     }
     fn syntax(&self) -> &SyntaxNode { &self.syntax }
 }
+impl AstNode for YieldExpr {
+    fn can_cast(kind: SyntaxKind) -> bool { kind == YIELD_EXPR }
+    fn cast(syntax: SyntaxNode) -> Option<Self> {
+        if Self::can_cast(syntax.kind()) {
+            Some(Self { syntax })
+        } else {
+            None
+        }
+    }
+    fn syntax(&self) -> &SyntaxNode { &self.syntax }
+}
 impl AstNode for Label {
     fn can_cast(kind: SyntaxKind) -> bool { kind == LABEL }
     fn cast(syntax: SyntaxNode) -> Option<Self> {
@@ -3028,6 +3049,9 @@ impl From<TupleExpr> for Expr {
 impl From<WhileExpr> for Expr {
     fn from(node: WhileExpr) -> Expr { Expr::WhileExpr(node) }
 }
+impl From<YieldExpr> for Expr {
+    fn from(node: YieldExpr) -> Expr { Expr::YieldExpr(node) }
+}
 impl AstNode for Expr {
     fn can_cast(kind: SyntaxKind) -> bool {
         match kind {
@@ -3035,7 +3059,8 @@ impl AstNode for Expr {
             | CAST_EXPR | CLOSURE_EXPR | CONTINUE_EXPR | EFFECT_EXPR | FIELD_EXPR | FOR_EXPR
             | IF_EXPR | INDEX_EXPR | LITERAL | LOOP_EXPR | MACRO_CALL | MATCH_EXPR
             | METHOD_CALL_EXPR | PAREN_EXPR | PATH_EXPR | PREFIX_EXPR | RANGE_EXPR
-            | RECORD_EXPR | REF_EXPR | RETURN_EXPR | TRY_EXPR | TUPLE_EXPR | WHILE_EXPR => true,
+            | RECORD_EXPR | REF_EXPR | RETURN_EXPR | TRY_EXPR | TUPLE_EXPR | WHILE_EXPR
+            | YIELD_EXPR => true,
             _ => false,
         }
     }
@@ -3071,6 +3096,7 @@ impl AstNode for Expr {
             TRY_EXPR => Expr::TryExpr(TryExpr { syntax }),
             TUPLE_EXPR => Expr::TupleExpr(TupleExpr { syntax }),
             WHILE_EXPR => Expr::WhileExpr(WhileExpr { syntax }),
+            YIELD_EXPR => Expr::YieldExpr(YieldExpr { syntax }),
             _ => return None,
         };
         Some(res)
@@ -3107,6 +3133,7 @@ impl AstNode for Expr {
             Expr::TryExpr(it) => &it.syntax,
             Expr::TupleExpr(it) => &it.syntax,
             Expr::WhileExpr(it) => &it.syntax,
+            Expr::YieldExpr(it) => &it.syntax,
         }
     }
 }
@@ -3983,6 +4010,11 @@ impl std::fmt::Display for WhileExpr {
         std::fmt::Display::fmt(self.syntax(), f)
     }
 }
+impl std::fmt::Display for YieldExpr {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        std::fmt::Display::fmt(self.syntax(), f)
+    }
+}
 impl std::fmt::Display for Label {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         std::fmt::Display::fmt(self.syntax(), f)
diff --git a/crates/syntax/test_data/parser/inline/ok/0159_yield_expr.rast b/crates/syntax/test_data/parser/inline/ok/0159_yield_expr.rast
new file mode 100644
index 000000000..05fc90743
--- /dev/null
+++ b/crates/syntax/test_data/parser/inline/ok/0159_yield_expr.rast
@@ -0,0 +1,28 @@
+[email protected]
+  [email protected]
+    [email protected] "fn"
+    [email protected] " "
+    [email protected]
+      [email protected] "foo"
+    [email protected]
+      [email protected] "("
+      [email protected] ")"
+    [email protected] " "
+    [email protected]
+      [email protected] "{"
+      [email protected] "\n    "
+      [email protected]
+        [email protected]
+          [email protected] "yield"
+        [email protected] ";"
+      [email protected] "\n    "
+      [email protected]
+        [email protected]
+          [email protected] "yield"
+          [email protected] " "
+          [email protected]
+            [email protected] "1"
+        [email protected] ";"
+      [email protected] "\n"
+      [email protected] "}"
+  [email protected] "\n"
diff --git a/crates/syntax/test_data/parser/inline/ok/0159_yield_expr.rs b/crates/syntax/test_data/parser/inline/ok/0159_yield_expr.rs
new file mode 100644
index 000000000..596e221f7
--- /dev/null
+++ b/crates/syntax/test_data/parser/inline/ok/0159_yield_expr.rs
@@ -0,0 +1,4 @@
+fn foo() {
+    yield;
+    yield 1;
+}
diff --git a/xtask/Cargo.toml b/xtask/Cargo.toml
index 7a2937f0e..61a944c13 100644
--- a/xtask/Cargo.toml
+++ b/xtask/Cargo.toml
@@ -15,7 +15,7 @@ flate2 = "1.0"
 pico-args = "0.3.1"
 proc-macro2 = "1.0.8"
 quote = "1.0.2"
-ungrammar = "1.6"
+ungrammar = "1.7"
 walkdir = "2.3.1"
 write-json = "0.1.0"
 xshell = "0.1"
diff --git a/xtask/src/ast_src.rs b/xtask/src/ast_src.rs
index 2b8012bdd..046d68f52 100644
--- a/xtask/src/ast_src.rs
+++ b/xtask/src/ast_src.rs
@@ -68,7 +68,7 @@ pub(crate) const KINDS_SRC: KindsSrc = KindsSrc {
         "as", "async", "await", "box", "break", "const", "continue", "crate", "dyn", "else",
         "enum", "extern", "false", "fn", "for", "if", "impl", "in", "let", "loop", "macro",
         "match", "mod", "move", "mut", "pub", "ref", "return", "self", "static", "struct", "super",
-        "trait", "true", "try", "type", "unsafe", "use", "where", "while",
+        "trait", "true", "try", "type", "unsafe", "use", "where", "while", "yield",
     ],
     contextual_keywords: &["auto", "default", "existential", "union", "raw", "macro_rules"],
     literals: &["INT_NUMBER", "FLOAT_NUMBER", "CHAR", "BYTE", "STRING", "BYTE_STRING"],
@@ -149,6 +149,7 @@ pub(crate) const KINDS_SRC: KindsSrc = KindsSrc {
         "LABEL",
         "BLOCK_EXPR",
         "RETURN_EXPR",
+        "YIELD_EXPR",
         "MATCH_EXPR",
         "MATCH_ARM_LIST",
         "MATCH_ARM",