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 <sasurau4@gmail.com>

Author: bors[bot]

Cargo.lock

@@ -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<_>, _>>()?;

crates/assists/src/handlers/inline_local_variable.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();

crates/hir_def/src/body/lower.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);
                 }

crates/hir_def/src/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 {

crates/hir_ty/src/infer/expr.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() {