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authorbors[bot] <26634292+bors[bot]@users.noreply.github.com>2020-09-13 18:28:22 +0100
committerGitHub <[email protected]>2020-09-13 18:28:22 +0100
commit0d03fe6ef57d3956e92382e0e1f1a916015191cb (patch)
tree02d51d9e08c50812b895e5b5d1b2fc30ff9150d6 /crates/hir_def/src
parentfda6937d7f91dc723229d1045d9a57b22a846dc7 (diff)
parent529c369c9bc15a73e7a03260eca84ccef99ac281 (diff)
Merge #5971
5971: Implement async blocks r=flodiebold a=oxalica Fix #4018 @flodiebold already gave a generic guide in the issue. Here's some concern about implementation detail: - Chalk doesn't support generator type yet. - Adding generator type as a brand new type (ctor) can be complex and need to *re-introduced* builtin impls. (Like how we implement closures before native closure support of chalk, which is already removed in #5401 ) - The output type of async block should be known after type inference of the whole body. - We cannot directly get the type from source like return-positon-impl-trait. But we still need to provide trait bounds when chalk asking for `opaque_ty_data`. - During the inference, the output type of async block can be temporary unknown and participate the later inference. `let a = async { None }; let _: i32 = a.await.unwrap();` So in this PR, the type of async blocks is inferred as an opaque type parameterized by the `Future::Output` type it should be, like what we do with closure type. And it really works now. Well, I still have some questions: - The bounds `AsyncBlockImplType<T>: Future<Output = T>` is currently generated in `opaque_ty_data`. I'm not sure if we should put this code here. - Type of async block is now rendered as `impl Future<Output = OutputType>`. Do we need to special display to hint that it's a async block? Note that closure type has its special format, instead of `impl Fn(..) -> ..` or function type. Co-authored-by: oxalica <[email protected]>
Diffstat (limited to 'crates/hir_def/src')
-rw-r--r--crates/hir_def/src/body/lower.rs5
-rw-r--r--crates/hir_def/src/expr.rs5
2 files changed, 8 insertions, 2 deletions
diff --git a/crates/hir_def/src/body/lower.rs b/crates/hir_def/src/body/lower.rs
index 9ea3d5291..2d91bb21f 100644
--- a/crates/hir_def/src/body/lower.rs
+++ b/crates/hir_def/src/body/lower.rs
@@ -239,7 +239,10 @@ impl ExprCollector<'_> {
239 None => self.missing_expr(), 239 None => self.missing_expr(),
240 }, 240 },
241 // FIXME: we need to record these effects somewhere... 241 // FIXME: we need to record these effects somewhere...
242 ast::Effect::Async(_) => self.collect_block_opt(e.block_expr()), 242 ast::Effect::Async(_) => {
243 let body = self.collect_block_opt(e.block_expr());
244 self.alloc_expr(Expr::Async { body }, syntax_ptr)
245 }
243 }, 246 },
244 ast::Expr::BlockExpr(e) => self.collect_block(e), 247 ast::Expr::BlockExpr(e) => self.collect_block(e),
245 ast::Expr::LoopExpr(e) => { 248 ast::Expr::LoopExpr(e) => {
diff --git a/crates/hir_def/src/expr.rs b/crates/hir_def/src/expr.rs
index dc975d42f..e5d740a36 100644
--- a/crates/hir_def/src/expr.rs
+++ b/crates/hir_def/src/expr.rs
@@ -111,6 +111,9 @@ pub enum Expr {
111 TryBlock { 111 TryBlock {
112 body: ExprId, 112 body: ExprId,
113 }, 113 },
114 Async {
115 body: ExprId,
116 },
114 Cast { 117 Cast {
115 expr: ExprId, 118 expr: ExprId,
116 type_ref: TypeRef, 119 type_ref: TypeRef,
@@ -250,7 +253,7 @@ impl Expr {
250 f(*expr); 253 f(*expr);
251 } 254 }
252 } 255 }
253 Expr::TryBlock { body } | Expr::Unsafe { body } => f(*body), 256 Expr::TryBlock { body } | Expr::Unsafe { body } | Expr::Async { body } => f(*body),
254 Expr::Loop { body, .. } => f(*body), 257 Expr::Loop { body, .. } => f(*body),
255 Expr::While { condition, body, .. } => { 258 Expr::While { condition, body, .. } => {
256 f(*condition); 259 f(*condition);