Rollup merge of rust-lang#70739 - Centril:fix-70736, r=petrochenkov

Centril · web-flow · commit 17fa3440d2c2 · 2020-04-06T04:24:20.000+02:00
def_collector, visit_fn: account for no body Fixes rust-lang#70736 r? @petrochenkov
diff --git a/src/librustc_resolve/def_collector.rs b/src/librustc_resolve/def_collector.rs
@@ -2,6 +2,7 @@ use log::debug;
 use rustc_ast::ast::*;
 use rustc_ast::token::{self, Token};
 use rustc_ast::visit::{self, FnKind};
+use rustc_ast::walk_list;
 use rustc_expand::expand::AstFragment;
 use rustc_hir::def_id::LocalDefId;
 use rustc_hir::definitions::*;
@@ -117,10 +118,8 @@ impl<'a> visit::Visitor<'a> for DefCollector<'a> {
                 // we must mirror everything that `visit::walk_fn` below does.
                 self.visit_fn_header(&sig.header);
                 visit::walk_fn_decl(self, &sig.decl);
-                if let Some(body) = body {
-                    let closure_def = self.create_def(closure_id, DefPathData::ClosureExpr, span);
-                    self.with_parent(closure_def, |this| this.visit_block(body));
-                }
+                let closure_def = self.create_def(closure_id, DefPathData::ClosureExpr, span);
+                self.with_parent(closure_def, |this| walk_list!(this, visit_block, body));
                 return;
             }
         }
diff --git a/src/test/ui/resolve/issue-70736-async-fn-no-body-def-collector.rs b/src/test/ui/resolve/issue-70736-async-fn-no-body-def-collector.rs
@@ -0,0 +1,20 @@
+// edition:2018
+
+async fn free(); //~ ERROR without a body
+
+struct A;
+impl A {
+    async fn inherent(); //~ ERROR without body
+}
+
+trait B {
+    async fn associated();
+    //~^ ERROR cannot be declared `async`
+}
+impl B for A {
+    async fn associated(); //~ ERROR without body
+    //~^ ERROR cannot be declared `async`
+    //~| ERROR incompatible type for trait
+}
+
+fn main() {}
diff --git a/src/test/ui/resolve/issue-70736-async-fn-no-body-def-collector.stderr b/src/test/ui/resolve/issue-70736-async-fn-no-body-def-collector.stderr
@@ -0,0 +1,65 @@
+error: free function without a body
+  --> $DIR/issue-70736-async-fn-no-body-def-collector.rs:3:1
+   |
+LL | async fn free();
+   | ^^^^^^^^^^^^^^^-
+   |                |
+   |                help: provide a definition for the function: `{ <body> }`
+
+error: associated function in `impl` without body
+  --> $DIR/issue-70736-async-fn-no-body-def-collector.rs:7:5
+   |
+LL |     async fn inherent();
+   |     ^^^^^^^^^^^^^^^^^^^-
+   |                        |
+   |                        help: provide a definition for the function: `{ <body> }`
+
+error[E0706]: functions in traits cannot be declared `async`
+  --> $DIR/issue-70736-async-fn-no-body-def-collector.rs:11:5
+   |
+LL |     async fn associated();
+   |     -----^^^^^^^^^^^^^^^^^
+   |     |
+   |     `async` because of this
+   |
+   = note: `async` trait functions are not currently supported
+   = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
+
+error: associated function in `impl` without body
+  --> $DIR/issue-70736-async-fn-no-body-def-collector.rs:15:5
+   |
+LL |     async fn associated();
+   |     ^^^^^^^^^^^^^^^^^^^^^-
+   |                          |
+   |                          help: provide a definition for the function: `{ <body> }`
+
+error[E0706]: functions in traits cannot be declared `async`
+  --> $DIR/issue-70736-async-fn-no-body-def-collector.rs:15:5
+   |
+LL |     async fn associated();
+   |     -----^^^^^^^^^^^^^^^^^
+   |     |
+   |     `async` because of this
+   |
+   = note: `async` trait functions are not currently supported
+   = note: consider using the `async-trait` crate: https://crates.io/crates/async-trait
+
+error[E0053]: method `associated` has an incompatible type for trait
+  --> $DIR/issue-70736-async-fn-no-body-def-collector.rs:15:26
+   |
+LL |     async fn associated();
+   |                          - type in trait
+...
+LL |     async fn associated();
+   |                          ^
+   |                          |
+   |                          the `Output` of this `async fn`'s found opaque type
+   |                          expected `()`, found opaque type
+   |
+   = note: expected fn pointer `fn()`
+              found fn pointer `fn() -> impl std::future::Future`
+
+error: aborting due to 6 previous errors
+
+Some errors have detailed explanations: E0053, E0706.
+For more information about an error, try `rustc --explain E0053`.
