From 2fe50bc01bf9023b64a72407bb41a1f3b7245abd Mon Sep 17 00:00:00 2001
From: Taiki Endo <te316e89@gmail.com>
Date: Fri, 3 May 2019 13:04:26 +0900
Subject: [PATCH] Propagate mutability from arguments to local bindings in
async fn
---
src/libsyntax/parse/parser.rs | 10 ++++------
src/test/ui/async-await/mutable-arguments.rs | 10 ++++++++++
2 files changed, 14 insertions(+), 6 deletions(-)
create mode 100644 src/test/ui/async-await/mutable-arguments.rs
diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs
index f70acb3e7da9a..c5173aa556953 100644
--- a/src/libsyntax/parse/parser.rs
+++ b/src/libsyntax/parse/parser.rs
@@ -8725,9 +8725,9 @@ impl<'a> Parser<'a> {
// Check if this is a ident pattern, if so, we can optimize and avoid adding a
// `let <pat> = __argN;` statement, instead just adding a `let <pat> = <pat>;`
// statement.
- let (ident, is_simple_pattern) = match input.pat.node {
- PatKind::Ident(_, ident, _) => (ident, true),
- _ => (ident, false),
+ let (binding_mode, ident, is_simple_pattern) = match input.pat.node {
+ PatKind::Ident(binding_mode, ident, _) => (binding_mode, ident, true),
+ _ => (BindingMode::ByValue(Mutability::Immutable), ident, false),
};
// Construct an argument representing `__argN: <ty>` to replace the argument of the
@@ -8755,9 +8755,7 @@ impl<'a> Parser<'a> {
let move_local = Local {
pat: P(Pat {
id,
- node: PatKind::Ident(
- BindingMode::ByValue(Mutability::Immutable), ident, None,
- ),
+ node: PatKind::Ident(binding_mode, ident, None),
span,
}),
// We explicitly do not specify the type for this statement. When the user's
diff --git a/src/test/ui/async-await/mutable-arguments.rs b/src/test/ui/async-await/mutable-arguments.rs
new file mode 100644
index 0000000000000..4d6dba74097ca
--- /dev/null
+++ b/src/test/ui/async-await/mutable-arguments.rs
@@ -0,0 +1,10 @@
+// edition:2018
+// run-pass
+
+#![feature(async_await)]
+
+async fn foo(n: u32, mut vec: Vec<u32>) {
+ vec.push(n);
+}
+
+fn main() {}