From 8901ea29b93eeff11c86986f620108e9f34330df Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tomasz=20Mi=C4=85sko?= <tomasz.miasko@gmail.com>
Date: Tue, 28 Sep 2021 00:00:00 +0000
Subject: [PATCH] Rebase resume argument projections during state transform
When remapping a resume argument with projections rebase them on top of
the new base.
The case where resume argument has projections is unusual, but might
arise with box syntax where the assignment is performed directly into
the box without an intermediate temporary.
---
compiler/rustc_mir_transform/src/generator.rs | 5 +++--
src/test/ui/generator/yield-in-box.rs | 10 ++++++++--
src/test/ui/generator/yield-in-box.stderr | 2 +-
3 files changed, 12 insertions(+), 5 deletions(-)
diff --git a/compiler/rustc_mir_transform/src/generator.rs b/compiler/rustc_mir_transform/src/generator.rs
index 06366b6fc31..bc72e9d94a9 100644
--- a/compiler/rustc_mir_transform/src/generator.rs
+++ b/compiler/rustc_mir_transform/src/generator.rs
@@ -342,7 +342,7 @@ impl MutVisitor<'tcx> for TransformVisitor<'tcx> {
let source_info = data.terminator().source_info;
// We must assign the value first in case it gets declared dead below
data.statements.extend(self.make_state(state_idx, v, source_info));
- let state = if let Some((resume, resume_arg)) = resume {
+ let state = if let Some((resume, mut resume_arg)) = resume {
// Yield
let state = 3 + self.suspension_points.len();
@@ -350,7 +350,8 @@ impl MutVisitor<'tcx> for TransformVisitor<'tcx> {
// live across a yield.
let resume_arg =
if let Some(&(ty, variant, idx)) = self.remap.get(&resume_arg.local) {
- self.make_field(variant, idx, ty)
+ replace_base(&mut resume_arg, self.make_field(variant, idx, ty), self.tcx);
+ resume_arg
} else {
resume_arg
};
diff --git a/src/test/ui/generator/yield-in-box.rs b/src/test/ui/generator/yield-in-box.rs
index 65f368df9cb..dd6fa7c151a 100644
--- a/src/test/ui/generator/yield-in-box.rs
+++ b/src/test/ui/generator/yield-in-box.rs
@@ -1,8 +1,10 @@
// run-pass
-
// Test that box-statements with yields in them work.
-#![feature(generators, box_syntax)]
+#![feature(generators, box_syntax, generator_trait)]
+use std::pin::Pin;
+use std::ops::Generator;
+use std::ops::GeneratorState;
fn main() {
let x = 0i32;
@@ -15,4 +17,8 @@ fn main() {
_t => {}
}
};
+
+ let mut g = |_| box yield;
+ assert_eq!(Pin::new(&mut g).resume(1), GeneratorState::Yielded(()));
+ assert_eq!(Pin::new(&mut g).resume(2), GeneratorState::Complete(box 2));
}
diff --git a/src/test/ui/generator/yield-in-box.stderr b/src/test/ui/generator/yield-in-box.stderr
index 24de18edb0f..7602e803945 100644
--- a/src/test/ui/generator/yield-in-box.stderr
+++ b/src/test/ui/generator/yield-in-box.stderr
@@ -1,5 +1,5 @@
warning: unused generator that must be used
- --> $DIR/yield-in-box.rs:9:5
+ --> $DIR/yield-in-box.rs:11:5
|
LL | / || {
LL | | let y = 2u32;