From 16334cdfd4640dbae4c3f5699d4f81ae358c715f Mon Sep 17 00:00:00 2001
From: Jieyou Xu <jieyouxu@outlook.com>
Date: Sun, 13 Apr 2025 17:33:55 +0800
Subject: [PATCH] tests: convert `tests/ui/lint/dead-code/self-assign.rs` to
known-bug
---
tests/ui/lint/dead-code/self-assign.rs | 30 ++++++++++-----
tests/ui/lint/dead-code/self-assign.stderr | 44 ----------------------
2 files changed, 20 insertions(+), 54 deletions(-)
delete mode 100644 tests/ui/lint/dead-code/self-assign.stderr
diff --git a/tests/ui/lint/dead-code/self-assign.rs b/tests/ui/lint/dead-code/self-assign.rs
index 072a899e1bd..357846baf22 100644
--- a/tests/ui/lint/dead-code/self-assign.rs
+++ b/tests/ui/lint/dead-code/self-assign.rs
@@ -1,19 +1,29 @@
-// Test that dead code warnings are issued for superfluous assignments of
-// fields or variables to themselves (issue #75356).
-
-//@ ignore-test FIXME(81658, 83171)
+//! Test that dead code warnings are issued for superfluous assignments of fields or variables to
+//! themselves (issue #75356).
+//!
+//! # History of this test (to aid relanding of a fixed version of #81473)
+//!
+//! - Original lint request was about self-assignments not triggering sth like `dead_code`.
+//! - `dead_code` lint expansion for self-assignments was implemented in #87129.
+//! - Unfortunately implementation components of #87129 had to be disabled as part of reverts
+//! #86212, #83171 (to revert #81473) to address regressions #81626 and #81658.
+//! - Consequently, none of the following warnings are emitted.
//@ check-pass
+
+// Implementation of self-assignment `dead_code` lint expansions disabled due to reverts.
+//@ known-bug: #75356
+
#![allow(unused_assignments)]
#![warn(dead_code)]
fn main() {
let mut x = 0;
x = x;
- //~^ WARNING: useless assignment of variable of type `i32` to itself
+ // FIXME ~^ WARNING: useless assignment of variable of type `i32` to itself
x = (x);
- //~^ WARNING: useless assignment of variable of type `i32` to itself
+ // FIXME ~^ WARNING: useless assignment of variable of type `i32` to itself
x = {x};
// block expressions don't count as self-assignments
@@ -22,10 +32,10 @@ fn main() {
struct S<'a> { f: &'a str }
let mut s = S { f: "abc" };
s = s;
- //~^ WARNING: useless assignment of variable of type `S` to itself
+ // FIXME ~^ WARNING: useless assignment of variable of type `S` to itself
s.f = s.f;
- //~^ WARNING: useless assignment of field of type `&str` to itself
+ // FIXME ~^ WARNING: useless assignment of field of type `&str` to itself
struct N0 { x: Box<i32> }
@@ -34,11 +44,11 @@ fn main() {
struct N3 { n: N2 };
let mut n3 = N3 { n: N2(N1 { n: N0 { x: Box::new(42) } }) };
n3.n.0.n.x = n3.n.0.n.x;
- //~^ WARNING: useless assignment of field of type `Box<i32>` to itself
+ // FIXME ~^ WARNING: useless assignment of field of type `Box<i32>` to itself
let mut t = (1, ((2, 3, (4, 5)),));
t.1.0.2.1 = t.1.0.2.1;
- //~^ WARNING: useless assignment of field of type `i32` to itself
+ // FIXME ~^ WARNING: useless assignment of field of type `i32` to itself
let mut y = 0;
diff --git a/tests/ui/lint/dead-code/self-assign.stderr b/tests/ui/lint/dead-code/self-assign.stderr
deleted file mode 100644
index bb79c0ec72a..00000000000
--- a/tests/ui/lint/dead-code/self-assign.stderr
+++ /dev/null
@@ -1,44 +0,0 @@
-warning: useless assignment of variable of type `i32` to itself
- --> $DIR/self-assign.rs:10:5
- |
-LL | x = x;
- | ^^^^^
- |
-note: the lint level is defined here
- --> $DIR/self-assign.rs:6:9
- |
-LL | #![warn(dead_code)]
- | ^^^^^^^^^
-
-warning: useless assignment of variable of type `i32` to itself
- --> $DIR/self-assign.rs:13:5
- |
-LL | x = (x);
- | ^^^^^^^
-
-warning: useless assignment of variable of type `S` to itself
- --> $DIR/self-assign.rs:22:5
- |
-LL | s = s;
- | ^^^^^
-
-warning: useless assignment of field of type `&str` to itself
- --> $DIR/self-assign.rs:25:5
- |
-LL | s.f = s.f;
- | ^^^^^^^^^
-
-warning: useless assignment of field of type `Box<i32>` to itself
- --> $DIR/self-assign.rs:34:5
- |
-LL | n3.n.0.n.x = n3.n.0.n.x;
- | ^^^^^^^^^^^^^^^^^^^^^^^
-
-warning: useless assignment of field of type `i32` to itself
- --> $DIR/self-assign.rs:38:5
- |
-LL | t.1.0.2.1 = t.1.0.2.1;
- | ^^^^^^^^^^^^^^^^^^^^^
-
-warning: 6 warnings emitted
-