From efdf2192d0005b6ae6dd56bd0a2b04ebd04244eb Mon Sep 17 00:00:00 2001
From: Michael Goulet <michael@errs.io>
Date: Tue, 30 Jul 2024 12:28:57 -0400
Subject: [PATCH] Revert "Rollup merge of #128104 -
mu001999-contrib:fix/128053, r=petrochenkov"
This reverts commit 91b18a058c4661f82e420b633dc0a3e1ccd14b88, reversing
changes made to 9aedec9313dc8ecf9bdcb5f09c4eb0ad8b9a4875.
---
compiler/rustc_passes/src/dead.rs | 36 +++++++++----------
...lone-debug-dead-code-in-the-same-struct.rs | 4 +--
...-debug-dead-code-in-the-same-struct.stderr | 16 ++-------
.../dead-code/unconstructible-pub-struct.rs | 35 ------------------
.../unconstructible-pub-struct.stderr | 14 --------
5 files changed, 22 insertions(+), 83 deletions(-)
delete mode 100644 tests/ui/lint/dead-code/unconstructible-pub-struct.rs
delete mode 100644 tests/ui/lint/dead-code/unconstructible-pub-struct.stderr
diff --git a/compiler/rustc_passes/src/dead.rs b/compiler/rustc_passes/src/dead.rs
index 8a931fc4158e3..3b1a796130c43 100644
--- a/compiler/rustc_passes/src/dead.rs
+++ b/compiler/rustc_passes/src/dead.rs
@@ -73,26 +73,24 @@ fn adt_of<'tcx>(ty: &hir::Ty<'tcx>) -> Option<(LocalDefId, DefKind)> {
}
fn struct_all_fields_are_public(tcx: TyCtxt<'_>, id: LocalDefId) -> bool {
- let adt_def = tcx.adt_def(id);
-
- // skip types contain fields of unit and never type,
- // it's usually intentional to make the type not constructible
- let not_require_constructor = adt_def.all_fields().any(|field| {
+ // treat PhantomData and positional ZST as public,
+ // we don't want to lint types which only have them,
+ // cause it's a common way to use such types to check things like well-formedness
+ tcx.adt_def(id).all_fields().all(|field| {
let field_type = tcx.type_of(field.did).instantiate_identity();
- field_type.is_unit() || field_type.is_never()
- });
-
- not_require_constructor
- || adt_def.all_fields().all(|field| {
- let field_type = tcx.type_of(field.did).instantiate_identity();
- // skip fields of PhantomData,
- // cause it's a common way to check things like well-formedness
- if field_type.is_phantom_data() {
- return true;
- }
-
- field.vis.is_public()
- })
+ if field_type.is_phantom_data() {
+ return true;
+ }
+ let is_positional = field.name.as_str().starts_with(|c: char| c.is_ascii_digit());
+ if is_positional
+ && tcx
+ .layout_of(tcx.param_env(field.did).and(field_type))
+ .map_or(true, |layout| layout.is_zst())
+ {
+ return true;
+ }
+ field.vis.is_public()
+ })
}
/// check struct and its fields are public or not,
diff --git a/tests/ui/derives/clone-debug-dead-code-in-the-same-struct.rs b/tests/ui/derives/clone-debug-dead-code-in-the-same-struct.rs
index 6ab1fb7b039bd..885dacc727af6 100644
--- a/tests/ui/derives/clone-debug-dead-code-in-the-same-struct.rs
+++ b/tests/ui/derives/clone-debug-dead-code-in-the-same-struct.rs
@@ -1,9 +1,9 @@
#![forbid(dead_code)]
#[derive(Debug)]
-pub struct Whatever {
+pub struct Whatever { //~ ERROR struct `Whatever` is never constructed
pub field0: (),
- field1: (), //~ ERROR fields `field1`, `field2`, `field3`, and `field4` are never read
+ field1: (),
field2: (),
field3: (),
field4: (),
diff --git a/tests/ui/derives/clone-debug-dead-code-in-the-same-struct.stderr b/tests/ui/derives/clone-debug-dead-code-in-the-same-struct.stderr
index e9b757b6bae72..e10d28ad03a4e 100644
--- a/tests/ui/derives/clone-debug-dead-code-in-the-same-struct.stderr
+++ b/tests/ui/derives/clone-debug-dead-code-in-the-same-struct.stderr
@@ -1,19 +1,9 @@
-error: fields `field1`, `field2`, `field3`, and `field4` are never read
- --> $DIR/clone-debug-dead-code-in-the-same-struct.rs:6:5
+error: struct `Whatever` is never constructed
+ --> $DIR/clone-debug-dead-code-in-the-same-struct.rs:4:12
|
LL | pub struct Whatever {
- | -------- fields in this struct
-LL | pub field0: (),
-LL | field1: (),
- | ^^^^^^
-LL | field2: (),
- | ^^^^^^
-LL | field3: (),
- | ^^^^^^
-LL | field4: (),
- | ^^^^^^
+ | ^^^^^^^^
|
- = note: `Whatever` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysis
note: the lint level is defined here
--> $DIR/clone-debug-dead-code-in-the-same-struct.rs:1:11
|
diff --git a/tests/ui/lint/dead-code/unconstructible-pub-struct.rs b/tests/ui/lint/dead-code/unconstructible-pub-struct.rs
deleted file mode 100644
index 2202cbb673098..0000000000000
--- a/tests/ui/lint/dead-code/unconstructible-pub-struct.rs
+++ /dev/null
@@ -1,35 +0,0 @@
-#![feature(never_type)]
-#![deny(dead_code)]
-
-pub struct T1(!);
-pub struct T2(());
-pub struct T3<X>(std::marker::PhantomData<X>);
-
-pub struct T4 {
- _x: !,
-}
-
-pub struct T5<X> {
- _x: !,
- _y: X,
-}
-
-pub struct T6 {
- _x: (),
-}
-
-pub struct T7<X> {
- _x: (),
- _y: X,
-}
-
-pub struct T8<X> {
- _x: std::marker::PhantomData<X>,
-}
-
-pub struct T9<X> { //~ ERROR struct `T9` is never constructed
- _x: std::marker::PhantomData<X>,
- _y: i32,
-}
-
-fn main() {}
diff --git a/tests/ui/lint/dead-code/unconstructible-pub-struct.stderr b/tests/ui/lint/dead-code/unconstructible-pub-struct.stderr
deleted file mode 100644
index a3dde042bbe15..0000000000000
--- a/tests/ui/lint/dead-code/unconstructible-pub-struct.stderr
+++ /dev/null
@@ -1,14 +0,0 @@
-error: struct `T9` is never constructed
- --> $DIR/unconstructible-pub-struct.rs:30:12
- |
-LL | pub struct T9<X> {
- | ^^
- |
-note: the lint level is defined here
- --> $DIR/unconstructible-pub-struct.rs:2:9
- |
-LL | #![deny(dead_code)]
- | ^^^^^^^^^
-
-error: aborting due to 1 previous error
-