Improve dead code analysis

This commit is contained in:
mu001999 2024-07-04 22:05:00 +08:00
parent bae813a265
commit 0adb82528f
21 changed files with 173 additions and 69 deletions

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@ -277,7 +277,10 @@ fn handle_field_pattern_match(
pats: &[hir::PatField<'_>],
) {
let variant = match self.typeck_results().node_type(lhs.hir_id).kind() {
ty::Adt(adt, _) => adt.variant_of_res(res),
ty::Adt(adt, _) => {
self.check_def_id(adt.did());
adt.variant_of_res(res)
}
_ => span_bug!(lhs.span, "non-ADT in struct pattern"),
};
for pat in pats {
@ -297,7 +300,10 @@ fn handle_tuple_field_pattern_match(
dotdot: hir::DotDotPos,
) {
let variant = match self.typeck_results().node_type(lhs.hir_id).kind() {
ty::Adt(adt, _) => adt.variant_of_res(res),
ty::Adt(adt, _) => {
self.check_def_id(adt.did());
adt.variant_of_res(res)
}
_ => {
self.tcx.dcx().span_delayed_bug(lhs.span, "non-ADT in tuple struct pattern");
return;
@ -402,31 +408,6 @@ fn should_ignore_item(&mut self, def_id: DefId) -> bool {
return false;
}
// don't ignore impls for Enums and pub Structs whose methods don't have self receiver,
// cause external crate may call such methods to construct values of these types
if let Some(local_impl_of) = impl_of.as_local()
&& let Some(local_def_id) = def_id.as_local()
&& let Some(fn_sig) =
self.tcx.hir().fn_sig_by_hir_id(self.tcx.local_def_id_to_hir_id(local_def_id))
&& matches!(fn_sig.decl.implicit_self, hir::ImplicitSelfKind::None)
&& let TyKind::Path(hir::QPath::Resolved(_, path)) =
self.tcx.hir().expect_item(local_impl_of).expect_impl().self_ty.kind
&& let Res::Def(def_kind, did) = path.res
{
match def_kind {
// for example, #[derive(Default)] pub struct T(i32);
// external crate can call T::default() to construct T,
// so that don't ignore impl Default for pub Enum and Structs
DefKind::Struct | DefKind::Union if self.tcx.visibility(did).is_public() => {
return false;
}
// don't ignore impl Default for Enums,
// cause we don't know which variant is constructed
DefKind::Enum => return false,
_ => (),
};
}
if let Some(trait_of) = self.tcx.trait_id_of_impl(impl_of)
&& self.tcx.has_attr(trait_of, sym::rustc_trivial_field_reads)
{
@ -690,6 +671,9 @@ fn visit_pat(&mut self, pat: &'tcx hir::Pat<'tcx>) {
self.handle_field_pattern_match(pat, res, fields);
}
PatKind::Path(ref qpath) => {
if let ty::Adt(adt, _) = self.typeck_results().node_type(pat.hir_id).kind() {
self.check_def_id(adt.did());
}
let res = self.typeck_results().qpath_res(qpath, pat.hir_id);
self.handle_res(res);
}
@ -845,7 +829,7 @@ fn check_item<'tcx>(
// mark the method live if the self_ty is public,
// or the method is public and may construct self
if tcx.visibility(local_def_id).is_public()
&& (ty_and_all_fields_are_public || may_construct_self)
&& (ty_and_all_fields_are_public || (ty_is_public && may_construct_self))
{
// if the impl item is public,
// and the ty may be constructed or can be constructed in foreign crates,

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@ -103,7 +103,6 @@
/// ```
#[cfg_attr(not(test), rustc_diagnostic_item = "Default")]
#[stable(feature = "rust1", since = "1.0.0")]
#[cfg_attr(not(bootstrap), rustc_trivial_field_reads)]
pub trait Default: Sized {
/// Returns the "default value" for a type.
///

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@ -241,11 +241,3 @@ fn parse(input: ParseStream<'_>) -> syn::Result<Self> {
Ok(QueryGroup { group_path })
}
}
struct Nothing;
impl Parse for Nothing {
fn parse(_input: ParseStream<'_>) -> syn::Result<Self> {
Ok(Nothing)
}
}

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@ -17,18 +17,21 @@ mod submod {
// if any of these are implemented without global calls for any
// function calls, then being in a submodule will (correctly)
// cause errors about unrecognised module `std` (or `extra`)
#[allow(dead_code)]
#[derive(PartialEq, PartialOrd, Eq, Ord, Hash, Clone, Debug, Encodable, Decodable)]
enum A {
A1(usize),
A2(isize),
}
#[allow(dead_code)]
#[derive(PartialEq, PartialOrd, Eq, Ord, Hash, Clone, Debug, Encodable, Decodable)]
struct B {
x: usize,
y: isize,
}
#[allow(dead_code)]
#[derive(PartialEq, PartialOrd, Eq, Ord, Hash, Clone, Debug, Encodable, Decodable)]
struct C(usize, isize);
}

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@ -20,6 +20,7 @@
pub const state: u8 = 1;
pub const cmp: u8 = 1;
#[allow(dead_code)]
#[derive(Ord, Eq, PartialOrd, PartialEq, Debug, Decodable, Encodable, Hash)]
struct Foo {}

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@ -7,6 +7,7 @@ pub trait Foo {
fn foo() where [(); Self::ASSOC_C]:;
}
#[allow(dead_code)]
struct Bar<const N: &'static ()>;
impl<const N: &'static ()> Foo for Bar<N> {
const ASSOC_C: usize = 3;

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@ -2,6 +2,7 @@
#![feature(adt_const_params, generic_const_exprs)]
#![allow(incomplete_features, unused_variables)]
#[allow(dead_code)]
struct F<const S: &'static str>;
impl<const S: &'static str> X for F<{ S }> {
const W: usize = 3;

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@ -1,6 +1,8 @@
//@ run-rustfix
#[allow(dead_code)]
struct S<T>(T);
#[allow(dead_code)]
struct S2;
impl<T: Default> Default for S<T> {

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@ -1,6 +1,8 @@
//@ run-rustfix
#[allow(dead_code)]
struct S<T>(T);
#[allow(dead_code)]
struct S2;
impl<T: Default> impl Default for S<T> {

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@ -1,23 +1,23 @@
error: unexpected `impl` keyword
--> $DIR/extra-impl-in-trait-impl.rs:6:18
--> $DIR/extra-impl-in-trait-impl.rs:8:18
|
LL | impl<T: Default> impl Default for S<T> {
| ^^^^^ help: remove the extra `impl`
|
note: this is parsed as an `impl Trait` type, but a trait is expected at this position
--> $DIR/extra-impl-in-trait-impl.rs:6:18
--> $DIR/extra-impl-in-trait-impl.rs:8:18
|
LL | impl<T: Default> impl Default for S<T> {
| ^^^^^^^^^^^^
error: unexpected `impl` keyword
--> $DIR/extra-impl-in-trait-impl.rs:12:6
--> $DIR/extra-impl-in-trait-impl.rs:14:6
|
LL | impl impl Default for S2 {
| ^^^^^ help: remove the extra `impl`
|
note: this is parsed as an `impl Trait` type, but a trait is expected at this position
--> $DIR/extra-impl-in-trait-impl.rs:12:6
--> $DIR/extra-impl-in-trait-impl.rs:14:6
|
LL | impl impl Default for S2 {
| ^^^^^^^^^^^^

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@ -4,8 +4,8 @@
#![deny(dead_code)]
struct Foo {
#[allow(dead_code)]
struct Foo {
inner: u32,
}

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@ -0,0 +1,37 @@
#![deny(dead_code)]
struct Foo(u8); //~ ERROR struct `Foo` is never constructed
enum Bar { //~ ERROR enum `Bar` is never used
Var1(u8),
Var2(u8),
}
pub trait Tr1 {
fn f1() -> Self;
}
impl Tr1 for Foo {
fn f1() -> Foo {
let f = Foo(0);
let Foo(tag) = f;
Foo(tag)
}
}
impl Tr1 for Bar {
fn f1() -> Bar {
let b = Bar::Var1(0);
let b = if let Bar::Var1(_) = b {
Bar::Var1(0)
} else {
Bar::Var2(0)
};
match b {
Bar::Var1(_) => Bar::Var2(0),
Bar::Var2(_) => Bar::Var1(0),
}
}
}
fn main() {}

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@ -0,0 +1,20 @@
error: struct `Foo` is never constructed
--> $DIR/lint-unused-adt-appeared-in-pattern.rs:3:8
|
LL | struct Foo(u8);
| ^^^
|
note: the lint level is defined here
--> $DIR/lint-unused-adt-appeared-in-pattern.rs:1:9
|
LL | #![deny(dead_code)]
| ^^^^^^^^^
error: enum `Bar` is never used
--> $DIR/lint-unused-adt-appeared-in-pattern.rs:5:6
|
LL | enum Bar {
| ^^^
error: aborting due to 2 previous errors

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@ -0,0 +1,32 @@
//@ check-pass
#![deny(dead_code)]
#[repr(u8)]
#[derive(Copy, Clone, Debug)]
pub enum RecordField {
Target = 1,
Level,
Module,
File,
Line,
NumArgs,
}
unsafe trait Pod {}
#[repr(transparent)]
struct RecordFieldWrapper(RecordField);
unsafe impl Pod for RecordFieldWrapper {}
fn try_read<T: Pod>(buf: &[u8]) -> T {
unsafe { std::ptr::read_unaligned(buf.as_ptr() as *const T) }
}
pub fn foo(buf: &[u8]) -> RecordField {
let RecordFieldWrapper(tag) = try_read(buf);
tag
}
fn main() {}

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@ -1,8 +1,9 @@
#![deny(dead_code)]
struct T1; //~ ERROR struct `T1` is never constructed
pub struct T2(i32); //~ ERROR struct `T2` is never constructed
struct T3;
struct T2; //~ ERROR struct `T2` is never constructed
pub struct T3(i32); //~ ERROR struct `T3` is never constructed
pub struct T4(i32); //~ ERROR field `0` is never read
trait Trait1 { //~ ERROR trait `Trait1` is never used
const UNUSED: i32;
@ -11,13 +12,13 @@ fn unused(&self) {}
}
pub trait Trait2 {
const USED: i32;
fn used(&self) {}
const MAY_USED: i32;
fn may_used(&self) {}
}
pub trait Trait3 {
const USED: i32;
fn construct_self() -> Self;
const MAY_USED: i32;
fn may_used() -> Self;
}
impl Trait1 for T1 {
@ -29,24 +30,35 @@ fn construct_self() -> Self {
impl Trait1 for T2 {
const UNUSED: i32 = 0;
fn construct_self() -> Self {
T2(0)
}
}
impl Trait2 for T1 {
const USED: i32 = 0;
}
impl Trait2 for T2 {
const USED: i32 = 0;
}
impl Trait3 for T3 {
const USED: i32 = 0;
fn construct_self() -> Self {
Self
}
}
impl Trait2 for T1 {
const MAY_USED: i32 = 0;
}
impl Trait2 for T2 {
const MAY_USED: i32 = 0;
}
impl Trait2 for T3 {
const MAY_USED: i32 = 0;
}
impl Trait3 for T2 {
const MAY_USED: i32 = 0;
fn may_used() -> Self {
Self
}
}
impl Trait3 for T4 {
const MAY_USED: i32 = 0;
fn may_used() -> Self {
T4(0)
}
}
fn main() {}

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@ -11,16 +11,32 @@ LL | #![deny(dead_code)]
| ^^^^^^^^^
error: struct `T2` is never constructed
--> $DIR/unused-adt-impl-pub-trait-with-assoc-const.rs:4:12
--> $DIR/unused-adt-impl-pub-trait-with-assoc-const.rs:4:8
|
LL | pub struct T2(i32);
LL | struct T2;
| ^^
error: struct `T3` is never constructed
--> $DIR/unused-adt-impl-pub-trait-with-assoc-const.rs:5:12
|
LL | pub struct T3(i32);
| ^^
error: field `0` is never read
--> $DIR/unused-adt-impl-pub-trait-with-assoc-const.rs:6:15
|
LL | pub struct T4(i32);
| -- ^^^
| |
| field in this struct
|
= help: consider removing this field
error: trait `Trait1` is never used
--> $DIR/unused-adt-impl-pub-trait-with-assoc-const.rs:7:7
--> $DIR/unused-adt-impl-pub-trait-with-assoc-const.rs:8:7
|
LL | trait Trait1 {
| ^^^^^^
error: aborting due to 3 previous errors
error: aborting due to 5 previous errors

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@ -22,4 +22,5 @@ pub struct T2 {
fn main() {
let _x: Used = Default::default();
let _e: E = Default::default();
}

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@ -4,7 +4,6 @@ error: struct `T` is never constructed
LL | struct T;
| ^
|
= note: `T` has a derived impl for the trait `Default`, but this is intentionally ignored during dead code analysis
note: the lint level is defined here
--> $DIR/unused-struct-derive-default.rs:1:9
|

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@ -1,5 +1,6 @@
//@ run-rustfix
#[allow(dead_code)]
struct Foo;
impl From<i32> for Foo {

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@ -1,5 +1,6 @@
//@ run-rustfix
#[allow(dead_code)]
struct Foo;
fn From<i32> for Foo {

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@ -1,5 +1,5 @@
error: you might have meant to write `impl` instead of `fn`
--> $DIR/issue-105366.rs:5:1
--> $DIR/issue-105366.rs:6:1
|
LL | fn From<i32> for Foo {
| ^^