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Merge unused_tuple_struct_fields into dead_code

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This implicitly upgrades the lint from `allow` to `warn` and places it
into the `unused` lint group.
This commit is contained in:
Jake Goulding 2023-11-26 14:48:34 -05:00
parent 2f6fc05186
commit 9fcf9c1410
3 changed files with 43 additions and 52 deletions
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1
compiler/rustc_lint/src/lib.rs
View file

@ -328,6 +328,7 @@ macro_rules! add_lint_group {
store.register_renamed("disjoint_capture_migration", "rust_2021_incompatible_closure_captures");
store.register_renamed("or_patterns_back_compat", "rust_2021_incompatible_or_patterns");
store.register_renamed("non_fmt_panic", "non_fmt_panics");
store.register_renamed("unused_tuple_struct_fields", "dead_code");
// These were moved to tool lints, but rustc still sees them when compiling normally, before
// tool lints are registered, so `check_tool_name_for_backwards_compat` doesn't work. Use

36
compiler/rustc_lint_defs/src/builtin.rs
View file

@ -125,7 +125,6 @@
UNUSED_MACROS,
UNUSED_MUT,
UNUSED_QUALIFICATIONS,
UNUSED_TUPLE_STRUCT_FIELDS,
UNUSED_UNSAFE,
UNUSED_VARIABLES,
USELESS_DEPRECATED,
@ -697,8 +696,13 @@
/// Dead code may signal a mistake or unfinished code. To silence the
/// warning for individual items, prefix the name with an underscore such
/// as `_foo`. If it was intended to expose the item outside of the crate,
/// consider adding a visibility modifier like `pub`. Otherwise consider
/// removing the unused code.
/// consider adding a visibility modifier like `pub`.
///
/// To preserve the numbering of tuple structs with unused fields,
/// change the unused fields to have unit type or use
/// `PhantomData`.
///
/// Otherwise consider removing the unused code.
pub DEAD_CODE,
Warn,
"detect unused, unexported items"
@ -732,32 +736,6 @@
"detects attributes that were not used by the compiler"
}
declare_lint! {
/// The `unused_tuple_struct_fields` lint detects fields of tuple structs
/// that are never read.
///
/// ### Example
///
/// ```rust
/// #[warn(unused_tuple_struct_fields)]
/// struct S(i32, i32, i32);
/// let s = S(1, 2, 3);
/// let _ = (s.0, s.2);
/// ```
///
/// {{produces}}
///
/// ### Explanation
///
/// Tuple struct fields that are never read anywhere may indicate a
/// mistake or unfinished code. To silence this warning, consider
/// removing the unused field(s) or, to preserve the numbering of the
/// remaining fields, change the unused field(s) to have unit type.
pub UNUSED_TUPLE_STRUCT_FIELDS,
Allow,
"detects tuple struct fields that are never read"
}
declare_lint! {
/// The `unreachable_code` lint detects unreachable code paths.
///

58
compiler/rustc_passes/src/dead.rs
View file

@ -15,8 +15,8 @@
use rustc_middle::middle::privacy::Level;
use rustc_middle::query::Providers;
use rustc_middle::ty::{self, TyCtxt};
use rustc_session::lint::builtin::{DEAD_CODE, UNUSED_TUPLE_STRUCT_FIELDS};
use rustc_session::lint::{self, Lint, LintId};
use rustc_session::lint;
use rustc_session::lint::builtin::DEAD_CODE;
use rustc_span::symbol::{sym, Symbol};
use rustc_target::abi::FieldIdx;
use std::mem;
@ -766,6 +766,12 @@ enum ShouldWarnAboutField {
No,
}
#[derive(Debug, Copy, Clone, PartialEq, Eq)]
enum ReportOn {
TupleField,
NamedField,
}
impl<'tcx> DeadVisitor<'tcx> {
fn should_warn_about_field(&mut self, field: &ty::FieldDef) -> ShouldWarnAboutField {
if self.live_symbols.contains(&field.did.expect_local()) {
@ -787,9 +793,9 @@ fn should_warn_about_field(&mut self, field: &ty::FieldDef) -> ShouldWarnAboutFi
ShouldWarnAboutField::Yes
}
fn def_lint_level(&self, lint: &'static Lint, id: LocalDefId) -> lint::Level {
fn def_lint_level(&self, id: LocalDefId) -> lint::Level {
let hir_id = self.tcx.local_def_id_to_hir_id(id);
self.tcx.lint_level_at_node(lint, hir_id).0
self.tcx.lint_level_at_node(DEAD_CODE, hir_id).0
}
// # Panics
@ -803,7 +809,7 @@ fn lint_at_single_level(
dead_codes: &[&DeadItem],
participle: &str,
parent_item: Option<LocalDefId>,
lint: &'static Lint,
report_on: ReportOn,
) {
let Some(&first_item) = dead_codes.first() else {
return;
@ -864,8 +870,8 @@ fn lint_at_single_level(
None
};
let diag = if LintId::of(lint) == LintId::of(UNUSED_TUPLE_STRUCT_FIELDS) {
MultipleDeadCodes::UnusedTupleStructFields {
let diag = match report_on {
ReportOn::TupleField => MultipleDeadCodes::UnusedTupleStructFields {
multiple,
num,
descr,
@ -874,9 +880,9 @@ fn lint_at_single_level(
change_fields_suggestion: ChangeFieldsToBeOfUnitType { num, spans: spans.clone() },
parent_info,
ignored_derived_impls,
}
} else {
MultipleDeadCodes::DeadCodes {
},
ReportOn::NamedField => MultipleDeadCodes::DeadCodes {
multiple,
num,
descr,
@ -884,11 +890,11 @@ fn lint_at_single_level(
name_list,
parent_info,
ignored_derived_impls,
}
},
};
let hir_id = tcx.local_def_id_to_hir_id(first_item.def_id);
self.tcx.emit_spanned_lint(lint, hir_id, MultiSpan::from_spans(spans), diag);
self.tcx.emit_spanned_lint(DEAD_CODE, hir_id, MultiSpan::from_spans(spans), diag);
}
fn warn_multiple(
@ -896,7 +902,7 @@ fn warn_multiple(
def_id: LocalDefId,
participle: &str,
dead_codes: Vec<DeadItem>,
lint: &'static Lint,
report_on: ReportOn,
) {
let mut dead_codes = dead_codes
.iter()
@ -907,7 +913,7 @@ fn warn_multiple(
}
dead_codes.sort_by_key(|v| v.level);
for group in dead_codes[..].group_by(|a, b| a.level == b.level) {
self.lint_at_single_level(&group, participle, Some(def_id), lint);
self.lint_at_single_level(&group, participle, Some(def_id), report_on);
}
}
@ -915,9 +921,9 @@ fn warn_dead_code(&mut self, id: LocalDefId, participle: &str) {
let item = DeadItem {
def_id: id,
name: self.tcx.item_name(id.to_def_id()),
level: self.def_lint_level(DEAD_CODE, id),
level: self.def_lint_level(id),
};
self.lint_at_single_level(&[&item], participle, None, DEAD_CODE);
self.lint_at_single_level(&[&item], participle, None, ReportOn::NamedField);
}
fn check_definition(&mut self, def_id: LocalDefId) {
@ -964,12 +970,12 @@ fn check_mod_deathness(tcx: TyCtxt<'_>, module: LocalModDefId) {
let def_id = item.id.owner_id.def_id;
if !visitor.is_live_code(def_id) {
let name = tcx.item_name(def_id.to_def_id());
let level = visitor.def_lint_level(DEAD_CODE, def_id);
let level = visitor.def_lint_level(def_id);
dead_items.push(DeadItem { def_id, name, level })
}
}
visitor.warn_multiple(item.owner_id.def_id, "used", dead_items, DEAD_CODE);
visitor.warn_multiple(item.owner_id.def_id, "used", dead_items, ReportOn::NamedField);
}
if !live_symbols.contains(&item.owner_id.def_id) {
@ -991,7 +997,7 @@ fn check_mod_deathness(tcx: TyCtxt<'_>, module: LocalModDefId) {
let def_id = variant.def_id.expect_local();
if !live_symbols.contains(&def_id) {
// Record to group diagnostics.
let level = visitor.def_lint_level(DEAD_CODE, def_id);
let level = visitor.def_lint_level(def_id);
dead_variants.push(DeadItem { def_id, name: variant.name, level });
continue;
}
@ -999,24 +1005,30 @@ fn check_mod_deathness(tcx: TyCtxt<'_>, module: LocalModDefId) {
let is_positional = variant.fields.raw.first().map_or(false, |field| {
field.name.as_str().starts_with(|c: char| c.is_ascii_digit())
});
let lint = if is_positional { UNUSED_TUPLE_STRUCT_FIELDS } else { DEAD_CODE };
let report_on =
if is_positional { ReportOn::TupleField } else { ReportOn::NamedField };
let dead_fields = variant
.fields
.iter()
.filter_map(|field| {
let def_id = field.did.expect_local();
if let ShouldWarnAboutField::Yes = visitor.should_warn_about_field(field) {
let level = visitor.def_lint_level(lint, def_id);
let level = visitor.def_lint_level(def_id);
Some(DeadItem { def_id, name: field.name, level })
} else {
None
}
})
.collect();
visitor.warn_multiple(def_id, "read", dead_fields, lint);
visitor.warn_multiple(def_id, "read", dead_fields, report_on);
}
visitor.warn_multiple(item.owner_id.def_id, "constructed", dead_variants, DEAD_CODE);
visitor.warn_multiple(
item.owner_id.def_id,
"constructed",
dead_variants,
ReportOn::NamedField,
);
}
}