rust/compiler/rustc_lint/src/lib.rs
2021-04-06 22:01:00 +02:00

500 lines
19 KiB
Rust

//! Lints, aka compiler warnings.
//!
//! A 'lint' check is a kind of miscellaneous constraint that a user _might_
//! want to enforce, but might reasonably want to permit as well, on a
//! module-by-module basis. They contrast with static constraints enforced by
//! other phases of the compiler, which are generally required to hold in order
//! to compile the program at all.
//!
//! Most lints can be written as [LintPass] instances. These run after
//! all other analyses. The `LintPass`es built into rustc are defined
//! within [rustc_session::lint::builtin],
//! which has further comments on how to add such a lint.
//! rustc can also load user-defined lint plugins via the plugin mechanism.
//!
//! Some of rustc's lints are defined elsewhere in the compiler and work by
//! calling `add_lint()` on the overall `Session` object. This works when
//! it happens before the main lint pass, which emits the lints stored by
//! `add_lint()`. To emit lints after the main lint pass (from codegen, for
//! example) requires more effort. See `emit_lint` and `GatherNodeLevels`
//! in `context.rs`.
//!
//! Some code also exists in [rustc_session::lint], [rustc_middle::lint].
//!
//! ## Note
//!
//! This API is completely unstable and subject to change.
#![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
#![cfg_attr(test, feature(test))]
#![feature(array_windows)]
#![feature(bool_to_option)]
#![feature(box_syntax)]
#![feature(box_patterns)]
#![feature(crate_visibility_modifier)]
#![feature(iter_order_by)]
#![feature(iter_zip)]
#![feature(never_type)]
#![feature(nll)]
#![cfg_attr(bootstrap, feature(or_patterns))]
#![feature(half_open_range_patterns)]
#![feature(exclusive_range_pattern)]
#![feature(control_flow_enum)]
#![recursion_limit = "256"]
#[macro_use]
extern crate rustc_middle;
#[macro_use]
extern crate rustc_session;
mod array_into_iter;
pub mod builtin;
mod context;
mod early;
mod internal;
mod late;
mod levels;
mod methods;
mod non_ascii_idents;
mod non_fmt_panic;
mod nonstandard_style;
mod noop_method_call;
mod passes;
mod redundant_semicolon;
mod traits;
mod types;
mod unused;
use rustc_ast as ast;
use rustc_hir as hir;
use rustc_hir::def_id::LocalDefId;
use rustc_middle::ty::query::Providers;
use rustc_middle::ty::TyCtxt;
use rustc_session::lint::builtin::{
BARE_TRAIT_OBJECTS, ELIDED_LIFETIMES_IN_PATHS, EXPLICIT_OUTLIVES_REQUIREMENTS,
};
use rustc_span::symbol::{Ident, Symbol};
use rustc_span::Span;
use array_into_iter::ArrayIntoIter;
use builtin::*;
use internal::*;
use methods::*;
use non_ascii_idents::*;
use non_fmt_panic::NonPanicFmt;
use nonstandard_style::*;
use noop_method_call::*;
use redundant_semicolon::*;
use traits::*;
use types::*;
use unused::*;
/// Useful for other parts of the compiler / Clippy.
pub use builtin::SoftLints;
pub use context::{CheckLintNameResult, EarlyContext, LateContext, LintContext, LintStore};
pub use early::check_ast_crate;
pub use late::check_crate;
pub use passes::{EarlyLintPass, LateLintPass};
pub use rustc_session::lint::Level::{self, *};
pub use rustc_session::lint::{BufferedEarlyLint, FutureIncompatibleInfo, Lint, LintId};
pub use rustc_session::lint::{LintArray, LintPass};
pub fn provide(providers: &mut Providers) {
levels::provide(providers);
*providers = Providers { lint_mod, ..*providers };
}
fn lint_mod(tcx: TyCtxt<'_>, module_def_id: LocalDefId) {
late::late_lint_mod(tcx, module_def_id, BuiltinCombinedModuleLateLintPass::new());
}
macro_rules! pre_expansion_lint_passes {
($macro:path, $args:tt) => {
$macro!($args, [KeywordIdents: KeywordIdents,]);
};
}
macro_rules! early_lint_passes {
($macro:path, $args:tt) => {
$macro!(
$args,
[
UnusedParens: UnusedParens,
UnusedBraces: UnusedBraces,
UnusedImportBraces: UnusedImportBraces,
UnsafeCode: UnsafeCode,
AnonymousParameters: AnonymousParameters,
EllipsisInclusiveRangePatterns: EllipsisInclusiveRangePatterns::default(),
NonCamelCaseTypes: NonCamelCaseTypes,
DeprecatedAttr: DeprecatedAttr::new(),
WhileTrue: WhileTrue,
NonAsciiIdents: NonAsciiIdents,
IncompleteFeatures: IncompleteFeatures,
RedundantSemicolons: RedundantSemicolons,
UnusedDocComment: UnusedDocComment,
]
);
};
}
macro_rules! declare_combined_early_pass {
([$name:ident], $passes:tt) => (
early_lint_methods!(declare_combined_early_lint_pass, [pub $name, $passes]);
)
}
pre_expansion_lint_passes!(declare_combined_early_pass, [BuiltinCombinedPreExpansionLintPass]);
early_lint_passes!(declare_combined_early_pass, [BuiltinCombinedEarlyLintPass]);
macro_rules! late_lint_passes {
($macro:path, $args:tt) => {
$macro!(
$args,
[
// FIXME: Look into regression when this is used as a module lint
// May Depend on constants elsewhere
UnusedBrokenConst: UnusedBrokenConst,
// Uses attr::is_used which is untracked, can't be an incremental module pass.
UnusedAttributes: UnusedAttributes::new(),
// Needs to run after UnusedAttributes as it marks all `feature` attributes as used.
UnstableFeatures: UnstableFeatures,
// Tracks state across modules
UnnameableTestItems: UnnameableTestItems::new(),
// Tracks attributes of parents
MissingDoc: MissingDoc::new(),
// Depends on access levels
// FIXME: Turn the computation of types which implement Debug into a query
// and change this to a module lint pass
MissingDebugImplementations: MissingDebugImplementations::default(),
ArrayIntoIter: ArrayIntoIter,
ClashingExternDeclarations: ClashingExternDeclarations::new(),
DropTraitConstraints: DropTraitConstraints,
TemporaryCStringAsPtr: TemporaryCStringAsPtr,
NonPanicFmt: NonPanicFmt,
NoopMethodCall: NoopMethodCall,
]
);
};
}
macro_rules! late_lint_mod_passes {
($macro:path, $args:tt) => {
$macro!(
$args,
[
HardwiredLints: HardwiredLints,
ImproperCTypesDeclarations: ImproperCTypesDeclarations,
ImproperCTypesDefinitions: ImproperCTypesDefinitions,
VariantSizeDifferences: VariantSizeDifferences,
BoxPointers: BoxPointers,
PathStatements: PathStatements,
// Depends on referenced function signatures in expressions
UnusedResults: UnusedResults,
NonUpperCaseGlobals: NonUpperCaseGlobals,
NonShorthandFieldPatterns: NonShorthandFieldPatterns,
UnusedAllocation: UnusedAllocation,
// Depends on types used in type definitions
MissingCopyImplementations: MissingCopyImplementations,
// Depends on referenced function signatures in expressions
MutableTransmutes: MutableTransmutes,
TypeAliasBounds: TypeAliasBounds,
TrivialConstraints: TrivialConstraints,
TypeLimits: TypeLimits::new(),
NonSnakeCase: NonSnakeCase,
InvalidNoMangleItems: InvalidNoMangleItems,
// Depends on access levels
UnreachablePub: UnreachablePub,
ExplicitOutlivesRequirements: ExplicitOutlivesRequirements,
InvalidValue: InvalidValue,
DerefNullPtr: DerefNullPtr,
]
);
};
}
macro_rules! declare_combined_late_pass {
([$v:vis $name:ident], $passes:tt) => (
late_lint_methods!(declare_combined_late_lint_pass, [$v $name, $passes], ['tcx]);
)
}
// FIXME: Make a separate lint type which do not require typeck tables
late_lint_passes!(declare_combined_late_pass, [pub BuiltinCombinedLateLintPass]);
late_lint_mod_passes!(declare_combined_late_pass, [BuiltinCombinedModuleLateLintPass]);
pub fn new_lint_store(no_interleave_lints: bool, internal_lints: bool) -> LintStore {
let mut lint_store = LintStore::new();
register_builtins(&mut lint_store, no_interleave_lints);
if internal_lints {
register_internals(&mut lint_store);
}
lint_store
}
/// Tell the `LintStore` about all the built-in lints (the ones
/// defined in this crate and the ones defined in
/// `rustc_session::lint::builtin`).
fn register_builtins(store: &mut LintStore, no_interleave_lints: bool) {
macro_rules! add_lint_group {
($name:expr, $($lint:ident),*) => (
store.register_group(false, $name, None, vec![$(LintId::of($lint)),*]);
)
}
macro_rules! register_pass {
($method:ident, $ty:ident, $constructor:expr) => {
store.register_lints(&$ty::get_lints());
store.$method(|| box $constructor);
};
}
macro_rules! register_passes {
($method:ident, [$($passes:ident: $constructor:expr,)*]) => (
$(
register_pass!($method, $passes, $constructor);
)*
)
}
if no_interleave_lints {
pre_expansion_lint_passes!(register_passes, register_pre_expansion_pass);
early_lint_passes!(register_passes, register_early_pass);
late_lint_passes!(register_passes, register_late_pass);
late_lint_mod_passes!(register_passes, register_late_mod_pass);
} else {
store.register_lints(&BuiltinCombinedPreExpansionLintPass::get_lints());
store.register_lints(&BuiltinCombinedEarlyLintPass::get_lints());
store.register_lints(&BuiltinCombinedModuleLateLintPass::get_lints());
store.register_lints(&BuiltinCombinedLateLintPass::get_lints());
}
add_lint_group!(
"nonstandard_style",
NON_CAMEL_CASE_TYPES,
NON_SNAKE_CASE,
NON_UPPER_CASE_GLOBALS
);
add_lint_group!(
"unused",
UNUSED_IMPORTS,
UNUSED_VARIABLES,
UNUSED_ASSIGNMENTS,
DEAD_CODE,
UNUSED_MUT,
UNREACHABLE_CODE,
UNREACHABLE_PATTERNS,
UNUSED_MUST_USE,
UNUSED_UNSAFE,
PATH_STATEMENTS,
UNUSED_ATTRIBUTES,
UNUSED_MACROS,
UNUSED_ALLOCATION,
UNUSED_DOC_COMMENTS,
UNUSED_EXTERN_CRATES,
UNUSED_FEATURES,
UNUSED_LABELS,
UNUSED_PARENS,
UNUSED_BRACES,
REDUNDANT_SEMICOLONS
);
add_lint_group!(
"rust_2018_idioms",
BARE_TRAIT_OBJECTS,
UNUSED_EXTERN_CRATES,
ELLIPSIS_INCLUSIVE_RANGE_PATTERNS,
ELIDED_LIFETIMES_IN_PATHS,
EXPLICIT_OUTLIVES_REQUIREMENTS // FIXME(#52665, #47816) not always applicable and not all
// macros are ready for this yet.
// UNREACHABLE_PUB,
// FIXME macro crates are not up for this yet, too much
// breakage is seen if we try to encourage this lint.
// MACRO_USE_EXTERN_CRATE
);
// Register renamed and removed lints.
store.register_renamed("single_use_lifetime", "single_use_lifetimes");
store.register_renamed("elided_lifetime_in_path", "elided_lifetimes_in_paths");
store.register_renamed("bare_trait_object", "bare_trait_objects");
store.register_renamed("unstable_name_collision", "unstable_name_collisions");
store.register_renamed("unused_doc_comment", "unused_doc_comments");
store.register_renamed("async_idents", "keyword_idents");
store.register_renamed("exceeding_bitshifts", "arithmetic_overflow");
store.register_renamed("redundant_semicolon", "redundant_semicolons");
store.register_renamed("overlapping_patterns", "overlapping_range_endpoints");
store.register_renamed("safe_packed_borrows", "unaligned_references");
// 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
// `register_removed` explicitly.
const RUSTDOC_LINTS: &[&str] = &[
"broken_intra_doc_links",
"private_intra_doc_links",
"missing_crate_level_docs",
"missing_doc_code_examples",
"private_doc_tests",
"invalid_codeblock_attributes",
"invalid_html_tags",
"non_autolinks",
];
for rustdoc_lint in RUSTDOC_LINTS {
store.register_ignored(rustdoc_lint);
}
store.register_removed(
"intra_doc_link_resolution_failure",
"use `rustdoc::broken_intra_doc_links` instead",
);
store.register_removed("rustdoc", "use `rustdoc::all` instead");
store.register_removed("unknown_features", "replaced by an error");
store.register_removed("unsigned_negation", "replaced by negate_unsigned feature gate");
store.register_removed("negate_unsigned", "cast a signed value instead");
store.register_removed("raw_pointer_derive", "using derive with raw pointers is ok");
// Register lint group aliases.
store.register_group_alias("nonstandard_style", "bad_style");
// This was renamed to `raw_pointer_derive`, which was then removed,
// so it is also considered removed.
store.register_removed("raw_pointer_deriving", "using derive with raw pointers is ok");
store.register_removed("drop_with_repr_extern", "drop flags have been removed");
store.register_removed("fat_ptr_transmutes", "was accidentally removed back in 2014");
store.register_removed("deprecated_attr", "use `deprecated` instead");
store.register_removed(
"transmute_from_fn_item_types",
"always cast functions before transmuting them",
);
store.register_removed(
"hr_lifetime_in_assoc_type",
"converted into hard error, see issue #33685 \
<https://github.com/rust-lang/rust/issues/33685> for more information",
);
store.register_removed(
"inaccessible_extern_crate",
"converted into hard error, see issue #36886 \
<https://github.com/rust-lang/rust/issues/36886> for more information",
);
store.register_removed(
"super_or_self_in_global_path",
"converted into hard error, see issue #36888 \
<https://github.com/rust-lang/rust/issues/36888> for more information",
);
store.register_removed(
"overlapping_inherent_impls",
"converted into hard error, see issue #36889 \
<https://github.com/rust-lang/rust/issues/36889> for more information",
);
store.register_removed(
"illegal_floating_point_constant_pattern",
"converted into hard error, see issue #36890 \
<https://github.com/rust-lang/rust/issues/36890> for more information",
);
store.register_removed(
"illegal_struct_or_enum_constant_pattern",
"converted into hard error, see issue #36891 \
<https://github.com/rust-lang/rust/issues/36891> for more information",
);
store.register_removed(
"lifetime_underscore",
"converted into hard error, see issue #36892 \
<https://github.com/rust-lang/rust/issues/36892> for more information",
);
store.register_removed(
"extra_requirement_in_impl",
"converted into hard error, see issue #37166 \
<https://github.com/rust-lang/rust/issues/37166> for more information",
);
store.register_removed(
"legacy_imports",
"converted into hard error, see issue #38260 \
<https://github.com/rust-lang/rust/issues/38260> for more information",
);
store.register_removed(
"coerce_never",
"converted into hard error, see issue #48950 \
<https://github.com/rust-lang/rust/issues/48950> for more information",
);
store.register_removed(
"resolve_trait_on_defaulted_unit",
"converted into hard error, see issue #48950 \
<https://github.com/rust-lang/rust/issues/48950> for more information",
);
store.register_removed(
"private_no_mangle_fns",
"no longer a warning, `#[no_mangle]` functions always exported",
);
store.register_removed(
"private_no_mangle_statics",
"no longer a warning, `#[no_mangle]` statics always exported",
);
store.register_removed("bad_repr", "replaced with a generic attribute input check");
store.register_removed(
"duplicate_matcher_binding_name",
"converted into hard error, see issue #57742 \
<https://github.com/rust-lang/rust/issues/57742> for more information",
);
store.register_removed(
"incoherent_fundamental_impls",
"converted into hard error, see issue #46205 \
<https://github.com/rust-lang/rust/issues/46205> for more information",
);
store.register_removed(
"legacy_constructor_visibility",
"converted into hard error, see issue #39207 \
<https://github.com/rust-lang/rust/issues/39207> for more information",
);
store.register_removed(
"legacy_directory_ownership",
"converted into hard error, see issue #37872 \
<https://github.com/rust-lang/rust/issues/37872> for more information",
);
store.register_removed(
"safe_extern_statics",
"converted into hard error, see issue #36247 \
<https://github.com/rust-lang/rust/issues/36247> for more information",
);
store.register_removed(
"parenthesized_params_in_types_and_modules",
"converted into hard error, see issue #42238 \
<https://github.com/rust-lang/rust/issues/42238> for more information",
);
store.register_removed(
"duplicate_macro_exports",
"converted into hard error, see issue #35896 \
<https://github.com/rust-lang/rust/issues/35896> for more information",
);
store.register_removed(
"nested_impl_trait",
"converted into hard error, see issue #59014 \
<https://github.com/rust-lang/rust/issues/59014> for more information",
);
store.register_removed("plugin_as_library", "plugins have been deprecated and retired");
}
fn register_internals(store: &mut LintStore) {
store.register_lints(&DefaultHashTypes::get_lints());
store.register_early_pass(|| box DefaultHashTypes::new());
store.register_lints(&LintPassImpl::get_lints());
store.register_early_pass(|| box LintPassImpl);
store.register_lints(&ExistingDocKeyword::get_lints());
store.register_late_pass(|| box ExistingDocKeyword);
store.register_lints(&TyTyKind::get_lints());
store.register_late_pass(|| box TyTyKind);
store.register_group(
false,
"rustc::internal",
None,
vec![
LintId::of(DEFAULT_HASH_TYPES),
LintId::of(USAGE_OF_TY_TYKIND),
LintId::of(LINT_PASS_IMPL_WITHOUT_MACRO),
LintId::of(TY_PASS_BY_REFERENCE),
LintId::of(USAGE_OF_QUALIFIED_TY),
LintId::of(EXISTING_DOC_KEYWORD),
],
);
}