Crate rustc_lint

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 LintPasses 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 external lint plugins, as is done for Clippy.

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.

Re-exports

• pub use builtin::MissingDoc;
• pub use builtin::SoftLints;
• pub use rustc_session::lint::Level::*;

Modules

• async_closures 🔒
• async_fn_in_trait 🔒
• builtin
  Lints in the Rust compiler.
• context 🔒
  Implementation of lint checking.
• deref_into_dyn_supertrait 🔒
• drop_forget_useless 🔒
• early 🔒
  Implementation of lint checking.
• enum_intrinsics_non_enums 🔒
• errors 🔒
• expect 🔒
• for_loops_over_fallibles 🔒
• foreign_modules 🔒
• hidden_unicode_codepoints
• if_let_rescope 🔒
• impl_trait_overcaptures 🔒
• internal 🔒
  Some lints that are only useful in the compiler or crates that use compiler internals, such as Clippy.
• invalid_from_utf8 🔒
• late 🔒
  Implementation of lint checking.
• let_underscore 🔒
• levels 🔒
• lints 🔒
• macro_expr_fragment_specifier_2024_migration 🔒
  Migration code for the expr_fragment_specifier_2024 rule.
• map_unit_fn 🔒
• methods 🔒
• multiple_supertrait_upcastable 🔒
• non_ascii_idents 🔒
• non_fmt_panic 🔒
• non_local_def 🔒
• nonstandard_style 🔒
• noop_method_call 🔒
• opaque_hidden_inferred_bound 🔒
• pass_by_value 🔒
• passes 🔒
• precedence 🔒
• ptr_nulls 🔒
• redundant_semicolon 🔒
• reference_casting 🔒
• shadowed_into_iter 🔒
• static_mut_refs 🔒
• tail_expr_drop_order 🔒
• traits 🔒
• types 🔒
• unit_bindings 🔒
• unqualified_local_imports 🔒
• unused 🔒

Macros

• declare_combined_early_lint_pass
  Combines multiple lints passes into a single lint pass, at compile time, for maximum speed. Each check_foo method in $methods within this pass simply calls check_foo once per $pass. Compare with EarlyLintPassObjects, which is similar, but combines lint passes at runtime.
• declare_combined_late_lint_pass
  Combines multiple lints passes into a single lint pass, at compile time, for maximum speed. Each check_foo method in $methods within this pass simply calls check_foo once per $pass. Compare with LateLintPassObjects, which is similar, but combines lint passes at runtime.
• early_lint_methods
• expand_combined_early_lint_pass_method
• expand_combined_early_lint_pass_methods
• expand_combined_late_lint_pass_method
• expand_combined_late_lint_pass_methods
• late_lint_methods

Structs

• BufferedEarlyLint
  Lints that are buffered up early on in the Session before the LintLevels is calculated.
• BuiltinCombinedEarlyLintPass
• BuiltinCombinedModuleLateLintPass 🔒
• BuiltinCombinedPreExpansionLintPass
• EarlyContext
  Context for lint checking of the AST, after expansion, before lowering to HIR.
• FutureIncompatibleInfo
  Extra information for a future incompatibility lint.
• LateContext
  Context for lint checking outside of type inference.
• Lint
  Specification of a single lint.
• LintId
  Identifies a lint known to the compiler.
• LintStore
  Information about the registered lints.

Enums

• CheckLintNameResult
• FindLintError
• Level
  Setting for how to handle a lint.

Statics

• ARRAY_INTO_ITER
  The array_into_iter lint detects calling into_iter on arrays.
• BOXED_SLICE_INTO_ITER
  The boxed_slice_into_iter lint detects calling into_iter on boxed slices.
• DEFAULT_LOCALE_RESOURCE
  Raw content of Fluent resource for this crate, generated by fluent_messages macro, imported by rustc_driver to include all crates’ resources in one bundle.

Traits

• EarlyCheckNode
  Early lints work on different nodes - either on the crate root, or on freshly loaded modules. This trait generalizes over those nodes.
• EarlyLintPass
• LateLintPass
• LintContext
• LintPass

Functions

• check_ast_node
• check_crate
  Performs lint checking on a crate.
• late_lint_mod
• lint_mod 🔒
• new_lint_store
• provide
• register_builtins 🔒
  Tell the LintStore about all the built-in lints (the ones defined in this crate and the ones defined in rustc_session::lint::builtin).
• register_internals 🔒
• unerased_lint_store
  Extract the LintStore from Session.

Type Aliases

• LintVec