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Some lints that are built in to the compiler.

These are the built-in lints that are emitted direct in the main compiler code, rather than using their own custom pass. Those lints are all available in rustc_lint::builtin.


Does nothing as a lint pass, but registers some Lints that are used by other parts of the compiler.


The absolute_paths_not_starting_with_crate lint detects fully qualified paths that start with a module name instead of crate, self, or an extern crate name
The ambiguous_associated_items lint detects ambiguity between associated items and enum variants.
The arithmetic_overflow lint detects that an arithmetic operation will overflow.
The asm_sub_register lint detects using only a subset of a register for inline asm inputs.
The bad_asm_style lint detects the use of the .intel_syntax and .att_syntax directives.
The bare_trait_objects lint suggests using dyn Trait for trait objects.
The bindings_with_variant_name lint detects pattern bindings with the same name as one of the matched variants.
The break_with_label_and_loop lint detects labeled break expressions with an unlabeled loop as their value expression.
The cenum_impl_drop_cast lint detects an as cast of a field-less enum that implements Drop.
The coherence_leak_check lint detects conflicting implementations of a trait that are only distinguished by the old leak-check code.
The conflicting_repr_hints lint detects repr attributes with conflicting hints.
The const_evaluatable_unchecked lint detects a generic constant used in a type.
The const_item_mutation lint detects attempts to mutate a const item.
The dead_code lint detects unused, unexported items.
The deprecated lint detects use of deprecated items.
The deprecated_cfg_attr_crate_type_name lint detects uses of the #![cfg_attr(..., crate_type = "...")] and #![cfg_attr(..., crate_name = "...")] attributes to conditionally specify the crate type and name in the source code.
The deprecated_in_future lint is internal to rustc and should not be used by user code.
The deprecated_where_clause_location lint detects when a where clause in front of the equals in an associated type.
The duplicate_macro_attributes lint detects when a #[test]-like built-in macro attribute is duplicated on an item. This lint may trigger on bench, cfg_eval, test and test_case.
The elided_lifetimes_in_paths lint detects the use of hidden lifetime parameters.
The explicit_outlives_requirements lint detects unnecessary lifetime bounds that can be inferred.
The exported_private_dependencies lint detects private dependencies that are exposed in a public interface.
The ffi_unwind_calls lint detects calls to foreign functions or function pointers with C-unwind or other FFI-unwind ABIs.
The forbidden_lint_groups lint detects violations of forbid applied to a lint group. Due to a bug in the compiler, these used to be overlooked entirely. They now generate a warning.
The function_item_references lint detects function references that are formatted with fmt::Pointer or transmuted.
The fuzzy_provenance_casts lint detects an as cast between an integer and a pointer.
The illegal_floating_point_literal_pattern lint detects floating-point literals used in patterns.
The ill_formed_attribute_input lint detects ill-formed attribute inputs that were previously accepted and used in practice.
The implied_bounds_entailment lint detects cases where the arguments of an impl method have stronger implied bounds than those from the trait method it’s implementing.
The incomplete_include lint detects the use of the include! macro with a file that contains more than one expression.
The indirect_structural_match lint detects a const in a pattern that manually implements PartialEq and Eq.
The ineffective_unstable_trait_impl lint detects #[unstable] attributes which are not used.
The inline_no_sanitize lint detects incompatible use of #[inline(always)] and #[no_sanitize(...)].
The invalid_alignment lint detects dereferences of misaligned pointers during constant evluation.
The invalid_doc_attributes lint detects when the #[doc(...)] is misused.
The invalid_type_param_default lint detects type parameter defaults erroneously allowed in an invalid location.
The irrefutable_let_patterns lint detects irrefutable patterns in if lets, while lets, and if let guards.
The large_assignments lint detects when objects of large types are being moved around.
The late_bound_lifetime_arguments lint detects generic lifetime arguments in path segments with late bound lifetime parameters.
The legacy_derive_helpers lint detects derive helper attributes that are used before they are introduced.
The lossy_provenance_casts lint detects an as cast between a pointer and an integer.
The macro_expanded_macro_exports_accessed_by_absolute_paths lint detects macro-expanded macro_export macros from the current crate that cannot be referred to by absolute paths.
The macro_use_extern_crate lint detects the use of the macro_use attribute.
The meta_variable_misuse lint detects possible meta-variable misuse in macro definitions.
The missing_abi lint detects cases where the ABI is omitted from extern declarations.
The missing_fragment_specifier lint is issued when an unused pattern in a macro_rules! macro definition has a meta-variable (e.g. $e) that is not followed by a fragment specifier (e.g. :expr).
The must_not_suspend lint guards against values that shouldn’t be held across suspend points (.await)
The named_arguments_used_positionally lint detects cases where named arguments are only used positionally in format strings. This usage is valid but potentially very confusing.
The nontrivial_structural_match lint detects constants that are used in patterns, whose type is not structural-match and whose initializer body actually uses values that are not structural-match. So Option<NotStructuralMatch> is ok if the constant is just None.
The non_exhaustive_omitted_patterns lint detects when a wildcard (_ or ..) in a pattern for a #[non_exhaustive] struct or enum is reachable.
The order_dependent_trait_objects lint detects a trait coherency violation that would allow creating two trait impls for the same dynamic trait object involving marker traits.
The overlapping_range_endpoints lint detects match arms that have range patterns that overlap on their endpoints.
The patterns_in_fns_without_body lint detects mut identifier patterns as a parameter in functions without a body.
The pointer_structural_match lint detects pointers used in patterns whose behaviour cannot be relied upon across compiler versions and optimization levels.
The private_in_public lint detects private items in public interfaces not caught by the old implementation.
The proc_macro_back_compat lint detects uses of old versions of certain proc-macro crates, which have hardcoded workarounds in the compiler.
The proc_macro_derive_resolution_fallback lint detects proc macro derives using inaccessible names from parent modules.
The pub_use_of_private_extern_crate lint detects a specific situation of re-exporting a private extern crate.
The renamed_and_removed_lints lint detects lints that have been renamed or removed.
The repr_transparent_external_private_fields lint detects types marked #[repr(transparent)] that (transitively) contain an external ZST type marked #[non_exhaustive] or containing private fields
The rust_2021_incompatible_closure_captures lint detects variables that aren’t completely captured in Rust 2021, such that the Drop order of their fields may differ between Rust 2018 and 2021.
The rust_2021_incompatible_or_patterns lint detects usage of old versions of or-patterns.
The rust_2021_prefixes_incompatible_syntax lint detects identifiers that will be parsed as a prefix instead in Rust 2021.
The rust_2021_prelude_collisions lint detects the usage of trait methods which are ambiguous with traits added to the prelude in future editions.
The semicolon_in_expressions_from_macros lint detects trailing semicolons in macro bodies when the macro is invoked in expression position. This was previous accepted, but is being phased out.
The single_use_lifetimes lint detects lifetimes that are only used once.
The soft_unstable lint detects unstable features that were unintentionally allowed on stable.
The stable_features lint detects a feature attribute that has since been made stable.
The suspicious_auto_trait_impls lint checks for potentially incorrect implementations of auto traits.
The test_unstable_lint lint tests unstable lints and is perma-unstable.
The text_direction_codepoint_in_comment lint detects Unicode codepoints in comments that change the visual representation of text on screen in a way that does not correspond to their on memory representation.
The trivial_casts lint detects trivial casts which could be replaced with coercion, which may require a temporary variable.
The trivial_numeric_casts lint detects trivial numeric casts of types which could be removed.
The tyvar_behind_raw_pointer lint detects raw pointer to an inference variable.
The unaligned_references lint detects unaligned references to fields of packed structs.
The unconditional_panic lint detects an operation that will cause a panic at runtime.
The unconditional_recursion lint detects functions that cannot return without calling themselves.
The undefined_naked_function_abi lint detects naked function definitions that either do not specify an ABI or specify the Rust ABI.
The unexpected_cfgs lint detects unexpected conditional compilation conditions.
The unfulfilled_lint_expectations lint detects lint trigger expectations that have not been fulfilled.
The uninhabited_static lint detects uninhabited statics.
The unknown_crate_types lint detects an unknown crate type found in a crate_type attribute.
The unknown_lints lint detects unrecognized lint attributes.
The unreachable_code lint detects unreachable code paths.
The unreachable_patterns lint detects unreachable patterns.
The unsafe_op_in_unsafe_fn lint detects unsafe operations in unsafe functions without an explicit unsafe block.
The unstable_name_collisions lint detects that you have used a name that the standard library plans to add in the future.
The unstable_syntax_pre_expansion lint detects the use of unstable syntax that is discarded during attribute expansion.
The unsupported_calling_conventions lint is output whenever there is a use of the stdcall, fastcall, thiscall, vectorcall calling conventions (or their unwind variants) on targets that cannot meaningfully be supported for the requested target.
The unused_assignments lint detects assignments that will never be read.
The unused_attributes lint detects attributes that were not used by the compiler.
The unused_crate_dependencies lint detects crate dependencies that are never used.
The unused_doc_comments lint detects doc comments that aren’t used by rustdoc.
The unused_extern_crates lint guards against extern crate items that are never used.
The unused_features lint detects unused or unknown features found in crate-level feature attributes.
The unused_imports lint detects imports that are never used.
The unused_labels lint detects labels that are never used.
The unused_lifetimes lint detects lifetime parameters that are never used.
The unused_macros lint detects macros that were not used.
The unused_macro_rules lint detects macro rules that were not used.
The unused_mut lint detects mut variables which don’t need to be mutable.
The unused_qualifications lint detects unnecessarily qualified names.
The unused_tuple_struct_fields lint detects fields of tuple structs that are never read.
The unused_unsafe lint detects unnecessary use of an unsafe block.
The unused_variables lint detects variables which are not used in any way.
The useless_deprecated lint detects deprecation attributes with no effect.
The warnings lint allows you to change the level of other lints which produce warnings.
The where_clauses_object_safety lint detects for object safety of where clauses.