clippy::disallowed_macros: Denies the configured macros in clippy.toml Note: Even though this lint is warn-by-default, it will only trigger if macros are defined in the clippy.toml file

use serde::Serialize;

println!("warns");

// The diagnostic will contain the message "no serializing"
#[derive(Serialize)]
struct Data {
    name: String,
    value: usize,
}

#[allow(clippy::disallowed_macros)]
fn my_function() { /* ... */ }

[lints.clippy]
disallowed_macros = "allow"

cargo clippy -- -A clippy::disallowed-macros

Clippy's own documentation

What it does

Denies the configured macros in clippy.toml

Note: Even though this lint is warn-by-default, it will only trigger if macros are defined in the clippy.toml file.

Why is this bad?

Some macros are undesirable in certain contexts, and it’s beneficial to lint for them as needed.

Example

An example clippy.toml configuration:

disallowed-macros = [
    # Can use a string as the path of the disallowed macro.
    "std::print",
    # Can also use an inline table with a `path` key.
    { path = "std::println" },
    # When using an inline table, can add a `reason` for why the macro
    # is disallowed.
    { path = "serde::Serialize", reason = "no serializing" },
    # This would normally error if the path is incorrect, but with `allow-invalid` = `true`,
    # it will be silently ignored
    { path = "std::invalid_macro", reason = "use alternative instead", allow-invalid = true }
]

use serde::Serialize;

println!("warns");

// The diagnostic will contain the message "no serializing"
#[derive(Serialize)]
struct Data {
    name: String,
    value: usize,
}

Configuration

• disallowed-macros: The list of disallowed macros, written as fully qualified paths.

Fields:

• path (required): the fully qualified path to the macro that should be disallowed

• reason (optional): explanation why this macro is disallowed

• replacement (optional): suggested alternative macro

• allow-invalid (optional, false by default): when set to true, it will ignore this entry if the path doesn’t exist, instead of emitting an error

  (default: [])

From the Clippy lint list (0.1.99), part of the Rust project, MIT or Apache-2.0. Official entry.

Related lints

• needless_returnunneeded `return` statement
• new_without_defaultChecks for public types with a pub fn new() -> Self method and no implementation of Default
• len_zeroChecks for getting the length of something via .len() just to compare to zero, and suggests using .is_empty() where applicable
• comparison_to_emptyChecks for comparing to an empty slice such as "" or [], and suggests using .is_empty() where applicable
• default_instead_of_iter_empty`std::iter::empty()` is the more idiomatic way
• disallowed_fieldsDenies the configured fields in clippy.toml Note: Even though this lint is warn-by-default, it will only trigger if fields are defined in the clippy.toml file
• disallowed_methodsDenies the configured methods and functions in clippy.toml Note: Even though this lint is warn-by-default, it will only trigger if methods are defined in the clippy.toml file
• disallowed_namesuse of a disallowed/placeholder name `foo`
• disallowed_typesDenies the configured types in clippy.toml. Note: Even though this lint is warn-by-default, it will only trigger if types are defined in the clippy.toml file

All 847 Clippy lints · Rust compiler errors · Cargo.toml checker