102 lines
2.5 KiB
Rust
102 lines
2.5 KiB
Rust
// aux-build:proc_macro_derive.rs
|
|
|
|
#![warn(clippy::all)]
|
|
#![allow(clippy::blacklisted_name)]
|
|
#![warn(clippy::used_underscore_binding)]
|
|
|
|
#[macro_use]
|
|
extern crate proc_macro_derive;
|
|
|
|
// This should not trigger the lint. There's underscore binding inside the external derive that
|
|
// would trigger the `used_underscore_binding` lint.
|
|
#[derive(DeriveSomething)]
|
|
struct Baz;
|
|
|
|
macro_rules! test_macro {
|
|
() => {{
|
|
let _foo = 42;
|
|
_foo + 1
|
|
}};
|
|
}
|
|
|
|
/// Tests that we lint if we use a binding with a single leading underscore
|
|
fn prefix_underscore(_foo: u32) -> u32 {
|
|
_foo + 1
|
|
}
|
|
|
|
/// Tests that we lint if we use a `_`-variable defined outside within a macro expansion
|
|
fn in_macro_or_desugar(_foo: u32) {
|
|
println!("{}", _foo);
|
|
assert_eq!(_foo, _foo);
|
|
|
|
test_macro!() + 1;
|
|
}
|
|
|
|
// Struct for testing use of fields prefixed with an underscore
|
|
struct StructFieldTest {
|
|
_underscore_field: u32,
|
|
}
|
|
|
|
/// Tests that we lint the use of a struct field which is prefixed with an underscore
|
|
fn in_struct_field() {
|
|
let mut s = StructFieldTest { _underscore_field: 0 };
|
|
s._underscore_field += 1;
|
|
}
|
|
|
|
/// Tests that we do not lint if the underscore is not a prefix
|
|
fn non_prefix_underscore(some_foo: u32) -> u32 {
|
|
some_foo + 1
|
|
}
|
|
|
|
/// Tests that we do not lint if we do not use the binding (simple case)
|
|
fn unused_underscore_simple(_foo: u32) -> u32 {
|
|
1
|
|
}
|
|
|
|
/// Tests that we do not lint if we do not use the binding (complex case). This checks for
|
|
/// compatibility with the built-in `unused_variables` lint.
|
|
fn unused_underscore_complex(mut _foo: u32) -> u32 {
|
|
_foo += 1;
|
|
_foo = 2;
|
|
1
|
|
}
|
|
|
|
/// Test that we do not lint for multiple underscores
|
|
fn multiple_underscores(__foo: u32) -> u32 {
|
|
__foo + 1
|
|
}
|
|
|
|
// Non-variable bindings with preceding underscore
|
|
fn _fn_test() {}
|
|
struct _StructTest;
|
|
enum _EnumTest {
|
|
_Empty,
|
|
_Value(_StructTest),
|
|
}
|
|
|
|
/// Tests that we do not lint for non-variable bindings
|
|
fn non_variables() {
|
|
_fn_test();
|
|
let _s = _StructTest;
|
|
let _e = match _EnumTest::_Value(_StructTest) {
|
|
_EnumTest::_Empty => 0,
|
|
_EnumTest::_Value(_st) => 1,
|
|
};
|
|
let f = _fn_test;
|
|
f();
|
|
}
|
|
|
|
fn main() {
|
|
let foo = 0u32;
|
|
// tests of unused_underscore lint
|
|
let _ = prefix_underscore(foo);
|
|
in_macro_or_desugar(foo);
|
|
in_struct_field();
|
|
// possible false positives
|
|
let _ = non_prefix_underscore(foo);
|
|
let _ = unused_underscore_simple(foo);
|
|
let _ = unused_underscore_complex(foo);
|
|
let _ = multiple_underscores(foo);
|
|
non_variables();
|
|
}
|