5 #![allow(blacklisted_name)]
6 #![deny(used_underscore_binding)]
8 /// Test that we lint if we use a binding with a single leading underscore
9 fn prefix_underscore(_foo: u32) -> u32 {
10 _foo + 1 //~ ERROR used binding `_foo` which is prefixed with an underscore
13 /// Test that we lint even if the use is within a macro expansion
14 fn in_macro(_foo: u32) {
15 println!("{}", _foo); //~ ERROR used binding `_foo` which is prefixed with an underscore
18 // Struct for testing use of fields prefixed with an underscore
19 struct StructFieldTest {
20 _underscore_field: u32,
23 /// Test that we lint the use of a struct field which is prefixed with an underscore
24 fn in_struct_field() {
25 let mut s = StructFieldTest { _underscore_field: 0 };
26 s._underscore_field += 1; //~ Error used binding `_underscore_field` which is prefixed with an underscore
29 /// Test that we do not lint if the underscore is not a prefix
30 fn non_prefix_underscore(some_foo: u32) -> u32 {
34 /// Test that we do not lint if we do not use the binding (simple case)
35 fn unused_underscore_simple(_foo: u32) -> u32 {
39 /// Test that we do not lint if we do not use the binding (complex case). This checks for
40 /// compatibility with the built-in `unused_variables` lint.
41 fn unused_underscore_complex(mut _foo: u32) -> u32 {
47 ///Test that we do not lint for multiple underscores
48 fn multiple_underscores(__foo: u32) -> u32 {
52 // Non-variable bindings with preceding underscore
60 /// Test that we do not lint for non-variable bindings
64 let _e = match _EnumTest::_Value(_StructTest) {
65 _EnumTest::_Empty => 0,
66 _EnumTest::_Value(_st) => 1,
74 // tests of unused_underscore lint
75 let _ = prefix_underscore(foo);
78 // possible false positives
79 let _ = non_prefix_underscore(foo);
80 let _ = unused_underscore_simple(foo);
81 let _ = unused_underscore_complex(foo);
82 let _ = multiple_underscores(foo);