diff options
| -rw-r--r-- | CHANGELOG.md | 1 | ||||
| -rw-r--r-- | clippy_lints/src/declared_lints.rs | 1 | ||||
| -rw-r--r-- | clippy_lints/src/misc.rs | 174 | ||||
| -rw-r--r-- | tests/ui/used_underscore_binding.stderr | 24 | ||||
| -rw-r--r-- | tests/ui/used_underscore_items.rs | 51 | ||||
| -rw-r--r-- | tests/ui/used_underscore_items.stderr | 112 |
6 files changed, 308 insertions, 55 deletions
diff --git a/CHANGELOG.md b/CHANGELOG.md index fddc2fd994e..2ba323997cf 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -6012,6 +6012,7 @@ Released 2018-09-13 [`use_debug`]: https://rust-lang.github.io/rust-clippy/master/index.html#use_debug [`use_self`]: https://rust-lang.github.io/rust-clippy/master/index.html#use_self [`used_underscore_binding`]: https://rust-lang.github.io/rust-clippy/master/index.html#used_underscore_binding +[`used_underscore_items`]: https://rust-lang.github.io/rust-clippy/master/index.html#used_underscore_items [`useless_asref`]: https://rust-lang.github.io/rust-clippy/master/index.html#useless_asref [`useless_attribute`]: https://rust-lang.github.io/rust-clippy/master/index.html#useless_attribute [`useless_conversion`]: https://rust-lang.github.io/rust-clippy/master/index.html#useless_conversion diff --git a/clippy_lints/src/declared_lints.rs b/clippy_lints/src/declared_lints.rs index 8754a4dff87..8d8b9056404 100644 --- a/clippy_lints/src/declared_lints.rs +++ b/clippy_lints/src/declared_lints.rs @@ -485,6 +485,7 @@ pub static LINTS: &[&crate::LintInfo] = &[ crate::misc::SHORT_CIRCUIT_STATEMENT_INFO, crate::misc::TOPLEVEL_REF_ARG_INFO, crate::misc::USED_UNDERSCORE_BINDING_INFO, + crate::misc::USED_UNDERSCORE_ITEMS_INFO, crate::misc_early::BUILTIN_TYPE_SHADOW_INFO, crate::misc_early::DOUBLE_NEG_INFO, crate::misc_early::DUPLICATE_UNDERSCORE_ARGUMENT_INFO, diff --git a/clippy_lints/src/misc.rs b/clippy_lints/src/misc.rs index a9aafe7ed56..3fc3f2b3b7f 100644 --- a/clippy_lints/src/misc.rs +++ b/clippy_lints/src/misc.rs @@ -82,6 +82,45 @@ declare_clippy_lint! { declare_clippy_lint! { /// ### What it does + /// Checks for the use of item with a single leading + /// underscore. + /// + /// ### Why is this bad? + /// A single leading underscore is usually used to indicate + /// that a item will not be used. Using such a item breaks this + /// expectation. + /// + /// ### Example + /// ```no_run + /// fn _foo() {} + /// + /// struct _FooStruct {} + /// + /// fn main() { + /// _foo(); + /// let _ = _FooStruct{}; + /// } + /// ``` + /// + /// Use instead: + /// ```no_run + /// fn foo() {} + /// + /// struct FooStruct {} + /// + /// fn main() { + /// foo(); + /// let _ = FooStruct{}; + /// } + /// ``` + #[clippy::version = "pre 1.29.0"] + pub USED_UNDERSCORE_ITEMS, + pedantic, + "using a item which is prefixed with an underscore" +} + +declare_clippy_lint! { + /// ### What it does /// Checks for the use of short circuit boolean conditions as /// a /// statement. @@ -104,6 +143,7 @@ declare_clippy_lint! { declare_lint_pass!(LintPass => [ TOPLEVEL_REF_ARG, USED_UNDERSCORE_BINDING, + USED_UNDERSCORE_ITEMS, SHORT_CIRCUIT_STATEMENT, ]); @@ -205,51 +245,99 @@ impl<'tcx> LateLintPass<'tcx> for LintPass { { return; } - let (definition_hir_id, ident) = match expr.kind { - ExprKind::Path(ref qpath) => { - if let QPath::Resolved(None, path) = qpath - && let Res::Local(id) = path.res - && is_used(cx, expr) - { - (id, last_path_segment(qpath).ident) - } else { - return; - } - }, - ExprKind::Field(recv, ident) => { - if let Some(adt_def) = cx.typeck_results().expr_ty_adjusted(recv).ty_adt_def() - && let Some(field) = adt_def.all_fields().find(|field| field.name == ident.name) - && let Some(local_did) = field.did.as_local() - && !cx.tcx.type_of(field.did).skip_binder().is_phantom_data() - { - (cx.tcx.local_def_id_to_hir_id(local_did), ident) - } else { - return; - } + + used_underscore_binding(cx, expr); + used_underscore_items(cx, expr); + } +} + +fn used_underscore_items<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) { + let (def_id, ident) = match expr.kind { + ExprKind::Call(func, ..) => { + if let ExprKind::Path(QPath::Resolved(.., path)) = func.kind + && let Some(last_segment) = path.segments.last() + && let Res::Def(_, def_id) = last_segment.res + { + (def_id, last_segment.ident) + } else { + return; + } + }, + ExprKind::MethodCall(path, ..) => { + if let Some(def_id) = cx.typeck_results().type_dependent_def_id(expr.hir_id) { + (def_id, path.ident) + } else { + return; + } + }, + ExprKind::Struct(QPath::Resolved(_, path), ..) => { + if let Some(last_segment) = path.segments.last() + && let Res::Def(_, def_id) = last_segment.res + { + (def_id, last_segment.ident) + } else { + return; + } + }, + _ => return, + }; + let name = ident.name.as_str(); + let definition_span = cx.tcx.def_span(def_id); + if name.starts_with('_') && !name.starts_with("__") && !definition_span.from_expansion() { + span_lint_and_then( + cx, + USED_UNDERSCORE_ITEMS, + expr.span, + "used underscore-prefixed item".to_string(), + |diag| { + diag.span_note(definition_span, "item is defined here".to_string()); }, - _ => return, - }; + ); + } +} - let name = ident.name.as_str(); - if name.starts_with('_') - && !name.starts_with("__") - && let definition_span = cx.tcx.hir().span(definition_hir_id) - && !definition_span.from_expansion() - && !fulfill_or_allowed(cx, USED_UNDERSCORE_BINDING, [expr.hir_id, definition_hir_id]) - { - span_lint_and_then( - cx, - USED_UNDERSCORE_BINDING, - expr.span, - format!( - "used binding `{name}` which is prefixed with an underscore. A leading \ - underscore signals that a binding will not be used" - ), - |diag| { - diag.span_note(definition_span, format!("`{name}` is defined here")); - }, - ); - } +fn used_underscore_binding<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) { + let (definition_hir_id, ident) = match expr.kind { + ExprKind::Path(ref qpath) => { + if let QPath::Resolved(None, path) = qpath + && let Res::Local(id) = path.res + && is_used(cx, expr) + { + (id, last_path_segment(qpath).ident) + } else { + return; + } + }, + ExprKind::Field(recv, ident) => { + if let Some(adt_def) = cx.typeck_results().expr_ty_adjusted(recv).ty_adt_def() + && let Some(field) = adt_def.all_fields().find(|field| field.name == ident.name) + && let Some(local_did) = field.did.as_local() + && !cx.tcx.type_of(field.did).skip_binder().is_phantom_data() + { + (cx.tcx.local_def_id_to_hir_id(local_did), ident) + } else { + return; + } + }, + _ => return, + }; + + let name = ident.name.as_str(); + if name.starts_with('_') + && !name.starts_with("__") + && let definition_span = cx.tcx.hir().span(definition_hir_id) + && !definition_span.from_expansion() + && !fulfill_or_allowed(cx, USED_UNDERSCORE_BINDING, [expr.hir_id, definition_hir_id]) + { + span_lint_and_then( + cx, + USED_UNDERSCORE_BINDING, + expr.span, + "used underscore-prefixed binding".to_string(), + |diag| { + diag.span_note(definition_span, "binding is defined here".to_string()); + }, + ); } } diff --git a/tests/ui/used_underscore_binding.stderr b/tests/ui/used_underscore_binding.stderr index 556e1792b3e..f9e8013d3ad 100644 --- a/tests/ui/used_underscore_binding.stderr +++ b/tests/ui/used_underscore_binding.stderr @@ -1,10 +1,10 @@ -error: used binding `_foo` which is prefixed with an underscore. A leading underscore signals that a binding will not be used +error: used underscore-prefixed binding --> tests/ui/used_underscore_binding.rs:23:5 | LL | _foo + 1 | ^^^^ | -note: `_foo` is defined here +note: binding is defined here --> tests/ui/used_underscore_binding.rs:22:22 | LL | fn prefix_underscore(_foo: u32) -> u32 { @@ -12,61 +12,61 @@ LL | fn prefix_underscore(_foo: u32) -> u32 { = note: `-D clippy::used-underscore-binding` implied by `-D warnings` = help: to override `-D warnings` add `#[allow(clippy::used_underscore_binding)]` -error: used binding `_foo` which is prefixed with an underscore. A leading underscore signals that a binding will not be used +error: used underscore-prefixed binding --> tests/ui/used_underscore_binding.rs:28:20 | LL | println!("{}", _foo); | ^^^^ | -note: `_foo` is defined here +note: binding is defined here --> tests/ui/used_underscore_binding.rs:27:24 | LL | fn in_macro_or_desugar(_foo: u32) { | ^^^^ -error: used binding `_foo` which is prefixed with an underscore. A leading underscore signals that a binding will not be used +error: used underscore-prefixed binding --> tests/ui/used_underscore_binding.rs:29:16 | LL | assert_eq!(_foo, _foo); | ^^^^ | -note: `_foo` is defined here +note: binding is defined here --> tests/ui/used_underscore_binding.rs:27:24 | LL | fn in_macro_or_desugar(_foo: u32) { | ^^^^ -error: used binding `_foo` which is prefixed with an underscore. A leading underscore signals that a binding will not be used +error: used underscore-prefixed binding --> tests/ui/used_underscore_binding.rs:29:22 | LL | assert_eq!(_foo, _foo); | ^^^^ | -note: `_foo` is defined here +note: binding is defined here --> tests/ui/used_underscore_binding.rs:27:24 | LL | fn in_macro_or_desugar(_foo: u32) { | ^^^^ -error: used binding `_underscore_field` which is prefixed with an underscore. A leading underscore signals that a binding will not be used +error: used underscore-prefixed binding --> tests/ui/used_underscore_binding.rs:42:5 | LL | s._underscore_field += 1; | ^^^^^^^^^^^^^^^^^^^ | -note: `_underscore_field` is defined here +note: binding is defined here --> tests/ui/used_underscore_binding.rs:36:5 | LL | _underscore_field: u32, | ^^^^^^^^^^^^^^^^^^^^^^ -error: used binding `_i` which is prefixed with an underscore. A leading underscore signals that a binding will not be used +error: used underscore-prefixed binding --> tests/ui/used_underscore_binding.rs:103:16 | LL | uses_i(_i); | ^^ | -note: `_i` is defined here +note: binding is defined here --> tests/ui/used_underscore_binding.rs:102:13 | LL | let _i = 5; diff --git a/tests/ui/used_underscore_items.rs b/tests/ui/used_underscore_items.rs new file mode 100644 index 00000000000..6b2ca44e32c --- /dev/null +++ b/tests/ui/used_underscore_items.rs @@ -0,0 +1,51 @@ +#![allow(unused)] +#![warn(clippy::used_underscore_items)] + +// should not lint macro +macro_rules! macro_wrap_func { + () => { + fn _marco_foo() {} + }; +} + +macro_wrap_func!(); + +struct _FooStruct {} + +impl _FooStruct { + fn _method_call(self) {} +} + +fn _foo1() {} + +fn _foo2() -> i32 { + 0 +} + +mod a { + pub mod b { + pub mod c { + pub fn _foo3() {} + + pub struct _FooStruct2 {} + + impl _FooStruct2 { + pub fn _method_call(self) {} + } + } + } +} + +fn main() { + _foo1(); + let _ = _foo2(); + a::b::c::_foo3(); + let _ = &_FooStruct {}; + let _ = _FooStruct {}; + + let foo_struct = _FooStruct {}; + foo_struct._method_call(); + + let foo_struct2 = a::b::c::_FooStruct2 {}; + foo_struct2._method_call(); +} diff --git a/tests/ui/used_underscore_items.stderr b/tests/ui/used_underscore_items.stderr new file mode 100644 index 00000000000..127d8248a94 --- /dev/null +++ b/tests/ui/used_underscore_items.stderr @@ -0,0 +1,112 @@ +error: used underscore-prefixed item + --> tests/ui/used_underscore_items.rs:40:5 + | +LL | _foo1(); + | ^^^^^^^ + | +note: item is defined here + --> tests/ui/used_underscore_items.rs:19:1 + | +LL | fn _foo1() {} + | ^^^^^^^^^^ + = note: `-D clippy::used-underscore-items` implied by `-D warnings` + = help: to override `-D warnings` add `#[allow(clippy::used_underscore_items)]` + +error: used underscore-prefixed item + --> tests/ui/used_underscore_items.rs:41:13 + | +LL | let _ = _foo2(); + | ^^^^^^^ + | +note: item is defined here + --> tests/ui/used_underscore_items.rs:21:1 + | +LL | fn _foo2() -> i32 { + | ^^^^^^^^^^^^^^^^^ + +error: used underscore-prefixed item + --> tests/ui/used_underscore_items.rs:42:5 + | +LL | a::b::c::_foo3(); + | ^^^^^^^^^^^^^^^^ + | +note: item is defined here + --> tests/ui/used_underscore_items.rs:28:13 + | +LL | pub fn _foo3() {} + | ^^^^^^^^^^^^^^ + +error: used underscore-prefixed item + --> tests/ui/used_underscore_items.rs:43:14 + | +LL | let _ = &_FooStruct {}; + | ^^^^^^^^^^^^^ + | +note: item is defined here + --> tests/ui/used_underscore_items.rs:13:1 + | +LL | struct _FooStruct {} + | ^^^^^^^^^^^^^^^^^ + +error: used underscore-prefixed item + --> tests/ui/used_underscore_items.rs:44:13 + | +LL | let _ = _FooStruct {}; + | ^^^^^^^^^^^^^ + | +note: item is defined here + --> tests/ui/used_underscore_items.rs:13:1 + | +LL | struct _FooStruct {} + | ^^^^^^^^^^^^^^^^^ + +error: used underscore-prefixed item + --> tests/ui/used_underscore_items.rs:46:22 + | +LL | let foo_struct = _FooStruct {}; + | ^^^^^^^^^^^^^ + | +note: item is defined here + --> tests/ui/used_underscore_items.rs:13:1 + | +LL | struct _FooStruct {} + | ^^^^^^^^^^^^^^^^^ + +error: used underscore-prefixed item + --> tests/ui/used_underscore_items.rs:47:5 + | +LL | foo_struct._method_call(); + | ^^^^^^^^^^^^^^^^^^^^^^^^^ + | +note: item is defined here + --> tests/ui/used_underscore_items.rs:16:5 + | +LL | fn _method_call(self) {} + | ^^^^^^^^^^^^^^^^^^^^^ + +error: used underscore-prefixed item + --> tests/ui/used_underscore_items.rs:49:23 + | +LL | let foo_struct2 = a::b::c::_FooStruct2 {}; + | ^^^^^^^^^^^^^^^^^^^^^^^ + | +note: item is defined here + --> tests/ui/used_underscore_items.rs:30:13 + | +LL | pub struct _FooStruct2 {} + | ^^^^^^^^^^^^^^^^^^^^^^ + +error: used underscore-prefixed item + --> tests/ui/used_underscore_items.rs:50:5 + | +LL | foo_struct2._method_call(); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^ + | +note: item is defined here + --> tests/ui/used_underscore_items.rs:33:17 + | +LL | pub fn _method_call(self) {} + | ^^^^^^^^^^^^^^^^^^^^^^^^^ + +error: aborting due to 9 previous errors + |