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Auto merge of #5437 - rabisg0:should-impl-trait, r=flip1995
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Check fn header along with decl when suggesting to implement trait

When checking for functions that are potential candidates for trait
implementations check the function header to make sure modifiers like
asyncness, constness and safety match before triggering the lint.

Fixes #5413, #4290

changelog: check fn header along with decl for should_implement_trait
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@bors
bors committed Apr 8, 2020
2 parents 7bfdee5 + c2e5534 commit 940bbd6
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Showing 3 changed files with 77 additions and 48 deletions.
84 changes: 49 additions & 35 deletions clippy_lints/src/methods/mod.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1453,11 +1453,12 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Methods {
then {
if cx.access_levels.is_exported(impl_item.hir_id) {
// check missing trait implementations
for &(method_name, n_args, self_kind, out_type, trait_name) in &TRAIT_METHODS {
for &(method_name, n_args, fn_header, self_kind, out_type, trait_name) in &TRAIT_METHODS {
if name == method_name &&
sig.decl.inputs.len() == n_args &&
out_type.matches(cx, &sig.decl.output) &&
self_kind.matches(cx, self_ty, first_arg_ty) {
sig.decl.inputs.len() == n_args &&
out_type.matches(cx, &sig.decl.output) &&
self_kind.matches(cx, self_ty, first_arg_ty) &&
fn_header_equals(*fn_header, sig.header) {
span_lint(cx, SHOULD_IMPLEMENT_TRAIT, impl_item.span, &format!(
"defining a method called `{}` on this type; consider implementing \
the `{}` trait or choosing a less ambiguous name", name, trait_name));
Expand Down Expand Up @@ -3352,38 +3353,45 @@ const CONVENTIONS: [(Convention, &[SelfKind]); 7] = [
(Convention::StartsWith("to_"), &[SelfKind::Ref]),
];

const FN_HEADER: hir::FnHeader = hir::FnHeader {
unsafety: hir::Unsafety::Normal,
constness: hir::Constness::NotConst,
asyncness: hir::IsAsync::NotAsync,
abi: rustc_target::spec::abi::Abi::Rust,
};

#[rustfmt::skip]
const TRAIT_METHODS: [(&str, usize, SelfKind, OutType, &str); 30] = [
("add", 2, SelfKind::Value, OutType::Any, "std::ops::Add"),
("as_mut", 1, SelfKind::RefMut, OutType::Ref, "std::convert::AsMut"),
("as_ref", 1, SelfKind::Ref, OutType::Ref, "std::convert::AsRef"),
("bitand", 2, SelfKind::Value, OutType::Any, "std::ops::BitAnd"),
("bitor", 2, SelfKind::Value, OutType::Any, "std::ops::BitOr"),
("bitxor", 2, SelfKind::Value, OutType::Any, "std::ops::BitXor"),
("borrow", 1, SelfKind::Ref, OutType::Ref, "std::borrow::Borrow"),
("borrow_mut", 1, SelfKind::RefMut, OutType::Ref, "std::borrow::BorrowMut"),
("clone", 1, SelfKind::Ref, OutType::Any, "std::clone::Clone"),
("cmp", 2, SelfKind::Ref, OutType::Any, "std::cmp::Ord"),
("default", 0, SelfKind::No, OutType::Any, "std::default::Default"),
("deref", 1, SelfKind::Ref, OutType::Ref, "std::ops::Deref"),
("deref_mut", 1, SelfKind::RefMut, OutType::Ref, "std::ops::DerefMut"),
("div", 2, SelfKind::Value, OutType::Any, "std::ops::Div"),
("drop", 1, SelfKind::RefMut, OutType::Unit, "std::ops::Drop"),
("eq", 2, SelfKind::Ref, OutType::Bool, "std::cmp::PartialEq"),
("from_iter", 1, SelfKind::No, OutType::Any, "std::iter::FromIterator"),
("from_str", 1, SelfKind::No, OutType::Any, "std::str::FromStr"),
("hash", 2, SelfKind::Ref, OutType::Unit, "std::hash::Hash"),
("index", 2, SelfKind::Ref, OutType::Ref, "std::ops::Index"),
("index_mut", 2, SelfKind::RefMut, OutType::Ref, "std::ops::IndexMut"),
("into_iter", 1, SelfKind::Value, OutType::Any, "std::iter::IntoIterator"),
("mul", 2, SelfKind::Value, OutType::Any, "std::ops::Mul"),
("neg", 1, SelfKind::Value, OutType::Any, "std::ops::Neg"),
("next", 1, SelfKind::RefMut, OutType::Any, "std::iter::Iterator"),
("not", 1, SelfKind::Value, OutType::Any, "std::ops::Not"),
("rem", 2, SelfKind::Value, OutType::Any, "std::ops::Rem"),
("shl", 2, SelfKind::Value, OutType::Any, "std::ops::Shl"),
("shr", 2, SelfKind::Value, OutType::Any, "std::ops::Shr"),
("sub", 2, SelfKind::Value, OutType::Any, "std::ops::Sub"),
const TRAIT_METHODS: [(&str, usize, &hir::FnHeader, SelfKind, OutType, &str); 30] = [
("add", 2, &FN_HEADER, SelfKind::Value, OutType::Any, "std::ops::Add"),
("as_mut", 1, &FN_HEADER, SelfKind::RefMut, OutType::Ref, "std::convert::AsMut"),
("as_ref", 1, &FN_HEADER, SelfKind::Ref, OutType::Ref, "std::convert::AsRef"),
("bitand", 2, &FN_HEADER, SelfKind::Value, OutType::Any, "std::ops::BitAnd"),
("bitor", 2, &FN_HEADER, SelfKind::Value, OutType::Any, "std::ops::BitOr"),
("bitxor", 2, &FN_HEADER, SelfKind::Value, OutType::Any, "std::ops::BitXor"),
("borrow", 1, &FN_HEADER, SelfKind::Ref, OutType::Ref, "std::borrow::Borrow"),
("borrow_mut", 1, &FN_HEADER, SelfKind::RefMut, OutType::Ref, "std::borrow::BorrowMut"),
("clone", 1, &FN_HEADER, SelfKind::Ref, OutType::Any, "std::clone::Clone"),
("cmp", 2, &FN_HEADER, SelfKind::Ref, OutType::Any, "std::cmp::Ord"),
("default", 0, &FN_HEADER, SelfKind::No, OutType::Any, "std::default::Default"),
("deref", 1, &FN_HEADER, SelfKind::Ref, OutType::Ref, "std::ops::Deref"),
("deref_mut", 1, &FN_HEADER, SelfKind::RefMut, OutType::Ref, "std::ops::DerefMut"),
("div", 2, &FN_HEADER, SelfKind::Value, OutType::Any, "std::ops::Div"),
("drop", 1, &FN_HEADER, SelfKind::RefMut, OutType::Unit, "std::ops::Drop"),
("eq", 2, &FN_HEADER, SelfKind::Ref, OutType::Bool, "std::cmp::PartialEq"),
("from_iter", 1, &FN_HEADER, SelfKind::No, OutType::Any, "std::iter::FromIterator"),
("from_str", 1, &FN_HEADER, SelfKind::No, OutType::Any, "std::str::FromStr"),
("hash", 2, &FN_HEADER, SelfKind::Ref, OutType::Unit, "std::hash::Hash"),
("index", 2, &FN_HEADER, SelfKind::Ref, OutType::Ref, "std::ops::Index"),
("index_mut", 2, &FN_HEADER, SelfKind::RefMut, OutType::Ref, "std::ops::IndexMut"),
("into_iter", 1, &FN_HEADER, SelfKind::Value, OutType::Any, "std::iter::IntoIterator"),
("mul", 2, &FN_HEADER, SelfKind::Value, OutType::Any, "std::ops::Mul"),
("neg", 1, &FN_HEADER, SelfKind::Value, OutType::Any, "std::ops::Neg"),
("next", 1, &FN_HEADER, SelfKind::RefMut, OutType::Any, "std::iter::Iterator"),
("not", 1, &FN_HEADER, SelfKind::Value, OutType::Any, "std::ops::Not"),
("rem", 2, &FN_HEADER, SelfKind::Value, OutType::Any, "std::ops::Rem"),
("shl", 2, &FN_HEADER, SelfKind::Value, OutType::Any, "std::ops::Shl"),
("shr", 2, &FN_HEADER, SelfKind::Value, OutType::Any, "std::ops::Shr"),
("sub", 2, &FN_HEADER, SelfKind::Value, OutType::Any, "std::ops::Sub"),
];

#[rustfmt::skip]
Expand Down Expand Up @@ -3596,3 +3604,9 @@ fn lint_filetype_is_file(cx: &LateContext<'_, '_>, expr: &hir::Expr<'_>, args: &
let help_msg = format!("use `{}FileType::is_dir()` instead", help_unary);
span_lint_and_help(cx, FILETYPE_IS_FILE, span, &lint_msg, &help_msg);
}

fn fn_header_equals(expected: hir::FnHeader, actual: hir::FnHeader) -> bool {
expected.constness == actual.constness
&& expected.unsafety == actual.unsafety
&& expected.asyncness == actual.asyncness
}
15 changes: 15 additions & 0 deletions tests/ui/methods.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -6,6 +6,7 @@
clippy::blacklisted_name,
clippy::default_trait_access,
clippy::missing_docs_in_private_items,
clippy::missing_safety_doc,
clippy::non_ascii_literal,
clippy::new_without_default,
clippy::needless_pass_by_value,
Expand Down Expand Up @@ -83,6 +84,20 @@ impl T {
}
}

pub struct T1;

impl T1 {
// Shouldn't trigger lint as it is unsafe.
pub unsafe fn add(self, rhs: T1) -> T1 {
self
}

// Should not trigger lint since this is an async function.
pub async fn next(&mut self) -> Option<T1> {
None
}
}

struct Lt<'a> {
foo: &'a u32,
}
Expand Down
26 changes: 13 additions & 13 deletions tests/ui/methods.stderr
View file
Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
error: defining a method called `add` on this type; consider implementing the `std::ops::Add` trait or choosing a less ambiguous name
--> $DIR/methods.rs:38:5
--> $DIR/methods.rs:39:5
|
LL | / pub fn add(self, other: T) -> T {
LL | | self
Expand All @@ -9,7 +9,7 @@ LL | | }
= note: `-D clippy::should-implement-trait` implied by `-D warnings`

error: methods called `new` usually return `Self`
--> $DIR/methods.rs:154:5
--> $DIR/methods.rs:169:5
|
LL | / fn new() -> i32 {
LL | | 0
Expand All @@ -19,7 +19,7 @@ LL | | }
= note: `-D clippy::new-ret-no-self` implied by `-D warnings`

error: called `filter(p).next()` on an `Iterator`. This is more succinctly expressed by calling `.find(p)` instead.
--> $DIR/methods.rs:173:13
--> $DIR/methods.rs:188:13
|
LL | let _ = v.iter().filter(|&x| *x < 0).next();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Expand All @@ -28,7 +28,7 @@ LL | let _ = v.iter().filter(|&x| *x < 0).next();
= note: replace `filter(|&x| *x < 0).next()` with `find(|&x| *x < 0)`

error: called `filter(p).next()` on an `Iterator`. This is more succinctly expressed by calling `.find(p)` instead.
--> $DIR/methods.rs:176:13
--> $DIR/methods.rs:191:13
|
LL | let _ = v.iter().filter(|&x| {
| _____________^
Expand All @@ -38,33 +38,33 @@ LL | | ).next();
| |___________________________^

error: called `is_some()` after searching an `Iterator` with find. This is more succinctly expressed by calling `any()`.
--> $DIR/methods.rs:193:22
--> $DIR/methods.rs:208:22
|
LL | let _ = v.iter().find(|&x| *x < 0).is_some();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `any(|x| *x < 0)`
|
= note: `-D clippy::search-is-some` implied by `-D warnings`

error: called `is_some()` after searching an `Iterator` with find. This is more succinctly expressed by calling `any()`.
--> $DIR/methods.rs:194:20
--> $DIR/methods.rs:209:20
|
LL | let _ = (0..1).find(|x| **y == *x).is_some(); // one dereference less
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `any(|x| **y == x)`

error: called `is_some()` after searching an `Iterator` with find. This is more succinctly expressed by calling `any()`.
--> $DIR/methods.rs:195:20
--> $DIR/methods.rs:210:20
|
LL | let _ = (0..1).find(|x| *x == 0).is_some();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `any(|x| x == 0)`

error: called `is_some()` after searching an `Iterator` with find. This is more succinctly expressed by calling `any()`.
--> $DIR/methods.rs:196:22
--> $DIR/methods.rs:211:22
|
LL | let _ = v.iter().find(|x| **x == 0).is_some();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `any(|x| *x == 0)`

error: called `is_some()` after searching an `Iterator` with find. This is more succinctly expressed by calling `any()`.
--> $DIR/methods.rs:199:13
--> $DIR/methods.rs:214:13
|
LL | let _ = v.iter().find(|&x| {
| _____________^
Expand All @@ -74,13 +74,13 @@ LL | | ).is_some();
| |______________________________^

error: called `is_some()` after searching an `Iterator` with position. This is more succinctly expressed by calling `any()`.
--> $DIR/methods.rs:205:22
--> $DIR/methods.rs:220:22
|
LL | let _ = v.iter().position(|&x| x < 0).is_some();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `any(|&x| x < 0)`

error: called `is_some()` after searching an `Iterator` with position. This is more succinctly expressed by calling `any()`.
--> $DIR/methods.rs:208:13
--> $DIR/methods.rs:223:13
|
LL | let _ = v.iter().position(|&x| {
| _____________^
Expand All @@ -90,13 +90,13 @@ LL | | ).is_some();
| |______________________________^

error: called `is_some()` after searching an `Iterator` with rposition. This is more succinctly expressed by calling `any()`.
--> $DIR/methods.rs:214:22
--> $DIR/methods.rs:229:22
|
LL | let _ = v.iter().rposition(|&x| x < 0).is_some();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try this: `any(|&x| x < 0)`

error: called `is_some()` after searching an `Iterator` with rposition. This is more succinctly expressed by calling `any()`.
--> $DIR/methods.rs:217:13
--> $DIR/methods.rs:232:13
|
LL | let _ = v.iter().rposition(|&x| {
| _____________^
Expand Down

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