mirror of
https://github.com/rust-lang/rust-clippy
synced 2024-11-27 15:11:30 +00:00
Auto merge of #5616 - euclio:no-derive-suggestion, r=phansch,flip1995
new_without_default: do not suggest deriving --- changelog: do not suggest deriving `Default` in `new_without_default` This commit changes the behavior of the `new_without_default` lint to not suggest deriving `Default`. This suggestion is misleading if the `new` implementation does something different than what a derived `Default` implementation would do, because then the two methods would not be equivalent. Instead, the `can_derive_default` check is removed, and we always suggest implementing `Default` in terms of `new()`.
This commit is contained in:
bors
commit
c41916d9bd
3 changed files with 64 additions and 100 deletions
|
|
@ -1,27 +1,20 @@
|
|||
use crate::utils::paths;
|
||||
use crate::utils::sugg::DiagnosticBuilderExt;
|
||||
use crate::utils::{get_trait_def_id, implements_trait, return_ty, same_tys, span_lint_hir_and_then};
|
||||
use crate::utils::{get_trait_def_id, return_ty, same_tys, span_lint_hir_and_then};
|
||||
use if_chain::if_chain;
|
||||
use rustc_errors::Applicability;
|
||||
use rustc_hir as hir;
|
||||
use rustc_hir::def_id::DefId;
|
||||
use rustc_hir::HirIdSet;
|
||||
use rustc_lint::{LateContext, LateLintPass, LintContext};
|
||||
use rustc_middle::lint::in_external_macro;
|
||||
use rustc_middle::ty::{self, Ty};
|
||||
use rustc_middle::ty::Ty;
|
||||
use rustc_session::{declare_tool_lint, impl_lint_pass};
|
||||
use rustc_span::source_map::Span;
|
||||
|
||||
declare_clippy_lint! {
|
||||
/// **What it does:** Checks for types with a `fn new() -> Self` method and no
|
||||
/// implementation of
|
||||
/// [`Default`](https://doc.rust-lang.org/std/default/trait.Default.html).
|
||||
///
|
||||
/// It detects both the case when a manual
|
||||
/// [`Default`](https://doc.rust-lang.org/std/default/trait.Default.html)
|
||||
/// implementation is required and also when it can be created with
|
||||
/// `#[derive(Default)]`
|
||||
///
|
||||
/// **Why is this bad?** The user might expect to be able to use
|
||||
/// [`Default`](https://doc.rust-lang.org/std/default/trait.Default.html) as the
|
||||
/// type can be constructed without arguments.
|
||||
|
|
@ -40,46 +33,17 @@ declare_clippy_lint! {
|
|||
/// }
|
||||
/// ```
|
||||
///
|
||||
/// Instead, use:
|
||||
/// To fix the lint, and a `Default` implementation that delegates to `new`:
|
||||
///
|
||||
/// ```ignore
|
||||
/// struct Foo(Bar);
|
||||
///
|
||||
/// impl Default for Foo {
|
||||
/// fn default() -> Self {
|
||||
/// Foo(Bar::new())
|
||||
/// Foo::new()
|
||||
/// }
|
||||
/// }
|
||||
/// ```
|
||||
///
|
||||
/// Or, if
|
||||
/// [`Default`](https://doc.rust-lang.org/std/default/trait.Default.html)
|
||||
/// can be derived by `#[derive(Default)]`:
|
||||
///
|
||||
/// ```rust
|
||||
/// struct Foo;
|
||||
///
|
||||
/// impl Foo {
|
||||
/// fn new() -> Self {
|
||||
/// Foo
|
||||
/// }
|
||||
/// }
|
||||
/// ```
|
||||
///
|
||||
/// Instead, use:
|
||||
///
|
||||
/// ```rust
|
||||
/// #[derive(Default)]
|
||||
/// struct Foo;
|
||||
///
|
||||
/// impl Foo {
|
||||
/// fn new() -> Self {
|
||||
/// Foo
|
||||
/// }
|
||||
/// }
|
||||
/// ```
|
||||
///
|
||||
/// You can also have `new()` call `Default::default()`.
|
||||
pub NEW_WITHOUT_DEFAULT,
|
||||
style,
|
||||
"`fn new() -> Self` method without `Default` implementation"
|
||||
|
|
@ -158,46 +122,25 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for NewWithoutDefault {
|
|||
}
|
||||
}
|
||||
|
||||
if let Some(sp) = can_derive_default(self_ty, cx, default_trait_id) {
|
||||
span_lint_hir_and_then(
|
||||
cx,
|
||||
NEW_WITHOUT_DEFAULT,
|
||||
id,
|
||||
impl_item.span,
|
||||
&format!(
|
||||
"you should consider deriving a `Default` implementation for `{}`",
|
||||
self_ty
|
||||
),
|
||||
|diag| {
|
||||
diag.suggest_item_with_attr(
|
||||
cx,
|
||||
sp,
|
||||
"try this",
|
||||
"#[derive(Default)]",
|
||||
Applicability::MaybeIncorrect,
|
||||
);
|
||||
});
|
||||
} else {
|
||||
span_lint_hir_and_then(
|
||||
cx,
|
||||
NEW_WITHOUT_DEFAULT,
|
||||
id,
|
||||
impl_item.span,
|
||||
&format!(
|
||||
"you should consider adding a `Default` implementation for `{}`",
|
||||
self_ty
|
||||
),
|
||||
|diag| {
|
||||
diag.suggest_prepend_item(
|
||||
cx,
|
||||
item.span,
|
||||
"try this",
|
||||
&create_new_without_default_suggest_msg(self_ty),
|
||||
Applicability::MaybeIncorrect,
|
||||
);
|
||||
},
|
||||
);
|
||||
}
|
||||
span_lint_hir_and_then(
|
||||
cx,
|
||||
NEW_WITHOUT_DEFAULT,
|
||||
id,
|
||||
impl_item.span,
|
||||
&format!(
|
||||
"you should consider adding a `Default` implementation for `{}`",
|
||||
self_ty
|
||||
),
|
||||
|diag| {
|
||||
diag.suggest_prepend_item(
|
||||
cx,
|
||||
item.span,
|
||||
"try this",
|
||||
&create_new_without_default_suggest_msg(self_ty),
|
||||
Applicability::MaybeIncorrect,
|
||||
);
|
||||
},
|
||||
);
|
||||
}
|
||||
}
|
||||
}
|
||||
|
|
@ -217,18 +160,3 @@ fn create_new_without_default_suggest_msg(ty: Ty<'_>) -> String {
|
|||
}}
|
||||
}}", ty)
|
||||
}
|
||||
|
||||
fn can_derive_default<'t, 'c>(ty: Ty<'t>, cx: &LateContext<'c, 't>, default_trait_id: DefId) -> Option<Span> {
|
||||
match ty.kind {
|
||||
ty::Adt(adt_def, substs) if adt_def.is_struct() => {
|
||||
for field in adt_def.all_fields() {
|
||||
let f_ty = field.ty(cx.tcx, substs);
|
||||
if !implements_trait(cx, f_ty, default_trait_id, &[]) {
|
||||
return None;
|
||||
}
|
||||
}
|
||||
Some(cx.tcx.def_span(adt_def.did))
|
||||
},
|
||||
_ => None,
|
||||
}
|
||||
}
|
||||
|
|
|
|||
|
|
@ -148,4 +148,15 @@ impl AllowDerive {
|
|||
}
|
||||
}
|
||||
|
||||
pub struct NewNotEqualToDerive {
|
||||
foo: i32,
|
||||
}
|
||||
|
||||
impl NewNotEqualToDerive {
|
||||
// This `new` implementation is not equal to a derived `Default`, so do not suggest deriving.
|
||||
pub fn new() -> Self {
|
||||
NewNotEqualToDerive { foo: 1 }
|
||||
}
|
||||
}
|
||||
|
||||
fn main() {}
|
||||
|
|
|
|||
|
|
@ -1,4 +1,4 @@
|
|||
error: you should consider deriving a `Default` implementation for `Foo`
|
||||
error: you should consider adding a `Default` implementation for `Foo`
|
||||
--> $DIR/new_without_default.rs:8:5
|
||||
|
|
||||
LL | / pub fn new() -> Foo {
|
||||
|
|
@ -9,10 +9,14 @@ LL | | }
|
|||
= note: `-D clippy::new-without-default` implied by `-D warnings`
|
||||
help: try this
|
||||
|
|
||||
LL | #[derive(Default)]
|
||||
LL | impl Default for Foo {
|
||||
LL | fn default() -> Self {
|
||||
LL | Self::new()
|
||||
LL | }
|
||||
LL | }
|
||||
|
|
||||
|
||||
error: you should consider deriving a `Default` implementation for `Bar`
|
||||
error: you should consider adding a `Default` implementation for `Bar`
|
||||
--> $DIR/new_without_default.rs:16:5
|
||||
|
|
||||
LL | / pub fn new() -> Self {
|
||||
|
|
@ -22,7 +26,11 @@ LL | | }
|
|||
|
|
||||
help: try this
|
||||
|
|
||||
LL | #[derive(Default)]
|
||||
LL | impl Default for Bar {
|
||||
LL | fn default() -> Self {
|
||||
LL | Self::new()
|
||||
LL | }
|
||||
LL | }
|
||||
|
|
||||
|
||||
error: you should consider adding a `Default` implementation for `LtKo<'c>`
|
||||
|
|
@ -42,5 +50,22 @@ LL | }
|
|||
LL | }
|
||||
|
|
||||
|
||||
error: aborting due to 3 previous errors
|
||||
error: you should consider adding a `Default` implementation for `NewNotEqualToDerive`
|
||||
--> $DIR/new_without_default.rs:157:5
|
||||
|
|
||||
LL | / pub fn new() -> Self {
|
||||
LL | | NewNotEqualToDerive { foo: 1 }
|
||||
LL | | }
|
||||
| |_____^
|
||||
|
|
||||
help: try this
|
||||
|
|
||||
LL | impl Default for NewNotEqualToDerive {
|
||||
LL | fn default() -> Self {
|
||||
LL | Self::new()
|
||||
LL | }
|
||||
LL | }
|
||||
|
|
||||
|
||||
error: aborting due to 4 previous errors
|
||||
|
||||
|
|
|
|||
Loading…
Reference in a new issue