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, span_lint_hir_and_then};
use if_chain::if_chain;
-use rustc::hir;
-use rustc::hir::def_id::DefId;
-use rustc::impl_lint_pass;
-use rustc::lint::{in_external_macro, LateContext, LateLintPass, LintArray, LintContext, LintPass};
-use rustc::ty::{self, Ty};
-use rustc::util::nodemap::HirIdSet;
use rustc_errors::Applicability;
-use rustc_session::declare_tool_lint;
-use syntax::source_map::Span;
+use rustc_hir as hir;
+use rustc_hir::HirIdSet;
+use rustc_lint::{LateContext, LateLintPass, LintContext};
+use rustc_middle::lint::in_external_macro;
+use rustc_middle::ty::{Ty, TyS};
+use rustc_session::{declare_tool_lint, impl_lint_pass};
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.
/// }
/// ```
///
- /// Instead, use:
+ /// To fix the lint, add 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"
impl_lint_pass!(NewWithoutDefault => [NEW_WITHOUT_DEFAULT]);
-impl<'a, 'tcx> LateLintPass<'a, 'tcx> for NewWithoutDefault {
- fn check_item(&mut self, cx: &LateContext<'a, 'tcx>, item: &'tcx hir::Item<'_>) {
- if let hir::ItemKind::Impl(_, _, _, _, None, _, ref items) = item.kind {
+impl<'tcx> LateLintPass<'tcx> for NewWithoutDefault {
+ #[allow(clippy::too_many_lines)]
+ fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx hir::Item<'_>) {
+ if let hir::ItemKind::Impl {
+ of_trait: None, items, ..
+ } = item.kind
+ {
for assoc_item in items {
- if let hir::AssocItemKind::Method { has_self: false } = assoc_item.kind {
+ if let hir::AssocItemKind::Fn { has_self: false } = assoc_item.kind {
let impl_item = cx.tcx.hir().impl_item(assoc_item.id);
if in_external_macro(cx.sess(), impl_item.span) {
return;
}
- if let hir::ImplItemKind::Method(ref sig, _) = impl_item.kind {
+ if let hir::ImplItemKind::Fn(ref sig, _) = impl_item.kind {
let name = impl_item.ident.name;
let id = impl_item.hir_id;
if sig.header.constness == hir::Constness::Const {
// can't be implemented for unsafe new
return;
}
- if impl_item.generics.params.iter().any(|gen| match gen.kind {
- hir::GenericParamKind::Type { .. } => true,
- _ => false,
- }) {
+ if impl_item
+ .generics
+ .params
+ .iter()
+ .any(|gen| matches!(gen.kind, hir::GenericParamKind::Type { .. }))
+ {
// when the result of `new()` depends on a type parameter we should not require
// an
// impl of `Default`
return;
}
if sig.decl.inputs.is_empty() && name == sym!(new) && cx.access_levels.is_reachable(id) {
- let self_did = cx.tcx.hir().local_def_id(cx.tcx.hir().get_parent_item(id));
- let self_ty = cx.tcx.type_of(self_did);
+ let self_def_id = cx.tcx.hir().local_def_id(cx.tcx.hir().get_parent_item(id));
+ let self_ty = cx.tcx.type_of(self_def_id);
if_chain! {
- if same_tys(cx, self_ty, return_ty(cx, id));
+ if TyS::same_type(self_ty, return_ty(cx, id));
if let Some(default_trait_id) = get_trait_def_id(cx, &paths::DEFAULT_TRAIT);
then {
if self.impling_types.is_none() {
let mut impls = HirIdSet::default();
cx.tcx.for_each_impl(default_trait_id, |d| {
if let Some(ty_def) = cx.tcx.type_of(d).ty_adt_def() {
- if let Some(hir_id) = cx.tcx.hir().as_local_hir_id(ty_def.did) {
- impls.insert(hir_id);
+ if let Some(local_def_id) = ty_def.did.as_local() {
+ impls.insert(cx.tcx.hir().local_def_id_to_hir_id(local_def_id));
}
}
});
// generics
if_chain! {
if let Some(ref impling_types) = self.impling_types;
- if let Some(self_def) = cx.tcx.type_of(self_did).ty_adt_def();
- if self_def.did.is_local();
+ if let Some(self_def) = cx.tcx.type_of(self_def_id).ty_adt_def();
+ if let Some(self_local_did) = self_def.did.as_local();
then {
- let self_id = cx.tcx.hir().local_def_id_to_hir_id(self_def.did.to_local());
+ let self_id = cx.tcx.hir().local_def_id_to_hir_id(self_local_did);
if impling_types.contains(&self_id) {
return;
}
}
}
- 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
- ),
- |db| {
- db.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
- ),
- |db| {
- db.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,
+ );
+ },
+ );
}
}
}
}}
}}", 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,
- }
-}
projects / rust.git / blobdiff