-use rustc::hir::intravisit::FnKind;
use rustc::hir::def_id::DefId;
use rustc::hir;
use rustc::lint::*;
+use rustc::{declare_lint, lint_array};
+use if_chain::if_chain;
use rustc::ty::{self, Ty};
-use syntax::ast;
use syntax::codemap::Span;
-use utils::paths;
-use utils::{get_trait_def_id, implements_trait, in_external_macro, return_ty, same_tys, span_lint_and_then};
-use utils::sugg::DiagnosticBuilderExt;
+use crate::utils::paths;
+use crate::utils::{get_trait_def_id, implements_trait, in_external_macro, return_ty, same_tys, span_lint_and_then};
+use crate::utils::sugg::DiagnosticBuilderExt;
/// **What it does:** Checks for types with a `fn new() -> Self` method and no
/// implementation of
/// ```
///
/// You can also have `new()` call `Default::default()`.
-declare_lint! {
+declare_clippy_lint! {
pub NEW_WITHOUT_DEFAULT,
- Warn,
+ style,
"`fn new() -> Self` method without `Default` implementation"
}
/// ```
///
/// Just prepend `#[derive(Default)]` before the `struct` definition.
-declare_lint! {
+declare_clippy_lint! {
pub NEW_WITHOUT_DEFAULT_DERIVE,
- Warn,
+ style,
"`fn new() -> Self` without `#[derive]`able `Default` implementation"
}
}
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for NewWithoutDefault {
- fn check_fn(
- &mut self,
- cx: &LateContext<'a, 'tcx>,
- kind: FnKind<'tcx>,
- decl: &'tcx hir::FnDecl,
- _: &'tcx hir::Body,
- span: Span,
- id: ast::NodeId,
- ) {
- if in_external_macro(cx, span) {
- return;
- }
-
- if let FnKind::Method(name, sig, _, _) = kind {
- if sig.constness == hir::Constness::Const {
- // can't be implemented by default
- return;
- }
- if !cx.generics.expect("method must have generics").ty_params.is_empty() {
- // when the result of `new()` depends on a type parameter we should not require
- // an
- // impl of `Default`
- return;
- }
- if decl.inputs.is_empty() && name == "new" && cx.access_levels.is_reachable(id) {
- let self_ty = cx.tcx
- .type_of(cx.tcx.hir.local_def_id(cx.tcx.hir.get_parent(id)));
- if_chain! {
- if same_tys(cx, self_ty, return_ty(cx, id));
- if let Some(default_trait_id) = get_trait_def_id(cx, &paths::DEFAULT_TRAIT);
- if !implements_trait(cx, self_ty, default_trait_id, &[]);
- then {
- if let Some(sp) = can_derive_default(self_ty, cx, default_trait_id) {
- span_lint_and_then(cx,
- NEW_WITHOUT_DEFAULT_DERIVE, span,
- &format!("you should consider deriving a \
- `Default` implementation for `{}`",
- self_ty),
- |db| {
+ fn check_item(&mut self, cx: &LateContext<'a, 'tcx>, item: &'tcx hir::Item) {
+ if let hir::ItemKind::Impl(_, _, _, _, None, _, ref items) = item.node {
+ for assoc_item in items {
+ if let hir::AssociatedItemKind::Method { has_self: false } = assoc_item.kind {
+ let impl_item = cx.tcx.hir.impl_item(assoc_item.id);
+ if in_external_macro(cx, impl_item.span) {
+ return;
+ }
+ if let hir::ImplItemKind::Method(ref sig, _) = impl_item.node {
+ let name = impl_item.ident.name;
+ let id = impl_item.id;
+ if sig.header.constness == hir::Constness::Const {
+ // can't be implemented by default
+ return;
+ }
+ if impl_item.generics.params.iter().any(|gen| match gen.kind {
+ hir::GenericParamKind::Type { .. } => true,
+ _ => false
+ }) {
+ // 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 == "new" && cx.access_levels.is_reachable(id) {
+ let self_ty = cx.tcx
+ .type_of(cx.tcx.hir.local_def_id(cx.tcx.hir.get_parent(id)));
+ if_chain! {
+ if same_tys(cx, self_ty, return_ty(cx, id));
+ if let Some(default_trait_id) = get_trait_def_id(cx, &paths::DEFAULT_TRAIT);
+ if !implements_trait(cx, self_ty, default_trait_id, &[]);
+ then {
+ if let Some(sp) = can_derive_default(self_ty, cx, default_trait_id) {
+ span_lint_and_then(
+ cx,
+ NEW_WITHOUT_DEFAULT_DERIVE,
+ 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)]");
});
- } else {
- span_lint_and_then(cx,
- NEW_WITHOUT_DEFAULT, span,
- &format!("you should consider adding a \
- `Default` implementation for `{}`",
- self_ty),
- |db| {
- db.suggest_prepend_item(cx,
- span,
- "try this",
- &format!(
-"impl Default for {} {{
- fn default() -> Self {{
- Self::new()
- }}
-}}",
- self_ty));
- });
- }
+ } else {
+ span_lint_and_then(
+ cx,
+ NEW_WITHOUT_DEFAULT,
+ 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),
+ );
+ },
+ );
}
+ }
+ }
+ }
+ }
}
}
}
}
}
+fn create_new_without_default_suggest_msg(ty: Ty) -> String {
+ #[cfg_attr(rustfmt, rustfmt_skip)]
+ format!(
+"impl Default for {} {{
+ fn default() -> Self {{
+ Self::new()
+ }}
+}}", ty)
+}
+
fn can_derive_default<'t, 'c>(ty: Ty<'t>, cx: &LateContext<'c, 't>, default_trait_id: DefId) -> Option<Span> {
match ty.sty {
ty::TyAdt(adt_def, substs) if adt_def.is_struct() => {
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