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Fix #2196

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Oliver Schneider 2017-11-29 17:06:27 +01:00
parent e62727ee51
commit 317e97bae7
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2 changed files with 67 additions and 62 deletions
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123
clippy_lints/src/new_without_default.rs
View file

@ -1,9 +1,7 @@
use rustc::hir::intravisit::FnKind;
use rustc::hir::def_id::DefId;
use rustc::hir;
use rustc::lint::*;
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};
@ -90,66 +88,67 @@ impl LintPass for NewWithoutDefault {
}
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| {
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",
&create_new_without_default_suggest_msg(self_ty),
);
},
);
fn check_item(&mut self, cx: &LateContext<'a, 'tcx>, item: &'tcx hir::Item) {
if let hir::ItemImpl(_, _, _, _, 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.name;
let span = impl_item.span;
let id = impl_item.id;
let decl = &sig.decl;
if sig.constness == hir::Constness::Const {
// can't be implemented by default
return;
}
if !impl_item.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| {
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",
&create_new_without_default_suggest_msg(self_ty),
);
},
);
}
}
}
}
}
}

6
tests/ui/new_without_default.rs
View file

@ -83,4 +83,10 @@ impl IgnoreGenericNew {
pub fn new<T>() -> Self { IgnoreGenericNew } // the derived Default does not make sense here as the result depends on T
}
pub trait TraitWithNew: Sized {
fn new() -> Self {
panic!()
}
}
fn main() {}