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Fix len_zero ICE

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This commit is contained in:
Oliver Schneider 2017-09-04 17:05:47 +02:00
parent 009f5aaf83
commit 7757c893ef
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GPG Key ID: A69F8D225B3AD7D9
3 changed files with 28 additions and 19 deletions
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30
clippy_lints/src/len_zero.rs
View File

@ -104,34 +104,28 @@ fn check_trait_items(cx: &LateContext, visited_trait: &Item, trait_items: &[Trai
}
// fill the set with current and super traits
fn fill_trait_set<'a, 'b: 'a>(traitt: &'b Item, set: &'a mut HashSet<&'b Item>, cx: &'b LateContext) {
fn fill_trait_set(traitt: DefId, set: &mut HashSet<DefId>, cx: &LateContext) {
if set.insert(traitt) {
if let ItemTrait(.., ref ty_param_bounds, _) = traitt.node {
for ty_param_bound in ty_param_bounds {
if let TraitTyParamBound(ref poly_trait_ref, _) = *ty_param_bound {
let super_trait_node_id = cx.tcx
.hir
.as_local_node_id(poly_trait_ref.trait_ref.path.def.def_id())
.expect("the DefId is local, the NodeId should be available");
let super_trait = cx.tcx.hir.expect_item(super_trait_node_id);
fill_trait_set(super_trait, set, cx);
}
}
for supertrait in ::rustc::traits::supertrait_def_ids(cx.tcx, traitt) {
fill_trait_set(supertrait, set, cx);
}
}
}
if cx.access_levels.is_exported(visited_trait.id) && trait_items.iter().any(|i| is_named_self(cx, i, "len")) {
let mut current_and_super_traits = HashSet::new();
fill_trait_set(visited_trait, &mut current_and_super_traits, cx);
let visited_trait_def_id = cx.tcx.hir.local_def_id(visited_trait.id);
fill_trait_set(visited_trait_def_id, &mut current_and_super_traits, cx);
let is_empty_method_found = current_and_super_traits
.iter()
.flat_map(|i| match i.node {
ItemTrait(.., ref trait_items) => trait_items.iter(),
_ => bug!("should only handle traits"),
})
.any(|i| is_named_self(cx, i, "is_empty"));
.flat_map(|&i| cx.tcx.associated_items(i))
.any(|i| {
i.kind == ty::AssociatedKind::Method &&
i.method_has_self_argument &&
i.name == "is_empty" &&
cx.tcx.fn_sig(i.def_id).inputs().skip_binder().len() == 1
});
if !is_empty_method_found {
span_lint(

7
tests/ui/len_zero.rs
View File

@ -182,3 +182,10 @@ fn test_slice(b: &[u8]) {
if b.len() != 0 {
}
}
// this used to ICE
pub trait Foo: Sized {}
pub trait DependsOnFoo: Foo {
fn len(&mut self) -> usize;
}

10
tests/ui/len_zero.stderr
View File

@ -86,5 +86,13 @@ error: length comparison to zero
182 | if b.len() != 0 {
| ^^^^^^^^^^^^ help: using `is_empty` is more concise: `!b.is_empty()`
error: aborting due to 11 previous errors
error: trait `DependsOnFoo` has a `len` method but no (possibly inherited) `is_empty` method
--> $DIR/len_zero.rs:189:1
|
189 | / pub trait DependsOnFoo: Foo {
190 | | fn len(&mut self) -> usize;
191 | | }
| |_^
error: aborting due to 12 previous errors