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Auto merge of #9645 - Jarcho:ptr_arg_9542, r=llogiq

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Don't lint `ptr_arg` when used as an incompatible trait object

fixes #9542
changelog: [`ptr_arg`](https://rust-lang.github.io/rust-clippy/master/#ptr_arg): Don't lint when used as an incompatible trait object
This commit is contained in:
bors 2022-10-14 17:44:03 +00:00
commit b510557f89
3 changed files with 93 additions and 3 deletions
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46
clippy_lints/src/ptr.rs
View file

@ -15,13 +15,17 @@ use rustc_hir::{
ImplItemKind, ItemKind, Lifetime, LifetimeName, Mutability, Node, Param, ParamName, PatKind, QPath, TraitFn,
TraitItem, TraitItemKind, TyKind, Unsafety,
};
use rustc_infer::infer::TyCtxtInferExt;
use rustc_infer::traits::{Obligation, ObligationCause};
use rustc_lint::{LateContext, LateLintPass};
use rustc_middle::hir::nested_filter;
use rustc_middle::ty::{self, Ty};
use rustc_middle::ty::{self, Binder, ExistentialPredicate, List, PredicateKind, Ty};
use rustc_session::{declare_lint_pass, declare_tool_lint};
use rustc_span::source_map::Span;
use rustc_span::sym;
use rustc_span::symbol::Symbol;
use rustc_trait_selection::infer::InferCtxtExt as _;
use rustc_trait_selection::traits::query::evaluate_obligation::InferCtxtExt as _;
use std::fmt;
use std::iter;
@ -384,6 +388,17 @@ enum DerefTy<'tcx> {
Slice(Option<Span>, Ty<'tcx>),
}
impl<'tcx> DerefTy<'tcx> {
fn ty(&self, cx: &LateContext<'tcx>) -> Ty<'tcx> {
match *self {
Self::Str => cx.tcx.types.str_,
Self::Path => cx.tcx.mk_adt(
cx.tcx.adt_def(cx.tcx.get_diagnostic_item(sym::Path).unwrap()),
List::empty(),
),
Self::Slice(_, ty) => cx.tcx.mk_slice(ty),
}
}
fn argless_str(&self) -> &'static str {
match *self {
Self::Str => "str",
@ -581,6 +596,7 @@ fn check_ptr_arg_usage<'tcx>(cx: &LateContext<'tcx>, body: &'tcx Body<'_>, args:
let i = expr_args.iter().position(|arg| arg.hir_id == child_id).unwrap_or(0);
if expr_sig(self.cx, f).and_then(|sig| sig.input(i)).map_or(true, |ty| {
match *ty.skip_binder().peel_refs().kind() {
ty::Dynamic(preds, _, _) => !matches_preds(self.cx, args.deref_ty.ty(self.cx), preds),
ty::Param(_) => true,
ty::Adt(def, _) => def.did() == args.ty_did,
_ => false,
@ -614,6 +630,9 @@ fn check_ptr_arg_usage<'tcx>(cx: &LateContext<'tcx>, body: &'tcx Body<'_>, args:
};
match *self.cx.tcx.fn_sig(id).skip_binder().inputs()[i].peel_refs().kind() {
ty::Dynamic(preds, _, _) if !matches_preds(self.cx, args.deref_ty.ty(self.cx), preds) => {
set_skip_flag();
},
ty::Param(_) => {
set_skip_flag();
},
@ -665,6 +684,31 @@ fn check_ptr_arg_usage<'tcx>(cx: &LateContext<'tcx>, body: &'tcx Body<'_>, args:
v.results
}
fn matches_preds<'tcx>(
cx: &LateContext<'tcx>,
ty: Ty<'tcx>,
preds: &'tcx [Binder<'tcx, ExistentialPredicate<'tcx>>],
) -> bool {
cx.tcx.infer_ctxt().enter(|infcx| {
preds.iter().all(|&p| match cx.tcx.erase_late_bound_regions(p) {
ExistentialPredicate::Trait(p) => infcx
.type_implements_trait(p.def_id, ty, p.substs, cx.param_env)
.must_apply_modulo_regions(),
ExistentialPredicate::Projection(p) => infcx.predicate_must_hold_modulo_regions(&Obligation::new(
ObligationCause::dummy(),
cx.param_env,
cx.tcx.mk_predicate(Binder::bind_with_vars(
PredicateKind::Projection(p.with_self_ty(cx.tcx, ty)),
List::empty(),
)),
)),
ExistentialPredicate::AutoTrait(p) => infcx
.type_implements_trait(p, ty, List::empty(), cx.param_env)
.must_apply_modulo_regions(),
})
})
}
fn get_rptr_lm<'tcx>(ty: &'tcx hir::Ty<'tcx>) -> Option<(&'tcx Lifetime, Mutability, Span)> {
if let TyKind::Rptr(lt, ref m) = ty.kind {
Some((lt, m.mutbl, ty.span))

30
tests/ui/ptr_arg.rs
View file

@ -3,7 +3,7 @@
#![warn(clippy::ptr_arg)]
use std::borrow::Cow;
use std::path::PathBuf;
use std::path::{Path, PathBuf};
fn do_vec(x: &Vec<i64>) {
//Nothing here
@ -207,3 +207,31 @@ fn cow_conditional_to_mut(a: &mut Cow<str>) {
a.to_mut().push_str("foo");
}
}
// Issue #9542
fn dyn_trait_ok(a: &mut Vec<u32>, b: &mut String, c: &mut PathBuf) {
trait T {}
impl<U> T for Vec<U> {}
impl T for String {}
impl T for PathBuf {}
fn takes_dyn(_: &mut dyn T) {}
takes_dyn(a);
takes_dyn(b);
takes_dyn(c);
}
fn dyn_trait(a: &mut Vec<u32>, b: &mut String, c: &mut PathBuf) {
trait T {}
impl<U> T for Vec<U> {}
impl<U> T for [U] {}
impl T for String {}
impl T for str {}
impl T for PathBuf {}
impl T for Path {}
fn takes_dyn(_: &mut dyn T) {}
takes_dyn(a);
takes_dyn(b);
takes_dyn(c);
}

20
tests/ui/ptr_arg.stderr
View file

@ -162,5 +162,23 @@ error: writing `&mut Vec` instead of `&mut [_]` involves a new object where a sl
LL | fn mut_vec_slice_methods(v: &mut Vec<u32>) {
| ^^^^^^^^^^^^^ help: change this to: `&mut [u32]`
error: aborting due to 17 previous errors
error: writing `&mut Vec` instead of `&mut [_]` involves a new object where a slice will do
--> $DIR/ptr_arg.rs:224:17
|
LL | fn dyn_trait(a: &mut Vec<u32>, b: &mut String, c: &mut PathBuf) {
| ^^^^^^^^^^^^^ help: change this to: `&mut [u32]`
error: writing `&mut String` instead of `&mut str` involves a new object where a slice will do
--> $DIR/ptr_arg.rs:224:35
|
LL | fn dyn_trait(a: &mut Vec<u32>, b: &mut String, c: &mut PathBuf) {
| ^^^^^^^^^^^ help: change this to: `&mut str`
error: writing `&mut PathBuf` instead of `&mut Path` involves a new object where a slice will do
--> $DIR/ptr_arg.rs:224:51
|
LL | fn dyn_trait(a: &mut Vec<u32>, b: &mut String, c: &mut PathBuf) {
| ^^^^^^^^^^^^ help: change this to: `&mut Path`
error: aborting due to 20 previous errors