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Auto merge of #10386 - Jarcho:issue_10384, r=Manishearth

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Normalize projections types when checking `explicit_auto_deref`

fixes #10384

changelog: [`explicit_auto_deref`]: Better consider projection types when checking if auto deref is applicable
This commit is contained in:
bors 2023-02-21 21:27:41 +00:00
commit 51668820f4
4 changed files with 102 additions and 29 deletions
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78
clippy_lints/src/dereference.rs
View file

@ -3,7 +3,7 @@ use clippy_utils::mir::{enclosing_mir, expr_local, local_assignments, used_exact
use clippy_utils::msrvs::{self, Msrv};
use clippy_utils::source::{snippet_with_applicability, snippet_with_context};
use clippy_utils::sugg::has_enclosing_paren;
use clippy_utils::ty::{expr_sig, is_copy, peel_mid_ty_refs, ty_sig, variant_of_res};
use clippy_utils::ty::{adt_and_variant_of_res, expr_sig, is_copy, peel_mid_ty_refs, ty_sig};
use clippy_utils::{
fn_def_id, get_parent_expr, get_parent_expr_for_hir, is_lint_allowed, path_to_local, walk_to_expr_usage,
};
@ -26,8 +26,8 @@ use rustc_lint::{LateContext, LateLintPass};
use rustc_middle::mir::{Rvalue, StatementKind};
use rustc_middle::ty::adjustment::{Adjust, Adjustment, AutoBorrow, AutoBorrowMutability};
use rustc_middle::ty::{
self, Binder, BoundVariableKind, Clause, EarlyBinder, FnSig, GenericArgKind, List, ParamTy, PredicateKind,
ProjectionPredicate, Ty, TyCtxt, TypeVisitable, TypeckResults,
self, Binder, BoundVariableKind, Clause, EarlyBinder, FnSig, GenericArgKind, List, ParamEnv, ParamTy,
PredicateKind, ProjectionPredicate, Ty, TyCtxt, TypeVisitable, TypeckResults,
};
use rustc_session::{declare_tool_lint, impl_lint_pass};
use rustc_span::{symbol::sym, Span, Symbol};
@ -736,7 +736,7 @@ fn walk_parents<'tcx>(
..
}) if span.ctxt() == ctxt => {
let ty = cx.tcx.type_of(owner_id.def_id);
Some(ty_auto_deref_stability(cx, ty, precedence).position_for_result(cx))
Some(ty_auto_deref_stability(cx.tcx, cx.param_env, ty, precedence).position_for_result(cx))
},
Node::Item(&Item {
@ -760,7 +760,7 @@ fn walk_parents<'tcx>(
let output = cx
.tcx
.erase_late_bound_regions(cx.tcx.fn_sig(owner_id).subst_identity().output());
Some(ty_auto_deref_stability(cx, output, precedence).position_for_result(cx))
Some(ty_auto_deref_stability(cx.tcx, cx.param_env, output, precedence).position_for_result(cx))
},
Node::ExprField(field) if field.span.ctxt() == ctxt => match get_parent_expr_for_hir(cx, field.hir_id) {
@ -768,10 +768,23 @@ fn walk_parents<'tcx>(
hir_id,
kind: ExprKind::Struct(path, ..),
..
}) => variant_of_res(cx, cx.qpath_res(path, *hir_id))
.and_then(|variant| variant.fields.iter().find(|f| f.name == field.ident.name))
.map(|field_def| {
ty_auto_deref_stability(cx, cx.tcx.type_of(field_def.did), precedence).position_for_arg()
}) => adt_and_variant_of_res(cx, cx.qpath_res(path, *hir_id))
.and_then(|(adt, variant)| {
variant
.fields
.iter()
.find(|f| f.name == field.ident.name)
.map(|f| (adt, f))
})
.map(|(adt, field_def)| {
ty_auto_deref_stability(
cx.tcx,
// Use the param_env of the target type.
cx.tcx.param_env(adt.did()),
cx.tcx.type_of(field_def.did),
precedence,
)
.position_for_arg()
}),
_ => None,
},
@ -792,7 +805,7 @@ fn walk_parents<'tcx>(
let output = cx
.tcx
.erase_late_bound_regions(cx.tcx.fn_sig(owner_id).subst_identity().output());
ty_auto_deref_stability(cx, output, precedence).position_for_result(cx)
ty_auto_deref_stability(cx.tcx, cx.param_env, output, precedence).position_for_result(cx)
},
)
},
@ -835,15 +848,20 @@ fn walk_parents<'tcx>(
msrv,
)
} else {
ty_auto_deref_stability(cx, cx.tcx.erase_late_bound_regions(ty), precedence)
.position_for_arg()
ty_auto_deref_stability(
cx.tcx,
// Use the param_env of the target function.
sig.predicates_id().map_or(ParamEnv::empty(), |id| cx.tcx.param_env(id)),
cx.tcx.erase_late_bound_regions(ty),
precedence
).position_for_arg()
}
},
}
})
}),
ExprKind::MethodCall(method, receiver, args, _) => {
let id = cx.typeck_results().type_dependent_def_id(parent.hir_id).unwrap();
let fn_id = cx.typeck_results().type_dependent_def_id(parent.hir_id).unwrap();
if receiver.hir_id == child_id {
// Check for calls to trait methods where the trait is implemented on a reference.
// Two cases need to be handled:
@ -852,13 +870,17 @@ fn walk_parents<'tcx>(
// priority.
if e.hir_id != child_id {
return Some(Position::ReborrowStable(precedence))
} else if let Some(trait_id) = cx.tcx.trait_of_item(id)
} else if let Some(trait_id) = cx.tcx.trait_of_item(fn_id)
&& let arg_ty = cx.tcx.erase_regions(cx.typeck_results().expr_ty_adjusted(e))
&& let ty::Ref(_, sub_ty, _) = *arg_ty.kind()
&& let subs = cx
.typeck_results()
.node_substs_opt(parent.hir_id).map(|subs| &subs[1..]).unwrap_or_default()
&& let impl_ty = if cx.tcx.fn_sig(id).subst_identity().skip_binder().inputs()[0].is_ref() {
&& let impl_ty = if cx.tcx.fn_sig(fn_id)
.subst_identity()
.skip_binder()
.inputs()[0].is_ref()
{
// Trait methods taking `&self`
sub_ty
} else {
@ -879,10 +901,13 @@ fn walk_parents<'tcx>(
return Some(Position::MethodReceiver);
}
args.iter().position(|arg| arg.hir_id == child_id).map(|i| {
let ty = cx.tcx.fn_sig(id).subst_identity().skip_binder().inputs()[i + 1];
let ty = cx.tcx.fn_sig(fn_id).subst_identity().input(i + 1);
// `e.hir_id == child_id` for https://github.com/rust-lang/rust-clippy/issues/9739
// `method.args.is_none()` for https://github.com/rust-lang/rust-clippy/issues/9782
if e.hir_id == child_id && method.args.is_none() && let ty::Param(param_ty) = ty.kind() {
if e.hir_id == child_id
&& method.args.is_none()
&& let ty::Param(param_ty) = ty.skip_binder().kind()
{
needless_borrow_impl_arg_position(
cx,
possible_borrowers,
@ -895,8 +920,10 @@ fn walk_parents<'tcx>(
)
} else {
ty_auto_deref_stability(
cx,
cx.tcx.erase_late_bound_regions(cx.tcx.fn_sig(id).subst_identity().input(i + 1)),
cx.tcx,
// Use the param_env of the target function.
cx.tcx.param_env(fn_id),
cx.tcx.erase_late_bound_regions(ty),
precedence,
)
.position_for_arg()
@ -1378,11 +1405,18 @@ impl<'tcx> TyPosition<'tcx> {
}
// Checks whether a type is stable when switching to auto dereferencing,
fn ty_auto_deref_stability<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>, precedence: i8) -> TyPosition<'tcx> {
fn ty_auto_deref_stability<'tcx>(
tcx: TyCtxt<'tcx>,
param_env: ParamEnv<'tcx>,
ty: Ty<'tcx>,
precedence: i8,
) -> TyPosition<'tcx> {
let ty::Ref(_, mut ty, _) = *ty.kind() else {
return Position::Other(precedence).into();
};
ty = tcx.try_normalize_erasing_regions(param_env, ty).unwrap_or(ty);
loop {
break match *ty.kind() {
ty::Ref(_, ref_ty, _) => {
@ -1423,9 +1457,7 @@ fn ty_auto_deref_stability<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>, precedenc
| ty::Closure(..)
| ty::Never
| ty::Tuple(_)
| ty::Alias(ty::Projection, _) => {
Position::DerefStable(precedence, ty.is_sized(cx.tcx, cx.param_env.without_caller_bounds())).into()
},
| ty::Alias(ty::Projection, _) => Position::DerefStable(precedence, ty.is_sized(tcx, param_env)).into(),
};
}
}

25
clippy_utils/src/ty.rs
View file

@ -894,16 +894,29 @@ impl AdtVariantInfo {
}
/// Gets the struct or enum variant from the given `Res`
pub fn variant_of_res<'tcx>(cx: &LateContext<'tcx>, res: Res) -> Option<&'tcx VariantDef> {
pub fn adt_and_variant_of_res<'tcx>(cx: &LateContext<'tcx>, res: Res) -> Option<(AdtDef<'tcx>, &'tcx VariantDef)> {
match res {
Res::Def(DefKind::Struct, id) => Some(cx.tcx.adt_def(id).non_enum_variant()),
Res::Def(DefKind::Variant, id) => Some(cx.tcx.adt_def(cx.tcx.parent(id)).variant_with_id(id)),
Res::Def(DefKind::Ctor(CtorOf::Struct, _), id) => Some(cx.tcx.adt_def(cx.tcx.parent(id)).non_enum_variant()),
Res::Def(DefKind::Struct, id) => {
let adt = cx.tcx.adt_def(id);
Some((adt, adt.non_enum_variant()))
},
Res::Def(DefKind::Variant, id) => {
let adt = cx.tcx.adt_def(cx.tcx.parent(id));
Some((adt, adt.variant_with_id(id)))
},
Res::Def(DefKind::Ctor(CtorOf::Struct, _), id) => {
let adt = cx.tcx.adt_def(cx.tcx.parent(id));
Some((adt, adt.non_enum_variant()))
},
Res::Def(DefKind::Ctor(CtorOf::Variant, _), id) => {
let var_id = cx.tcx.parent(id);
Some(cx.tcx.adt_def(cx.tcx.parent(var_id)).variant_with_id(var_id))
let adt = cx.tcx.adt_def(cx.tcx.parent(var_id));
Some((adt, adt.variant_with_id(var_id)))
},
Res::SelfCtor(id) => {
let adt = cx.tcx.type_of(id).ty_adt_def().unwrap();
Some((adt, adt.non_enum_variant()))
},
Res::SelfCtor(id) => Some(cx.tcx.type_of(id).ty_adt_def().unwrap().non_enum_variant()),
_ => None,
}
}

14
tests/ui/explicit_auto_deref.fixed
View file

@ -269,6 +269,9 @@ fn main() {
trait WithAssoc {
type Assoc: ?Sized;
fn to_assoc(&self) -> &Self::Assoc {
panic!()
}
}
impl WithAssoc for String {
type Assoc = str;
@ -281,4 +284,15 @@ fn main() {
// Issue #9901
fn takes_ref(_: &i32) {}
takes_ref(*Box::new(&0i32));
// Issue #10384
impl<'a> WithAssoc for &'a u32 {
type Assoc = dyn core::fmt::Display;
fn to_assoc(&self) -> &Self::Assoc {
*self
}
}
fn return_dyn_assoc<'a>(x: &'a &'a u32) -> &'a <&'a u32 as WithAssoc>::Assoc {
*x
}
}

14
tests/ui/explicit_auto_deref.rs
View file

@ -269,6 +269,9 @@ fn main() {
trait WithAssoc {
type Assoc: ?Sized;
fn to_assoc(&self) -> &Self::Assoc {
panic!()
}
}
impl WithAssoc for String {
type Assoc = str;
@ -281,4 +284,15 @@ fn main() {
// Issue #9901
fn takes_ref(_: &i32) {}
takes_ref(*Box::new(&0i32));
// Issue #10384
impl<'a> WithAssoc for &'a u32 {
type Assoc = dyn core::fmt::Display;
fn to_assoc(&self) -> &Self::Assoc {
*self
}
}
fn return_dyn_assoc<'a>(x: &'a &'a u32) -> &'a <&'a u32 as WithAssoc>::Assoc {
*x
}
}