[unconditional_recursion]: catch From -> Into -> From

This commit is contained in:
y21 2024-03-10 19:40:31 +00:00
parent 7ee75f896f
commit 65defdb474
4 changed files with 174 additions and 85 deletions

View file

@ -1,5 +1,5 @@
use clippy_utils::diagnostics::span_lint_and_then;
use clippy_utils::{expr_or_init, get_trait_def_id, path_def_id};
use clippy_utils::{expr_or_init, fn_def_id_with_node_args, path_def_id};
use rustc_ast::BinOpKind;
use rustc_data_structures::fx::FxHashMap;
use rustc_hir as hir;
@ -19,11 +19,11 @@ use rustc_trait_selection::traits::error_reporting::suggestions::ReturnsVisitor;
declare_clippy_lint! {
/// ### What it does
/// Checks that there isn't an infinite recursion in `PartialEq` trait
/// implementation.
/// Checks that there isn't an infinite recursion in trait
/// implementations.
///
/// ### Why is this bad?
/// This is a hard to find infinite recursion which will crashing any code
/// This is a hard to find infinite recursion that will crash any code.
/// using it.
///
/// ### Example
@ -201,7 +201,6 @@ fn check_partial_eq(cx: &LateContext<'_>, method_span: Span, method_def_id: Loca
}
}
#[allow(clippy::unnecessary_def_path)]
fn check_to_string(cx: &LateContext<'_>, method_span: Span, method_def_id: LocalDefId, name: Ident, expr: &Expr<'_>) {
let args = cx
.tcx
@ -224,7 +223,7 @@ fn check_to_string(cx: &LateContext<'_>, method_span: Span, method_def_id: Local
&& let Some(trait_) = impl_.of_trait
&& let Some(trait_def_id) = trait_.trait_def_id()
// The trait is `ToString`.
&& Some(trait_def_id) == get_trait_def_id(cx, &["alloc", "string", "ToString"])
&& cx.tcx.is_diagnostic_item(sym::ToString, trait_def_id)
{
let is_bad = match expr.kind {
ExprKind::MethodCall(segment, _receiver, &[_arg], _) if segment.ident.name == name.name => {
@ -291,7 +290,6 @@ where
self.map
}
#[allow(clippy::unnecessary_def_path)]
fn visit_expr(&mut self, expr: &'tcx Expr<'tcx>) {
if self.found_default_call {
return;
@ -303,7 +301,7 @@ where
&& is_default_method_on_current_ty(self.cx.tcx, qpath, self.implemented_ty_id)
&& let Some(method_def_id) = path_def_id(self.cx, f)
&& let Some(trait_def_id) = self.cx.tcx.trait_of_item(method_def_id)
&& Some(trait_def_id) == get_trait_def_id(self.cx, &["core", "default", "Default"])
&& self.cx.tcx.is_diagnostic_item(sym::Default, trait_def_id)
{
self.found_default_call = true;
span_error(self.cx, self.method_span, expr);
@ -312,10 +310,9 @@ where
}
impl UnconditionalRecursion {
#[allow(clippy::unnecessary_def_path)]
fn init_default_impl_for_type_if_needed(&mut self, cx: &LateContext<'_>) {
if self.default_impl_for_type.is_empty()
&& let Some(default_trait_id) = get_trait_def_id(cx, &["core", "default", "Default"])
&& let Some(default_trait_id) = cx.tcx.get_diagnostic_item(sym::Default)
{
let impls = cx.tcx.trait_impls_of(default_trait_id);
for (ty, impl_def_ids) in impls.non_blanket_impls() {
@ -394,6 +391,34 @@ impl UnconditionalRecursion {
}
}
fn check_from(cx: &LateContext<'_>, method_span: Span, method_def_id: LocalDefId, expr: &Expr<'_>) {
let Some(sig) = cx
.typeck_results()
.liberated_fn_sigs()
.get(cx.tcx.local_def_id_to_hir_id(method_def_id))
else {
return;
};
// Check if we are calling `Into::into` where the node args match with our `From::from` signature:
// From::from signature: fn(S1) -> S2
// <S1 as Into<S2>>::into(s1), node_args=[S1, S2]
// If they do match, then it must mean that it is the blanket impl,
// which calls back into our `From::from` again (`Into` is not specializable).
// rustc's unconditional_recursion already catches calling `From::from` directly
if let Some((fn_def_id, node_args)) = fn_def_id_with_node_args(cx, expr)
&& let [s1, s2] = **node_args
&& let (Some(s1), Some(s2)) = (s1.as_type(), s2.as_type())
&& let Some(trait_def_id) = cx.tcx.trait_of_item(fn_def_id)
&& cx.tcx.is_diagnostic_item(sym::Into, trait_def_id)
&& get_impl_trait_def_id(cx, method_def_id) == cx.tcx.get_diagnostic_item(sym::From)
&& s1 == sig.inputs()[0]
&& s2 == sig.output()
{
span_error(cx, method_span, expr);
}
}
impl<'tcx> LateLintPass<'tcx> for UnconditionalRecursion {
fn check_fn(
&mut self,
@ -410,10 +435,11 @@ impl<'tcx> LateLintPass<'tcx> for UnconditionalRecursion {
// Doesn't have a conditional return.
&& !has_conditional_return(body, expr)
{
if name.name == sym::eq || name.name == sym::ne {
check_partial_eq(cx, method_span, method_def_id, name, expr);
} else if name.name == sym::to_string {
check_to_string(cx, method_span, method_def_id, name, expr);
match name.name {
sym::eq | sym::ne => check_partial_eq(cx, method_span, method_def_id, name, expr),
sym::to_string => check_to_string(cx, method_span, method_def_id, name, expr),
sym::from => check_from(cx, method_span, method_def_id, expr),
_ => {},
}
self.check_default_new(cx, decl, body, method_span, method_def_id);
}

View file

@ -2249,8 +2249,21 @@ pub fn fn_has_unsatisfiable_preds(cx: &LateContext<'_>, did: DefId) -> bool {
/// Returns the `DefId` of the callee if the given expression is a function or method call.
pub fn fn_def_id(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<DefId> {
fn_def_id_with_node_args(cx, expr).map(|(did, _)| did)
}
/// Returns the `DefId` of the callee if the given expression is a function or method call,
/// as well as its node args.
pub fn fn_def_id_with_node_args<'tcx>(
cx: &LateContext<'tcx>,
expr: &Expr<'_>,
) -> Option<(DefId, rustc_ty::GenericArgsRef<'tcx>)> {
let typeck = cx.typeck_results();
match &expr.kind {
ExprKind::MethodCall(..) => cx.typeck_results().type_dependent_def_id(expr.hir_id),
ExprKind::MethodCall(..) => Some((
typeck.type_dependent_def_id(expr.hir_id)?,
typeck.node_args(expr.hir_id),
)),
ExprKind::Call(
Expr {
kind: ExprKind::Path(qpath),
@ -2262,9 +2275,9 @@ pub fn fn_def_id(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<DefId> {
// Only return Fn-like DefIds, not the DefIds of statics/consts/etc that contain or
// deref to fn pointers, dyn Fn, impl Fn - #8850
if let Res::Def(DefKind::Fn | DefKind::Ctor(..) | DefKind::AssocFn, id) =
cx.typeck_results().qpath_res(qpath, *path_hir_id)
typeck.qpath_res(qpath, *path_hir_id)
{
Some(id)
Some((id, typeck.node_args(*path_hir_id)))
} else {
None
}

View file

@ -1,7 +1,11 @@
//@no-rustfix
#![warn(clippy::unconditional_recursion)]
#![allow(clippy::partialeq_ne_impl, clippy::default_constructed_unit_structs)]
#![allow(
clippy::partialeq_ne_impl,
clippy::default_constructed_unit_structs,
clippy::only_used_in_recursion
)]
enum Foo {
A,
@ -350,4 +354,48 @@ mod issue12154 {
}
}
// From::from -> Into::into -> From::from
struct BadFromTy1<'a>(&'a ());
struct BadIntoTy1<'b>(&'b ());
impl<'a> From<BadFromTy1<'a>> for BadIntoTy1<'static> {
fn from(f: BadFromTy1<'a>) -> Self {
f.into()
}
}
// Using UFCS syntax
struct BadFromTy2<'a>(&'a ());
struct BadIntoTy2<'b>(&'b ());
impl<'a> From<BadFromTy2<'a>> for BadIntoTy2<'static> {
fn from(f: BadFromTy2<'a>) -> Self {
Into::into(f)
}
}
// Different Into impl (<i16 as Into<i32>>), so no infinite recursion
struct BadFromTy3;
impl From<BadFromTy3> for i32 {
fn from(f: BadFromTy3) -> Self {
Into::into(1i16)
}
}
// A conditional return that ends the recursion
struct BadFromTy4;
impl From<BadFromTy4> for i32 {
fn from(f: BadFromTy4) -> Self {
if true {
return 42;
}
f.into()
}
}
// Types differ in refs, don't lint
impl From<&BadFromTy4> for i32 {
fn from(f: &BadFromTy4) -> Self {
BadFromTy4.into()
}
}
fn main() {}

View file

@ -1,5 +1,5 @@
error: function cannot return without recursing
--> tests/ui/unconditional_recursion.rs:42:5
--> tests/ui/unconditional_recursion.rs:46:5
|
LL | fn ne(&self, other: &Self) -> bool {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot return without recursing
@ -12,7 +12,7 @@ LL | self.ne(other)
= help: to override `-D warnings` add `#[allow(unconditional_recursion)]`
error: function cannot return without recursing
--> tests/ui/unconditional_recursion.rs:46:5
--> tests/ui/unconditional_recursion.rs:50:5
|
LL | fn eq(&self, other: &Self) -> bool {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot return without recursing
@ -23,7 +23,7 @@ LL | self.eq(other)
= help: a `loop` may express intention better if this is on purpose
error: function cannot return without recursing
--> tests/ui/unconditional_recursion.rs:211:5
--> tests/ui/unconditional_recursion.rs:215:5
|
LL | fn to_string(&self) -> String {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot return without recursing
@ -34,7 +34,7 @@ LL | self.to_string()
= help: a `loop` may express intention better if this is on purpose
error: function cannot return without recursing
--> tests/ui/unconditional_recursion.rs:221:5
--> tests/ui/unconditional_recursion.rs:225:5
|
LL | fn to_string(&self) -> String {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot return without recursing
@ -45,7 +45,7 @@ LL | x.to_string()
= help: a `loop` may express intention better if this is on purpose
error: function cannot return without recursing
--> tests/ui/unconditional_recursion.rs:232:5
--> tests/ui/unconditional_recursion.rs:236:5
|
LL | fn to_string(&self) -> String {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot return without recursing
@ -56,7 +56,7 @@ LL | (self as &Self).to_string()
= help: a `loop` may express intention better if this is on purpose
error: function cannot return without recursing
--> tests/ui/unconditional_recursion.rs:12:5
--> tests/ui/unconditional_recursion.rs:16:5
|
LL | / fn ne(&self, other: &Self) -> bool {
LL | |
@ -65,7 +65,7 @@ LL | | }
| |_____^
|
note: recursive call site
--> tests/ui/unconditional_recursion.rs:14:9
--> tests/ui/unconditional_recursion.rs:18:9
|
LL | self != other
| ^^^^^^^^^^^^^
@ -73,7 +73,7 @@ LL | self != other
= help: to override `-D warnings` add `#[allow(clippy::unconditional_recursion)]`
error: function cannot return without recursing
--> tests/ui/unconditional_recursion.rs:16:5
--> tests/ui/unconditional_recursion.rs:20:5
|
LL | / fn eq(&self, other: &Self) -> bool {
LL | |
@ -82,13 +82,13 @@ LL | | }
| |_____^
|
note: recursive call site
--> tests/ui/unconditional_recursion.rs:18:9
--> tests/ui/unconditional_recursion.rs:22:9
|
LL | self == other
| ^^^^^^^^^^^^^
error: function cannot return without recursing
--> tests/ui/unconditional_recursion.rs:28:5
--> tests/ui/unconditional_recursion.rs:32:5
|
LL | / fn ne(&self, other: &Self) -> bool {
LL | | self != &Foo2::B // no error here
@ -96,13 +96,13 @@ LL | | }
| |_____^
|
note: recursive call site
--> tests/ui/unconditional_recursion.rs:29:9
--> tests/ui/unconditional_recursion.rs:33:9
|
LL | self != &Foo2::B // no error here
| ^^^^^^^^^^^^^^^^
error: function cannot return without recursing
--> tests/ui/unconditional_recursion.rs:31:5
--> tests/ui/unconditional_recursion.rs:35:5
|
LL | / fn eq(&self, other: &Self) -> bool {
LL | | self == &Foo2::B // no error here
@ -110,13 +110,13 @@ LL | | }
| |_____^
|
note: recursive call site
--> tests/ui/unconditional_recursion.rs:32:9
--> tests/ui/unconditional_recursion.rs:36:9
|
LL | self == &Foo2::B // no error here
| ^^^^^^^^^^^^^^^^
error: function cannot return without recursing
--> tests/ui/unconditional_recursion.rs:42:5
--> tests/ui/unconditional_recursion.rs:46:5
|
LL | / fn ne(&self, other: &Self) -> bool {
LL | |
@ -125,27 +125,13 @@ LL | | }
| |_____^
|
note: recursive call site
--> tests/ui/unconditional_recursion.rs:44:9
--> tests/ui/unconditional_recursion.rs:48:9
|
LL | self.ne(other)
| ^^^^^^^^^^^^^^
error: parameter is only used in recursion
--> tests/ui/unconditional_recursion.rs:42:18
|
LL | fn ne(&self, other: &Self) -> bool {
| ^^^^^ help: if this is intentional, prefix it with an underscore: `_other`
|
note: parameter used here
--> tests/ui/unconditional_recursion.rs:44:17
|
LL | self.ne(other)
| ^^^^^
= note: `-D clippy::only-used-in-recursion` implied by `-D warnings`
= help: to override `-D warnings` add `#[allow(clippy::only_used_in_recursion)]`
error: function cannot return without recursing
--> tests/ui/unconditional_recursion.rs:46:5
--> tests/ui/unconditional_recursion.rs:50:5
|
LL | / fn eq(&self, other: &Self) -> bool {
LL | |
@ -154,25 +140,13 @@ LL | | }
| |_____^
|
note: recursive call site
--> tests/ui/unconditional_recursion.rs:48:9
--> tests/ui/unconditional_recursion.rs:52:9
|
LL | self.eq(other)
| ^^^^^^^^^^^^^^
error: parameter is only used in recursion
--> tests/ui/unconditional_recursion.rs:46:18
|
LL | fn eq(&self, other: &Self) -> bool {
| ^^^^^ help: if this is intentional, prefix it with an underscore: `_other`
|
note: parameter used here
--> tests/ui/unconditional_recursion.rs:48:17
|
LL | self.eq(other)
| ^^^^^
error: function cannot return without recursing
--> tests/ui/unconditional_recursion.rs:90:5
--> tests/ui/unconditional_recursion.rs:94:5
|
LL | / fn ne(&self, other: &Self) -> bool {
LL | |
@ -181,13 +155,13 @@ LL | | }
| |_____^
|
note: recursive call site
--> tests/ui/unconditional_recursion.rs:92:9
--> tests/ui/unconditional_recursion.rs:96:9
|
LL | other != self
| ^^^^^^^^^^^^^
error: function cannot return without recursing
--> tests/ui/unconditional_recursion.rs:94:5
--> tests/ui/unconditional_recursion.rs:98:5
|
LL | / fn eq(&self, other: &Self) -> bool {
LL | |
@ -196,13 +170,13 @@ LL | | }
| |_____^
|
note: recursive call site
--> tests/ui/unconditional_recursion.rs:96:9
--> tests/ui/unconditional_recursion.rs:100:9
|
LL | other == self
| ^^^^^^^^^^^^^
error: function cannot return without recursing
--> tests/ui/unconditional_recursion.rs:104:5
--> tests/ui/unconditional_recursion.rs:108:5
|
LL | / fn ne(&self, other: &Self) -> bool {
LL | |
@ -211,13 +185,13 @@ LL | | }
| |_____^
|
note: recursive call site
--> tests/ui/unconditional_recursion.rs:106:9
--> tests/ui/unconditional_recursion.rs:110:9
|
LL | other != other
| ^^^^^^^^^^^^^^
error: equal expressions as operands to `!=`
--> tests/ui/unconditional_recursion.rs:106:9
--> tests/ui/unconditional_recursion.rs:110:9
|
LL | other != other
| ^^^^^^^^^^^^^^
@ -225,7 +199,7 @@ LL | other != other
= note: `#[deny(clippy::eq_op)]` on by default
error: function cannot return without recursing
--> tests/ui/unconditional_recursion.rs:108:5
--> tests/ui/unconditional_recursion.rs:112:5
|
LL | / fn eq(&self, other: &Self) -> bool {
LL | |
@ -234,19 +208,19 @@ LL | | }
| |_____^
|
note: recursive call site
--> tests/ui/unconditional_recursion.rs:110:9
--> tests/ui/unconditional_recursion.rs:114:9
|
LL | other == other
| ^^^^^^^^^^^^^^
error: equal expressions as operands to `==`
--> tests/ui/unconditional_recursion.rs:110:9
--> tests/ui/unconditional_recursion.rs:114:9
|
LL | other == other
| ^^^^^^^^^^^^^^
error: function cannot return without recursing
--> tests/ui/unconditional_recursion.rs:117:5
--> tests/ui/unconditional_recursion.rs:121:5
|
LL | / fn ne(&self, _other: &Self) -> bool {
LL | |
@ -255,19 +229,19 @@ LL | | }
| |_____^
|
note: recursive call site
--> tests/ui/unconditional_recursion.rs:119:9
--> tests/ui/unconditional_recursion.rs:123:9
|
LL | self != self
| ^^^^^^^^^^^^
error: equal expressions as operands to `!=`
--> tests/ui/unconditional_recursion.rs:119:9
--> tests/ui/unconditional_recursion.rs:123:9
|
LL | self != self
| ^^^^^^^^^^^^
error: function cannot return without recursing
--> tests/ui/unconditional_recursion.rs:121:5
--> tests/ui/unconditional_recursion.rs:125:5
|
LL | / fn eq(&self, _other: &Self) -> bool {
LL | |
@ -276,19 +250,19 @@ LL | | }
| |_____^
|
note: recursive call site
--> tests/ui/unconditional_recursion.rs:123:9
--> tests/ui/unconditional_recursion.rs:127:9
|
LL | self == self
| ^^^^^^^^^^^^
error: equal expressions as operands to `==`
--> tests/ui/unconditional_recursion.rs:123:9
--> tests/ui/unconditional_recursion.rs:127:9
|
LL | self == self
| ^^^^^^^^^^^^
error: function cannot return without recursing
--> tests/ui/unconditional_recursion.rs:149:13
--> tests/ui/unconditional_recursion.rs:153:13
|
LL | / fn eq(&self, other: &Self) -> bool {
LL | |
@ -300,7 +274,7 @@ LL | impl_partial_eq!(S5);
| -------------------- in this macro invocation
|
note: recursive call site
--> tests/ui/unconditional_recursion.rs:151:17
--> tests/ui/unconditional_recursion.rs:155:17
|
LL | self == other
| ^^^^^^^^^^^^^
@ -310,7 +284,7 @@ LL | impl_partial_eq!(S5);
= note: this error originates in the macro `impl_partial_eq` (in Nightly builds, run with -Z macro-backtrace for more info)
error: function cannot return without recursing
--> tests/ui/unconditional_recursion.rs:178:5
--> tests/ui/unconditional_recursion.rs:182:5
|
LL | / fn eq(&self, other: &Self) -> bool {
LL | |
@ -321,13 +295,13 @@ LL | | }
| |_____^
|
note: recursive call site
--> tests/ui/unconditional_recursion.rs:182:9
--> tests/ui/unconditional_recursion.rs:186:9
|
LL | mine == theirs
| ^^^^^^^^^^^^^^
error: function cannot return without recursing
--> tests/ui/unconditional_recursion.rs:247:5
--> tests/ui/unconditional_recursion.rs:251:5
|
LL | / fn new() -> Self {
LL | |
@ -336,13 +310,13 @@ LL | | }
| |_____^
|
note: recursive call site
--> tests/ui/unconditional_recursion.rs:249:9
--> tests/ui/unconditional_recursion.rs:253:9
|
LL | Self::default()
| ^^^^^^^^^^^^^^^
error: function cannot return without recursing
--> tests/ui/unconditional_recursion.rs:286:5
--> tests/ui/unconditional_recursion.rs:290:5
|
LL | / fn eq(&self, other: &Self) -> bool {
LL | |
@ -353,10 +327,38 @@ LL | | }
| |_____^
|
note: recursive call site
--> tests/ui/unconditional_recursion.rs:290:9
--> tests/ui/unconditional_recursion.rs:294:9
|
LL | mine.eq(theirs)
| ^^^^^^^^^^^^^^^
error: function cannot return without recursing
--> tests/ui/unconditional_recursion.rs:361:5
|
LL | / fn from(f: BadFromTy1<'a>) -> Self {
LL | | f.into()
LL | | }
| |_____^
|
note: recursive call site
--> tests/ui/unconditional_recursion.rs:362:9
|
LL | f.into()
| ^^^^^^^^
error: function cannot return without recursing
--> tests/ui/unconditional_recursion.rs:370:5
|
LL | / fn from(f: BadFromTy2<'a>) -> Self {
LL | | Into::into(f)
LL | | }
| |_____^
|
note: recursive call site
--> tests/ui/unconditional_recursion.rs:371:9
|
LL | Into::into(f)
| ^^^^^^^^^^^^^
error: aborting due to 27 previous errors