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Move check for PartialEq in UNCONDITIONAL_RECURSION lint into its own function

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This commit is contained in:
Guillaume Gomez 2023-12-18 16:36:12 +01:00
parent 7e650b7610
commit 1c431f4da9
1 changed files with 75 additions and 62 deletions
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137
clippy_lints/src/unconditional_recursion.rs
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@ -8,6 +8,7 @@ use rustc_hir::{Body, Expr, ExprKind, FnDecl, Item, ItemKind, Node};
use rustc_lint::{LateContext, LateLintPass};
use rustc_middle::ty::{self, Ty};
use rustc_session::declare_lint_pass;
use rustc_span::symbol::Ident;
use rustc_span::{sym, Span};
declare_clippy_lint! {
@ -55,6 +56,76 @@ fn is_local(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
matches!(path_res(cx, expr), Res::Local(_))
}
fn check_partial_eq(
cx: &LateContext<'_>,
body: &Body<'_>,
method_span: Span,
method_def_id: LocalDefId,
name: Ident,
) {
let args = cx
.tcx
.instantiate_bound_regions_with_erased(cx.tcx.fn_sig(method_def_id).skip_binder())
.inputs();
// That has two arguments.
if let [self_arg, other_arg] = args
&& let Some(self_arg) = get_ty_def_id(*self_arg)
&& let Some(other_arg) = get_ty_def_id(*other_arg)
// The two arguments are of the same type.
&& self_arg == other_arg
&& let hir_id = cx.tcx.local_def_id_to_hir_id(method_def_id)
&& let Some((
_,
Node::Item(Item {
kind: ItemKind::Impl(impl_),
owner_id,
..
}),
)) = cx.tcx.hir().parent_iter(hir_id).next()
// We exclude `impl` blocks generated from rustc's proc macros.
&& !cx.tcx.has_attr(*owner_id, sym::automatically_derived)
// It is a implementation of a trait.
&& let Some(trait_) = impl_.of_trait
&& let Some(trait_def_id) = trait_.trait_def_id()
// The trait is `PartialEq`.
&& Some(trait_def_id) == get_trait_def_id(cx, &["core", "cmp", "PartialEq"])
{
let to_check_op = if name.name == sym::eq {
BinOpKind::Eq
} else {
BinOpKind::Ne
};
let expr = body.value.peel_blocks();
let is_bad = match expr.kind {
ExprKind::Binary(op, left, right) if op.node == to_check_op => is_local(cx, left) && is_local(cx, right),
ExprKind::MethodCall(segment, receiver, &[arg], _) if segment.ident.name == name.name => {
if is_local(cx, receiver)
&& is_local(cx, &arg)
&& let Some(fn_id) = cx.typeck_results().type_dependent_def_id(expr.hir_id)
&& let Some(trait_id) = cx.tcx.trait_of_item(fn_id)
&& trait_id == trait_def_id
{
true
} else {
false
}
},
_ => false,
};
if is_bad {
span_lint_and_then(
cx,
UNCONDITIONAL_RECURSION,
method_span,
"function cannot return without recursing",
|diag| {
diag.span_note(expr.span, "recursive call site");
},
);
}
}
}
impl<'tcx> LateLintPass<'tcx> for UnconditionalRecursion {
#[allow(clippy::unnecessary_def_path)]
fn check_fn(
@ -64,70 +135,12 @@ impl<'tcx> LateLintPass<'tcx> for UnconditionalRecursion {
_decl: &'tcx FnDecl<'tcx>,
body: &'tcx Body<'tcx>,
method_span: Span,
def_id: LocalDefId,
method_def_id: LocalDefId,
) {
// If the function is a method...
if let FnKind::Method(name, _) = kind
// That has two arguments.
&& let [self_arg, other_arg] = cx
.tcx
.instantiate_bound_regions_with_erased(cx.tcx.fn_sig(def_id).skip_binder())
.inputs()
&& let Some(self_arg) = get_ty_def_id(*self_arg)
&& let Some(other_arg) = get_ty_def_id(*other_arg)
// The two arguments are of the same type.
&& self_arg == other_arg
&& let hir_id = cx.tcx.local_def_id_to_hir_id(def_id)
&& let Some((
_,
Node::Item(Item {
kind: ItemKind::Impl(impl_),
owner_id,
..
}),
)) = cx.tcx.hir().parent_iter(hir_id).next()
// We exclude `impl` blocks generated from rustc's proc macros.
&& !cx.tcx.has_attr(*owner_id, sym::automatically_derived)
// It is a implementation of a trait.
&& let Some(trait_) = impl_.of_trait
&& let Some(trait_def_id) = trait_.trait_def_id()
// The trait is `PartialEq`.
&& Some(trait_def_id) == get_trait_def_id(cx, &["core", "cmp", "PartialEq"])
{
let to_check_op = if name.name == sym::eq {
BinOpKind::Eq
} else {
BinOpKind::Ne
};
let expr = body.value.peel_blocks();
let is_bad = match expr.kind {
ExprKind::Binary(op, left, right) if op.node == to_check_op => {
is_local(cx, left) && is_local(cx, right)
},
ExprKind::MethodCall(segment, receiver, &[arg], _) if segment.ident.name == name.name => {
if is_local(cx, receiver)
&& is_local(cx, &arg)
&& let Some(fn_id) = cx.typeck_results().type_dependent_def_id(expr.hir_id)
&& let Some(trait_id) = cx.tcx.trait_of_item(fn_id)
&& trait_id == trait_def_id
{
true
} else {
false
}
},
_ => false,
};
if is_bad {
span_lint_and_then(
cx,
UNCONDITIONAL_RECURSION,
method_span,
"function cannot return without recursing",
|diag| {
diag.span_note(expr.span, "recursive call site");
},
);
if let FnKind::Method(name, _) = kind {
if name.name == sym::eq || name.name == sym::ne {
check_partial_eq(cx, body, method_span, method_def_id, name);
}
}
}