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Auto merge of #11070 - y21:issue11065, r=flip1995

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[`useless_conversion`]: only lint on paths to fn items and fix FP in macro

Fixes #11065 (which is actually two issues: an ICE and a false positive)

It now makes sure that the function call path points to a function-like item (and not e.g. a `const` like in the linked issue), so that calling `TyCtxt::fn_sig` later in the lint does not ICE (fixes https://github.com/rust-lang/rust-clippy/issues/11065#issuecomment-1616836099).
It *also* makes sure that the expression is not part of a macro call (fixes https://github.com/rust-lang/rust-clippy/issues/11065#issuecomment-1616919639). ~~I'm not sure if there's a better way to check this other than to walk the parent expr chain and see if any of them are expansions.~~ (edit: it doesn't do this anymore)

changelog: [`useless_conversion`]: fix ICE when call receiver is a non-fn item
changelog: [`useless_conversion`]: don't lint if argument is a macro argument (fixes a FP)

r? `@llogiq` (reviewed #10814, which introduced these issues)
This commit is contained in:
bors 2023-08-17 14:41:46 +00:00
commit 701e77c87f
5 changed files with 72 additions and 13 deletions
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18
clippy_lints/src/useless_conversion.rs
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@ -5,6 +5,7 @@ use clippy_utils::ty::{is_copy, is_type_diagnostic_item, same_type_and_consts};
use clippy_utils::{get_parent_expr, is_trait_method, is_ty_alias, match_def_path, path_to_local, paths};
use if_chain::if_chain;
use rustc_errors::Applicability;
use rustc_hir::def::DefKind;
use rustc_hir::def_id::DefId;
use rustc_hir::{BindingAnnotation, Expr, ExprKind, HirId, MatchSource, Node, PatKind};
use rustc_lint::{LateContext, LateLintPass};
@ -39,6 +40,7 @@ declare_clippy_lint! {
#[derive(Default)]
pub struct UselessConversion {
try_desugar_arm: Vec<HirId>,
expn_depth: u32,
}
impl_lint_pass!(UselessConversion => [USELESS_CONVERSION]);
@ -105,6 +107,7 @@ fn into_iter_deep_call<'hir>(cx: &LateContext<'_>, mut expr: &'hir Expr<'hir>) -
impl<'tcx> LateLintPass<'tcx> for UselessConversion {
fn check_expr(&mut self, cx: &LateContext<'tcx>, e: &'tcx Expr<'_>) {
if e.span.from_expansion() {
self.expn_depth += 1;
return;
}
@ -150,9 +153,14 @@ impl<'tcx> LateLintPass<'tcx> for UselessConversion {
{
if let Some(parent) = get_parent_expr(cx, e) {
let parent_fn = match parent.kind {
ExprKind::Call(recv, args) if let ExprKind::Path(ref qpath) = recv.kind => {
cx.qpath_res(qpath, recv.hir_id).opt_def_id()
.map(|did| (did, args, MethodOrFunction::Function))
ExprKind::Call(recv, args)
if let ExprKind::Path(ref qpath) = recv.kind
&& let Some(did) = cx.qpath_res(qpath, recv.hir_id).opt_def_id()
// make sure that the path indeed points to a fn-like item, so that
// `fn_sig` does not ICE. (see #11065)
&& cx.tcx.opt_def_kind(did).is_some_and(DefKind::is_fn_like) =>
{
Some((did, args, MethodOrFunction::Function))
}
ExprKind::MethodCall(.., args, _) => {
cx.typeck_results().type_dependent_def_id(parent.hir_id)
@ -168,6 +176,7 @@ impl<'tcx> LateLintPass<'tcx> for UselessConversion {
&& let Some(&into_iter_param) = sig.inputs().get(kind.param_pos(arg_pos))
&& let ty::Param(param) = into_iter_param.kind()
&& let Some(span) = into_iter_bound(cx, parent_fn_did, into_iter_did, param.index)
&& self.expn_depth == 0
{
// Get the "innermost" `.into_iter()` call, e.g. given this expression:
// `foo.into_iter().into_iter()`
@ -303,5 +312,8 @@ impl<'tcx> LateLintPass<'tcx> for UselessConversion {
if Some(&e.hir_id) == self.try_desugar_arm.last() {
self.try_desugar_arm.pop();
}
if e.span.from_expansion() {
self.expn_depth -= 1;
}
}
}