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Auto merge of #13045 - J-ZhengLi:missing_const_for_fn_FP, r=blyxyas

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[`missing_const_for_fn`]: fix FP when arg ty is impl trait alias ty

closes: #13009

---

changelog: [`missing_const_for_fn`]: fix FP when arg ty is impl trait alias ty
This commit is contained in:
bors 2024-07-08 14:39:12 +00:00
commit 2ad8cdc81b
5 changed files with 68 additions and 1 deletions
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17
clippy_lints/src/missing_const_for_fn.rs
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@ -8,6 +8,7 @@ use rustc_hir::intravisit::FnKind;
use rustc_hir::{self as hir, Body, Constness, FnDecl, GenericParamKind};
use rustc_lint::{LateContext, LateLintPass};
use rustc_middle::lint::in_external_macro;
use rustc_middle::ty;
use rustc_session::impl_lint_pass;
use rustc_span::def_id::LocalDefId;
use rustc_span::Span;
@ -131,6 +132,10 @@ impl<'tcx> LateLintPass<'tcx> for MissingConstForFn {
FnKind::Closure => return,
}
if fn_inputs_has_impl_trait_ty(cx, def_id) {
return;
}
let hir_id = cx.tcx.local_def_id_to_hir_id(def_id);
// Const fns are not allowed as methods in a trait.
@ -185,3 +190,15 @@ fn could_be_const_with_abi(cx: &LateContext<'_>, msrv: &Msrv, abi: Abi) -> bool
_ => cx.tcx.features().const_extern_fn,
}
}
/// Return `true` when the given `def_id` is a function that has `impl Trait` ty as one of
/// its parameter types.
fn fn_inputs_has_impl_trait_ty(cx: &LateContext<'_>, def_id: LocalDefId) -> bool {
let inputs = cx.tcx.fn_sig(def_id).instantiate_identity().inputs().skip_binder();
inputs.iter().any(|input| {
matches!(
input.kind(),
ty::Alias(ty::AliasTyKind::Weak, alias_ty) if cx.tcx.type_of(alias_ty.def_id).skip_binder().is_impl_trait()
)
})
}