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inline function
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@y21
y21 committed Sep 21, 2023
1 parent fddd397 commit 6a58a19
Showing 1 changed file with 63 additions and 70 deletions.
133 changes: 63 additions & 70 deletions clippy_lints/src/iter_without_into_iter.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -3,7 +3,7 @@ use clippy_utils::get_parent_as_impl;
use clippy_utils::source::snippet;
use clippy_utils::ty::{implements_trait, make_normalized_projection};
use rustc_errors::Applicability;
use rustc_hir::{FnRetTy, ImplItemKind, ImplicitSelfKind, Mutability, TyKind};
use rustc_hir::{FnRetTy, ImplItemKind, ImplicitSelfKind, TyKind};
use rustc_lint::{LateContext, LateLintPass};
use rustc_session::{declare_lint_pass, declare_tool_lint};
use rustc_span::sym;
Expand Down Expand Up @@ -56,58 +56,60 @@ fn is_nameable_in_impl_trait(ty: &rustc_hir::Ty<'_>) -> bool {
!matches!(ty.kind, TyKind::OpaqueDef(..))
}

fn check_for_mutability(cx: &LateContext<'_>, item: &rustc_hir::ImplItem<'_>, expected_mtbl: Mutability) {
let item_did = item.owner_id.to_def_id();
let (borrow_prefix, name, expected_implicit_self) = match expected_mtbl {
Mutability::Not => ("&", "iter", ImplicitSelfKind::ImmRef),
Mutability::Mut => ("&mut ", "iter_mut", ImplicitSelfKind::MutRef),
};
impl LateLintPass<'_> for IterWithoutIntoIter {
fn check_impl_item(&mut self, cx: &LateContext<'_>, item: &rustc_hir::ImplItem<'_>) {
let item_did = item.owner_id.to_def_id();
let (borrow_prefix, expected_implicit_self) = match item.ident.name {
sym::iter => ("&", ImplicitSelfKind::ImmRef),
sym::iter_mut => ("&mut ", ImplicitSelfKind::MutRef),
_ => return,
};

if let ImplItemKind::Fn(sig, _) = item.kind
&& let FnRetTy::Return(ret) = sig.decl.output
&& is_nameable_in_impl_trait(ret)
&& cx.tcx.generics_of(item_did).params.is_empty()
&& sig.decl.implicit_self == expected_implicit_self
&& sig.decl.inputs.len() == 1
&& let Some(imp) = get_parent_as_impl(cx.tcx, item.hir_id())
&& imp.of_trait.is_none()
&& let sig = cx.tcx.liberate_late_bound_regions(
item_did,
cx.tcx.fn_sig(item_did).skip_binder()
)
&& let ref_ty = sig.inputs()[0]
&& let Some(into_iter_did) = cx.tcx.get_diagnostic_item(sym::IntoIterator)
&& let ret_ty = sig.output()
// Order is important here, we need to check that the `fn iter` return type actually implements `IntoIterator`
// *before* normalizing `<_ as IntoIterator>::Item` (otherwise make_normalized_projection ICEs)
&& implements_trait(cx, ret_ty, into_iter_did, &[])
&& let Some(iter_ty) = make_normalized_projection(
cx.tcx,
cx.param_env,
into_iter_did,
sym!(Item),
[ret_ty],
)
// Only lint if the `IntoIterator` impl doesn't actually exist
&& !implements_trait(cx, ref_ty, into_iter_did, &[])
{
let self_ty_snippet = format!("{borrow_prefix}{}", snippet(cx, imp.self_ty.span, ".."));
if let ImplItemKind::Fn(sig, _) = item.kind
&& let FnRetTy::Return(ret) = sig.decl.output
&& is_nameable_in_impl_trait(ret)
&& cx.tcx.generics_of(item_did).params.is_empty()
&& sig.decl.implicit_self == expected_implicit_self
&& sig.decl.inputs.len() == 1
&& let Some(imp) = get_parent_as_impl(cx.tcx, item.hir_id())
&& imp.of_trait.is_none()
&& let sig = cx.tcx.liberate_late_bound_regions(
item_did,
cx.tcx.fn_sig(item_did).skip_binder()
)
&& let ref_ty = sig.inputs()[0]
&& let Some(into_iter_did) = cx.tcx.get_diagnostic_item(sym::IntoIterator)
&& let ret_ty = sig.output()
// Order is important here, we need to check that the `fn iter` return type actually implements `IntoIterator`
// *before* normalizing `<_ as IntoIterator>::Item` (otherwise make_normalized_projection ICEs)
&& implements_trait(cx, ret_ty, into_iter_did, &[])
&& let Some(iter_ty) = make_normalized_projection(
cx.tcx,
cx.param_env,
into_iter_did,
sym!(Item),
[ret_ty],
)
// Only lint if the `IntoIterator` impl doesn't actually exist
&& !implements_trait(cx, ref_ty, into_iter_did, &[])
{
let self_ty_snippet = format!("{borrow_prefix}{}", snippet(cx, imp.self_ty.span, ".."));

span_lint_and_then(
cx,
ITER_WITHOUT_INTO_ITER,
item.span,
&format!("`{name}` method without an `IntoIterator` impl for `{self_ty_snippet}`"),
|diag| {
// Get the lower span of the `impl` block, and insert the suggestion right before it:
// impl X {
// ^ fn iter(&self) -> impl IntoIterator { ... }
// }
let span_behind_impl = cx.tcx
.def_span(cx.tcx.hir().parent_id(item.hir_id()).owner.def_id)
.shrink_to_lo();
span_lint_and_then(
cx,
ITER_WITHOUT_INTO_ITER,
item.span,
&format!("`{}` method without an `IntoIterator` impl for `{self_ty_snippet}`", item.ident),
|diag| {
// Get the lower span of the `impl` block, and insert the suggestion right before it:
// impl X {
// ^ fn iter(&self) -> impl IntoIterator { ... }
// }
let span_behind_impl = cx.tcx
.def_span(cx.tcx.hir().parent_id(item.hir_id()).owner.def_id)
.shrink_to_lo();

let sugg = format!(
let sugg = format!(
"
impl IntoIterator for {self_ty_snippet} {{
type IntoIter = {ret_ty};
Expand All @@ -117,25 +119,16 @@ impl IntoIterator for {self_ty_snippet} {{
}}
}}
"
);
diag.span_suggestion_verbose(
span_behind_impl,
format!("consider implementing `IntoIterator` for `{self_ty_snippet}`"),
sugg,
// Suggestion is on a best effort basis, might need some adjustments by the user
// such as adding some lifetimes in the associated types, or importing types.
Applicability::Unspecified,
);
});
}
}

impl LateLintPass<'_> for IterWithoutIntoIter {
fn check_impl_item(&mut self, cx: &LateContext<'_>, item: &rustc_hir::ImplItem<'_>) {
match item.ident.name {
sym::iter => check_for_mutability(cx, item, Mutability::Not),
sym::iter_mut => check_for_mutability(cx, item, Mutability::Mut),
_ => {},
};
);
diag.span_suggestion_verbose(
span_behind_impl,
format!("consider implementing `IntoIterator` for `{self_ty_snippet}`"),
sugg,
// Suggestion is on a best effort basis, might need some adjustments by the user
// such as adding some lifetimes in the associated types, or importing types.
Applicability::Unspecified,
);
});
}
}
}

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