-// Copyright 2014-2018 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
-
//! lint when there is a large size difference between variants on an enum
-use crate::rustc::hir::*;
-use crate::rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
-use crate::rustc::ty::layout::LayoutOf;
-use crate::rustc::{declare_tool_lint, lint_array};
-use crate::rustc_errors::Applicability;
use crate::utils::{snippet_opt, span_lint_and_then};
+use rustc::ty::layout::LayoutOf;
+use rustc_errors::Applicability;
+use rustc_hir::*;
+use rustc_lint::{LateContext, LateLintPass};
+use rustc_session::{declare_tool_lint, impl_lint_pass};
-/// **What it does:** Checks for large size differences between variants on
-/// `enum`s.
-///
-/// **Why is this bad?** Enum size is bounded by the largest variant. Having a
-/// large variant
-/// can penalize the memory layout of that enum.
-///
-/// **Known problems:** None.
-///
-/// **Example:**
-/// ```rust
-/// enum Test {
-/// A(i32),
-/// B([i32; 8000]),
-/// }
-/// ```
declare_clippy_lint! {
+ /// **What it does:** Checks for large size differences between variants on
+ /// `enum`s.
+ ///
+ /// **Why is this bad?** Enum size is bounded by the largest variant. Having a
+ /// large variant
+ /// can penalize the memory layout of that enum.
+ ///
+ /// **Known problems:** None.
+ ///
+ /// **Example:**
+ /// ```rust
+ /// enum Test {
+ /// A(i32),
+ /// B([i32; 8000]),
+ /// }
+ /// ```
pub LARGE_ENUM_VARIANT,
perf,
"large size difference between variants on an enum"
}
impl LargeEnumVariant {
+ #[must_use]
pub fn new(maximum_size_difference_allowed: u64) -> Self {
Self {
maximum_size_difference_allowed,
}
}
-impl LintPass for LargeEnumVariant {
- fn get_lints(&self) -> LintArray {
- lint_array!(LARGE_ENUM_VARIANT)
- }
-}
+impl_lint_pass!(LargeEnumVariant => [LARGE_ENUM_VARIANT]);
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for LargeEnumVariant {
- fn check_item(&mut self, cx: &LateContext<'_, '_>, item: &Item) {
- let did = cx.tcx.hir().local_def_id(item.id);
- if let ItemKind::Enum(ref def, _) = item.node {
+ fn check_item(&mut self, cx: &LateContext<'_, '_>, item: &Item<'_>) {
+ let did = cx.tcx.hir().local_def_id(item.hir_id);
+ if let ItemKind::Enum(ref def, _) = item.kind {
let ty = cx.tcx.type_of(did);
let adt = ty.ty_adt_def().expect("already checked whether this is an enum");
"large size difference between variants",
|db| {
if variant.fields.len() == 1 {
- let span = match def.variants[i].node.data {
- VariantData::Struct(ref fields, _) | VariantData::Tuple(ref fields, _) => {
+ let span = match def.variants[i].data {
+ VariantData::Struct(ref fields, ..) | VariantData::Tuple(ref fields, ..) => {
fields[0].ty.span
},
- VariantData::Unit(_) => unreachable!(),
+ VariantData::Unit(..) => unreachable!(),
};
if let Some(snip) = snippet_opt(cx, span) {
- db.span_suggestion_with_applicability(
+ db.span_suggestion(
span,
"consider boxing the large fields to reduce the total size of the \
enum",