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assertions_on_constants: ignore indirect cfg!

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This commit is contained in:
Peter Jaszkowiak 2022-03-31 22:28:59 -06:00
parent b6645d022e
commit 9f131e5a0b
2 changed files with 25 additions and 3 deletions
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18
clippy_utils/src/consts.rs
View file

@ -5,7 +5,7 @@ use if_chain::if_chain;
use rustc_ast::ast::{self, LitFloatType, LitKind};
use rustc_data_structures::sync::Lrc;
use rustc_hir::def::{DefKind, Res};
use rustc_hir::{BinOp, BinOpKind, Block, Expr, ExprKind, HirId, QPath, UnOp};
use rustc_hir::{BinOp, BinOpKind, Block, Expr, ExprKind, HirId, Item, ItemKind, Node, QPath, UnOp};
use rustc_lint::LateContext;
use rustc_middle::mir::interpret::Scalar;
use rustc_middle::ty::subst::{Subst, SubstsRef};
@ -400,6 +400,22 @@ impl<'a, 'tcx> ConstEvalLateContext<'a, 'tcx> {
let res = self.typeck_results.qpath_res(qpath, id);
match res {
Res::Def(DefKind::Const | DefKind::AssocConst, def_id) => {
// Check if this constant is based on `cfg!(..)`,
// which is NOT constant for our purposes.
if let Some(node) = self.lcx.tcx.hir().get_if_local(def_id) &&
let Node::Item(&Item {
kind: ItemKind::Const(_, body_id),
..
}) = node &&
let Node::Expr(&Expr {
kind: ExprKind::Lit(_),
span,
..
}) = self.lcx.tcx.hir().get(body_id.hir_id) &&
is_direct_expn_of(span, "cfg").is_some() {
return None;
}
let substs = self.typeck_results.node_substs(id);
let substs = if self.substs.is_empty() {
substs

10
tests/ui/assertions_on_constants.rs
View file

@ -1,4 +1,4 @@
#![allow(non_fmt_panics)]
#![allow(non_fmt_panics, clippy::needless_bool)]
macro_rules! assert_const {
($len:expr) => {
@ -28,6 +28,12 @@ fn main() {
assert_const!(3);
assert_const!(-1);
// Don't lint on this:
// Don't lint if based on `cfg!(..)`:
assert!(cfg!(feature = "hey") || cfg!(not(feature = "asdf")));
let flag: bool = cfg!(not(feature = "asdf"));
assert!(flag);
const CFG_FLAG: &bool = &cfg!(feature = "hey");
assert!(!CFG_FLAG);
}