diff options
| -rw-r--r-- | clippy_utils/src/consts.rs | 18 | ||||
| -rw-r--r-- | tests/ui/assertions_on_constants.rs | 10 |
2 files changed, 25 insertions, 3 deletions
diff --git a/clippy_utils/src/consts.rs b/clippy_utils/src/consts.rs index 1d6f7acab13..0e916ca8164 100644 --- a/clippy_utils/src/consts.rs +++ b/clippy_utils/src/consts.rs @@ -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 diff --git a/tests/ui/assertions_on_constants.rs b/tests/ui/assertions_on_constants.rs index 7477c01ca78..7bea9563d47 100644 --- a/tests/ui/assertions_on_constants.rs +++ b/tests/ui/assertions_on_constants.rs @@ -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); } |