use crate::utils::{match_def_path, span_lint_and_sugg};
use if_chain::if_chain;
-use rustc::hir;
-use rustc::hir::def::Def;
-use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
-use rustc::{declare_tool_lint, lint_array};
use rustc_errors::Applicability;
+use rustc_hir::def::{DefKind, Res};
+use rustc_hir::*;
+use rustc_lint::{LateContext, LateLintPass};
+use rustc_session::{declare_lint_pass, declare_tool_lint};
declare_clippy_lint! {
- /// **What it does:** Checks for usage of `ATOMIC_X_INIT`, `ONCE_INIT`, and
- /// `uX/iX::MIN/MAX`.
+ /// **What it does:** Checks for usage of standard library
+ /// `const`s that could be replaced by `const fn`s.
///
/// **Why is this bad?** `const fn`s exist
///
///
/// **Example:**
/// ```rust
- /// static FOO: AtomicIsize = ATOMIC_ISIZE_INIT;
+ /// let x = std::u32::MIN;
+ /// let y = std::u32::MAX;
/// ```
///
/// Could be written:
///
/// ```rust
- /// static FOO: AtomicIsize = AtomicIsize::new(0);
+ /// let x = u32::min_value();
+ /// let y = u32::max_value();
/// ```
pub REPLACE_CONSTS,
pedantic,
"Lint usages of standard library `const`s that could be replaced by `const fn`s"
}
-pub struct ReplaceConsts;
+declare_lint_pass!(ReplaceConsts => [REPLACE_CONSTS]);
-impl LintPass for ReplaceConsts {
- fn get_lints(&self) -> LintArray {
- lint_array!(REPLACE_CONSTS)
- }
+fn in_pattern(cx: &LateContext<'_, '_>, expr: &Expr<'_>) -> bool {
+ let map = &cx.tcx.hir();
+ let parent_id = map.get_parent_node(expr.hir_id);
- fn name(&self) -> &'static str {
- "ReplaceConsts"
+ if let Some(node) = map.find(parent_id) {
+ if let Node::Pat(_) = node {
+ return true;
+ }
}
+
+ false
}
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for ReplaceConsts {
- fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx hir::Expr) {
+ fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr<'_>) {
if_chain! {
- if let hir::ExprKind::Path(ref qp) = expr.node;
- if let Def::Const(def_id) = cx.tables.qpath_def(qp, expr.hir_id);
+ if let ExprKind::Path(ref qp) = expr.kind;
+ if let Res::Def(DefKind::Const, def_id) = cx.tables.qpath_res(qp, expr.hir_id);
+ // Do not lint within patterns as function calls are disallowed in them
+ if !in_pattern(cx, expr);
then {
- for &(const_path, repl_snip) in REPLACEMENTS {
- if match_def_path(cx.tcx, def_id, const_path) {
+ for &(ref const_path, repl_snip) in &REPLACEMENTS {
+ if match_def_path(cx, def_id, const_path) {
span_lint_and_sugg(
cx,
REPLACE_CONSTS,
}
}
-const REPLACEMENTS: &[(&[&str], &str)] = &[
- // Once
- (&["core", "sync", "ONCE_INIT"], "Once::new()"),
+const REPLACEMENTS: [([&str; 3], &str); 24] = [
// Min
- (&["core", "isize", "MIN"], "isize::min_value()"),
- (&["core", "i8", "MIN"], "i8::min_value()"),
- (&["core", "i16", "MIN"], "i16::min_value()"),
- (&["core", "i32", "MIN"], "i32::min_value()"),
- (&["core", "i64", "MIN"], "i64::min_value()"),
- (&["core", "i128", "MIN"], "i128::min_value()"),
- (&["core", "usize", "MIN"], "usize::min_value()"),
- (&["core", "u8", "MIN"], "u8::min_value()"),
- (&["core", "u16", "MIN"], "u16::min_value()"),
- (&["core", "u32", "MIN"], "u32::min_value()"),
- (&["core", "u64", "MIN"], "u64::min_value()"),
- (&["core", "u128", "MIN"], "u128::min_value()"),
+ (["core", "isize", "MIN"], "isize::min_value()"),
+ (["core", "i8", "MIN"], "i8::min_value()"),
+ (["core", "i16", "MIN"], "i16::min_value()"),
+ (["core", "i32", "MIN"], "i32::min_value()"),
+ (["core", "i64", "MIN"], "i64::min_value()"),
+ (["core", "i128", "MIN"], "i128::min_value()"),
+ (["core", "usize", "MIN"], "usize::min_value()"),
+ (["core", "u8", "MIN"], "u8::min_value()"),
+ (["core", "u16", "MIN"], "u16::min_value()"),
+ (["core", "u32", "MIN"], "u32::min_value()"),
+ (["core", "u64", "MIN"], "u64::min_value()"),
+ (["core", "u128", "MIN"], "u128::min_value()"),
// Max
- (&["core", "isize", "MAX"], "isize::max_value()"),
- (&["core", "i8", "MAX"], "i8::max_value()"),
- (&["core", "i16", "MAX"], "i16::max_value()"),
- (&["core", "i32", "MAX"], "i32::max_value()"),
- (&["core", "i64", "MAX"], "i64::max_value()"),
- (&["core", "i128", "MAX"], "i128::max_value()"),
- (&["core", "usize", "MAX"], "usize::max_value()"),
- (&["core", "u8", "MAX"], "u8::max_value()"),
- (&["core", "u16", "MAX"], "u16::max_value()"),
- (&["core", "u32", "MAX"], "u32::max_value()"),
- (&["core", "u64", "MAX"], "u64::max_value()"),
- (&["core", "u128", "MAX"], "u128::max_value()"),
+ (["core", "isize", "MAX"], "isize::max_value()"),
+ (["core", "i8", "MAX"], "i8::max_value()"),
+ (["core", "i16", "MAX"], "i16::max_value()"),
+ (["core", "i32", "MAX"], "i32::max_value()"),
+ (["core", "i64", "MAX"], "i64::max_value()"),
+ (["core", "i128", "MAX"], "i128::max_value()"),
+ (["core", "usize", "MAX"], "usize::max_value()"),
+ (["core", "u8", "MAX"], "u8::max_value()"),
+ (["core", "u16", "MAX"], "u16::max_value()"),
+ (["core", "u32", "MAX"], "u32::max_value()"),
+ (["core", "u64", "MAX"], "u64::max_value()"),
+ (["core", "u128", "MAX"], "u128::max_value()"),
];