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| 1 | +use clippy_config::msrvs::{Msrv, NUMERIC_ASSOCIATED_CONSTANTS}; |
| 2 | +use clippy_utils::diagnostics::{span_lint_and_then, span_lint_hir_and_then}; |
| 3 | +use clippy_utils::{get_parent_expr, is_from_proc_macro}; |
| 4 | +use hir::def_id::DefId; |
| 5 | +use rustc_errors::{Applicability, SuggestionStyle}; |
| 6 | +use rustc_hir as hir; |
| 7 | +use rustc_hir::{ExprKind, Item, ItemKind, QPath, UseKind}; |
| 8 | +use rustc_lint::{LateContext, LateLintPass, LintContext}; |
| 9 | +use rustc_middle::lint::in_external_macro; |
| 10 | +use rustc_session::impl_lint_pass; |
| 11 | +use rustc_span::symbol::kw; |
| 12 | +use rustc_span::{sym, Symbol}; |
| 13 | + |
| 14 | +declare_clippy_lint! { |
| 15 | + /// ### What it does |
| 16 | + /// Checks for usage of `<integer>::max_value()`, `std::<integer>::MAX`, |
| 17 | + /// `std::<float>::EPSILON`, etc. |
| 18 | + /// |
| 19 | + /// ### Why is this bad? |
| 20 | + /// All of these have been superceded by the associated constants on their respective types, |
| 21 | + /// such as `i128::MAX`. These legacy items may be deprecated in a future version of rust. |
| 22 | + /// |
| 23 | + /// ### Example |
| 24 | + /// ```rust |
| 25 | + /// let eps = std::f32::EPSILON; |
| 26 | + /// ``` |
| 27 | + /// Use instead: |
| 28 | + /// ```rust |
| 29 | + /// let eps = f32::EPSILON; |
| 30 | + /// ``` |
| 31 | + #[clippy::version = "1.72.0"] |
| 32 | + pub LEGACY_NUMERIC_CONSTANTS, |
| 33 | + style, |
| 34 | + "checks for usage of legacy std numeric constants and methods" |
| 35 | +} |
| 36 | +pub struct LegacyNumericConstants { |
| 37 | + msrv: Msrv, |
| 38 | +} |
| 39 | + |
| 40 | +impl LegacyNumericConstants { |
| 41 | + #[must_use] |
| 42 | + pub fn new(msrv: Msrv) -> Self { |
| 43 | + Self { msrv } |
| 44 | + } |
| 45 | +} |
| 46 | + |
| 47 | +impl_lint_pass!(LegacyNumericConstants => [LEGACY_NUMERIC_CONSTANTS]); |
| 48 | + |
| 49 | +impl<'tcx> LateLintPass<'tcx> for LegacyNumericConstants { |
| 50 | + fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx Item<'tcx>) { |
| 51 | + let Self { msrv } = self; |
| 52 | + |
| 53 | + if !msrv.meets(NUMERIC_ASSOCIATED_CONSTANTS) || in_external_macro(cx.sess(), item.span) { |
| 54 | + return; |
| 55 | + } |
| 56 | + |
| 57 | + // Integer modules are "TBD" deprecated, and the contents are too, |
| 58 | + // so lint on the `use` statement directly. |
| 59 | + if let ItemKind::Use(path, kind @ (UseKind::Single | UseKind::Glob)) = item.kind |
| 60 | + && let Some(def_id) = path.res[0].opt_def_id() |
| 61 | + { |
| 62 | + let module = if is_integer_module(cx, def_id) { |
| 63 | + true |
| 64 | + } else if is_numeric_const(cx, def_id) { |
| 65 | + false |
| 66 | + } else { |
| 67 | + return; |
| 68 | + }; |
| 69 | + |
| 70 | + span_lint_and_then( |
| 71 | + cx, |
| 72 | + LEGACY_NUMERIC_CONSTANTS, |
| 73 | + path.span, |
| 74 | + if module { |
| 75 | + "importing legacy numeric constants" |
| 76 | + } else { |
| 77 | + "importing a legacy numeric constant" |
| 78 | + }, |
| 79 | + |diag| { |
| 80 | + if item.ident.name == kw::Underscore { |
| 81 | + diag.help("remove this import"); |
| 82 | + return; |
| 83 | + } |
| 84 | + |
| 85 | + let def_path = cx.get_def_path(def_id); |
| 86 | + |
| 87 | + if module && let [.., module_name] = &*def_path { |
| 88 | + if kind == UseKind::Glob { |
| 89 | + diag.help(format!("remove this import and use associated constants `{module_name}::<CONST>` from the primitive type instead")); |
| 90 | + } else { |
| 91 | + diag.help("remove this import").note(format!( |
| 92 | + "then `{module_name}::<CONST>` will resolve to the respective associated constant" |
| 93 | + )); |
| 94 | + } |
| 95 | + } else if let [.., module_name, name] = &*def_path { |
| 96 | + diag.help( |
| 97 | + format!("remove this import and use the associated constant `{module_name}::{name}` from the primitive type instead") |
| 98 | + ); |
| 99 | + } |
| 100 | + }, |
| 101 | + ); |
| 102 | + } |
| 103 | + } |
| 104 | + |
| 105 | + fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx rustc_hir::Expr<'tcx>) { |
| 106 | + let Self { msrv } = self; |
| 107 | + |
| 108 | + if !msrv.meets(NUMERIC_ASSOCIATED_CONSTANTS) || in_external_macro(cx.sess(), expr.span) { |
| 109 | + return; |
| 110 | + } |
| 111 | + let ExprKind::Path(qpath) = expr.kind else { |
| 112 | + return; |
| 113 | + }; |
| 114 | + |
| 115 | + // `std::<integer>::<CONST>` check |
| 116 | + let (span, sugg, msg) = if let QPath::Resolved(None, path) = qpath |
| 117 | + && let Some(def_id) = path.res.opt_def_id() |
| 118 | + && is_numeric_const(cx, def_id) |
| 119 | + && let def_path = cx.get_def_path(def_id) |
| 120 | + && let [.., mod_name, name] = &*def_path |
| 121 | + // Skip linting if this usage looks identical to the associated constant, |
| 122 | + // since this would only require removing a `use` import (which is already linted). |
| 123 | + && !is_numeric_const_path_canonical(path, [*mod_name, *name]) |
| 124 | + { |
| 125 | + ( |
| 126 | + expr.span, |
| 127 | + format!("{mod_name}::{name}"), |
| 128 | + "usage of a legacy numeric constant", |
| 129 | + ) |
| 130 | + // `<integer>::xxx_value` check |
| 131 | + } else if let QPath::TypeRelative(_, last_segment) = qpath |
| 132 | + && let Some(def_id) = cx.qpath_res(&qpath, expr.hir_id).opt_def_id() |
| 133 | + && is_integer_method(cx, def_id) |
| 134 | + && let Some(par_expr) = get_parent_expr(cx, expr) |
| 135 | + && let ExprKind::Call(_, _) = par_expr.kind |
| 136 | + { |
| 137 | + let name = last_segment.ident.name.as_str(); |
| 138 | + |
| 139 | + ( |
| 140 | + last_segment.ident.span.with_hi(par_expr.span.hi()), |
| 141 | + name[..=2].to_ascii_uppercase(), |
| 142 | + "usage of a legacy numeric method", |
| 143 | + ) |
| 144 | + } else { |
| 145 | + return; |
| 146 | + }; |
| 147 | + |
| 148 | + if is_from_proc_macro(cx, expr) { |
| 149 | + return; |
| 150 | + } |
| 151 | + |
| 152 | + span_lint_hir_and_then(cx, LEGACY_NUMERIC_CONSTANTS, expr.hir_id, span, msg, |diag| { |
| 153 | + diag.span_suggestion_with_style( |
| 154 | + span, |
| 155 | + "use the associated constant instead", |
| 156 | + sugg, |
| 157 | + Applicability::MaybeIncorrect, |
| 158 | + SuggestionStyle::ShowAlways, |
| 159 | + ); |
| 160 | + }); |
| 161 | + } |
| 162 | + |
| 163 | + extract_msrv_attr!(LateContext); |
| 164 | +} |
| 165 | + |
| 166 | +fn is_integer_module(cx: &LateContext<'_>, did: DefId) -> bool { |
| 167 | + matches!( |
| 168 | + cx.tcx.get_diagnostic_name(did), |
| 169 | + Some( |
| 170 | + sym::isize_legacy_mod |
| 171 | + | sym::i128_legacy_mod |
| 172 | + | sym::i64_legacy_mod |
| 173 | + | sym::i32_legacy_mod |
| 174 | + | sym::i16_legacy_mod |
| 175 | + | sym::i8_legacy_mod |
| 176 | + | sym::usize_legacy_mod |
| 177 | + | sym::u128_legacy_mod |
| 178 | + | sym::u64_legacy_mod |
| 179 | + | sym::u32_legacy_mod |
| 180 | + | sym::u16_legacy_mod |
| 181 | + | sym::u8_legacy_mod |
| 182 | + ) |
| 183 | + ) |
| 184 | +} |
| 185 | + |
| 186 | +fn is_numeric_const(cx: &LateContext<'_>, did: DefId) -> bool { |
| 187 | + matches!( |
| 188 | + cx.tcx.get_diagnostic_name(did), |
| 189 | + Some( |
| 190 | + sym::isize_legacy_const_max |
| 191 | + | sym::isize_legacy_const_min |
| 192 | + | sym::i128_legacy_const_max |
| 193 | + | sym::i128_legacy_const_min |
| 194 | + | sym::i16_legacy_const_max |
| 195 | + | sym::i16_legacy_const_min |
| 196 | + | sym::i32_legacy_const_max |
| 197 | + | sym::i32_legacy_const_min |
| 198 | + | sym::i64_legacy_const_max |
| 199 | + | sym::i64_legacy_const_min |
| 200 | + | sym::i8_legacy_const_max |
| 201 | + | sym::i8_legacy_const_min |
| 202 | + | sym::usize_legacy_const_max |
| 203 | + | sym::usize_legacy_const_min |
| 204 | + | sym::u128_legacy_const_max |
| 205 | + | sym::u128_legacy_const_min |
| 206 | + | sym::u16_legacy_const_max |
| 207 | + | sym::u16_legacy_const_min |
| 208 | + | sym::u32_legacy_const_max |
| 209 | + | sym::u32_legacy_const_min |
| 210 | + | sym::u64_legacy_const_max |
| 211 | + | sym::u64_legacy_const_min |
| 212 | + | sym::u8_legacy_const_max |
| 213 | + | sym::u8_legacy_const_min |
| 214 | + | sym::f32_legacy_const_digits |
| 215 | + | sym::f32_legacy_const_epsilon |
| 216 | + | sym::f32_legacy_const_infinity |
| 217 | + | sym::f32_legacy_const_mantissa_dig |
| 218 | + | sym::f32_legacy_const_max |
| 219 | + | sym::f32_legacy_const_max_10_exp |
| 220 | + | sym::f32_legacy_const_max_exp |
| 221 | + | sym::f32_legacy_const_min |
| 222 | + | sym::f32_legacy_const_min_10_exp |
| 223 | + | sym::f32_legacy_const_min_exp |
| 224 | + | sym::f32_legacy_const_min_positive |
| 225 | + | sym::f32_legacy_const_nan |
| 226 | + | sym::f32_legacy_const_neg_infinity |
| 227 | + | sym::f32_legacy_const_radix |
| 228 | + | sym::f64_legacy_const_digits |
| 229 | + | sym::f64_legacy_const_epsilon |
| 230 | + | sym::f64_legacy_const_infinity |
| 231 | + | sym::f64_legacy_const_mantissa_dig |
| 232 | + | sym::f64_legacy_const_max |
| 233 | + | sym::f64_legacy_const_max_10_exp |
| 234 | + | sym::f64_legacy_const_max_exp |
| 235 | + | sym::f64_legacy_const_min |
| 236 | + | sym::f64_legacy_const_min_10_exp |
| 237 | + | sym::f64_legacy_const_min_exp |
| 238 | + | sym::f64_legacy_const_min_positive |
| 239 | + | sym::f64_legacy_const_nan |
| 240 | + | sym::f64_legacy_const_neg_infinity |
| 241 | + | sym::f64_legacy_const_radix |
| 242 | + ) |
| 243 | + ) |
| 244 | +} |
| 245 | + |
| 246 | +// Whether path expression looks like `i32::MAX` |
| 247 | +fn is_numeric_const_path_canonical(expr_path: &hir::Path<'_>, [mod_name, name]: [Symbol; 2]) -> bool { |
| 248 | + let [ |
| 249 | + hir::PathSegment { |
| 250 | + ident: one, args: None, .. |
| 251 | + }, |
| 252 | + hir::PathSegment { |
| 253 | + ident: two, args: None, .. |
| 254 | + }, |
| 255 | + ] = expr_path.segments |
| 256 | + else { |
| 257 | + return false; |
| 258 | + }; |
| 259 | + |
| 260 | + one.name == mod_name && two.name == name |
| 261 | +} |
| 262 | + |
| 263 | +fn is_integer_method(cx: &LateContext<'_>, did: DefId) -> bool { |
| 264 | + matches!( |
| 265 | + cx.tcx.get_diagnostic_name(did), |
| 266 | + Some( |
| 267 | + sym::isize_legacy_fn_max_value |
| 268 | + | sym::isize_legacy_fn_min_value |
| 269 | + | sym::i128_legacy_fn_max_value |
| 270 | + | sym::i128_legacy_fn_min_value |
| 271 | + | sym::i16_legacy_fn_max_value |
| 272 | + | sym::i16_legacy_fn_min_value |
| 273 | + | sym::i32_legacy_fn_max_value |
| 274 | + | sym::i32_legacy_fn_min_value |
| 275 | + | sym::i64_legacy_fn_max_value |
| 276 | + | sym::i64_legacy_fn_min_value |
| 277 | + | sym::i8_legacy_fn_max_value |
| 278 | + | sym::i8_legacy_fn_min_value |
| 279 | + | sym::usize_legacy_fn_max_value |
| 280 | + | sym::usize_legacy_fn_min_value |
| 281 | + | sym::u128_legacy_fn_max_value |
| 282 | + | sym::u128_legacy_fn_min_value |
| 283 | + | sym::u16_legacy_fn_max_value |
| 284 | + | sym::u16_legacy_fn_min_value |
| 285 | + | sym::u32_legacy_fn_max_value |
| 286 | + | sym::u32_legacy_fn_min_value |
| 287 | + | sym::u64_legacy_fn_max_value |
| 288 | + | sym::u64_legacy_fn_min_value |
| 289 | + | sym::u8_legacy_fn_max_value |
| 290 | + | sym::u8_legacy_fn_min_value |
| 291 | + ) |
| 292 | + ) |
| 293 | +} |
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