clippy_utils/
msrvs.rs

1use crate::sym;
2use rustc_ast::Attribute;
3use rustc_ast::attr::AttributeExt;
4use rustc_attr_parsing::parse_version;
5use rustc_data_structures::smallvec::SmallVec;
6use rustc_hir::attrs::RustcVersion;
7use rustc_hir::def_id::DefId;
8use rustc_hir::{HirId, StabilityLevel, StableSince};
9use rustc_lint::LateContext;
10use rustc_middle::ty::TyCtxt;
11use rustc_session::Session;
12use std::iter::once;
13use std::sync::atomic::{AtomicBool, Ordering};
14
15macro_rules! msrv_aliases {
16    ($($major:literal,$minor:literal,$patch:literal {
17        $($name:ident),* $(,)?
18    })*) => {
19        $($(
20        pub const $name: RustcVersion = RustcVersion { major: $major, minor :$minor, patch: $patch };
21        )*)*
22    };
23}
24
25// names may refer to stabilized feature flags or library items
26msrv_aliases! {
27    1,99,0 { BOX_INTO_NON_NULL }
28    1,97,0 { ISOLATE_LOWEST_ONE, BIT_WIDTH }
29    1,94,0 { EULER_GAMMA, GOLDEN_RATIO }
30    1,93,0 { VEC_DEQUE_POP_BACK_IF, VEC_DEQUE_POP_FRONT_IF }
31    1,91,0 { DURATION_FROM_MINUTES_HOURS }
32    1,89,0 { NONNULL_FROM_MUT }
33    1,88,0 { LET_CHAINS, AS_CHUNKS, RAW_PTR_DEFAULT }
34    1,87,0 { OS_STR_DISPLAY, INT_MIDPOINT, CONST_CHAR_IS_DIGIT, UNSIGNED_IS_MULTIPLE_OF, INTEGER_SIGN_CAST }
35    1,86,0 { VEC_POP_IF }
36    1,85,0 { UINT_FLOAT_MIDPOINT, CONST_SIZE_OF_VAL, WAKER_NOOP }
37    1,84,0 { CONST_OPTION_AS_SLICE, MANUAL_DANGLING_PTR }
38    1,83,0 { CONST_EXTERN_FN, CONST_FLOAT_BITS_CONV, CONST_FLOAT_CLASSIFY, CONST_MUT_REFS, CONST_UNWRAP }
39    1,82,0 { IS_NONE_OR, REPEAT_N, RAW_REF_OP, SPECIALIZED_TO_STRING_FOR_REFS }
40    1,81,0 { LINT_REASONS_STABILIZATION, ERROR_IN_CORE, EXPLICIT_SELF_TYPE_ELISION, DURATION_ABS_DIFF }
41    1,80,0 { BOX_INTO_ITER, LAZY_CELL }
42    1,79,0 { CONST_BLOCKS, CSTR_COUNT_BYTES }
43    1,77,0 { C_STR_LITERALS }
44    1,76,0 { PTR_FROM_REF, OPTION_RESULT_INSPECT }
45    1,75,0 { OPTION_AS_SLICE }
46    1,74,0 { REPR_RUST, IO_ERROR_OTHER }
47    1,73,0 { DIV_CEIL }
48    1,71,0 { TUPLE_ARRAY_CONVERSIONS, BUILD_HASHER_HASH_ONE }
49    1,70,0 { OPTION_RESULT_IS_VARIANT_AND, BINARY_HEAP_RETAIN }
50    1,68,0 { PATH_MAIN_SEPARATOR_STR }
51    1,67,0 { ILOG2 }
52    1,65,0 { LET_ELSE, POINTER_CAST_CONSTNESS }
53    1,63,0 { CLONE_INTO, CONST_SLICE_FROM_REF }
54    1,62,0 { BOOL_THEN_SOME, DEFAULT_ENUM_ATTRIBUTE, CONST_EXTERN_C_FN }
55    1,61,0 { CONST_FN_TRAIT_BOUND }
56    1,60,0 { ABS_DIFF }
57    1,59,0 { THREAD_LOCAL_CONST_INIT }
58    1,58,0 { FORMAT_ARGS_CAPTURE, PATTERN_TRAIT_CHAR_ARRAY, CONST_RAW_PTR_DEREF }
59    1,57,0 { MAP_WHILE, CONST_PANIC }
60    1,56,0 { CONST_FN_UNION }
61    1,55,0 { SEEK_REWIND }
62    1,54,0 { INTO_KEYS }
63    1,53,0 { OR_PATTERNS, INTEGER_BITS, BTREE_MAP_RETAIN, BTREE_SET_RETAIN, ARRAY_INTO_ITERATOR }
64    1,52,0 { STR_SPLIT_ONCE, REM_EUCLID_CONST }
65    1,51,0 { BORROW_AS_PTR, SEEK_FROM_CURRENT, UNSIGNED_ABS }
66    1,50,0 { BOOL_THEN, CLAMP, SLICE_FILL }
67    1,47,0 { TAU, IS_ASCII_DIGIT_CONST, ARRAY_IMPL_ANY_LEN, SATURATING_SUB_CONST }
68    1,46,0 { CONST_IF_MATCH, OPTION_ZIP }
69    1,45,0 { STR_STRIP_PREFIX }
70    1,43,0 { LOG2_10, LOG10_2, NUMERIC_ASSOCIATED_CONSTANTS }
71    1,42,0 { MATCHES_MACRO, SLICE_PATTERNS, PTR_SLICE_RAW_PARTS }
72    1,41,0 { RE_REBALANCING_COHERENCE, RESULT_MAP_OR, RESULT_MAP_OR_ELSE }
73    1,40,0 { MEM_TAKE, NON_EXHAUSTIVE, OPTION_AS_DEREF }
74    1,38,0 { POINTER_CAST, REM_EUCLID }
75    1,37,0 { TYPE_ALIAS_ENUM_VARIANTS }
76    1,36,0 { ITERATOR_COPIED }
77    1,35,0 { OPTION_COPIED, RANGE_CONTAINS }
78    1,34,0 { TRY_FROM }
79    1,33,0 { UNDERSCORE_IMPORTS }
80    1,32,0 { CONST_IS_POWER_OF_TWO, CONST_DURATION_FROM_NANOS_MICROS_MILLIS_SECS }
81    1,31,0 { OPTION_REPLACE }
82    1,30,0 { ITERATOR_FIND_MAP, TOOL_ATTRIBUTES }
83    1,29,0 { ITER_FLATTEN }
84    1,28,0 { FROM_BOOL, REPEAT_WITH, SLICE_FROM_REF }
85    1,27,0 { ITERATOR_TRY_FOLD, DOUBLE_ENDED_ITERATOR_RFIND, DURATION_FROM_NANOS_MICROS }
86    1,26,0 { RANGE_INCLUSIVE, STRING_RETAIN, POINTER_ADD_SUB_METHODS, BOX_LEAK }
87    1,24,0 { IS_ASCII_DIGIT, PTR_NULL }
88    1,18,0 { HASH_MAP_RETAIN, HASH_SET_RETAIN }
89    1,17,0 { FIELD_INIT_SHORTHAND, STATIC_IN_CONST, EXPECT_ERR }
90    1,16,0 { STR_REPEAT, RESULT_UNWRAP_OR_DEFAULT }
91    1,15,0 { MAYBE_BOUND_IN_WHERE }
92    1,13,0 { QUESTION_MARK_OPERATOR }
93    1,3,0 { DURATION_FROM_MILLIS_SECS }
94}
95
96/// `#[clippy::msrv]` attributes are rarely used outside of Clippy's test suite, as a basic
97/// optimization we can skip traversing the HIR in [`Msrv::meets`] if we never saw an MSRV attribute
98/// during the early lint passes
99static SEEN_MSRV_ATTR: AtomicBool = AtomicBool::new(false);
100
101/// Tracks the current MSRV from `clippy.toml`, `Cargo.toml` or set via `#[clippy::msrv]` in late
102/// lint passes, use [`MsrvStack`] for early passes
103#[derive(Copy, Clone, Debug, Default)]
104pub struct Msrv(Option<RustcVersion>);
105
106impl From<Option<RustcVersion>> for Msrv {
107    #[inline]
108    fn from(value: Option<RustcVersion>) -> Self {
109        Self(value)
110    }
111}
112
113impl Msrv {
114    /// Returns the MSRV at the current node
115    ///
116    /// If the crate being linted uses an `#[clippy::msrv]` attribute this will search the parent
117    /// nodes for that attribute, prefer to run this check after cheaper pattern matching operations
118    pub fn current(self, cx: &LateContext<'_>) -> Option<RustcVersion> {
119        if SEEN_MSRV_ATTR.load(Ordering::Relaxed) {
120            self.for_attrs(cx.tcx, cx.last_node_with_lint_attrs)
121        } else {
122            self.0
123        }
124    }
125
126    /// Returns the MSRV at the specified node
127    ///
128    /// If the crate being linted uses an `#[clippy::msrv]` attribute this will search the parent
129    /// nodes for that attribute, prefer to run this check after cheaper pattern matching operations
130    pub fn at(self, tcx: TyCtxt<'_>, node: HirId) -> Option<RustcVersion> {
131        if SEEN_MSRV_ATTR.load(Ordering::Relaxed) {
132            self.for_attrs(tcx, node)
133        } else {
134            self.0
135        }
136    }
137
138    fn for_attrs(self, tcx: TyCtxt<'_>, node: HirId) -> Option<RustcVersion> {
139        once(node)
140            .chain(tcx.hir_parent_id_iter(node))
141            .find_map(|id| parse_attrs(tcx.sess, tcx.hir_attrs(id)))
142            .or(self.0)
143    }
144
145    /// Checks if a required version from [this module](self) is met at the current node
146    ///
147    /// If the crate being linted uses an `#[clippy::msrv]` attribute this will search the parent
148    /// nodes for that attribute, prefer to run this check after cheaper pattern matching operations
149    pub fn meets(self, cx: &LateContext<'_>, required: RustcVersion) -> bool {
150        self.current(cx).is_none_or(|msrv| msrv >= required)
151    }
152    /// Checks if a required version from [this module](self) is met at the specified node
153    ///
154    /// If the crate being linted uses an `#[clippy::msrv]` attribute this will search the parent
155    /// nodes for that attribute, prefer to run this check after cheaper pattern matching operations
156    pub fn meets_at(self, tcx: TyCtxt<'_>, node: HirId, required: RustcVersion) -> bool {
157        self.at(tcx, node).is_none_or(|msrv| msrv >= required)
158    }
159
160    pub fn is_stable(self, cx: &LateContext<'_>, def_id: DefId) -> bool {
161        cx.tcx.lookup_stability(def_id).is_none_or(|stability| {
162            if let StabilityLevel::Stable { since, .. } = stability.level {
163                let version = match since {
164                    StableSince::Version(version) => version,
165                    StableSince::Current => RustcVersion::CURRENT,
166                    StableSince::Err(_) => return false,
167                };
168
169                self.meets(cx, version)
170            } else {
171                // Unstable fn.
172                // FIXME: can we check that the feature is enabled?
173                // Please see https://github.com/rust-lang/rust-clippy/pull/17309#discussion_r3486693263 for false-positive concerns.
174                false
175            }
176        })
177    }
178}
179
180/// Tracks the current MSRV from `clippy.toml`, `Cargo.toml` or set via `#[clippy::msrv]` in early
181/// lint passes, use [`Msrv`] for late passes
182#[derive(Debug, Clone)]
183pub struct MsrvStack {
184    stack: SmallVec<[RustcVersion; 2]>,
185}
186
187impl From<Option<RustcVersion>> for MsrvStack {
188    #[inline]
189    fn from(value: Option<RustcVersion>) -> Self {
190        Self {
191            stack: SmallVec::from_iter(value),
192        }
193    }
194}
195
196impl MsrvStack {
197    pub fn current(&self) -> Option<RustcVersion> {
198        self.stack.last().copied()
199    }
200
201    pub fn meets(&self, required: RustcVersion) -> bool {
202        self.current().is_none_or(|msrv| msrv >= required)
203    }
204
205    pub fn check_attributes(&mut self, sess: &Session, attrs: &[Attribute]) {
206        if let Some(version) = parse_attrs(sess, attrs) {
207            SEEN_MSRV_ATTR.store(true, Ordering::Relaxed);
208            self.stack.push(version);
209        }
210    }
211
212    pub fn check_attributes_post(&mut self, sess: &Session, attrs: &[Attribute]) {
213        if parse_attrs(sess, attrs).is_some() {
214            self.stack.pop();
215        }
216    }
217}
218
219fn parse_attrs(sess: &Session, attrs: &[impl AttributeExt]) -> Option<RustcVersion> {
220    let mut msrv_attrs = attrs.iter().filter(|attr| attr.path_matches(&[sym::clippy, sym::msrv]));
221
222    let msrv_attr = msrv_attrs.next()?;
223
224    if let Some(duplicate) = msrv_attrs.next_back() {
225        sess.dcx()
226            .struct_span_err(duplicate.span(), "`clippy::msrv` is defined multiple times")
227            .with_span_note(msrv_attr.span(), "first definition found here")
228            .emit();
229    }
230
231    let Some(msrv) = msrv_attr.value_str() else {
232        sess.dcx().span_err(msrv_attr.span(), "bad clippy attribute");
233        return None;
234    };
235
236    let Some(version) = parse_version(msrv) else {
237        sess.dcx()
238            .span_err(msrv_attr.span(), format!("`{msrv}` is not a valid Rust version"));
239        return None;
240    };
241
242    Some(version)
243}
clippy_utils/msrvs.rs

clippy_utils/
msrvs.rs
