clippy_utils/
msrvs.rs

1use crate::sym;
2use rustc_ast::Attribute;
3use rustc_ast::attr::AttributeExt;
4use rustc_attr_data_structures::RustcVersion;
5use rustc_attr_parsing::parse_version;
6use rustc_lint::LateContext;
7use rustc_session::Session;
8use rustc_span::Symbol;
9use serde::Deserialize;
10use smallvec::SmallVec;
11use std::iter::once;
12use std::sync::atomic::{AtomicBool, Ordering};
13
14macro_rules! msrv_aliases {
15    ($($major:literal,$minor:literal,$patch:literal {
16        $($name:ident),* $(,)?
17    })*) => {
18        $($(
19        pub const $name: RustcVersion = RustcVersion { major: $major, minor :$minor, patch: $patch };
20        )*)*
21    };
22}
23
24// names may refer to stabilized feature flags or library items
25msrv_aliases! {
26    1,88,0 { LET_CHAINS }
27    1,87,0 { OS_STR_DISPLAY, INT_MIDPOINT, CONST_CHAR_IS_DIGIT, UNSIGNED_IS_MULTIPLE_OF }
28    1,85,0 { UINT_FLOAT_MIDPOINT, CONST_SIZE_OF_VAL }
29    1,84,0 { CONST_OPTION_AS_SLICE, MANUAL_DANGLING_PTR }
30    1,83,0 { CONST_EXTERN_FN, CONST_FLOAT_BITS_CONV, CONST_FLOAT_CLASSIFY, CONST_MUT_REFS, CONST_UNWRAP }
31    1,82,0 { IS_NONE_OR, REPEAT_N, RAW_REF_OP }
32    1,81,0 { LINT_REASONS_STABILIZATION, ERROR_IN_CORE, EXPLICIT_SELF_TYPE_ELISION, DURATION_ABS_DIFF }
33    1,80,0 { BOX_INTO_ITER, LAZY_CELL }
34    1,77,0 { C_STR_LITERALS }
35    1,76,0 { PTR_FROM_REF, OPTION_RESULT_INSPECT }
36    1,75,0 { OPTION_AS_SLICE }
37    1,74,0 { REPR_RUST, IO_ERROR_OTHER }
38    1,73,0 { DIV_CEIL }
39    1,71,0 { TUPLE_ARRAY_CONVERSIONS, BUILD_HASHER_HASH_ONE }
40    1,70,0 { OPTION_RESULT_IS_VARIANT_AND, BINARY_HEAP_RETAIN }
41    1,68,0 { PATH_MAIN_SEPARATOR_STR }
42    1,65,0 { LET_ELSE, POINTER_CAST_CONSTNESS }
43    1,63,0 { CLONE_INTO, CONST_SLICE_FROM_REF }
44    1,62,0 { BOOL_THEN_SOME, DEFAULT_ENUM_ATTRIBUTE, CONST_EXTERN_C_FN }
45    1,61,0 { CONST_FN_TRAIT_BOUND }
46    1,60,0 { ABS_DIFF }
47    1,59,0 { THREAD_LOCAL_CONST_INIT }
48    1,58,0 { FORMAT_ARGS_CAPTURE, PATTERN_TRAIT_CHAR_ARRAY, CONST_RAW_PTR_DEREF }
49    1,57,0 { MAP_WHILE }
50    1,56,0 { CONST_FN_UNION }
51    1,55,0 { SEEK_REWIND }
52    1,54,0 { INTO_KEYS }
53    1,53,0 { OR_PATTERNS, INTEGER_BITS, BTREE_MAP_RETAIN, BTREE_SET_RETAIN, ARRAY_INTO_ITERATOR }
54    1,52,0 { STR_SPLIT_ONCE, REM_EUCLID_CONST }
55    1,51,0 { BORROW_AS_PTR, SEEK_FROM_CURRENT, UNSIGNED_ABS }
56    1,50,0 { BOOL_THEN, CLAMP, SLICE_FILL }
57    1,47,0 { TAU, IS_ASCII_DIGIT_CONST, ARRAY_IMPL_ANY_LEN, SATURATING_SUB_CONST }
58    1,46,0 { CONST_IF_MATCH }
59    1,45,0 { STR_STRIP_PREFIX }
60    1,43,0 { LOG2_10, LOG10_2, NUMERIC_ASSOCIATED_CONSTANTS }
61    1,42,0 { MATCHES_MACRO, SLICE_PATTERNS, PTR_SLICE_RAW_PARTS }
62    1,41,0 { RE_REBALANCING_COHERENCE, RESULT_MAP_OR_ELSE }
63    1,40,0 { MEM_TAKE, NON_EXHAUSTIVE, OPTION_AS_DEREF }
64    1,38,0 { POINTER_CAST, REM_EUCLID }
65    1,37,0 { TYPE_ALIAS_ENUM_VARIANTS }
66    1,36,0 { ITERATOR_COPIED }
67    1,35,0 { OPTION_COPIED, RANGE_CONTAINS }
68    1,34,0 { TRY_FROM }
69    1,33,0 { UNDERSCORE_IMPORTS }
70    1,32,0 { CONST_IS_POWER_OF_TWO }
71    1,31,0 { OPTION_REPLACE }
72    1,30,0 { ITERATOR_FIND_MAP, TOOL_ATTRIBUTES }
73    1,29,0 { ITER_FLATTEN }
74    1,28,0 { FROM_BOOL, REPEAT_WITH, SLICE_FROM_REF }
75    1,27,0 { ITERATOR_TRY_FOLD }
76    1,26,0 { RANGE_INCLUSIVE, STRING_RETAIN }
77    1,24,0 { IS_ASCII_DIGIT }
78    1,18,0 { HASH_MAP_RETAIN, HASH_SET_RETAIN }
79    1,17,0 { FIELD_INIT_SHORTHAND, STATIC_IN_CONST, EXPECT_ERR }
80    1,16,0 { STR_REPEAT }
81    1,15,0 { MAYBE_BOUND_IN_WHERE }
82    1,13,0 { QUESTION_MARK_OPERATOR }
83}
84
85/// `#[clippy::msrv]` attributes are rarely used outside of Clippy's test suite, as a basic
86/// optimization we can skip traversing the HIR in [`Msrv::meets`] if we never saw an MSRV attribute
87/// during the early lint passes
88static SEEN_MSRV_ATTR: AtomicBool = AtomicBool::new(false);
89
90/// Tracks the current MSRV from `clippy.toml`, `Cargo.toml` or set via `#[clippy::msrv]` in late
91/// lint passes, use [`MsrvStack`] for early passes
92#[derive(Copy, Clone, Debug, Default)]
93pub struct Msrv(Option<RustcVersion>);
94
95impl<'de> Deserialize<'de> for Msrv {
96    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
97    where
98        D: serde::Deserializer<'de>,
99    {
100        let v = String::deserialize(deserializer)?;
101        parse_version(Symbol::intern(&v))
102            .map(|v| Self(Some(v)))
103            .ok_or_else(|| serde::de::Error::custom("not a valid Rust version"))
104    }
105}
106
107impl Msrv {
108    /// Returns the MSRV at the current node
109    ///
110    /// If the crate being linted uses an `#[clippy::msrv]` attribute this will search the parent
111    /// nodes for that attribute, prefer to run this check after cheaper pattern matching operations
112    pub fn current(self, cx: &LateContext<'_>) -> Option<RustcVersion> {
113        if SEEN_MSRV_ATTR.load(Ordering::Relaxed) {
114            let start = cx.last_node_with_lint_attrs;
115            if let Some(msrv_attr) = once(start)
116                .chain(cx.tcx.hir_parent_id_iter(start))
117                .find_map(|id| parse_attrs(cx.tcx.sess, cx.tcx.hir_attrs(id)))
118            {
119                return Some(msrv_attr);
120            }
121        }
122
123        self.0
124    }
125
126    /// Checks if a required version from [this module](self) is met at the current 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 meets(self, cx: &LateContext<'_>, required: RustcVersion) -> bool {
131        self.current(cx).is_none_or(|msrv| msrv >= required)
132    }
133
134    pub fn read_cargo(&mut self, sess: &Session) {
135        let cargo_msrv = std::env::var("CARGO_PKG_RUST_VERSION")
136            .ok()
137            .and_then(|v| parse_version(Symbol::intern(&v)));
138
139        match (self.0, cargo_msrv) {
140            (None, Some(cargo_msrv)) => self.0 = Some(cargo_msrv),
141            (Some(clippy_msrv), Some(cargo_msrv)) => {
142                if clippy_msrv != cargo_msrv {
143                    sess.dcx().warn(format!(
144                        "the MSRV in `clippy.toml` and `Cargo.toml` differ; using `{clippy_msrv}` from `clippy.toml`"
145                    ));
146                }
147            },
148            _ => {},
149        }
150    }
151}
152
153/// Tracks the current MSRV from `clippy.toml`, `Cargo.toml` or set via `#[clippy::msrv]` in early
154/// lint passes, use [`Msrv`] for late passes
155#[derive(Debug, Clone)]
156pub struct MsrvStack {
157    stack: SmallVec<[RustcVersion; 2]>,
158}
159
160impl MsrvStack {
161    pub fn new(initial: Msrv) -> Self {
162        Self {
163            stack: SmallVec::from_iter(initial.0),
164        }
165    }
166
167    pub fn current(&self) -> Option<RustcVersion> {
168        self.stack.last().copied()
169    }
170
171    pub fn meets(&self, required: RustcVersion) -> bool {
172        self.current().is_none_or(|msrv| msrv >= required)
173    }
174
175    pub fn check_attributes(&mut self, sess: &Session, attrs: &[Attribute]) {
176        if let Some(version) = parse_attrs(sess, attrs) {
177            SEEN_MSRV_ATTR.store(true, Ordering::Relaxed);
178            self.stack.push(version);
179        }
180    }
181
182    pub fn check_attributes_post(&mut self, sess: &Session, attrs: &[Attribute]) {
183        if parse_attrs(sess, attrs).is_some() {
184            self.stack.pop();
185        }
186    }
187}
188
189fn parse_attrs(sess: &Session, attrs: &[impl AttributeExt]) -> Option<RustcVersion> {
190    let mut msrv_attrs = attrs.iter().filter(|attr| attr.path_matches(&[sym::clippy, sym::msrv]));
191
192    if let Some(msrv_attr) = msrv_attrs.next() {
193        if let Some(duplicate) = msrv_attrs.next_back() {
194            sess.dcx()
195                .struct_span_err(duplicate.span(), "`clippy::msrv` is defined multiple times")
196                .with_span_note(msrv_attr.span(), "first definition found here")
197                .emit();
198        }
199
200        if let Some(msrv) = msrv_attr.value_str() {
201            if let Some(version) = parse_version(msrv) {
202                return Some(version);
203            }
204
205            sess.dcx()
206                .span_err(msrv_attr.span(), format!("`{msrv}` is not a valid Rust version"));
207        } else {
208            sess.dcx().span_err(msrv_attr.span(), "bad clippy attribute");
209        }
210    }
211
212    None
213}
clippy_utils/msrvs.rs

clippy_utils/
msrvs.rs
