//! lint on manually implemented checked conversions that could be transformed into `try_from`
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::source::snippet_with_applicability;
+use clippy_utils::{meets_msrv, SpanlessEq};
use if_chain::if_chain;
use rustc_ast::ast::LitKind;
use rustc_errors::Applicability;
use rustc_hir::{BinOp, BinOpKind, Expr, ExprKind, QPath, TyKind};
use rustc_lint::{LateContext, LateLintPass, LintContext};
use rustc_middle::lint::in_external_macro;
-use rustc_session::{declare_lint_pass, declare_tool_lint};
+use rustc_semver::RustcVersion;
+use rustc_session::{declare_tool_lint, impl_lint_pass};
-use crate::utils::{snippet_with_applicability, span_lint_and_sugg, SpanlessEq};
+const CHECKED_CONVERSIONS_MSRV: RustcVersion = RustcVersion::new(1, 34, 0);
declare_clippy_lint! {
/// **What it does:** Checks for explicit bounds checking when casting.
"`try_from` could replace manual bounds checking when casting"
}
-declare_lint_pass!(CheckedConversions => [CHECKED_CONVERSIONS]);
+pub struct CheckedConversions {
+ msrv: Option<RustcVersion>,
+}
+
+impl CheckedConversions {
+ #[must_use]
+ pub fn new(msrv: Option<RustcVersion>) -> Self {
+ Self { msrv }
+ }
+}
+
+impl_lint_pass!(CheckedConversions => [CHECKED_CONVERSIONS]);
+
+impl<'tcx> LateLintPass<'tcx> for CheckedConversions {
+ fn check_expr(&mut self, cx: &LateContext<'_>, item: &Expr<'_>) {
+ if !meets_msrv(self.msrv.as_ref(), &CHECKED_CONVERSIONS_MSRV) {
+ return;
+ }
-impl<'a, 'tcx> LateLintPass<'a, 'tcx> for CheckedConversions {
- fn check_expr(&mut self, cx: &LateContext<'_, '_>, item: &Expr<'_>) {
let result = if_chain! {
if !in_external_macro(cx.sess(), item.span);
- if let ExprKind::Binary(op, ref left, ref right) = &item.kind;
+ if let ExprKind::Binary(op, left, right) = &item.kind;
then {
match op.node {
}
};
- if_chain! {
- if let Some(cv) = result;
- if let Some(to_type) = cv.to_type;
-
- then {
+ if let Some(cv) = result {
+ if let Some(to_type) = cv.to_type {
let mut applicability = Applicability::MachineApplicable;
- let snippet = snippet_with_applicability(cx, cv.expr_to_cast.span, "_", &mut
- applicability);
+ let snippet = snippet_with_applicability(cx, cv.expr_to_cast.span, "_", &mut applicability);
span_lint_and_sugg(
cx,
CHECKED_CONVERSIONS,
item.span,
- "Checked cast can be simplified.",
+ "checked cast can be simplified",
"try",
- format!("{}::try_from({}).is_ok()",
- to_type,
- snippet),
- applicability
+ format!("{}::try_from({}).is_ok()", to_type, snippet),
+ applicability,
);
}
}
}
+
+ extract_msrv_attr!(LateContext);
}
/// Searches for a single check from unsigned to _ is done
}
/// Searches for a combination of upper & lower bound checks
-fn double_check<'a>(cx: &LateContext<'_, '_>, left: &'a Expr<'_>, right: &'a Expr<'_>) -> Option<Conversion<'a>> {
+fn double_check<'a>(cx: &LateContext<'_>, left: &'a Expr<'_>, right: &'a Expr<'_>) -> Option<Conversion<'a>> {
let upper_lower = |l, r| {
let upper = check_upper_bound(l);
let lower = check_lower_bound(r);
- transpose(upper, lower).and_then(|(l, r)| l.combine(r, cx))
+ upper.zip(lower).and_then(|(l, r)| l.combine(r, cx))
};
upper_lower(left, right).or_else(|| upper_lower(right, left))
impl<'a> Conversion<'a> {
/// Combine multiple conversions if the are compatible
- pub fn combine(self, other: Self, cx: &LateContext<'_, '_>) -> Option<Conversion<'a>> {
+ pub fn combine(self, other: Self, cx: &LateContext<'_>) -> Option<Conversion<'a>> {
if self.is_compatible(&other, cx) {
// Prefer a Conversion that contains a type-constraint
Some(if self.to_type.is_some() { self } else { other })
/// Checks if two conversions are compatible
/// same type of conversion, same 'castee' and same 'to type'
- pub fn is_compatible(&self, other: &Self, cx: &LateContext<'_, '_>) -> bool {
+ pub fn is_compatible(&self, other: &Self, cx: &LateContext<'_>) -> bool {
(self.cvt == other.cvt)
&& (SpanlessEq::new(cx).eq_expr(self.expr_to_cast, other.expr_to_cast))
&& (self.has_compatible_to_type(other))
/// Checks if the to-type is the same (if there is a type constraint)
fn has_compatible_to_type(&self, other: &Self) -> bool {
- transpose(self.to_type.as_ref(), other.to_type.as_ref()).map_or(true, |(l, r)| l == r)
+ match (self.to_type, other.to_type) {
+ (Some(l), Some(r)) => l == r,
+ _ => true,
+ }
}
/// Try to construct a new conversion if the conversion type is valid
/// Check for `expr <= (to_type::MAX as from_type)`
fn check_upper_bound<'tcx>(expr: &'tcx Expr<'tcx>) -> Option<Conversion<'tcx>> {
if_chain! {
- if let ExprKind::Binary(ref op, ref left, ref right) = &expr.kind;
+ if let ExprKind::Binary(ref op, left, right) = &expr.kind;
if let Some((candidate, check)) = normalize_le_ge(op, left, right);
- if let Some((from, to)) = get_types_from_cast(check, MAX_VALUE, INTS);
+ if let Some((from, to)) = get_types_from_cast(check, INTS, "max_value", "MAX");
then {
Conversion::try_new(candidate, from, to)
}
// First of we need a binary containing the expression & the cast
- if let ExprKind::Binary(ref op, ref left, ref right) = &expr.kind {
+ if let ExprKind::Binary(ref op, left, right) = &expr.kind {
normalize_le_ge(op, right, left).and_then(|(l, r)| check_function(l, r))
} else {
None
/// Check for `expr >= (to_type::MIN as from_type)`
fn check_lower_bound_min<'a>(candidate: &'a Expr<'_>, check: &'a Expr<'_>) -> Option<Conversion<'a>> {
- if let Some((from, to)) = get_types_from_cast(check, MIN_VALUE, SINTS) {
+ if let Some((from, to)) = get_types_from_cast(check, SINTS, "min_value", "MIN") {
Conversion::try_new(candidate, from, to)
} else {
None
}
/// Tries to extract the from- and to-type from a cast expression
-fn get_types_from_cast<'a>(expr: &'a Expr<'_>, func: &'a str, types: &'a [&str]) -> Option<(&'a str, &'a str)> {
- // `to_type::maxmin_value() as from_type`
+fn get_types_from_cast<'a>(
+ expr: &'a Expr<'_>,
+ types: &'a [&str],
+ func: &'a str,
+ assoc_const: &'a str,
+) -> Option<(&'a str, &'a str)> {
+ // `to_type::max_value() as from_type`
+ // or `to_type::MAX as from_type`
let call_from_cast: Option<(&Expr<'_>, &str)> = if_chain! {
- // to_type::maxmin_value(), from_type
- if let ExprKind::Cast(ref limit, ref from_type) = &expr.kind;
+ // to_type::max_value(), from_type
+ if let ExprKind::Cast(limit, from_type) = &expr.kind;
if let TyKind::Path(ref from_type_path) = &from_type.kind;
if let Some(from_sym) = int_ty_to_sym(from_type_path);
}
};
- // `from_type::from(to_type::maxmin_value())`
+ // `from_type::from(to_type::max_value())`
let limit_from: Option<(&Expr<'_>, &str)> = call_from_cast.or_else(|| {
if_chain! {
- // `from_type::from, to_type::maxmin_value()`
- if let ExprKind::Call(ref from_func, ref args) = &expr.kind;
- // `to_type::maxmin_value()`
+ // `from_type::from, to_type::max_value()`
+ if let ExprKind::Call(from_func, args) = &expr.kind;
+ // `to_type::max_value()`
if args.len() == 1;
if let limit = &args[0];
// `from_type::from`
if let ExprKind::Path(ref path) = &from_func.kind;
- if let Some(from_sym) = get_implementing_type(path, INTS, FROM);
+ if let Some(from_sym) = get_implementing_type(path, INTS, "from");
then {
Some((limit, from_sym))
});
if let Some((limit, from_type)) = limit_from {
- if_chain! {
- if let ExprKind::Call(ref fun_name, _) = &limit.kind;
- // `to_type, maxmin_value`
- if let ExprKind::Path(ref path) = &fun_name.kind;
- // `to_type`
- if let Some(to_type) = get_implementing_type(path, types, func);
-
- then {
- Some((from_type, to_type))
- } else {
- None
- }
+ match limit.kind {
+ // `from_type::from(_)`
+ ExprKind::Call(path, _) => {
+ if let ExprKind::Path(ref path) = path.kind {
+ // `to_type`
+ if let Some(to_type) = get_implementing_type(path, types, func) {
+ return Some((from_type, to_type));
+ }
+ }
+ },
+ // `to_type::MAX`
+ ExprKind::Path(ref path) => {
+ if let Some(to_type) = get_implementing_type(path, types, assoc_const) {
+ return Some((from_type, to_type));
+ }
+ },
+ _ => {},
}
- } else {
- None
- }
+ };
+ None
}
/// Gets the type which implements the called function
fn get_implementing_type<'a>(path: &QPath<'_>, candidates: &'a [&str], function: &str) -> Option<&'a str> {
if_chain! {
- if let QPath::TypeRelative(ref ty, ref path) = &path;
+ if let QPath::TypeRelative(ty, path) = &path;
if path.ident.name.as_str() == function;
- if let TyKind::Path(QPath::Resolved(None, ref tp)) = &ty.kind;
+ if let TyKind::Path(QPath::Resolved(None, tp)) = &ty.kind;
if let [int] = &*tp.segments;
- let name = &int.ident.name.as_str();
-
then {
- candidates.iter().find(|c| name == *c).cloned()
+ let name = &int.ident.name.as_str();
+ candidates.iter().find(|c| name == *c).copied()
} else {
None
}
/// Gets the type as a string, if it is a supported integer
fn int_ty_to_sym<'tcx>(path: &QPath<'_>) -> Option<&'tcx str> {
if_chain! {
- if let QPath::Resolved(_, ref path) = *path;
+ if let QPath::Resolved(_, path) = *path;
if let [ty] = &*path.segments;
- let name = &ty.ident.name.as_str();
-
then {
- INTS.iter().find(|c| name == *c).cloned()
+ let name = &ty.ident.name.as_str();
+ INTS.iter().find(|c| name == *c).copied()
} else {
None
}
}
}
-/// (Option<T>, Option<U>) -> Option<(T, U)>
-fn transpose<T, U>(lhs: Option<T>, rhs: Option<U>) -> Option<(T, U)> {
- match (lhs, rhs) {
- (Some(l), Some(r)) => Some((l, r)),
- _ => None,
- }
-}
-
/// Will return the expressions as if they were expr1 <= expr2
fn normalize_le_ge<'a>(op: &BinOp, left: &'a Expr<'a>, right: &'a Expr<'a>) -> Option<(&'a Expr<'a>, &'a Expr<'a>)> {
match op.node {
}
// Constants
-const FROM: &str = "from";
-const MAX_VALUE: &str = "max_value";
-const MIN_VALUE: &str = "min_value";
-
const UINTS: &[&str] = &["u8", "u16", "u32", "u64", "usize"];
const SINTS: &[&str] = &["i8", "i16", "i32", "i64", "isize"];
const INTS: &[&str] = &["u8", "u16", "u32", "u64", "usize", "i8", "i16", "i32", "i64", "isize"];
projects / rust.git / blobdiff