use crate::utils::usage::is_unused;
use crate::utils::{
expr_block, get_arg_name, get_parent_expr, in_macro, indent_of, is_allowed, is_expn_of, is_refutable,
- is_type_diagnostic_item, is_wild, match_qpath, match_type, match_var, multispan_sugg, remove_blocks, snippet,
- snippet_block, snippet_with_applicability, span_lint_and_help, span_lint_and_note, span_lint_and_sugg,
- span_lint_and_then,
+ is_type_diagnostic_item, is_wild, match_qpath, match_type, match_var, meets_msrv, multispan_sugg, remove_blocks,
+ snippet, snippet_block, snippet_opt, snippet_with_applicability, span_lint_and_help, span_lint_and_note,
+ span_lint_and_sugg, span_lint_and_then,
};
use crate::utils::{paths, search_same, SpanlessEq, SpanlessHash};
use if_chain::if_chain;
use rustc_lint::{LateContext, LateLintPass, LintContext};
use rustc_middle::lint::in_external_macro;
use rustc_middle::ty::{self, Ty, TyS};
+use rustc_semver::RustcVersion;
use rustc_session::{declare_tool_lint, impl_lint_pass};
use rustc_span::source_map::{Span, Spanned};
use rustc_span::{sym, Symbol};
}
declare_clippy_lint! {
- /// **What it does:** Lint for redundant pattern matching over `Result` or
- /// `Option`
+ /// **What it does:** Lint for redundant pattern matching over `Result`, `Option`,
+ /// `std::task::Poll` or `std::net::IpAddr`
///
/// **Why is this bad?** It's more concise and clear to just use the proper
/// utility function
/// **Example:**
///
/// ```rust
+ /// # use std::task::Poll;
+ /// # use std::net::{IpAddr, Ipv4Addr, Ipv6Addr};
/// if let Ok(_) = Ok::<i32, i32>(42) {}
/// if let Err(_) = Err::<i32, i32>(42) {}
/// if let None = None::<()> {}
/// if let Some(_) = Some(42) {}
+ /// if let Poll::Pending = Poll::Pending::<()> {}
+ /// if let Poll::Ready(_) = Poll::Ready(42) {}
+ /// if let IpAddr::V4(_) = IpAddr::V4(Ipv4Addr::LOCALHOST) {}
+ /// if let IpAddr::V6(_) = IpAddr::V6(Ipv6Addr::LOCALHOST) {}
/// match Ok::<i32, i32>(42) {
/// Ok(_) => true,
/// Err(_) => false,
/// The more idiomatic use would be:
///
/// ```rust
+ /// # use std::task::Poll;
+ /// # use std::net::{IpAddr, Ipv4Addr, Ipv6Addr};
/// if Ok::<i32, i32>(42).is_ok() {}
/// if Err::<i32, i32>(42).is_err() {}
/// if None::<()>.is_none() {}
/// if Some(42).is_some() {}
+ /// if Poll::Pending::<()>.is_pending() {}
+ /// if Poll::Ready(42).is_ready() {}
+ /// if IpAddr::V4(Ipv4Addr::LOCALHOST).is_ipv4() {}
+ /// if IpAddr::V6(Ipv6Addr::LOCALHOST).is_ipv6() {}
/// Ok::<i32, i32>(42).is_ok();
/// ```
pub REDUNDANT_PATTERN_MATCHING,
///
/// **Why is this bad?** Readability and needless complexity.
///
- /// **Known problems:** None
+ /// **Known problems:** This lint falsely triggers, if there are arms with
+ /// `cfg` attributes that remove an arm evaluating to `false`.
///
/// **Example:**
/// ```rust
#[derive(Default)]
pub struct Matches {
+ msrv: Option<RustcVersion>,
infallible_destructuring_match_linted: bool,
}
+impl Matches {
+ #[must_use]
+ pub fn new(msrv: Option<RustcVersion>) -> Self {
+ Self {
+ msrv,
+ ..Matches::default()
+ }
+ }
+}
+
impl_lint_pass!(Matches => [
SINGLE_MATCH,
MATCH_REF_PATS,
MATCH_SAME_ARMS,
]);
+const MATCH_LIKE_MATCHES_MACRO_MSRV: RustcVersion = RustcVersion::new(1, 42, 0);
+
impl<'tcx> LateLintPass<'tcx> for Matches {
fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
if in_external_macro(cx.sess(), expr.span) || in_macro(expr.span) {
}
redundant_pattern_match::check(cx, expr);
- if !check_match_like_matches(cx, expr) {
+
+ if meets_msrv(self.msrv.as_ref(), &MATCH_LIKE_MATCHES_MACRO_MSRV) {
+ if !check_match_like_matches(cx, expr) {
+ lint_match_arms(cx, expr);
+ }
+ } else {
lint_match_arms(cx, expr);
}
if_chain! {
if !in_external_macro(cx.sess(), pat.span);
if !in_macro(pat.span);
- if let PatKind::Struct(ref qpath, fields, true) = pat.kind;
- if let QPath::Resolved(_, ref path) = qpath;
+ if let PatKind::Struct(QPath::Resolved(_, ref path), fields, true) = pat.kind;
if let Some(def_id) = path.res.opt_def_id();
let ty = cx.tcx.type_of(def_id);
if let ty::Adt(def, _) = ty.kind();
}
}
}
+
+ extract_msrv_attr!(LateContext);
}
#[rustfmt::skip]
if stmts.len() == 1 && block_expr.is_none() || stmts.is_empty() && block_expr.is_some() {
// single statement/expr "else" block, don't lint
return;
- } else {
- // block with 2+ statements or 1 expr and 1+ statement
- Some(els)
}
+ // block with 2+ statements or 1 expr and 1+ statement
+ Some(els)
} else {
// not a block, don't lint
return;
if let QPath::Resolved(_, p) = path {
missing_variants.retain(|e| e.ctor_def_id != Some(p.res.def_id()));
}
- } else if let PatKind::TupleStruct(ref path, ref patterns, ..) = arm.pat.kind {
- if let QPath::Resolved(_, p) = path {
- // Some simple checks for exhaustive patterns.
- // There is a room for improvements to detect more cases,
- // but it can be more expensive to do so.
- let is_pattern_exhaustive =
- |pat: &&Pat<'_>| matches!(pat.kind, PatKind::Wild | PatKind::Binding(.., None));
- if patterns.iter().all(is_pattern_exhaustive) {
- missing_variants.retain(|e| e.ctor_def_id != Some(p.res.def_id()));
- }
+ } else if let PatKind::TupleStruct(QPath::Resolved(_, p), ref patterns, ..) = arm.pat.kind {
+ // Some simple checks for exhaustive patterns.
+ // There is a room for improvements to detect more cases,
+ // but it can be more expensive to do so.
+ let is_pattern_exhaustive =
+ |pat: &&Pat<'_>| matches!(pat.kind, PatKind::Wild | PatKind::Binding(.., None));
+ if patterns.iter().all(is_pattern_exhaustive) {
+ missing_variants.retain(|e| e.ctor_def_id != Some(p.res.def_id()));
}
}
}
if b0 != b1;
let if_guard = &b0_arms[0].guard;
if if_guard.is_none() || b0_arms.len() == 1;
+ if b0_arms[0].attrs.is_empty();
if b0_arms[1..].iter()
.all(|arm| {
find_bool_lit(&arm.body.kind, desugared).map_or(false, |b| b == b0) &&
- arm.guard.is_none()
+ arm.guard.is_none() && arm.attrs.is_empty()
});
then {
- let mut applicability = Applicability::MachineApplicable;
+ // The suggestion may be incorrect, because some arms can have `cfg` attributes
+ // evaluated into `false` and so such arms will be stripped before.
+ let mut applicability = Applicability::MaybeIncorrect;
let pat = {
use itertools::Itertools as _;
b0_arms.iter()
if in_macro(expr.span) || arms.len() != 1 || is_refutable(cx, arms[0].pat) {
return;
}
+
+ // HACK:
+ // This is a hack to deal with arms that are excluded by macros like `#[cfg]`. It is only used here
+ // to prevent false positives as there is currently no better way to detect if code was excluded by
+ // a macro. See PR #6435
+ if_chain! {
+ if let Some(match_snippet) = snippet_opt(cx, expr.span);
+ if let Some(arm_snippet) = snippet_opt(cx, arms[0].span);
+ if let Some(ex_snippet) = snippet_opt(cx, ex.span);
+ let rest_snippet = match_snippet.replace(&arm_snippet, "").replace(&ex_snippet, "");
+ if rest_snippet.contains("=>");
+ then {
+ // The code it self contains another thick arrow "=>"
+ // -> Either another arm or a comment
+ return;
+ }
+ }
+
let matched_vars = ex.span;
let bind_names = arms[0].pat.span;
let match_body = remove_blocks(&arms[0].body);
if let ExprKind::Call(ref e, ref args) = remove_blocks(&arm.body).kind;
if let ExprKind::Path(ref some_path) = e.kind;
if match_qpath(some_path, &paths::OPTION_SOME) && args.len() == 1;
- if let ExprKind::Path(ref qpath) = args[0].kind;
- if let &QPath::Resolved(_, ref path2) = qpath;
+ if let ExprKind::Path(QPath::Resolved(_, ref path2)) = args[0].kind;
if path2.segments.len() == 1 && ident.name == path2.segments[0].ident.name;
then {
return Some(rb)
"is_err()"
} else if match_qpath(path, &paths::OPTION_SOME) {
"is_some()"
+ } else if match_qpath(path, &paths::POLL_READY) {
+ "is_ready()"
+ } else if match_qpath(path, &paths::IPADDR_V4) {
+ "is_ipv4()"
+ } else if match_qpath(path, &paths::IPADDR_V6) {
+ "is_ipv6()"
} else {
return;
}
return;
}
},
- PatKind::Path(ref path) if match_qpath(path, &paths::OPTION_NONE) => "is_none()",
+ PatKind::Path(ref path) => {
+ if match_qpath(path, &paths::OPTION_NONE) {
+ "is_none()"
+ } else if match_qpath(path, &paths::POLL_PENDING) {
+ "is_pending()"
+ } else {
+ return;
+ }
+ },
_ => return,
};
"is_ok()",
"is_err()",
)
+ .or_else(|| {
+ find_good_method_for_match(
+ arms,
+ path_left,
+ path_right,
+ &paths::IPADDR_V4,
+ &paths::IPADDR_V6,
+ "is_ipv4()",
+ "is_ipv6()",
+ )
+ })
} else {
None
}
"is_some()",
"is_none()",
)
+ .or_else(|| {
+ find_good_method_for_match(
+ arms,
+ path_left,
+ path_right,
+ &paths::POLL_READY,
+ &paths::POLL_PENDING,
+ "is_ready()",
+ "is_pending()",
+ )
+ })
} else {
None
}
projects / rust.git / blobdiff