-use crate::consts::{constant, miri_to_const, Constant};
+use clippy_utils::consts::{constant, miri_to_const, Constant};
use clippy_utils::diagnostics::{
multispan_sugg, span_lint_and_help, span_lint_and_note, span_lint_and_sugg, span_lint_and_then,
};
+use clippy_utils::higher;
use clippy_utils::source::{expr_block, indent_of, snippet, snippet_block, snippet_opt, snippet_with_applicability};
use clippy_utils::sugg::Sugg;
use clippy_utils::ty::{implements_trait, is_type_diagnostic_item, match_type, peel_mid_ty_refs};
use clippy_utils::visitors::LocalUsedVisitor;
use clippy_utils::{
- get_parent_expr, in_macro, is_allowed, is_expn_of, is_lang_ctor, is_refutable, is_wild, meets_msrv, msrvs,
+ get_parent_expr, in_macro, is_expn_of, is_lang_ctor, is_lint_allowed, is_refutable, is_wild, meets_msrv, msrvs,
path_to_local, path_to_local_id, peel_hir_pat_refs, peel_n_hir_expr_refs, recurse_or_patterns, remove_blocks,
strip_pat_refs,
};
use clippy_utils::{paths, search_same, SpanlessEq, SpanlessHash};
+use core::array;
+use core::iter::{once, ExactSizeIterator};
use if_chain::if_chain;
-use rustc_ast::ast::LitKind;
+use rustc_ast::ast::{Attribute, LitKind};
use rustc_errors::Applicability;
use rustc_hir::def::{CtorKind, DefKind, Res};
use rustc_hir::LangItem::{OptionNone, OptionSome};
use std::ops::Bound;
declare_clippy_lint! {
- /// **What it does:** Checks for matches with a single arm where an `if let`
+ /// ### What it does
+ /// Checks for matches with a single arm where an `if let`
/// will usually suffice.
///
- /// **Why is this bad?** Just readability – `if let` nests less than a `match`.
+ /// ### Why is this bad?
+ /// Just readability – `if let` nests less than a `match`.
///
- /// **Known problems:** None.
- ///
- /// **Example:**
+ /// ### Example
/// ```rust
/// # fn bar(stool: &str) {}
/// # let x = Some("abc");
}
declare_clippy_lint! {
- /// **What it does:** Checks for matches with two arms where an `if let else` will
+ /// ### What it does
+ /// Checks for matches with two arms where an `if let else` will
/// usually suffice.
///
- /// **Why is this bad?** Just readability – `if let` nests less than a `match`.
- ///
- /// **Known problems:** Personal style preferences may differ.
+ /// ### Why is this bad?
+ /// Just readability – `if let` nests less than a `match`.
///
- /// **Example:**
+ /// ### Known problems
+ /// Personal style preferences may differ.
///
+ /// ### Example
/// Using `match`:
///
/// ```rust
}
declare_clippy_lint! {
- /// **What it does:** Checks for matches where all arms match a reference,
+ /// ### What it does
+ /// Checks for matches where all arms match a reference,
/// suggesting to remove the reference and deref the matched expression
/// instead. It also checks for `if let &foo = bar` blocks.
///
- /// **Why is this bad?** It just makes the code less readable. That reference
+ /// ### Why is this bad?
+ /// It just makes the code less readable. That reference
/// destructuring adds nothing to the code.
///
- /// **Known problems:** None.
- ///
- /// **Example:**
+ /// ### Example
/// ```rust,ignore
/// // Bad
/// match x {
}
declare_clippy_lint! {
- /// **What it does:** Checks for matches where match expression is a `bool`. It
+ /// ### What it does
+ /// Checks for matches where match expression is a `bool`. It
/// suggests to replace the expression with an `if...else` block.
///
- /// **Why is this bad?** It makes the code less readable.
+ /// ### Why is this bad?
+ /// It makes the code less readable.
///
- /// **Known problems:** None.
- ///
- /// **Example:**
+ /// ### Example
/// ```rust
/// # fn foo() {}
/// # fn bar() {}
}
declare_clippy_lint! {
- /// **What it does:** Checks for overlapping match arms.
+ /// ### What it does
+ /// Checks for overlapping match arms.
///
- /// **Why is this bad?** It is likely to be an error and if not, makes the code
+ /// ### Why is this bad?
+ /// It is likely to be an error and if not, makes the code
/// less obvious.
///
- /// **Known problems:** None.
- ///
- /// **Example:**
+ /// ### Example
/// ```rust
/// let x = 5;
/// match x {
}
declare_clippy_lint! {
- /// **What it does:** Checks for arm which matches all errors with `Err(_)`
+ /// ### What it does
+ /// Checks for arm which matches all errors with `Err(_)`
/// and take drastic actions like `panic!`.
///
- /// **Why is this bad?** It is generally a bad practice, similar to
+ /// ### Why is this bad?
+ /// It is generally a bad practice, similar to
/// catching all exceptions in java with `catch(Exception)`
///
- /// **Known problems:** None.
- ///
- /// **Example:**
+ /// ### Example
/// ```rust
/// let x: Result<i32, &str> = Ok(3);
/// match x {
}
declare_clippy_lint! {
- /// **What it does:** Checks for match which is used to add a reference to an
+ /// ### What it does
+ /// Checks for match which is used to add a reference to an
/// `Option` value.
///
- /// **Why is this bad?** Using `as_ref()` or `as_mut()` instead is shorter.
+ /// ### Why is this bad?
+ /// Using `as_ref()` or `as_mut()` instead is shorter.
///
- /// **Known problems:** None.
- ///
- /// **Example:**
+ /// ### Example
/// ```rust
/// let x: Option<()> = None;
///
}
declare_clippy_lint! {
- /// **What it does:** Checks for wildcard enum matches using `_`.
+ /// ### What it does
+ /// Checks for wildcard enum matches using `_`.
///
- /// **Why is this bad?** New enum variants added by library updates can be missed.
+ /// ### Why is this bad?
+ /// New enum variants added by library updates can be missed.
///
- /// **Known problems:** Suggested replacements may be incorrect if guards exhaustively cover some
+ /// ### Known problems
+ /// Suggested replacements may be incorrect if guards exhaustively cover some
/// variants, and also may not use correct path to enum if it's not present in the current scope.
///
- /// **Example:**
+ /// ### Example
/// ```rust
/// # enum Foo { A(usize), B(usize) }
/// # let x = Foo::B(1);
}
declare_clippy_lint! {
- /// **What it does:** Checks for wildcard enum matches for a single variant.
+ /// ### What it does
+ /// Checks for wildcard enum matches for a single variant.
///
- /// **Why is this bad?** New enum variants added by library updates can be missed.
+ /// ### Why is this bad?
+ /// New enum variants added by library updates can be missed.
///
- /// **Known problems:** Suggested replacements may not use correct path to enum
+ /// ### Known problems
+ /// Suggested replacements may not use correct path to enum
/// if it's not present in the current scope.
///
- /// **Example:**
- ///
+ /// ### Example
/// ```rust
/// # enum Foo { A, B, C }
/// # let x = Foo::B;
}
declare_clippy_lint! {
- /// **What it does:** Checks for wildcard pattern used with others patterns in same match arm.
+ /// ### What it does
+ /// Checks for wildcard pattern used with others patterns in same match arm.
///
- /// **Why is this bad?** Wildcard pattern already covers any other pattern as it will match anyway.
+ /// ### Why is this bad?
+ /// Wildcard pattern already covers any other pattern as it will match anyway.
/// It makes the code less readable, especially to spot wildcard pattern use in match arm.
///
- /// **Known problems:** None.
- ///
- /// **Example:**
+ /// ### Example
/// ```rust
/// // Bad
/// match "foo" {
}
declare_clippy_lint! {
- /// **What it does:** Checks for matches being used to destructure a single-variant enum
+ /// ### What it does
+ /// Checks for matches being used to destructure a single-variant enum
/// or tuple struct where a `let` will suffice.
///
- /// **Why is this bad?** Just readability – `let` doesn't nest, whereas a `match` does.
+ /// ### Why is this bad?
+ /// Just readability – `let` doesn't nest, whereas a `match` does.
///
- /// **Known problems:** None.
- ///
- /// **Example:**
+ /// ### Example
/// ```rust
/// enum Wrapper {
/// Data(i32),
}
declare_clippy_lint! {
- /// **What it does:** Checks for useless match that binds to only one value.
+ /// ### What it does
+ /// Checks for useless match that binds to only one value.
///
- /// **Why is this bad?** Readability and needless complexity.
+ /// ### Why is this bad?
+ /// Readability and needless complexity.
///
- /// **Known problems:** Suggested replacements may be incorrect when `match`
+ /// ### Known problems
+ /// Suggested replacements may be incorrect when `match`
/// is actually binding temporary value, bringing a 'dropped while borrowed' error.
///
- /// **Example:**
+ /// ### Example
/// ```rust
/// # let a = 1;
/// # let b = 2;
}
declare_clippy_lint! {
- /// **What it does:** Checks for unnecessary '..' pattern binding on struct when all fields are explicitly matched.
+ /// ### What it does
+ /// Checks for unnecessary '..' pattern binding on struct when all fields are explicitly matched.
///
- /// **Why is this bad?** Correctness and readability. It's like having a wildcard pattern after
+ /// ### Why is this bad?
+ /// Correctness and readability. It's like having a wildcard pattern after
/// matching all enum variants explicitly.
///
- /// **Known problems:** None.
- ///
- /// **Example:**
+ /// ### Example
/// ```rust
/// # struct A { a: i32 }
/// let a = A { a: 5 };
}
declare_clippy_lint! {
- /// **What it does:** Lint for redundant pattern matching over `Result`, `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
+ /// ### Why is this bad?
+ /// It's more concise and clear to just use the proper
/// utility function
///
- /// **Known problems:** This will change the drop order for the matched type. Both `if let` and
+ /// ### Known problems
+ /// This will change the drop order for the matched type. Both `if let` and
/// `while let` will drop the value at the end of the block, both `if` and `while` will drop the
/// value before entering the block. For most types this change will not matter, but for a few
/// types this will not be an acceptable change (e.g. locks). See the
/// [reference](https://doc.rust-lang.org/reference/destructors.html#drop-scopes) for more about
/// drop order.
///
- /// **Example:**
- ///
+ /// ### Example
/// ```rust
/// # use std::task::Poll;
/// # use std::net::{IpAddr, Ipv4Addr, Ipv6Addr};
}
declare_clippy_lint! {
- /// **What it does:** Checks for `match` or `if let` expressions producing a
+ /// ### What it does
+ /// Checks for `match` or `if let` expressions producing a
/// `bool` that could be written using `matches!`
///
- /// **Why is this bad?** Readability and needless complexity.
+ /// ### Why is this bad?
+ /// Readability and needless complexity.
///
- /// **Known problems:** This lint falsely triggers, if there are arms with
+ /// ### Known problems
+ /// This lint falsely triggers, if there are arms with
/// `cfg` attributes that remove an arm evaluating to `false`.
///
- /// **Example:**
+ /// ### Example
/// ```rust
/// let x = Some(5);
///
}
declare_clippy_lint! {
- /// **What it does:** Checks for `match` with identical arm bodies.
+ /// ### What it does
+ /// Checks for `match` with identical arm bodies.
///
- /// **Why is this bad?** This is probably a copy & paste error. If arm bodies
+ /// ### Why is this bad?
+ /// This is probably a copy & paste error. If arm bodies
/// are the same on purpose, you can factor them
/// [using `|`](https://doc.rust-lang.org/book/patterns.html#multiple-patterns).
///
- /// **Known problems:** False positive possible with order dependent `match`
+ /// ### Known problems
+ /// False positive possible with order dependent `match`
/// (see issue
/// [#860](https://github.com/rust-lang/rust-clippy/issues/860)).
///
- /// **Example:**
+ /// ### Example
/// ```rust,ignore
/// match foo {
/// Bar => bar(),
check_match_single_binding(cx, ex, arms, expr);
}
}
- if let ExprKind::Match(ex, arms, _) = expr.kind {
- check_match_ref_pats(cx, ex, arms, expr);
+ if let ExprKind::Match(ref ex, ref arms, _) = expr.kind {
+ check_match_ref_pats(cx, ex, arms.iter().map(|el| el.pat), expr);
+ }
+ if let Some(higher::IfLet { let_pat, let_expr, .. }) = higher::IfLet::hir(expr) {
+ check_match_ref_pats(cx, let_expr, once(let_pat), expr);
}
}
if let PatKind::TupleStruct(
QPath::Resolved(None, variant_name), args, _) = arms[0].pat.kind;
if args.len() == 1;
- if let PatKind::Binding(_, arg, ..) = strip_pat_refs(args[0]).kind;
+ if let PatKind::Binding(_, arg, ..) = strip_pat_refs(&args[0]).kind;
let body = remove_blocks(arms[0].body);
if path_to_local_id(body, arg);
};
let ty = cx.typeck_results().expr_ty(ex);
- if *ty.kind() != ty::Bool || is_allowed(cx, MATCH_BOOL, ex.hir_id) {
+ if *ty.kind() != ty::Bool || is_lint_allowed(cx, MATCH_BOOL, ex.hir_id) {
check_single_match_single_pattern(cx, ex, arms, expr, els);
check_single_match_opt_like(cx, ex, arms, expr, ty, els);
}
expr: &Expr<'_>,
els: Option<&Expr<'_>>,
) {
- if is_wild(&arms[1].pat) {
+ if is_wild(arms[1].pat) {
report_single_match_single_pattern(cx, ex, arms, expr, els);
}
}
}
}
-fn is_doc_hidden(cx: &LateContext<'_>, variant_def: &VariantDef) -> bool {
+fn is_hidden(cx: &LateContext<'_>, variant_def: &VariantDef) -> bool {
let attrs = cx.tcx.get_attrs(variant_def.def_id);
- clippy_utils::attrs::is_doc_hidden(attrs)
+ clippy_utils::attrs::is_doc_hidden(attrs) || clippy_utils::attrs::is_unstable(attrs)
}
#[allow(clippy::too_many_lines)]
// Accumulate the variants which should be put in place of the wildcard because they're not
// already covered.
- let mut missing_variants: Vec<_> = adt_def.variants.iter().collect();
+ let has_hidden = adt_def.variants.iter().any(|x| is_hidden(cx, x));
+ let mut missing_variants: Vec<_> = adt_def.variants.iter().filter(|x| !is_hidden(cx, x)).collect();
let mut path_prefix = CommonPrefixSearcher::None;
for arm in arms {
match missing_variants.as_slice() {
[] => (),
- [x] if !adt_def.is_variant_list_non_exhaustive() && !is_doc_hidden(cx, x) => span_lint_and_sugg(
+ [x] if !adt_def.is_variant_list_non_exhaustive() && !has_hidden => span_lint_and_sugg(
cx,
MATCH_WILDCARD_FOR_SINGLE_VARIANTS,
wildcard_span,
),
variants => {
let mut suggestions: Vec<_> = variants.iter().copied().map(format_suggestion).collect();
- let message = if adt_def.is_variant_list_non_exhaustive() {
+ let message = if adt_def.is_variant_list_non_exhaustive() || has_hidden {
suggestions.push("_".into());
"wildcard matches known variants and will also match future added variants"
} else {
"try this",
suggestions.join(" | "),
Applicability::MaybeIncorrect,
- )
+ );
},
};
}
}
}
-fn check_match_ref_pats(cx: &LateContext<'_>, ex: &Expr<'_>, arms: &[Arm<'_>], expr: &Expr<'_>) {
- if has_only_ref_pats(arms) {
- let mut suggs = Vec::with_capacity(arms.len() + 1);
- let (title, msg) = if let ExprKind::AddrOf(BorrowKind::Ref, Mutability::Not, inner) = ex.kind {
- let span = ex.span.source_callsite();
- suggs.push((span, Sugg::hir_with_macro_callsite(cx, inner, "..").to_string()));
- (
- "you don't need to add `&` to both the expression and the patterns",
- "try",
- )
- } else {
- let span = ex.span.source_callsite();
- suggs.push((span, Sugg::hir_with_macro_callsite(cx, ex, "..").deref().to_string()));
- (
- "you don't need to add `&` to all patterns",
- "instead of prefixing all patterns with `&`, you can dereference the expression",
- )
- };
-
- suggs.extend(arms.iter().filter_map(|a| {
- if let PatKind::Ref(refp, _) = a.pat.kind {
- Some((a.pat.span, snippet(cx, refp.span, "..").to_string()))
- } else {
- None
- }
- }));
+fn check_match_ref_pats<'a, 'b, I>(cx: &LateContext<'_>, ex: &Expr<'_>, pats: I, expr: &Expr<'_>)
+where
+ 'b: 'a,
+ I: Clone + Iterator<Item = &'a Pat<'b>>,
+{
+ if !has_only_ref_pats(pats.clone()) {
+ return;
+ }
- span_lint_and_then(cx, MATCH_REF_PATS, expr.span, title, |diag| {
- if !expr.span.from_expansion() {
- multispan_sugg(diag, msg, suggs);
- }
- });
+ let (first_sugg, msg, title);
+ let span = ex.span.source_callsite();
+ if let ExprKind::AddrOf(BorrowKind::Ref, Mutability::Not, ref inner) = ex.kind {
+ first_sugg = once((span, Sugg::hir_with_macro_callsite(cx, inner, "..").to_string()));
+ msg = "try";
+ title = "you don't need to add `&` to both the expression and the patterns";
+ } else {
+ first_sugg = once((span, Sugg::hir_with_macro_callsite(cx, ex, "..").deref().to_string()));
+ msg = "instead of prefixing all patterns with `&`, you can dereference the expression";
+ title = "you don't need to add `&` to all patterns";
}
+
+ let remaining_suggs = pats.filter_map(|pat| {
+ if let PatKind::Ref(ref refp, _) = pat.kind {
+ Some((pat.span, snippet(cx, refp.span, "..").to_string()))
+ } else {
+ None
+ }
+ });
+
+ span_lint_and_then(cx, MATCH_REF_PATS, expr.span, title, |diag| {
+ if !expr.span.from_expansion() {
+ multispan_sugg(diag, msg, first_sugg.chain(remaining_suggs));
+ }
+ });
}
fn check_match_as_ref(cx: &LateContext<'_>, ex: &Expr<'_>, arms: &[Arm<'_>], expr: &Expr<'_>) {
cast,
),
applicability,
- )
+ );
}
}
}
/// Lint a `match` or `if let .. { .. } else { .. }` expr that could be replaced by `matches!`
fn check_match_like_matches<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) -> bool {
- if let ExprKind::Match(ex, arms, ref match_source) = &expr.kind {
- match match_source {
- MatchSource::Normal => find_matches_sugg(cx, ex, arms, expr, false),
- MatchSource::IfLetDesugar { .. } => find_matches_sugg(cx, ex, arms, expr, true),
- _ => false,
- }
- } else {
- false
+ if let Some(higher::IfLet {
+ let_pat,
+ let_expr,
+ if_then,
+ if_else: Some(if_else),
+ }) = higher::IfLet::hir(expr)
+ {
+ return find_matches_sugg(
+ cx,
+ let_expr,
+ array::IntoIter::new([(&[][..], Some(let_pat), if_then, None), (&[][..], None, if_else, None)]),
+ expr,
+ true,
+ );
+ }
+
+ if let ExprKind::Match(scrut, arms, MatchSource::Normal) = expr.kind {
+ return find_matches_sugg(
+ cx,
+ scrut,
+ arms.iter().map(|arm| {
+ (
+ cx.tcx.hir().attrs(arm.hir_id),
+ Some(arm.pat),
+ arm.body,
+ arm.guard.as_ref(),
+ )
+ }),
+ expr,
+ false,
+ );
}
+
+ false
}
-/// Lint a `match` or desugared `if let` for replacement by `matches!`
-fn find_matches_sugg(cx: &LateContext<'_>, ex: &Expr<'_>, arms: &[Arm<'_>], expr: &Expr<'_>, desugared: bool) -> bool {
+/// Lint a `match` or `if let` for replacement by `matches!`
+fn find_matches_sugg<'a, 'b, I>(
+ cx: &LateContext<'_>,
+ ex: &Expr<'_>,
+ mut iter: I,
+ expr: &Expr<'_>,
+ is_if_let: bool,
+) -> bool
+where
+ 'b: 'a,
+ I: Clone
+ + DoubleEndedIterator
+ + ExactSizeIterator
+ + Iterator<
+ Item = (
+ &'a [Attribute],
+ Option<&'a Pat<'b>>,
+ &'a Expr<'b>,
+ Option<&'a Guard<'b>>,
+ ),
+ >,
+{
if_chain! {
- if arms.len() >= 2;
+ if iter.len() >= 2;
if cx.typeck_results().expr_ty(expr).is_bool();
- if let Some((b1_arm, b0_arms)) = arms.split_last();
- if let Some(b0) = find_bool_lit(&b0_arms[0].body.kind, desugared);
- if let Some(b1) = find_bool_lit(&b1_arm.body.kind, desugared);
- if is_wild(&b1_arm.pat);
+ if let Some((_, last_pat_opt, last_expr, _)) = iter.next_back();
+ let iter_without_last = iter.clone();
+ if let Some((first_attrs, _, first_expr, first_guard)) = iter.next();
+ if let Some(b0) = find_bool_lit(&first_expr.kind, is_if_let);
+ if let Some(b1) = find_bool_lit(&last_expr.kind, is_if_let);
if b0 != b1;
- let if_guard = &b0_arms[0].guard;
- if if_guard.is_none() || b0_arms.len() == 1;
- if cx.tcx.hir().attrs(b0_arms[0].hir_id).is_empty();
- if b0_arms[1..].iter()
+ if first_guard.is_none() || iter.len() == 0;
+ if first_attrs.is_empty();
+ if iter
.all(|arm| {
- find_bool_lit(&arm.body.kind, desugared).map_or(false, |b| b == b0) &&
- arm.guard.is_none() && cx.tcx.hir().attrs(arm.hir_id).is_empty()
+ find_bool_lit(&arm.2.kind, is_if_let).map_or(false, |b| b == b0) && arm.3.is_none() && arm.0.is_empty()
});
then {
+ if let Some(ref last_pat) = last_pat_opt {
+ if !is_wild(last_pat) {
+ return false;
+ }
+ }
+
// 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()
- .map(|arm| snippet_with_applicability(cx, arm.pat.span, "..", &mut applicability))
+ iter_without_last
+ .filter_map(|arm| {
+ let pat_span = arm.1?.span;
+ Some(snippet_with_applicability(cx, pat_span, "..", &mut applicability))
+ })
.join(" | ")
};
- let pat_and_guard = if let Some(Guard::If(g)) = if_guard {
+ let pat_and_guard = if let Some(Guard::If(g)) = first_guard {
format!("{} if {}", pat, snippet_with_applicability(cx, g.span, "..", &mut applicability))
} else {
pat
cx,
MATCH_LIKE_MATCHES_MACRO,
expr.span,
- &format!("{} expression looks like `matches!` macro", if desugared { "if let .. else" } else { "match" }),
+ &format!("{} expression looks like `matches!` macro", if is_if_let { "if let .. else" } else { "match" }),
"try this",
format!(
"{}matches!({}, {})",
}
/// Extract a `bool` or `{ bool }`
-fn find_bool_lit(ex: &ExprKind<'_>, desugared: bool) -> Option<bool> {
+fn find_bool_lit(ex: &ExprKind<'_>, is_if_let: bool) -> Option<bool> {
match ex {
ExprKind::Lit(Spanned {
node: LitKind::Bool(b), ..
..
},
_,
- ) if desugared => {
+ ) if is_if_let => {
if let ExprKind::Lit(Spanned {
node: LitKind::Bool(b), ..
}) = exp.kind
);
},
PatKind::Wild => {
- span_lint_and_sugg(
- cx,
- MATCH_SINGLE_BINDING,
- expr.span,
- "this match could be replaced by its body itself",
- "consider using the match body instead",
- snippet_body,
- Applicability::MachineApplicable,
- );
+ if ex.can_have_side_effects() {
+ let indent = " ".repeat(indent_of(cx, expr.span).unwrap_or(0));
+ let sugg = format!(
+ "{};\n{}{}",
+ snippet_with_applicability(cx, ex.span, "..", &mut applicability),
+ indent,
+ snippet_body
+ );
+ span_lint_and_sugg(
+ cx,
+ MATCH_SINGLE_BINDING,
+ expr.span,
+ "this match could be replaced by its scrutinee and body",
+ "consider using the scrutinee and body instead",
+ sugg,
+ applicability,
+ );
+ } else {
+ span_lint_and_sugg(
+ cx,
+ MATCH_SINGLE_BINDING,
+ expr.span,
+ "this match could be replaced by its body itself",
+ "consider using the match body instead",
+ snippet_body,
+ Applicability::MachineApplicable,
+ );
+ }
},
_ => (),
}
// Checks if arm has the form `Some(ref v) => Some(v)` (checks for `ref` and `ref mut`)
fn is_ref_some_arm(cx: &LateContext<'_>, arm: &Arm<'_>) -> Option<BindingAnnotation> {
if_chain! {
- if let PatKind::TupleStruct(ref qpath, pats, _) = arm.pat.kind;
+ if let PatKind::TupleStruct(ref qpath, [first_pat, ..], _) = arm.pat.kind;
if is_lang_ctor(cx, qpath, OptionSome);
- if let PatKind::Binding(rb, .., ident, _) = pats[0].kind;
+ if let PatKind::Binding(rb, .., ident, _) = first_pat.kind;
if rb == BindingAnnotation::Ref || rb == BindingAnnotation::RefMut;
if let ExprKind::Call(e, args) = remove_blocks(arm.body).kind;
if let ExprKind::Path(ref some_path) = e.kind;
None
}
-fn has_only_ref_pats(arms: &[Arm<'_>]) -> bool {
- let mapped = arms
- .iter()
- .map(|a| {
- match a.pat.kind {
- PatKind::Ref(..) => Some(true), // &-patterns
- PatKind::Wild => Some(false), // an "anything" wildcard is also fine
- _ => None, // any other pattern is not fine
+fn has_only_ref_pats<'a, 'b, I>(pats: I) -> bool
+where
+ 'b: 'a,
+ I: Iterator<Item = &'a Pat<'b>>,
+{
+ let mut at_least_one_is_true = false;
+ for opt in pats.map(|pat| match pat.kind {
+ PatKind::Ref(..) => Some(true), // &-patterns
+ PatKind::Wild => Some(false), // an "anything" wildcard is also fine
+ _ => None, // any other pattern is not fine
+ }) {
+ if let Some(inner) = opt {
+ if inner {
+ at_least_one_is_true = true;
}
- })
- .collect::<Option<Vec<bool>>>();
- // look for Some(v) where there's at least one true element
- mapped.map_or(false, |v| v.iter().any(|el| *el))
+ } else {
+ return false;
+ }
+ }
+ at_least_one_is_true
}
pub fn overlapping<T>(ranges: &[SpannedRange<T>]) -> Option<(&SpannedRange<T>, &SpannedRange<T>)>
mod redundant_pattern_match {
use super::REDUNDANT_PATTERN_MATCHING;
use clippy_utils::diagnostics::span_lint_and_then;
+ use clippy_utils::higher;
use clippy_utils::source::{snippet, snippet_with_applicability};
use clippy_utils::ty::{implements_trait, is_type_diagnostic_item, is_type_lang_item, match_type};
use clippy_utils::{is_lang_ctor, is_qpath_def_path, is_trait_method, paths};
use if_chain::if_chain;
use rustc_ast::ast::LitKind;
+ use rustc_data_structures::fx::FxHashSet;
use rustc_errors::Applicability;
use rustc_hir::LangItem::{OptionNone, OptionSome, PollPending, PollReady, ResultErr, ResultOk};
use rustc_hir::{
intravisit::{walk_expr, ErasedMap, NestedVisitorMap, Visitor},
- Arm, Block, Expr, ExprKind, LangItem, MatchSource, Node, PatKind, QPath,
+ Arm, Block, Expr, ExprKind, LangItem, MatchSource, Node, Pat, PatKind, QPath,
};
use rustc_lint::LateContext;
use rustc_middle::ty::{self, subst::GenericArgKind, Ty};
use rustc_span::sym;
pub fn check<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
- if let ExprKind::Match(op, arms, ref match_source) = &expr.kind {
- match match_source {
- MatchSource::Normal => find_sugg_for_match(cx, expr, op, arms),
- MatchSource::IfLetDesugar { contains_else_clause } => {
- find_sugg_for_if_let(cx, expr, op, &arms[0], "if", *contains_else_clause)
- },
- MatchSource::WhileLetDesugar => find_sugg_for_if_let(cx, expr, op, &arms[0], "while", false),
- _ => {},
- }
+ if let Some(higher::IfLet {
+ if_else,
+ let_pat,
+ let_expr,
+ ..
+ }) = higher::IfLet::ast(cx, expr)
+ {
+ find_sugg_for_if_let(cx, expr, let_pat, let_expr, "if", if_else.is_some())
+ }
+ if let ExprKind::Match(op, arms, MatchSource::Normal) = &expr.kind {
+ find_sugg_for_match(cx, expr, op, arms)
+ }
+ if let Some(higher::WhileLet { let_pat, let_expr, .. }) = higher::WhileLet::hir(expr) {
+ find_sugg_for_if_let(cx, expr, let_pat, let_expr, "while", false)
}
}
/// deallocate memory. For these types, and composites containing them, changing the drop order
/// won't result in any observable side effects.
fn type_needs_ordered_drop(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
+ type_needs_ordered_drop_inner(cx, ty, &mut FxHashSet::default())
+ }
+
+ fn type_needs_ordered_drop_inner(cx: &LateContext<'tcx>, ty: Ty<'tcx>, seen: &mut FxHashSet<Ty<'tcx>>) -> bool {
+ if !seen.insert(ty) {
+ return false;
+ }
if !ty.needs_drop(cx.tcx, cx.param_env) {
false
} else if !cx
// This type doesn't implement drop, so no side effects here.
// Check if any component type has any.
match ty.kind() {
- ty::Tuple(_) => ty.tuple_fields().any(|ty| type_needs_ordered_drop(cx, ty)),
- ty::Array(ty, _) => type_needs_ordered_drop(cx, ty),
+ ty::Tuple(_) => ty.tuple_fields().any(|ty| type_needs_ordered_drop_inner(cx, ty, seen)),
+ ty::Array(ty, _) => type_needs_ordered_drop_inner(cx, ty, seen),
ty::Adt(adt, subs) => adt
.all_fields()
.map(|f| f.ty(cx.tcx, subs))
- .any(|ty| type_needs_ordered_drop(cx, ty)),
+ .any(|ty| type_needs_ordered_drop_inner(cx, ty, seen)),
_ => true,
}
}
|| is_type_diagnostic_item(cx, ty, sym::Rc)
|| is_type_diagnostic_item(cx, ty, sym::Arc)
|| is_type_diagnostic_item(cx, ty, sym::cstring_type)
- || match_type(cx, ty, &paths::BTREEMAP)
- || match_type(cx, ty, &paths::LINKED_LIST)
+ || is_type_diagnostic_item(cx, ty, sym::BTreeMap)
+ || is_type_diagnostic_item(cx, ty, sym::LinkedList)
|| match_type(cx, ty, &paths::WEAK_RC)
|| match_type(cx, ty, &paths::WEAK_ARC)
{
// Check all of the generic arguments.
if let ty::Adt(_, subs) = ty.kind() {
- subs.types().any(|ty| type_needs_ordered_drop(cx, ty))
+ subs.types().any(|ty| type_needs_ordered_drop_inner(cx, ty, seen))
} else {
true
}
{
self.res = true;
} else {
- self.visit_expr(self_arg)
+ self.visit_expr(self_arg);
}
}
args.iter().for_each(|arg| self.visit_expr(arg));
fn find_sugg_for_if_let<'tcx>(
cx: &LateContext<'tcx>,
expr: &'tcx Expr<'_>,
- op: &'tcx Expr<'tcx>,
- arm: &Arm<'_>,
+ let_pat: &Pat<'_>,
+ let_expr: &'tcx Expr<'_>,
keyword: &'static str,
has_else: bool,
) {
// also look inside refs
- let mut kind = &arm.pat.kind;
+ let mut kind = &let_pat.kind;
// if we have &None for example, peel it so we can detect "if let None = x"
if let PatKind::Ref(inner, _mutability) = kind {
kind = &inner.kind;
}
- let op_ty = cx.typeck_results().expr_ty(op);
+ let op_ty = cx.typeck_results().expr_ty(let_expr);
// Determine which function should be used, and the type contained by the corresponding
// variant.
let (good_method, inner_ty) = match kind {
// scrutinee would be, so they have to be considered as well.
// e.g. in `if let Some(x) = foo.lock().unwrap().baz.as_ref() { .. }` the lock will be held
// for the duration if body.
- let needs_drop = type_needs_ordered_drop(cx, check_ty) || temporaries_need_ordered_drop(cx, op);
+ let needs_drop = type_needs_ordered_drop(cx, check_ty) || temporaries_need_ordered_drop(cx, let_expr);
// check that `while_let_on_iterator` lint does not trigger
if_chain! {
if keyword == "while";
- if let ExprKind::MethodCall(method_path, _, _, _) = op.kind;
+ if let ExprKind::MethodCall(method_path, _, _, _) = let_expr.kind;
if method_path.ident.name == sym::next;
- if is_trait_method(cx, op, sym::Iterator);
+ if is_trait_method(cx, let_expr, sym::Iterator);
then {
return;
}
}
- let result_expr = match &op.kind {
+ let result_expr = match &let_expr.kind {
ExprKind::AddrOf(_, _, borrowed) => borrowed,
- _ => op,
+ _ => let_expr,
};
span_lint_and_then(
cx,
REDUNDANT_PATTERN_MATCHING,
- arm.pat.span,
+ let_pat.span,
&format!("redundant pattern matching, consider using `{}`", good_method),
|diag| {
- // while let ... = ... { ... }
+ // if/while let ... = ... { ... }
// ^^^^^^^^^^^^^^^^^^^^^^^^^^^
let expr_span = expr.span;
- // while let ... = ... { ... }
+ // if/while let ... = ... { ... }
// ^^^
let op_span = result_expr.span.source_callsite();
- // while let ... = ... { ... }
+ // if/while let ... = ... { ... }
// ^^^^^^^^^^^^^^^^^^^
let span = expr_span.until(op_span.shrink_to_hi());
),
);
} else {
- diag.span_help(i.pat.span, &format!("consider refactoring into `{} | {}`", lhs, rhs));
+ diag.span_help(i.pat.span, &format!("consider refactoring into `{} | {}`", lhs, rhs,))
+ .help("...or consider changing the match arm bodies");
}
},
);
projects / rust.git / blobdiff