use crate::consts::{constant, miri_to_const, Constant};
use crate::utils::sugg::Sugg;
-use crate::utils::usage::is_unused;
+use crate::utils::visitors::LocalUsedVisitor;
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, 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,
+ expr_block, get_parent_expr, implements_trait, in_macro, indent_of, is_allowed, is_expn_of, is_refutable,
+ is_type_diagnostic_item, is_wild, match_qpath, match_type, meets_msrv, multispan_sugg, path_to_local_id,
+ peel_hir_pat_refs, peel_mid_ty_refs, peel_n_hir_expr_refs, 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,
+ strip_pat_refs,
};
use crate::utils::{paths, search_same, SpanlessEq, SpanlessHash};
use if_chain::if_chain;
if let PatKind::TupleStruct(
QPath::Resolved(None, ref variant_name), ref args, _) = arms[0].pat.kind;
if args.len() == 1;
- if let Some(arg) = get_arg_name(&args[0]);
+ if let PatKind::Binding(_, arg, ..) = strip_pat_refs(&args[0]).kind;
let body = remove_blocks(&arms[0].body);
- if match_var(body, arg);
+ if path_to_local_id(body, arg);
then {
let mut applicability = Applicability::MachineApplicable;
let els_str = els.map_or(String::new(), |els| {
format!(" else {}", expr_block(cx, els, None, "..", Some(expr.span)))
});
+
+ let (msg, sugg) = if_chain! {
+ let (pat, pat_ref_count) = peel_hir_pat_refs(arms[0].pat);
+ if let PatKind::Path(_) | PatKind::Lit(_) = pat.kind;
+ let (ty, ty_ref_count) = peel_mid_ty_refs(cx.typeck_results().expr_ty(ex));
+ if let Some(trait_id) = cx.tcx.lang_items().structural_peq_trait();
+ if ty.is_integral() || ty.is_char() || ty.is_str() || implements_trait(cx, ty, trait_id, &[]);
+ then {
+ // scrutinee derives PartialEq and the pattern is a constant.
+ let pat_ref_count = match pat.kind {
+ // string literals are already a reference.
+ PatKind::Lit(Expr { kind: ExprKind::Lit(lit), .. }) if lit.node.is_str() => pat_ref_count + 1,
+ _ => pat_ref_count,
+ };
+ // References are only implicitly added to the pattern, so no overflow here.
+ // e.g. will work: match &Some(_) { Some(_) => () }
+ // will not: match Some(_) { &Some(_) => () }
+ let ref_count_diff = ty_ref_count - pat_ref_count;
+
+ // Try to remove address of expressions first.
+ let (ex, removed) = peel_n_hir_expr_refs(ex, ref_count_diff);
+ let ref_count_diff = ref_count_diff - removed;
+
+ let msg = "you seem to be trying to use `match` for an equality check. Consider using `if`";
+ let sugg = format!(
+ "if {} == {}{} {}{}",
+ snippet(cx, ex.span, ".."),
+ // PartialEq for different reference counts may not exist.
+ "&".repeat(ref_count_diff),
+ snippet(cx, arms[0].pat.span, ".."),
+ expr_block(cx, &arms[0].body, None, "..", Some(expr.span)),
+ els_str,
+ );
+ (msg, sugg)
+ } else {
+ let msg = "you seem to be trying to use `match` for destructuring a single pattern. Consider using `if let`";
+ let sugg = format!(
+ "if let {} = {} {}{}",
+ snippet(cx, arms[0].pat.span, ".."),
+ snippet(cx, ex.span, ".."),
+ expr_block(cx, &arms[0].body, None, "..", Some(expr.span)),
+ els_str,
+ );
+ (msg, sugg)
+ }
+ };
+
span_lint_and_sugg(
cx,
lint,
expr.span,
- "you seem to be trying to use match for destructuring a single pattern. Consider using `if \
- let`",
+ msg,
"try this",
- format!(
- "if let {} = {} {}{}",
- snippet(cx, arms[0].pat.span, ".."),
- snippet(cx, ex.span, ".."),
- expr_block(cx, &arms[0].body, None, "..", Some(expr.span)),
- els_str,
- ),
+ sugg,
Applicability::HasPlaceholders,
);
}
}
}
-fn check_wild_err_arm(cx: &LateContext<'_>, ex: &Expr<'_>, arms: &[Arm<'_>]) {
+fn check_wild_err_arm<'tcx>(cx: &LateContext<'tcx>, ex: &Expr<'tcx>, arms: &[Arm<'tcx>]) {
let ex_ty = cx.typeck_results().expr_ty(ex).peel_refs();
if is_type_diagnostic_item(cx, ex_ty, sym::result_type) {
for arm in arms {
if !matching_wild {
// Looking for unused bindings (i.e.: `_e`)
inner.iter().for_each(|pat| {
- if let PatKind::Binding(.., ident, None) = &pat.kind {
- if ident.as_str().starts_with('_') && is_unused(ident, arm.body) {
+ if let PatKind::Binding(_, id, ident, None) = pat.kind {
+ if ident.as_str().starts_with('_')
+ && !LocalUsedVisitor::new(cx, id).check_expr(arm.body)
+ {
ident_bind_name = (&ident.name.as_str()).to_string();
matching_wild = true;
}
}
},
(&Kind::End(a, _), &Kind::Start(b, _)) if a != Bound::Included(b) => (),
- _ => return Some((a.range(), b.range())),
+ _ => {
+ // skip if the range `a` is completely included into the range `b`
+ if let Ordering::Equal | Ordering::Less = a.cmp(&b) {
+ let kind_a = Kind::End(a.range().node.1, a.range());
+ let kind_b = Kind::End(b.range().node.1, b.range());
+ if let Ordering::Equal | Ordering::Greater = kind_a.cmp(&kind_b) {
+ return None;
+ }
+ }
+ return Some((a.range(), b.range()));
+ },
}
}
projects / rust.git / blobdiff