102 lines
3.9 KiB
Rust
102 lines
3.9 KiB
Rust
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use crate::utils::{
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is_type_diagnostic_item, match_trait_method, paths, snippet, snippet_with_applicability, span_lint_and_help,
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span_lint_and_sugg, strip_pat_refs,
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};
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use if_chain::if_chain;
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use rustc_errors::Applicability;
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use rustc_hir as hir;
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use rustc_hir::PatKind;
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use rustc_lint::LateContext;
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use rustc_middle::ty;
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use rustc_span::source_map::Span;
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use rustc_span::symbol::sym;
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use super::SEARCH_IS_SOME;
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/// lint searching an Iterator followed by `is_some()`
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/// or calling `find()` on a string followed by `is_some()`
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pub(super) fn check<'tcx>(
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cx: &LateContext<'tcx>,
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expr: &'tcx hir::Expr<'_>,
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search_method: &str,
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search_args: &'tcx [hir::Expr<'_>],
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is_some_args: &'tcx [hir::Expr<'_>],
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method_span: Span,
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) {
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// lint if caller of search is an Iterator
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if match_trait_method(cx, &is_some_args[0], &paths::ITERATOR) {
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let msg = format!(
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"called `is_some()` after searching an `Iterator` with `{}`",
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search_method
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);
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let hint = "this is more succinctly expressed by calling `any()`";
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let search_snippet = snippet(cx, search_args[1].span, "..");
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if search_snippet.lines().count() <= 1 {
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// suggest `any(|x| ..)` instead of `any(|&x| ..)` for `find(|&x| ..).is_some()`
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// suggest `any(|..| *..)` instead of `any(|..| **..)` for `find(|..| **..).is_some()`
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let any_search_snippet = if_chain! {
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if search_method == "find";
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if let hir::ExprKind::Closure(_, _, body_id, ..) = search_args[1].kind;
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let closure_body = cx.tcx.hir().body(body_id);
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if let Some(closure_arg) = closure_body.params.get(0);
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then {
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if let hir::PatKind::Ref(..) = closure_arg.pat.kind {
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Some(search_snippet.replacen('&', "", 1))
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} else if let PatKind::Binding(_, _, ident, _) = strip_pat_refs(&closure_arg.pat).kind {
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let name = &*ident.name.as_str();
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Some(search_snippet.replace(&format!("*{}", name), name))
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} else {
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None
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}
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} else {
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None
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}
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};
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// add note if not multi-line
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span_lint_and_sugg(
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cx,
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SEARCH_IS_SOME,
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method_span.with_hi(expr.span.hi()),
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&msg,
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"use `any()` instead",
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format!(
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"any({})",
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any_search_snippet.as_ref().map_or(&*search_snippet, String::as_str)
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),
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Applicability::MachineApplicable,
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);
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} else {
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span_lint_and_help(cx, SEARCH_IS_SOME, expr.span, &msg, None, hint);
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}
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}
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// lint if `find()` is called by `String` or `&str`
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else if search_method == "find" {
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let is_string_or_str_slice = |e| {
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let self_ty = cx.typeck_results().expr_ty(e).peel_refs();
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if is_type_diagnostic_item(cx, self_ty, sym::string_type) {
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true
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} else {
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*self_ty.kind() == ty::Str
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}
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};
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if_chain! {
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if is_string_or_str_slice(&search_args[0]);
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if is_string_or_str_slice(&search_args[1]);
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then {
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let msg = "called `is_some()` after calling `find()` on a string";
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let mut applicability = Applicability::MachineApplicable;
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let find_arg = snippet_with_applicability(cx, search_args[1].span, "..", &mut applicability);
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span_lint_and_sugg(
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cx,
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SEARCH_IS_SOME,
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method_span.with_hi(expr.span.hi()),
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msg,
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"use `contains()` instead",
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format!("contains({})", find_arg),
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applicability,
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);
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}
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}
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}
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}
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