35 lines
1.1 KiB
Rust
35 lines
1.1 KiB
Rust
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use clippy_utils::diagnostics::span_lint_and_sugg;
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use clippy_utils::is_trait_method;
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use rustc_errors::Applicability;
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use rustc_hir as hir;
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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, sym};
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use super::FLAT_MAP_OPTION;
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use clippy_utils::ty::is_type_diagnostic_item;
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pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'_>, arg: &'tcx hir::Expr<'_>, span: Span) {
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if !is_trait_method(cx, expr, sym::Iterator) {
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return;
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}
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let arg_ty = cx.typeck_results().expr_ty_adjusted(arg);
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let sig = match arg_ty.kind() {
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ty::Closure(_, substs) => substs.as_closure().sig(),
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_ if arg_ty.is_fn() => arg_ty.fn_sig(cx.tcx),
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_ => return,
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};
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if !is_type_diagnostic_item(cx, sig.output().skip_binder(), sym::option_type) {
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return;
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}
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span_lint_and_sugg(
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cx,
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FLAT_MAP_OPTION,
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span,
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"used `flat_map` where `filter_map` could be used instead",
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"try",
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"filter_map".into(),
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Applicability::MachineApplicable,
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)
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}
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