29 lines
908 B
Rust
29 lines
908 B
Rust
use clippy_utils::diagnostics::span_lint_and_sugg;
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use clippy_utils::{is_expr_identity_function, 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_span::{source_map::Span, sym};
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use super::FLAT_MAP_IDENTITY;
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/// lint use of `flat_map` for `Iterators` where `flatten` would be sufficient
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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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flat_map_arg: &'tcx hir::Expr<'_>,
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flat_map_span: Span,
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) {
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if is_trait_method(cx, expr, sym::Iterator) && is_expr_identity_function(cx, flat_map_arg) {
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span_lint_and_sugg(
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cx,
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FLAT_MAP_IDENTITY,
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flat_map_span.with_hi(expr.span.hi()),
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"use of `flat_map` with an identity function",
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"try",
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"flatten()".to_string(),
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Applicability::MachineApplicable,
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);
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}
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}
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