46 lines
1.5 KiB
Rust
46 lines
1.5 KiB
Rust
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use crate::utils::{is_type_diagnostic_item, match_trait_method, paths, snippet, span_lint_and_sugg};
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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_lint::LateContext;
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use rustc_middle::ty;
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use rustc_span::symbol::sym;
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use super::MAP_COLLECT_RESULT_UNIT;
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pub(super) fn check(
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cx: &LateContext<'_>,
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expr: &hir::Expr<'_>,
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map_args: &[hir::Expr<'_>],
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collect_args: &[hir::Expr<'_>],
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) {
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if_chain! {
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// called on Iterator
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if let [map_expr] = collect_args;
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if match_trait_method(cx, map_expr, &paths::ITERATOR);
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// return of collect `Result<(),_>`
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let collect_ret_ty = cx.typeck_results().expr_ty(expr);
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if is_type_diagnostic_item(cx, collect_ret_ty, sym::result_type);
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if let ty::Adt(_, substs) = collect_ret_ty.kind();
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if let Some(result_t) = substs.types().next();
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if result_t.is_unit();
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// get parts for snippet
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if let [iter, map_fn] = map_args;
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then {
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span_lint_and_sugg(
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cx,
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MAP_COLLECT_RESULT_UNIT,
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expr.span,
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"`.map().collect()` can be replaced with `.try_for_each()`",
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"try this",
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format!(
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"{}.try_for_each({})",
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snippet(cx, iter.span, ".."),
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snippet(cx, map_fn.span, "..")
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),
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Applicability::MachineApplicable,
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);
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}
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}
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}
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