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move filter_map_flat_map to its own module

This commit is contained in:
Takayuki Maeda 2021-03-06 18:22:15 +09:00
parent 6d941616f9
commit f430384f04
2 changed files with 23 additions and 17 deletions
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21
clippy_lints/src/methods/filter_map_flat_map.rs Normal file
View File

@ -0,0 +1,21 @@
use crate::utils::{match_trait_method, paths, span_lint_and_help};
use rustc_hir as hir;
use rustc_lint::LateContext;
use super::FILTER_MAP;
/// lint use of `filter_map().flat_map()` for `Iterators`
pub(super) fn check<'tcx>(
cx: &LateContext<'tcx>,
expr: &'tcx hir::Expr<'_>,
_filter_args: &'tcx [hir::Expr<'_>],
_map_args: &'tcx [hir::Expr<'_>],
) {
// lint if caller of `.filter_map().flat_map()` is an Iterator
if match_trait_method(cx, expr, &paths::ITERATOR) {
let msg = "called `filter_map(..).flat_map(..)` on an `Iterator`";
let hint = "this is more succinctly expressed by calling `.flat_map(..)` \
and filtering by returning `iter::empty()`";
span_lint_and_help(cx, FILTER_MAP, expr.span, msg, None, hint);
}
}

19
clippy_lints/src/methods/mod.rs
View File

@ -5,6 +5,7 @@ mod expect_used;
mod filetype_is_file;
mod filter_flat_map;
mod filter_map;
mod filter_map_flat_map;
mod filter_map_identity;
mod filter_map_map;
mod filter_map_next;
@ -1707,7 +1708,7 @@ impl<'tcx> LateLintPass<'tcx> for Methods {
["next", "filter_map"] => filter_map_next::check(cx, expr, arg_lists[1], self.msrv.as_ref()),
["map", "find"] => filter_map::check(cx, expr, true),
["flat_map", "filter"] => filter_flat_map::check(cx, expr, arg_lists[1], arg_lists[0]),
["flat_map", "filter_map"] => lint_filter_map_flat_map(cx, expr, arg_lists[1], arg_lists[0]),
["flat_map", "filter_map"] => filter_map_flat_map::check(cx, expr, arg_lists[1], arg_lists[0]),
["flat_map", ..] => lint_flat_map_identity(cx, expr, arg_lists[0], method_spans[0]),
["flatten", "map"] => lint_map_flatten(cx, expr, arg_lists[1]),
["is_some", "find"] => lint_search_is_some(cx, expr, "find", arg_lists[1], arg_lists[0], method_spans[1]),
@ -2754,22 +2755,6 @@ fn lint_map_or_none<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'_>, map
);
}
/// lint use of `filter_map().flat_map()` for `Iterators`
fn lint_filter_map_flat_map<'tcx>(
cx: &LateContext<'tcx>,
expr: &'tcx hir::Expr<'_>,
_filter_args: &'tcx [hir::Expr<'_>],
_map_args: &'tcx [hir::Expr<'_>],
) {
// lint if caller of `.filter_map().flat_map()` is an Iterator
if match_trait_method(cx, expr, &paths::ITERATOR) {
let msg = "called `filter_map(..).flat_map(..)` on an `Iterator`";
let hint = "this is more succinctly expressed by calling `.flat_map(..)` \
and filtering by returning `iter::empty()`";
span_lint_and_help(cx, FILTER_MAP, expr.span, msg, None, hint);
}
}
/// lint use of `flat_map` for `Iterators` where `flatten` would be sufficient
fn lint_flat_map_identity<'tcx>(
cx: &LateContext<'tcx>,