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create a lint for each of the messages

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This commit is contained in:
Oliver Schneider 2016-06-21 13:04:50 +02:00
parent 69c796e118
commit 4e52852146
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1 changed files with 43 additions and 4 deletions
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47
clippy_lints/src/methods.rs
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@ -159,6 +159,42 @@ declare_lint! {
"using `filter(p).next()`, which is more succinctly expressed as `.find(p)`"
}
/// **What it does:** This lint `Warn`s on `_.filter(_).map(_)`.
///
/// **Why is this bad?** Readability, this can be written more concisely as `_.filter_map(_)`.
///
/// **Known problems:** Often requires a condition + Option creation in `filter_map`
///
/// **Example:** `iter.filter(|x| x == 0).map(|x| x * 2)`
declare_lint! {
pub FILTER_MAP, Allow,
"using `filter(_).map(_)`, which is more succinctly expressed as `.filter_map(_)`"
}
/// **What it does:** This lint `Warn`s on `_.filter(_).flat_map(_)`.
///
/// **Why is this bad?** Readability, this just needs the `flat_map` to return an empty iterator, if the value should be filtered.
///
/// **Known problems:** Often requires a condition + Iterator creation in `flat_map`
///
/// **Example:** `iter.filter(|x| x == 0).flat_map(|x| x.bits())`
declare_lint! {
pub FILTER_FLAT_MAP, Allow,
"using `filter(_).flat_map(_)`, which can be rewritten using just the flat_map"
}
/// **What it does:** This lint `Warn`s on `_.filter_map(_).flat_map(_)`.
///
/// **Why is this bad?** Readability, this just needs the `flat_map` to return an empty iterator, if the value should be filtered.
///
/// **Known problems:** Often requires a condition + Iterator creation in `flat_map`
///
/// **Example:** `iter.filter_map(|x| x.process()).flat_map(|x| x.bits())`
declare_lint! {
pub FILTER_MAP_FLAT_MAP, Allow,
"using `filter_map(_).flat_map(_)`, which can be rewritten using just the flat_map"
}
/// **What it does:** This lint `Warn`s on an iterator search (such as `find()`, `position()`, or
/// `rposition()`) followed by a call to `is_some()`.
///
@ -356,6 +392,9 @@ impl LintPass for Pass {
SINGLE_CHAR_PATTERN,
SEARCH_IS_SOME,
TEMPORARY_CSTRING_AS_PTR,
FILTER_MAP,
FILTER_FLAT_MAP,
FILTER_MAP_FLAT_MAP,
ITER_NTH)
}
}
@ -847,7 +886,7 @@ fn lint_filter_map(cx: &LateContext, expr: &hir::Expr, _filter_args: &MethodArgs
if match_trait_method(cx, expr, &paths::ITERATOR) {
let msg = "called `filter(p).map(q)` on an Iterator. This is more succinctly expressed by calling `.filter_map(..)` \
instead.";
span_lint(cx, FILTER_NEXT, expr.span, msg);
span_lint(cx, FILTER_MAP, expr.span, msg);
}
}
@ -858,7 +897,7 @@ fn lint_filter_flat_map(cx: &LateContext, expr: &hir::Expr, _filter_args: &Metho
if match_trait_method(cx, expr, &paths::ITERATOR) {
let msg = "called `filter(p).flat_map(q)` on an Iterator. This is more succinctly expressed by calling `.flat_map(..)` \
and filtering by returning an empty Iterator.";
span_lint(cx, FILTER_NEXT, expr.span, msg);
span_lint(cx, FILTER_FLAT_MAP, expr.span, msg);
}
}
@ -867,9 +906,9 @@ fn lint_filter_flat_map(cx: &LateContext, expr: &hir::Expr, _filter_args: &Metho
fn lint_filter_map_flat_map(cx: &LateContext, expr: &hir::Expr, _filter_args: &MethodArgs, _map_args: &MethodArgs) {
// lint if caller of `.filter_map().flat_map()` is an Iterator
if match_trait_method(cx, expr, &paths::ITERATOR) {
let msg = "called `filter(p).flat_map(q)` on an Iterator. This is more succinctly expressed by calling `.flat_map(..)` \
let msg = "called `filter_map(p).flat_map(q)` on an Iterator. This is more succinctly expressed by calling `.flat_map(..)` \
and filtering by returning an empty Iterator.";
span_lint(cx, FILTER_NEXT, expr.span, msg);
span_lint(cx, FILTER_MAP_FLAT_MAP, expr.span, msg);
}
}