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lint on filter(x).map(y), filter(x).flat_map(y), filter_map(x).flat_map(y)

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Oliver Schneider 2016-06-08 19:54:22 +02:00
parent 5b1d849c7e
commit 69c796e118
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1 changed files with 39 additions and 0 deletions
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39
clippy_lints/src/methods.rs
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@ -379,6 +379,12 @@ impl LateLintPass for Pass {
lint_map_unwrap_or_else(cx, expr, arglists[0], arglists[1]);
} else if let Some(arglists) = method_chain_args(expr, &["filter", "next"]) {
lint_filter_next(cx, expr, arglists[0]);
} else if let Some(arglists) = method_chain_args(expr, &["filter", "map"]) {
lint_filter_map(cx, expr, arglists[0], arglists[1]);
} else if let Some(arglists) = method_chain_args(expr, &["filter", "flat_map"]) {
lint_filter_flat_map(cx, expr, arglists[0], arglists[1]);
} else if let Some(arglists) = method_chain_args(expr, &["filter_map", "flat_map"]) {
lint_filter_map_flat_map(cx, expr, arglists[0], arglists[1]);
} else if let Some(arglists) = method_chain_args(expr, &["find", "is_some"]) {
lint_search_is_some(cx, expr, "find", arglists[0], arglists[1]);
} else if let Some(arglists) = method_chain_args(expr, &["position", "is_some"]) {
@ -834,6 +840,39 @@ fn lint_filter_next(cx: &LateContext, expr: &hir::Expr, filter_args: &MethodArgs
}
}
// Type of MethodArgs is potentially a Vec
/// lint use of `filter().map() for Iterators`
fn lint_filter_map(cx: &LateContext, expr: &hir::Expr, _filter_args: &MethodArgs, _map_args: &MethodArgs) {
// lint if caller of `.filter().map()` is an Iterator
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);
}
}
// Type of MethodArgs is potentially a Vec
/// lint use of `filter().flat_map() for Iterators`
fn lint_filter_flat_map(cx: &LateContext, expr: &hir::Expr, _filter_args: &MethodArgs, _map_args: &MethodArgs) {
// lint if caller of `.filter().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(..)` \
and filtering by returning an empty Iterator.";
span_lint(cx, FILTER_NEXT, expr.span, msg);
}
}
// Type of MethodArgs is potentially a Vec
/// lint use of `filter_map().flat_map() for Iterators`
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(..)` \
and filtering by returning an empty Iterator.";
span_lint(cx, FILTER_NEXT, expr.span, msg);
}
}
#[allow(ptr_arg)]
// Type of MethodArgs is potentially a Vec
/// lint searching an Iterator followed by `is_some()`