Implement unnecesary_filter_map lint
This commit is contained in:
parent
cdde22c2cc
commit
f5ffac4fce
|
@ -864,6 +864,7 @@ All notable changes to this project will be documented in this file.
|
||||||
[`unit_arg`]: https://rust-lang-nursery.github.io/rust-clippy/master/index.html#unit_arg
|
[`unit_arg`]: https://rust-lang-nursery.github.io/rust-clippy/master/index.html#unit_arg
|
||||||
[`unit_cmp`]: https://rust-lang-nursery.github.io/rust-clippy/master/index.html#unit_cmp
|
[`unit_cmp`]: https://rust-lang-nursery.github.io/rust-clippy/master/index.html#unit_cmp
|
||||||
[`unnecessary_cast`]: https://rust-lang-nursery.github.io/rust-clippy/master/index.html#unnecessary_cast
|
[`unnecessary_cast`]: https://rust-lang-nursery.github.io/rust-clippy/master/index.html#unnecessary_cast
|
||||||
|
[`unnecessary_filter_map`]: https://rust-lang-nursery.github.io/rust-clippy/master/index.html#unnecessary_filter_map
|
||||||
[`unnecessary_fold`]: https://rust-lang-nursery.github.io/rust-clippy/master/index.html#unnecessary_fold
|
[`unnecessary_fold`]: https://rust-lang-nursery.github.io/rust-clippy/master/index.html#unnecessary_fold
|
||||||
[`unnecessary_mut_passed`]: https://rust-lang-nursery.github.io/rust-clippy/master/index.html#unnecessary_mut_passed
|
[`unnecessary_mut_passed`]: https://rust-lang-nursery.github.io/rust-clippy/master/index.html#unnecessary_mut_passed
|
||||||
[`unnecessary_operation`]: https://rust-lang-nursery.github.io/rust-clippy/master/index.html#unnecessary_operation
|
[`unnecessary_operation`]: https://rust-lang-nursery.github.io/rust-clippy/master/index.html#unnecessary_operation
|
||||||
|
|
|
@ -9,7 +9,7 @@ We are currently in the process of discussing Clippy 1.0 via the RFC process in
|
||||||
|
|
||||||
A collection of lints to catch common mistakes and improve your [Rust](https://github.com/rust-lang/rust) code.
|
A collection of lints to catch common mistakes and improve your [Rust](https://github.com/rust-lang/rust) code.
|
||||||
|
|
||||||
[There are 278 lints included in this crate!](https://rust-lang-nursery.github.io/rust-clippy/master/index.html)
|
[There are 279 lints included in this crate!](https://rust-lang-nursery.github.io/rust-clippy/master/index.html)
|
||||||
|
|
||||||
We have a bunch of lint categories to allow you to choose how much Clippy is supposed to ~~annoy~~ help you:
|
We have a bunch of lint categories to allow you to choose how much Clippy is supposed to ~~annoy~~ help you:
|
||||||
|
|
||||||
|
|
|
@ -614,6 +614,7 @@ pub fn register_plugins(reg: &mut rustc_plugin::Registry<'_>, conf: &Conf) {
|
||||||
methods::SINGLE_CHAR_PATTERN,
|
methods::SINGLE_CHAR_PATTERN,
|
||||||
methods::STRING_EXTEND_CHARS,
|
methods::STRING_EXTEND_CHARS,
|
||||||
methods::TEMPORARY_CSTRING_AS_PTR,
|
methods::TEMPORARY_CSTRING_AS_PTR,
|
||||||
|
methods::UNNECESSARY_FILTER_MAP,
|
||||||
methods::UNNECESSARY_FOLD,
|
methods::UNNECESSARY_FOLD,
|
||||||
methods::USELESS_ASREF,
|
methods::USELESS_ASREF,
|
||||||
methods::WRONG_SELF_CONVENTION,
|
methods::WRONG_SELF_CONVENTION,
|
||||||
|
@ -829,6 +830,7 @@ pub fn register_plugins(reg: &mut rustc_plugin::Registry<'_>, conf: &Conf) {
|
||||||
methods::CLONE_ON_COPY,
|
methods::CLONE_ON_COPY,
|
||||||
methods::FILTER_NEXT,
|
methods::FILTER_NEXT,
|
||||||
methods::SEARCH_IS_SOME,
|
methods::SEARCH_IS_SOME,
|
||||||
|
methods::UNNECESSARY_FILTER_MAP,
|
||||||
methods::USELESS_ASREF,
|
methods::USELESS_ASREF,
|
||||||
misc::SHORT_CIRCUIT_STATEMENT,
|
misc::SHORT_CIRCUIT_STATEMENT,
|
||||||
misc_early::REDUNDANT_CLOSURE_CALL,
|
misc_early::REDUNDANT_CLOSURE_CALL,
|
||||||
|
|
|
@ -1,5 +1,6 @@
|
||||||
use crate::rustc::hir;
|
use crate::rustc::hir;
|
||||||
use crate::rustc::hir::def::Def;
|
use crate::rustc::hir::def::Def;
|
||||||
|
use crate::rustc::hir::intravisit::{walk_expr, NestedVisitorMap, Visitor};
|
||||||
use crate::rustc::lint::{in_external_macro, LateContext, LateLintPass, Lint, LintArray, LintContext, LintPass};
|
use crate::rustc::lint::{in_external_macro, LateContext, LateLintPass, Lint, LintArray, LintContext, LintPass};
|
||||||
use crate::rustc::ty::{self, Ty};
|
use crate::rustc::ty::{self, Ty};
|
||||||
use crate::rustc::{declare_tool_lint, lint_array};
|
use crate::rustc::{declare_tool_lint, lint_array};
|
||||||
|
@ -8,6 +9,7 @@ use crate::syntax::ast;
|
||||||
use crate::syntax::source_map::{BytePos, Span};
|
use crate::syntax::source_map::{BytePos, Span};
|
||||||
use crate::utils::paths;
|
use crate::utils::paths;
|
||||||
use crate::utils::sugg;
|
use crate::utils::sugg;
|
||||||
|
use crate::utils::usage::mutated_variables;
|
||||||
use crate::utils::{
|
use crate::utils::{
|
||||||
get_arg_name, get_trait_def_id, implements_trait, in_macro, is_copy, is_expn_of, is_self, is_self_ty,
|
get_arg_name, get_trait_def_id, implements_trait, in_macro, is_copy, is_expn_of, is_self, is_self_ty,
|
||||||
iter_input_pats, last_path_segment, match_def_path, match_path, match_qpath, match_trait_method, match_type,
|
iter_input_pats, last_path_segment, match_def_path, match_path, match_qpath, match_trait_method, match_type,
|
||||||
|
@ -692,6 +694,27 @@ declare_clippy_lint! {
|
||||||
"using `fold` when a more succinct alternative exists"
|
"using `fold` when a more succinct alternative exists"
|
||||||
}
|
}
|
||||||
|
|
||||||
|
|
||||||
|
/// **What it does:** Checks for `filter_map` calls which could be replaced by `filter` or `map`.
|
||||||
|
///
|
||||||
|
/// **Why is this bad?** Complexity
|
||||||
|
///
|
||||||
|
/// **Known problems:** None
|
||||||
|
///
|
||||||
|
/// **Example:**
|
||||||
|
/// ```rust
|
||||||
|
/// let _ = (0..3).filter_map(|x| if x > 2 { Some(x) } else { None });
|
||||||
|
/// ```
|
||||||
|
/// This could be written as:
|
||||||
|
/// ```rust
|
||||||
|
/// let _ = (0..3).filter(|&x| x > 2);
|
||||||
|
/// ```
|
||||||
|
declare_clippy_lint! {
|
||||||
|
pub UNNECESSARY_FILTER_MAP,
|
||||||
|
complexity,
|
||||||
|
"using `filter_map` when a more succinct alternative exists"
|
||||||
|
}
|
||||||
|
|
||||||
impl LintPass for Pass {
|
impl LintPass for Pass {
|
||||||
fn get_lints(&self) -> LintArray {
|
fn get_lints(&self) -> LintArray {
|
||||||
lint_array!(
|
lint_array!(
|
||||||
|
@ -725,7 +748,8 @@ impl LintPass for Pass {
|
||||||
STRING_EXTEND_CHARS,
|
STRING_EXTEND_CHARS,
|
||||||
ITER_CLONED_COLLECT,
|
ITER_CLONED_COLLECT,
|
||||||
USELESS_ASREF,
|
USELESS_ASREF,
|
||||||
UNNECESSARY_FOLD
|
UNNECESSARY_FOLD,
|
||||||
|
UNNECESSARY_FILTER_MAP
|
||||||
)
|
)
|
||||||
}
|
}
|
||||||
}
|
}
|
||||||
|
@ -791,6 +815,8 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Pass {
|
||||||
lint_asref(cx, expr, "as_mut", arglists[0]);
|
lint_asref(cx, expr, "as_mut", arglists[0]);
|
||||||
} else if let Some(arglists) = method_chain_args(expr, &["fold"]) {
|
} else if let Some(arglists) = method_chain_args(expr, &["fold"]) {
|
||||||
lint_unnecessary_fold(cx, expr, arglists[0]);
|
lint_unnecessary_fold(cx, expr, arglists[0]);
|
||||||
|
} else if let Some(arglists) = method_chain_args(expr, &["filter_map"]) {
|
||||||
|
unnecessary_filter_map::lint(cx, expr, arglists[0]);
|
||||||
}
|
}
|
||||||
|
|
||||||
lint_or_fun_call(cx, expr, *method_span, &method_call.ident.as_str(), args);
|
lint_or_fun_call(cx, expr, *method_span, &method_call.ident.as_str(), args);
|
||||||
|
@ -1398,6 +1424,144 @@ fn lint_unnecessary_fold(cx: &LateContext<'_, '_>, expr: &hir::Expr, fold_args:
|
||||||
};
|
};
|
||||||
}
|
}
|
||||||
|
|
||||||
|
mod unnecessary_filter_map {
|
||||||
|
use super::*;
|
||||||
|
|
||||||
|
pub(super) fn lint(cx: &LateContext<'_, '_>, expr: &hir::Expr, args: &[hir::Expr]) {
|
||||||
|
|
||||||
|
if !match_trait_method(cx, expr, &paths::ITERATOR) {
|
||||||
|
return;
|
||||||
|
}
|
||||||
|
|
||||||
|
if let hir::ExprKind::Closure(_, _, body_id, ..) = args[1].node {
|
||||||
|
|
||||||
|
let body = cx.tcx.hir.body(body_id);
|
||||||
|
let arg_id = body.arguments[0].pat.id;
|
||||||
|
let mutates_arg = match mutated_variables(&body.value, cx) {
|
||||||
|
Some(used_mutably) => used_mutably.contains(&arg_id),
|
||||||
|
None => true,
|
||||||
|
};
|
||||||
|
|
||||||
|
let (mut found_mapping, mut found_filtering) = check_expression(&cx, arg_id, &body.value);
|
||||||
|
|
||||||
|
let mut return_visitor = ReturnVisitor::new(&cx, arg_id);
|
||||||
|
return_visitor.visit_expr(&body.value);
|
||||||
|
found_mapping |= return_visitor.found_mapping;
|
||||||
|
found_filtering |= return_visitor.found_filtering;
|
||||||
|
|
||||||
|
if !found_filtering {
|
||||||
|
span_lint(
|
||||||
|
cx,
|
||||||
|
UNNECESSARY_FILTER_MAP,
|
||||||
|
expr.span,
|
||||||
|
"this `.filter_map` can be written more simply using `.map`",
|
||||||
|
);
|
||||||
|
return;
|
||||||
|
}
|
||||||
|
|
||||||
|
if !found_mapping && !mutates_arg {
|
||||||
|
span_lint(
|
||||||
|
cx,
|
||||||
|
UNNECESSARY_FILTER_MAP,
|
||||||
|
expr.span,
|
||||||
|
"this `.filter_map` can be written more simply using `.filter`",
|
||||||
|
);
|
||||||
|
return;
|
||||||
|
}
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
// returns (found_mapping, found_filtering)
|
||||||
|
fn check_expression<'a, 'tcx: 'a>(cx: &'a LateContext<'a, 'tcx>, arg_id: ast::NodeId, expr: &'tcx hir::Expr) -> (bool, bool) {
|
||||||
|
match &expr.node {
|
||||||
|
hir::ExprKind::Call(ref func, ref args) => {
|
||||||
|
if_chain! {
|
||||||
|
if let hir::ExprKind::Path(ref path) = func.node;
|
||||||
|
then {
|
||||||
|
if match_qpath(path, &paths::OPTION_SOME) {
|
||||||
|
if_chain! {
|
||||||
|
if let hir::ExprKind::Path(path) = &args[0].node;
|
||||||
|
if let Def::Local(ref local) = cx.tables.qpath_def(path, args[0].hir_id);
|
||||||
|
then {
|
||||||
|
if arg_id == *local {
|
||||||
|
return (false, false)
|
||||||
|
}
|
||||||
|
}
|
||||||
|
}
|
||||||
|
return (true, false);
|
||||||
|
} else {
|
||||||
|
// We don't know. It might do anything.
|
||||||
|
return (true, true);
|
||||||
|
}
|
||||||
|
}
|
||||||
|
}
|
||||||
|
(true, true)
|
||||||
|
},
|
||||||
|
hir::ExprKind::Block(ref block, _) => {
|
||||||
|
if let Some(expr) = &block.expr {
|
||||||
|
check_expression(cx, arg_id, &expr)
|
||||||
|
} else {
|
||||||
|
(false, false)
|
||||||
|
}
|
||||||
|
},
|
||||||
|
// There must be an else_arm or there will be a type error
|
||||||
|
hir::ExprKind::If(_, ref if_arm, Some(ref else_arm)) => {
|
||||||
|
let if_check = check_expression(cx, arg_id, if_arm);
|
||||||
|
let else_check = check_expression(cx, arg_id, else_arm);
|
||||||
|
(if_check.0 | else_check.0, if_check.1 | else_check.1)
|
||||||
|
},
|
||||||
|
hir::ExprKind::Match(_, ref arms, _) => {
|
||||||
|
let mut found_mapping = false;
|
||||||
|
let mut found_filtering = false;
|
||||||
|
for arm in arms {
|
||||||
|
let (m, f) = check_expression(cx, arg_id, &arm.body);
|
||||||
|
found_mapping |= m;
|
||||||
|
found_filtering |= f;
|
||||||
|
}
|
||||||
|
(found_mapping, found_filtering)
|
||||||
|
},
|
||||||
|
hir::ExprKind::Path(path) if match_qpath(path, &paths::OPTION_NONE) => (false, true),
|
||||||
|
_ => (true, true)
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
struct ReturnVisitor<'a, 'tcx: 'a> {
|
||||||
|
cx: &'a LateContext<'a, 'tcx>,
|
||||||
|
arg_id: ast::NodeId,
|
||||||
|
// Found a non-None return that isn't Some(input)
|
||||||
|
found_mapping: bool,
|
||||||
|
// Found a return that isn't Some
|
||||||
|
found_filtering: bool,
|
||||||
|
}
|
||||||
|
|
||||||
|
impl<'a, 'tcx: 'a> ReturnVisitor<'a, 'tcx> {
|
||||||
|
fn new(cx: &'a LateContext<'a, 'tcx>, arg_id: ast::NodeId) -> ReturnVisitor<'a, 'tcx> {
|
||||||
|
ReturnVisitor {
|
||||||
|
cx,
|
||||||
|
arg_id,
|
||||||
|
found_mapping: false,
|
||||||
|
found_filtering: false,
|
||||||
|
}
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
impl<'a, 'tcx> Visitor<'tcx> for ReturnVisitor<'a, 'tcx> {
|
||||||
|
fn visit_expr(&mut self, expr: &'tcx hir::Expr) {
|
||||||
|
if let hir::ExprKind::Ret(Some(expr)) = &expr.node {
|
||||||
|
let (found_mapping, found_filtering) = check_expression(self.cx, self.arg_id, expr);
|
||||||
|
self.found_mapping |= found_mapping;
|
||||||
|
self.found_filtering |= found_filtering;
|
||||||
|
} else {
|
||||||
|
walk_expr(self, expr);
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
|
fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
|
||||||
|
NestedVisitorMap::None
|
||||||
|
}
|
||||||
|
}
|
||||||
|
}
|
||||||
|
|
||||||
fn lint_iter_nth(cx: &LateContext<'_, '_>, expr: &hir::Expr, iter_args: &[hir::Expr], is_mut: bool) {
|
fn lint_iter_nth(cx: &LateContext<'_, '_>, expr: &hir::Expr, iter_args: &[hir::Expr], is_mut: bool) {
|
||||||
let mut_str = if is_mut { "_mut" } else { "" };
|
let mut_str = if is_mut { "_mut" } else { "" };
|
||||||
let caller_type = if derefs_to_slice(cx, &iter_args[0], cx.tables.expr_ty(&iter_args[0])).is_some() {
|
let caller_type = if derefs_to_slice(cx, &iter_args[0], cx.tables.expr_ty(&iter_args[0])).is_some() {
|
||||||
|
|
|
@ -443,3 +443,17 @@ fn main() {
|
||||||
let opt = Some(0);
|
let opt = Some(0);
|
||||||
let _ = opt.unwrap();
|
let _ = opt.unwrap();
|
||||||
}
|
}
|
||||||
|
|
||||||
|
/// Checks implementation of `UNNECESSARY_FILTER_MAP` lint
|
||||||
|
fn unnecessary_filter_map() {
|
||||||
|
let _ = (0..4).filter_map(|x| if x > 1 { Some(x) } else { None });
|
||||||
|
let _ = (0..4).filter_map(|x| { if x > 1 { return Some(x); }; None });
|
||||||
|
let _ = (0..4).filter_map(|x| match x {
|
||||||
|
0 | 1 => None,
|
||||||
|
_ => Some(x),
|
||||||
|
});
|
||||||
|
|
||||||
|
let _ = (0..4).filter_map(|x| Some(x + 1));
|
||||||
|
|
||||||
|
let _ = (0..4).filter_map(i32::checked_abs);
|
||||||
|
}
|
||||||
|
|
|
@ -453,5 +453,35 @@ error: used unwrap() on an Option value. If you don't want to handle the None ca
|
||||||
|
|
|
|
||||||
= note: `-D clippy::option-unwrap-used` implied by `-D warnings`
|
= note: `-D clippy::option-unwrap-used` implied by `-D warnings`
|
||||||
|
|
||||||
error: aborting due to 56 previous errors
|
error: this `.filter_map` can be written more simply using `.filter`
|
||||||
|
--> $DIR/methods.rs:449:13
|
||||||
|
|
|
||||||
|
449 | let _ = (0..4).filter_map(|x| if x > 1 { Some(x) } else { None });
|
||||||
|
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
||||||
|
|
|
||||||
|
= note: `-D clippy::unnecessary-filter-map` implied by `-D warnings`
|
||||||
|
|
||||||
|
error: this `.filter_map` can be written more simply using `.filter`
|
||||||
|
--> $DIR/methods.rs:450:13
|
||||||
|
|
|
||||||
|
450 | let _ = (0..4).filter_map(|x| { if x > 1 { return Some(x); }; None });
|
||||||
|
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
||||||
|
|
||||||
|
error: this `.filter_map` can be written more simply using `.filter`
|
||||||
|
--> $DIR/methods.rs:451:13
|
||||||
|
|
|
||||||
|
451 | let _ = (0..4).filter_map(|x| match x {
|
||||||
|
| _____________^
|
||||||
|
452 | | 0 | 1 => None,
|
||||||
|
453 | | _ => Some(x),
|
||||||
|
454 | | });
|
||||||
|
| |______^
|
||||||
|
|
||||||
|
error: this `.filter_map` can be written more simply using `.map`
|
||||||
|
--> $DIR/methods.rs:456:13
|
||||||
|
|
|
||||||
|
456 | let _ = (0..4).filter_map(|x| Some(x + 1));
|
||||||
|
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
||||||
|
|
||||||
|
error: aborting due to 60 previous errors
|
||||||
|
|
||||||
|
|
Loading…
Reference in New Issue