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Auto merge of #3756 - g-bartoszek:redundant-closure-for-methods, r=oli-obk

Browse source 
Redundant closure for methods

fixes  #3469
This commit is contained in:
bors 2019-02-12 13:31:44 +00:00
commit db13e6fa34
17 changed files with 253 additions and 69 deletions
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4
clippy_dev/src/lib.rs
View file

@ -47,7 +47,7 @@ impl Lint {
name: name.to_lowercase(),
group: group.to_string(),
desc: NL_ESCAPE_RE.replace(&desc.replace("\\\"", "\""), "").to_string(),
deprecation: deprecation.map(|d| d.to_string()),
deprecation: deprecation.map(std::string::ToString::to_string),
module: module.to_string(),
}
}
@ -178,7 +178,7 @@ fn lint_files() -> impl Iterator<Item = walkdir::DirEntry> {
// Otherwise we would not collect all the lints, for example in `clippy_lints/src/methods/`.
WalkDir::new("../clippy_lints/src")
.into_iter()
.filter_map(|f| f.ok())
.filter_map(std::result::Result::ok)
.filter(|f| f.path().extension() == Some(OsStr::new("rs")))
}

2
clippy_lints/src/attrs.rs
View file

@ -326,7 +326,7 @@ fn check_clippy_lint_names(cx: &LateContext<'_, '_>, items: &[NestedMetaItem]) {
lint.span,
&format!("unknown clippy lint: clippy::{}", name),
|db| {
if name.as_str().chars().any(|c| c.is_uppercase()) {
if name.as_str().chars().any(char::is_uppercase) {
let name_lower = name.as_str().to_lowercase();
match lint_store.check_lint_name(
&name_lower,

2
clippy_lints/src/cargo_common_metadata.rs
View file

@ -53,7 +53,7 @@ fn is_empty_str(value: &Option<String>) -> bool {
fn is_empty_vec(value: &[String]) -> bool {
// This works because empty iterators return true
value.iter().all(|v| v.is_empty())
value.iter().all(std::string::String::is_empty)
}
pub struct Pass;

169
clippy_lints/src/eta_reduction.rs
View file

@ -1,4 +1,5 @@
use crate::utils::{is_adjusted, iter_input_pats, snippet_opt, span_lint_and_then};
use crate::utils::{is_adjusted, iter_input_pats, snippet_opt, span_lint_and_then, type_is_unsafe_function};
use if_chain::if_chain;
use rustc::hir::*;
use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
use rustc::ty;
@ -59,56 +60,136 @@ fn check_closure(cx: &LateContext<'_, '_>, expr: &Expr) {
if let ExprKind::Closure(_, ref decl, eid, _, _) = expr.node {
let body = cx.tcx.hir().body(eid);
let ex = &body.value;
if let ExprKind::Call(ref caller, ref args) = ex.node {
if args.len() != decl.inputs.len() {
// Not the same number of arguments, there
// is no way the closure is the same as the function
return;
}
if is_adjusted(cx, ex) || args.iter().any(|arg| is_adjusted(cx, arg)) {
// Are the expression or the arguments type-adjusted? Then we need the closure
return;
}
if_chain!(
if let ExprKind::Call(ref caller, ref args) = ex.node;
// Not the same number of arguments, there is no way the closure is the same as the function return;
if args.len() == decl.inputs.len();
// Are the expression or the arguments type-adjusted? Then we need the closure
if !(is_adjusted(cx, ex) || args.iter().any(|arg| is_adjusted(cx, arg)));
let fn_ty = cx.tables.expr_ty(caller);
match fn_ty.sty {
// Is it an unsafe function? They don't implement the closure traits
ty::FnDef(..) | ty::FnPtr(_) => {
let sig = fn_ty.fn_sig(cx.tcx);
if sig.skip_binder().unsafety == Unsafety::Unsafe || sig.skip_binder().output().sty == ty::Never {
return;
if !type_is_unsafe_function(cx, fn_ty);
if compare_inputs(&mut iter_input_pats(decl, body), &mut args.into_iter());
then {
span_lint_and_then(cx, REDUNDANT_CLOSURE, expr.span, "redundant closure found", |db| {
if let Some(snippet) = snippet_opt(cx, caller.span) {
db.span_suggestion(
expr.span,
"remove closure as shown",
snippet,
Applicability::MachineApplicable,
);
}
},
_ => (),
});
}
for (a1, a2) in iter_input_pats(decl, body).zip(args) {
if let PatKind::Binding(.., ident, _) = a1.pat.node {
// XXXManishearth Should I be checking the binding mode here?
if let ExprKind::Path(QPath::Resolved(None, ref p)) = a2.node {
if p.segments.len() != 1 {
// If it's a proper path, it can't be a local variable
return;
}
if p.segments[0].ident.name != ident.name {
// The two idents should be the same
return;
}
} else {
return;
}
} else {
return;
}
}
span_lint_and_then(cx, REDUNDANT_CLOSURE, expr.span, "redundant closure found", |db| {
if let Some(snippet) = snippet_opt(cx, caller.span) {
);
if_chain!(
if let ExprKind::MethodCall(ref path, _, ref args) = ex.node;
// Not the same number of arguments, there is no way the closure is the same as the function return;
if args.len() == decl.inputs.len();
// Are the expression or the arguments type-adjusted? Then we need the closure
if !(is_adjusted(cx, ex) || args.iter().skip(1).any(|arg| is_adjusted(cx, arg)));
let method_def_id = cx.tables.type_dependent_defs()[ex.hir_id].def_id();
if !type_is_unsafe_function(cx, cx.tcx.type_of(method_def_id));
if compare_inputs(&mut iter_input_pats(decl, body), &mut args.into_iter());
if let Some(name) = get_ufcs_type_name(cx, method_def_id, &args[0]);
then {
span_lint_and_then(cx, REDUNDANT_CLOSURE, expr.span, "redundant closure found", |db| {
db.span_suggestion(
expr.span,
"remove closure as shown",
snippet,
format!("{}::{}", name, path.ident.name),
Applicability::MachineApplicable,
);
}
});
}
});
}
);
}
}
/// Tries to determine the type for universal function call to be used instead of the closure
fn get_ufcs_type_name(
cx: &LateContext<'_, '_>,
method_def_id: def_id::DefId,
self_arg: &Expr,
) -> std::option::Option<String> {
let expected_type_of_self = &cx.tcx.fn_sig(method_def_id).inputs_and_output().skip_binder()[0].sty;
let actual_type_of_self = &cx.tables.node_id_to_type(self_arg.hir_id).sty;
if let Some(trait_id) = cx.tcx.trait_of_item(method_def_id) {
//if the method expectes &self, ufcs requires explicit borrowing so closure can't be removed
return match (expected_type_of_self, actual_type_of_self) {
(ty::Ref(_, _, _), ty::Ref(_, _, _)) => Some(cx.tcx.item_path_str(trait_id)),
(l, r) => match (l, r) {
(ty::Ref(_, _, _), _) | (_, ty::Ref(_, _, _)) => None,
(_, _) => Some(cx.tcx.item_path_str(trait_id)),
},
};
}
cx.tcx.impl_of_method(method_def_id).and_then(|_| {
//a type may implicitly implement other types methods (e.g. Deref)
if match_types(expected_type_of_self, actual_type_of_self) {
return Some(get_type_name(cx, &actual_type_of_self));
}
None
})
}
fn match_types(lhs: &ty::TyKind<'_>, rhs: &ty::TyKind<'_>) -> bool {
match (lhs, rhs) {
(ty::Bool, ty::Bool)
| (ty::Char, ty::Char)
| (ty::Int(_), ty::Int(_))
| (ty::Uint(_), ty::Uint(_))
| (ty::Str, ty::Str) => true,
(ty::Ref(_, t1, _), ty::Ref(_, t2, _))
| (ty::Array(t1, _), ty::Array(t2, _))
| (ty::Slice(t1), ty::Slice(t2)) => match_types(&t1.sty, &t2.sty),
(ty::Adt(def1, _), ty::Adt(def2, _)) => def1 == def2,
(_, _) => false,
}
}
fn get_type_name(cx: &LateContext<'_, '_>, kind: &ty::TyKind<'_>) -> String {
match kind {
ty::Adt(t, _) => cx.tcx.item_path_str(t.did),
ty::Ref(_, r, _) => get_type_name(cx, &r.sty),
_ => kind.to_string(),
}
}
fn compare_inputs(closure_inputs: &mut dyn Iterator<Item = &Arg>, call_args: &mut dyn Iterator<Item = &Expr>) -> bool {
for (closure_input, function_arg) in closure_inputs.zip(call_args) {
if let PatKind::Binding(_, _, _, ident, _) = closure_input.pat.node {
// XXXManishearth Should I be checking the binding mode here?
if let ExprKind::Path(QPath::Resolved(None, ref p)) = function_arg.node {
if p.segments.len() != 1 {
// If it's a proper path, it can't be a local variable
return false;
}
if p.segments[0].ident.name != ident.name {
// The two idents should be the same
return false;
}
} else {
return false;
}
} else {
return false;
}
}
true
}

2
clippy_lints/src/lib.rs
View file

@ -321,7 +321,7 @@ pub fn read_conf(reg: &rustc_plugin::Registry<'_>) -> Conf {
}
});
let (conf, errors) = utils::conf::read(file_name.as_ref().map(|p| p.as_ref()));
let (conf, errors) = utils::conf::read(file_name.as_ref().map(std::convert::AsRef::as_ref));
// all conf errors are non-fatal, we just use the default conf in case of error
for error in errors {

4
clippy_lints/src/methods/mod.rs
View file

@ -829,7 +829,7 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for Pass {
let (method_names, arg_lists) = method_calls(expr, 2);
let method_names: Vec<LocalInternedString> = method_names.iter().map(|s| s.as_str()).collect();
let method_names: Vec<&str> = method_names.iter().map(|s| s.as_ref()).collect();
let method_names: Vec<&str> = method_names.iter().map(std::convert::AsRef::as_ref).collect();
match method_names.as_slice() {
["unwrap", "get"] => lint_get_unwrap(cx, expr, arg_lists[1], false),
@ -1695,7 +1695,7 @@ fn derefs_to_slice(cx: &LateContext<'_, '_>, expr: &hir::Expr, ty: Ty<'_>) -> Op
if let hir::ExprKind::MethodCall(ref path, _, ref args) = expr.node {
if path.ident.name == "iter" && may_slice(cx, cx.tables.expr_ty(&args[0])) {
sugg::Sugg::hir_opt(cx, &args[0]).map(|sugg| sugg.addr())
sugg::Sugg::hir_opt(cx, &args[0]).map(sugg::Sugg::addr)
} else {
None
}

2
clippy_lints/src/non_expressive_names.rs
View file

@ -241,7 +241,7 @@ impl<'a, 'tcx, 'b> SimilarNamesNameVisitor<'a, 'tcx, 'b> {
// or too many chars differ (x_foo, y_boo) or (xfoo, yboo)
continue;
}
split_at = interned_name.chars().next().map(|c| c.len_utf8());
split_at = interned_name.chars().next().map(char::len_utf8);
}
}
span_lint_and_then(

2
clippy_lints/src/utils/conf.rs
View file

@ -14,7 +14,7 @@ use toml;
pub fn file_from_args(
args: &[source_map::Spanned<ast::NestedMetaItemKind>],
) -> Result<Option<path::PathBuf>, (&'static str, source_map::Span)> {
for arg in args.iter().filter_map(|a| a.meta_item()) {
for arg in args.iter().filter_map(syntax::source_map::Spanned::meta_item) {
if arg.name() == "conf_file" {
return match arg.node {
ast::MetaItemKind::Word | ast::MetaItemKind::List(_) => {

5
clippy_lints/src/utils/mod.rs
View file

@ -142,7 +142,10 @@ pub fn match_def_path(tcx: TyCtxt<'_, '_, '_>, def_id: DefId, path: &[&str]) ->
pub fn get_def_path(tcx: TyCtxt<'_, '_, '_>, def_id: DefId) -> Vec<&'static str> {
let mut apb = AbsolutePathBuffer { names: vec![] };
tcx.push_item_path(&mut apb, def_id, false);
apb.names.iter().map(|n| n.get()).collect()
apb.names
.iter()
.map(syntax_pos::symbol::LocalInternedString::get)
.collect()
}
/// Check if type is struct, enum or union type with given def path.

4
rustc_tools_util/src/lib.rs
View file

@ -9,8 +9,8 @@ macro_rules! get_version_info {
let crate_name = String::from(env!("CARGO_PKG_NAME"));
let host_compiler = $crate::get_channel();
let commit_hash = option_env!("GIT_HASH").map(|s| s.to_string());
let commit_date = option_env!("COMMIT_DATE").map(|s| s.to_string());
let commit_hash = option_env!("GIT_HASH").map(str::to_string);
let commit_date = option_env!("COMMIT_DATE").map(str::to_string);
VersionInfo {
major,

4
src/driver.rs
View file

@ -47,7 +47,7 @@ fn arg_value<'a>(
fn test_arg_value() {
let args: Vec<_> = ["--bar=bar", "--foobar", "123", "--foo"]
.iter()
.map(|s| s.to_string())
.map(std::string::ToString::to_string)
.collect();
assert_eq!(arg_value(None, "--foobar", |_| true), None);
@ -84,7 +84,7 @@ pub fn main() {
let sys_root_arg = arg_value(&orig_args, "--sysroot", |_| true);
let have_sys_root_arg = sys_root_arg.is_some();
let sys_root = sys_root_arg
.map(|s| s.to_string())
.map(std::string::ToString::to_string)
.or_else(|| std::env::var("SYSROOT").ok())
.or_else(|| {
let home = option_env!("RUSTUP_HOME").or(option_env!("MULTIRUST_HOME"));

2
tests/missing-test-files.rs
View file

@ -32,7 +32,7 @@ fn explore_directory(dir: &Path) -> Vec<String> {
let mut missing_files: Vec<String> = Vec::new();
let mut current_file = String::new();
let mut files: Vec<DirEntry> = fs::read_dir(dir).unwrap().filter_map(Result::ok).collect();
files.sort_by_key(|e| e.path());
files.sort_by_key(std::fs::DirEntry::path);
for entry in &files {
let path = entry.path();
if path.is_dir() {

62
tests/ui/eta.rs
View file

@ -9,6 +9,8 @@
)]
#![warn(clippy::redundant_closure, clippy::needless_borrow)]
use std::path::PathBuf;
fn main() {
let a = Some(1u8).map(|a| foo(a));
meta(|a| foo(a));
@ -28,6 +30,66 @@ fn main() {
Some(vec![1i32, 2]).map(|v| -> Box<::std::ops::Deref<Target = [i32]>> { Box::new(v) });
}
trait TestTrait {
fn trait_foo(self) -> bool;
fn trait_foo_ref(&self) -> bool;
}
struct TestStruct<'a> {
some_ref: &'a i32,
}
impl<'a> TestStruct<'a> {
fn foo(self) -> bool {
false
}
unsafe fn foo_unsafe(self) -> bool {
true
}
}
impl<'a> TestTrait for TestStruct<'a> {
fn trait_foo(self) -> bool {
false
}
fn trait_foo_ref(&self) -> bool {
false
}
}
impl<'a> std::ops::Deref for TestStruct<'a> {
type Target = char;
fn deref(&self) -> &char {
&'a'
}
}
fn test_redundant_closures_containing_method_calls() {
let i = 10;
let e = Some(TestStruct { some_ref: &i }).map(|a| a.foo());
let e = Some(TestStruct { some_ref: &i }).map(TestStruct::foo);
let e = Some(TestStruct { some_ref: &i }).map(|a| a.trait_foo());
let e = Some(TestStruct { some_ref: &i }).map(|a| a.trait_foo_ref());
let e = Some(TestStruct { some_ref: &i }).map(TestTrait::trait_foo);
let e = Some(&mut vec![1, 2, 3]).map(|v| v.clear());
let e = Some(&mut vec![1, 2, 3]).map(std::vec::Vec::clear);
unsafe {
let e = Some(TestStruct { some_ref: &i }).map(|a| a.foo_unsafe());
}
let e = Some("str").map(|s| s.to_string());
let e = Some("str").map(str::to_string);
let e = Some('a').map(|s| s.to_uppercase());
let e = Some('a').map(char::to_uppercase);
let e: std::vec::Vec<usize> = vec!['a', 'b', 'c'].iter().map(|c| c.len_utf8()).collect();
let e: std::vec::Vec<char> = vec!['a', 'b', 'c'].iter().map(|c| c.to_ascii_uppercase()).collect();
let e: std::vec::Vec<char> = vec!['a', 'b', 'c'].iter().map(char::to_ascii_uppercase).collect();
let p = Some(PathBuf::new());
let e = p.as_ref().and_then(|s| s.to_str());
let c = Some(TestStruct { some_ref: &i })
.as_ref()
.map(|c| c.to_ascii_uppercase());
}
fn meta<F>(f: F)
where
F: Fn(u8),

48
tests/ui/eta.stderr
View file

@ -1,5 +1,5 @@
error: redundant closure found
--> $DIR/eta.rs:13:27
--> $DIR/eta.rs:15:27
|
LL | let a = Some(1u8).map(|a| foo(a));
| ^^^^^^^^^^ help: remove closure as shown: `foo`
@ -7,19 +7,19 @@ LL | let a = Some(1u8).map(|a| foo(a));
= note: `-D clippy::redundant-closure` implied by `-D warnings`
error: redundant closure found
--> $DIR/eta.rs:14:10
--> $DIR/eta.rs:16:10
|
LL | meta(|a| foo(a));
| ^^^^^^^^^^ help: remove closure as shown: `foo`
error: redundant closure found
--> $DIR/eta.rs:15:27
--> $DIR/eta.rs:17:27
|
LL | let c = Some(1u8).map(|a| {1+2; foo}(a));
| ^^^^^^^^^^^^^^^^^ help: remove closure as shown: `{1+2; foo}`
error: this expression borrows a reference that is immediately dereferenced by the compiler
--> $DIR/eta.rs:17:21
--> $DIR/eta.rs:19:21
|
LL | all(&[1, 2, 3], &&2, |x, y| below(x, y)); //is adjusted
| ^^^ help: change this to: `&2`
@ -27,10 +27,46 @@ LL | all(&[1, 2, 3], &&2, |x, y| below(x, y)); //is adjusted
= note: `-D clippy::needless-borrow` implied by `-D warnings`
error: redundant closure found
--> $DIR/eta.rs:24:27
--> $DIR/eta.rs:26:27
|
LL | let e = Some(1u8).map(|a| generic(a));
| ^^^^^^^^^^^^^^ help: remove closure as shown: `generic`
error: aborting due to 5 previous errors
error: redundant closure found
--> $DIR/eta.rs:69:51
|
LL | let e = Some(TestStruct { some_ref: &i }).map(|a| a.foo());
| ^^^^^^^^^^^ help: remove closure as shown: `TestStruct::foo`
error: redundant closure found
--> $DIR/eta.rs:71:51
|
LL | let e = Some(TestStruct { some_ref: &i }).map(|a| a.trait_foo());
| ^^^^^^^^^^^^^^^^^ help: remove closure as shown: `TestTrait::trait_foo`
error: redundant closure found
--> $DIR/eta.rs:74:42
|
LL | let e = Some(&mut vec![1, 2, 3]).map(|v| v.clear());
| ^^^^^^^^^^^^^ help: remove closure as shown: `std::vec::Vec::clear`
error: redundant closure found
--> $DIR/eta.rs:79:29
|
LL | let e = Some("str").map(|s| s.to_string());
| ^^^^^^^^^^^^^^^^^ help: remove closure as shown: `std::string::ToString::to_string`
error: redundant closure found
--> $DIR/eta.rs:81:27
|
LL | let e = Some('a').map(|s| s.to_uppercase());
| ^^^^^^^^^^^^^^^^^^^^ help: remove closure as shown: `char::to_uppercase`
error: redundant closure found
--> $DIR/eta.rs:84:65
|
LL | let e: std::vec::Vec<char> = vec!['a', 'b', 'c'].iter().map(|c| c.to_ascii_uppercase()).collect();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: remove closure as shown: `char::to_ascii_uppercase`
error: aborting due to 11 previous errors

1
tests/ui/map_clone.fixed
View file

@ -3,6 +3,7 @@
#![allow(clippy::iter_cloned_collect)]
#![allow(clippy::clone_on_copy)]
#![allow(clippy::missing_docs_in_private_items)]
#![allow(clippy::redundant_closure)]
fn main() {
let _: Vec<i8> = vec![5_i8; 6].iter().cloned().collect();

1
tests/ui/map_clone.rs
View file

@ -3,6 +3,7 @@
#![allow(clippy::iter_cloned_collect)]
#![allow(clippy::clone_on_copy)]
#![allow(clippy::missing_docs_in_private_items)]
#![allow(clippy::redundant_closure)]
fn main() {
let _: Vec<i8> = vec![5_i8; 6].iter().map(|x| *x).collect();

8
tests/ui/map_clone.stderr
View file

@ -1,5 +1,5 @@
error: You are using an explicit closure for cloning elements
--> $DIR/map_clone.rs:8:22
--> $DIR/map_clone.rs:9:22
|
LL | let _: Vec<i8> = vec![5_i8; 6].iter().map(|x| *x).collect();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Consider calling the dedicated `cloned` method: `vec![5_i8; 6].iter().cloned()`
@ -7,19 +7,19 @@ LL | let _: Vec<i8> = vec![5_i8; 6].iter().map(|x| *x).collect();
= note: `-D clippy::map-clone` implied by `-D warnings`
error: You are using an explicit closure for cloning elements
--> $DIR/map_clone.rs:9:26
--> $DIR/map_clone.rs:10:26
|
LL | let _: Vec<String> = vec![String::new()].iter().map(|x| x.clone()).collect();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Consider calling the dedicated `cloned` method: `vec![String::new()].iter().cloned()`
error: You are using an explicit closure for cloning elements
--> $DIR/map_clone.rs:10:23
--> $DIR/map_clone.rs:11:23
|
LL | let _: Vec<u32> = vec![42, 43].iter().map(|&x| x).collect();
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: Consider calling the dedicated `cloned` method: `vec![42, 43].iter().cloned()`
error: You are needlessly cloning iterator elements
--> $DIR/map_clone.rs:22:29
--> $DIR/map_clone.rs:23:29
|
LL | let _ = std::env::args().map(|v| v.clone());
| ^^^^^^^^^^^^^^^^^^^ help: Remove the map call