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Auto merge of #6826 - TaKO8Ki:refactor-methods-mod, r=phansch

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Refactor: arrange lints in `methods` module

This PR arranges methods lints so that they can be accessed more easily.
Basically, I refactored them following the instruction described in #6680.

changelog: Move lints in methods module into their own modules.
This commit is contained in:
bors 2021-03-11 19:54:48 +00:00
commit 6ed6f1e6a1
51 changed files with 2382 additions and 2023 deletions
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2
clippy_lints/src/methods/bind_instead_of_map.rs
View file

@ -158,7 +158,7 @@ pub(crate) trait BindInsteadOfMap {
}
/// Lint use of `_.and_then(|x| Some(y))` for `Option`s
fn lint(cx: &LateContext<'_>, expr: &hir::Expr<'_>, args: &[hir::Expr<'_>]) -> bool {
fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, args: &[hir::Expr<'_>]) -> bool {
if !match_type(cx, cx.typeck_results().expr_ty(&args[0]), Self::TYPE_QPATH) {
return false;
}

2
clippy_lints/src/methods/bytes_nth.rs
View file

@ -7,7 +7,7 @@ use rustc_span::sym;
use super::BYTES_NTH;
pub(super) fn lints<'tcx>(cx: &LateContext<'tcx>, expr: &Expr<'_>, iter_args: &'tcx [Expr<'tcx>]) {
pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &Expr<'_>, iter_args: &'tcx [Expr<'tcx>]) {
if_chain! {
if let ExprKind::MethodCall(_, _, ref args, _) = expr.kind;
let ty = cx.typeck_results().expr_ty(&iter_args[0]).peel_refs();

109
clippy_lints/src/methods/clone_on_copy.rs Normal file
View file

@ -0,0 +1,109 @@
use crate::utils::{is_copy, span_lint_and_then, sugg};
use rustc_errors::Applicability;
use rustc_hir as hir;
use rustc_lint::LateContext;
use rustc_middle::ty::{self, Ty};
use std::iter;
use super::CLONE_DOUBLE_REF;
use super::CLONE_ON_COPY;
/// Checks for the `CLONE_ON_COPY` lint.
pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, arg: &hir::Expr<'_>, arg_ty: Ty<'_>) {
let ty = cx.typeck_results().expr_ty(expr);
if let ty::Ref(_, inner, _) = arg_ty.kind() {
if let ty::Ref(_, innermost, _) = inner.kind() {
span_lint_and_then(
cx,
CLONE_DOUBLE_REF,
expr.span,
&format!(
"using `clone` on a double-reference; \
this will copy the reference of type `{}` instead of cloning the inner type",
ty
),
|diag| {
if let Some(snip) = sugg::Sugg::hir_opt(cx, arg) {
let mut ty = innermost;
let mut n = 0;
while let ty::Ref(_, inner, _) = ty.kind() {
ty = inner;
n += 1;
}
let refs: String = iter::repeat('&').take(n + 1).collect();
let derefs: String = iter::repeat('*').take(n).collect();
let explicit = format!("<{}{}>::clone({})", refs, ty, snip);
diag.span_suggestion(
expr.span,
"try dereferencing it",
format!("{}({}{}).clone()", refs, derefs, snip.deref()),
Applicability::MaybeIncorrect,
);
diag.span_suggestion(
expr.span,
"or try being explicit if you are sure, that you want to clone a reference",
explicit,
Applicability::MaybeIncorrect,
);
}
},
);
return; // don't report clone_on_copy
}
}
if is_copy(cx, ty) {
let snip;
if let Some(snippet) = sugg::Sugg::hir_opt(cx, arg) {
let parent = cx.tcx.hir().get_parent_node(expr.hir_id);
match &cx.tcx.hir().get(parent) {
hir::Node::Expr(parent) => match parent.kind {
// &*x is a nop, &x.clone() is not
hir::ExprKind::AddrOf(..) => return,
// (*x).func() is useless, x.clone().func() can work in case func borrows mutably
hir::ExprKind::MethodCall(_, _, parent_args, _) if expr.hir_id == parent_args[0].hir_id => {
return;
},
_ => {},
},
hir::Node::Stmt(stmt) => {
if let hir::StmtKind::Local(ref loc) = stmt.kind {
if let hir::PatKind::Ref(..) = loc.pat.kind {
// let ref y = *x borrows x, let ref y = x.clone() does not
return;
}
}
},
_ => {},
}
// x.clone() might have dereferenced x, possibly through Deref impls
if cx.typeck_results().expr_ty(arg) == ty {
snip = Some(("try removing the `clone` call", format!("{}", snippet)));
} else {
let deref_count = cx
.typeck_results()
.expr_adjustments(arg)
.iter()
.filter(|adj| matches!(adj.kind, ty::adjustment::Adjust::Deref(_)))
.count();
let derefs: String = iter::repeat('*').take(deref_count).collect();
snip = Some(("try dereferencing it", format!("{}{}", derefs, snippet)));
}
} else {
snip = None;
}
span_lint_and_then(
cx,
CLONE_ON_COPY,
expr.span,
&format!("using `clone` on type `{}` which implements the `Copy` trait", ty),
|diag| {
if let Some((text, snip)) = snip {
diag.span_suggestion(expr.span, text, snip, Applicability::MachineApplicable);
}
},
);
}
}

36
clippy_lints/src/methods/clone_on_ref_ptr.rs Normal file
View file

@ -0,0 +1,36 @@
use crate::utils::{is_type_diagnostic_item, match_type, paths, snippet_with_macro_callsite, span_lint_and_sugg};
use rustc_errors::Applicability;
use rustc_hir as hir;
use rustc_lint::LateContext;
use rustc_middle::ty;
use rustc_span::symbol::sym;
use super::CLONE_ON_REF_PTR;
pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, arg: &hir::Expr<'_>) {
let obj_ty = cx.typeck_results().expr_ty(arg).peel_refs();
if let ty::Adt(_, subst) = obj_ty.kind() {
let caller_type = if is_type_diagnostic_item(cx, obj_ty, sym::Rc) {
"Rc"
} else if is_type_diagnostic_item(cx, obj_ty, sym::Arc) {
"Arc"
} else if match_type(cx, obj_ty, &paths::WEAK_RC) || match_type(cx, obj_ty, &paths::WEAK_ARC) {
"Weak"
} else {
return;
};
let snippet = snippet_with_macro_callsite(cx, arg.span, "..");
span_lint_and_sugg(
cx,
CLONE_ON_REF_PTR,
expr.span,
"using `.clone()` on a ref-counted pointer",
"try this",
format!("{}::<{}>::clone(&{})", caller_type, subst.type_at(0), snippet),
Applicability::Unspecified, // Sometimes unnecessary ::<_> after Rc/Arc/Weak
);
}
}

199
clippy_lints/src/methods/expect_fun_call.rs Normal file
View file

@ -0,0 +1,199 @@
use crate::utils::{is_expn_of, is_type_diagnostic_item, snippet, snippet_with_applicability, span_lint_and_sugg};
use if_chain::if_chain;
use rustc_errors::Applicability;
use rustc_hir as hir;
use rustc_lint::LateContext;
use rustc_middle::ty;
use rustc_span::source_map::Span;
use rustc_span::symbol::sym;
use std::borrow::Cow;
use super::EXPECT_FUN_CALL;
/// Checks for the `EXPECT_FUN_CALL` lint.
#[allow(clippy::too_many_lines)]
pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, method_span: Span, name: &str, args: &[hir::Expr<'_>]) {
// Strip `&`, `as_ref()` and `as_str()` off `arg` until we're left with either a `String` or
// `&str`
fn get_arg_root<'a>(cx: &LateContext<'_>, arg: &'a hir::Expr<'a>) -> &'a hir::Expr<'a> {
let mut arg_root = arg;
loop {
arg_root = match &arg_root.kind {
hir::ExprKind::AddrOf(hir::BorrowKind::Ref, _, expr) => expr,
hir::ExprKind::MethodCall(method_name, _, call_args, _) => {
if call_args.len() == 1
&& (method_name.ident.name == sym::as_str || method_name.ident.name == sym!(as_ref))
&& {
let arg_type = cx.typeck_results().expr_ty(&call_args[0]);
let base_type = arg_type.peel_refs();
*base_type.kind() == ty::Str || is_type_diagnostic_item(cx, base_type, sym::string_type)
}
{
&call_args[0]
} else {
break;
}
},
_ => break,
};
}
arg_root
}
// Only `&'static str` or `String` can be used directly in the `panic!`. Other types should be
// converted to string.
fn requires_to_string(cx: &LateContext<'_>, arg: &hir::Expr<'_>) -> bool {
let arg_ty = cx.typeck_results().expr_ty(arg);
if is_type_diagnostic_item(cx, arg_ty, sym::string_type) {
return false;
}
if let ty::Ref(_, ty, ..) = arg_ty.kind() {
if *ty.kind() == ty::Str && can_be_static_str(cx, arg) {
return false;
}
};
true
}
// Check if an expression could have type `&'static str`, knowing that it
// has type `&str` for some lifetime.
fn can_be_static_str(cx: &LateContext<'_>, arg: &hir::Expr<'_>) -> bool {
match arg.kind {
hir::ExprKind::Lit(_) => true,
hir::ExprKind::Call(fun, _) => {
if let hir::ExprKind::Path(ref p) = fun.kind {
match cx.qpath_res(p, fun.hir_id) {
hir::def::Res::Def(hir::def::DefKind::Fn | hir::def::DefKind::AssocFn, def_id) => matches!(
cx.tcx.fn_sig(def_id).output().skip_binder().kind(),
ty::Ref(ty::ReStatic, ..)
),
_ => false,
}
} else {
false
}
},
hir::ExprKind::MethodCall(..) => {
cx.typeck_results()
.type_dependent_def_id(arg.hir_id)
.map_or(false, |method_id| {
matches!(
cx.tcx.fn_sig(method_id).output().skip_binder().kind(),
ty::Ref(ty::ReStatic, ..)
)
})
},
hir::ExprKind::Path(ref p) => matches!(
cx.qpath_res(p, arg.hir_id),
hir::def::Res::Def(hir::def::DefKind::Const | hir::def::DefKind::Static, _)
),
_ => false,
}
}
fn generate_format_arg_snippet(
cx: &LateContext<'_>,
a: &hir::Expr<'_>,
applicability: &mut Applicability,
) -> Vec<String> {
if_chain! {
if let hir::ExprKind::AddrOf(hir::BorrowKind::Ref, _, ref format_arg) = a.kind;
if let hir::ExprKind::Match(ref format_arg_expr, _, _) = format_arg.kind;
if let hir::ExprKind::Tup(ref format_arg_expr_tup) = format_arg_expr.kind;
then {
format_arg_expr_tup
.iter()
.map(|a| snippet_with_applicability(cx, a.span, "..", applicability).into_owned())
.collect()
} else {
unreachable!()
}
}
}
fn is_call(node: &hir::ExprKind<'_>) -> bool {
match node {
hir::ExprKind::AddrOf(hir::BorrowKind::Ref, _, expr) => {
is_call(&expr.kind)
},
hir::ExprKind::Call(..)
| hir::ExprKind::MethodCall(..)
// These variants are debatable or require further examination
| hir::ExprKind::If(..)
| hir::ExprKind::Match(..)
| hir::ExprKind::Block{ .. } => true,
_ => false,
}
}
if args.len() != 2 || name != "expect" || !is_call(&args[1].kind) {
return;
}
let receiver_type = cx.typeck_results().expr_ty_adjusted(&args[0]);
let closure_args = if is_type_diagnostic_item(cx, receiver_type, sym::option_type) {
"||"
} else if is_type_diagnostic_item(cx, receiver_type, sym::result_type) {
"|_|"
} else {
return;
};
let arg_root = get_arg_root(cx, &args[1]);
let span_replace_word = method_span.with_hi(expr.span.hi());
let mut applicability = Applicability::MachineApplicable;
//Special handling for `format!` as arg_root
if_chain! {
if let hir::ExprKind::Block(block, None) = &arg_root.kind;
if block.stmts.len() == 1;
if let hir::StmtKind::Local(local) = &block.stmts[0].kind;
if let Some(arg_root) = &local.init;
if let hir::ExprKind::Call(ref inner_fun, ref inner_args) = arg_root.kind;
if is_expn_of(inner_fun.span, "format").is_some() && inner_args.len() == 1;
if let hir::ExprKind::Call(_, format_args) = &inner_args[0].kind;
then {
let fmt_spec = &format_args[0];
let fmt_args = &format_args[1];
let mut args = vec![snippet(cx, fmt_spec.span, "..").into_owned()];
args.extend(generate_format_arg_snippet(cx, fmt_args, &mut applicability));
let sugg = args.join(", ");
span_lint_and_sugg(
cx,
EXPECT_FUN_CALL,
span_replace_word,
&format!("use of `{}` followed by a function call", name),
"try this",
format!("unwrap_or_else({} panic!({}))", closure_args, sugg),
applicability,
);
return;
}
}
let mut arg_root_snippet: Cow<'_, _> = snippet_with_applicability(cx, arg_root.span, "..", &mut applicability);
if requires_to_string(cx, arg_root) {
arg_root_snippet.to_mut().push_str(".to_string()");
}
span_lint_and_sugg(
cx,
EXPECT_FUN_CALL,
span_replace_word,
&format!("use of `{}` followed by a function call", name),
"try this",
format!(
"unwrap_or_else({} {{ panic!(\"{{}}\", {}) }})",
closure_args, arg_root_snippet
),
applicability,
);
}

30
clippy_lints/src/methods/expect_used.rs Normal file
View file

@ -0,0 +1,30 @@
use crate::utils::{is_type_diagnostic_item, span_lint_and_help};
use rustc_hir as hir;
use rustc_lint::LateContext;
use rustc_span::sym;
use super::EXPECT_USED;
/// lint use of `expect()` for `Option`s and `Result`s
pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, expect_args: &[hir::Expr<'_>]) {
let obj_ty = cx.typeck_results().expr_ty(&expect_args[0]).peel_refs();
let mess = if is_type_diagnostic_item(cx, obj_ty, sym::option_type) {
Some((EXPECT_USED, "an Option", "None"))
} else if is_type_diagnostic_item(cx, obj_ty, sym::result_type) {
Some((EXPECT_USED, "a Result", "Err"))
} else {
None
};
if let Some((lint, kind, none_value)) = mess {
span_lint_and_help(
cx,
lint,
expr.span,
&format!("used `expect()` on `{}` value", kind,),
None,
&format!("if this value is an `{}`, it will panic", none_value,),
);
}
}

39
clippy_lints/src/methods/filetype_is_file.rs Normal file
View file

@ -0,0 +1,39 @@
use crate::utils::{get_parent_expr, match_type, paths, span_lint_and_help};
use if_chain::if_chain;
use rustc_hir as hir;
use rustc_lint::LateContext;
use rustc_span::source_map::Span;
use super::FILETYPE_IS_FILE;
pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, args: &[hir::Expr<'_>]) {
let ty = cx.typeck_results().expr_ty(&args[0]);
if !match_type(cx, ty, &paths::FILE_TYPE) {
return;
}
let span: Span;
let verb: &str;
let lint_unary: &str;
let help_unary: &str;
if_chain! {
if let Some(parent) = get_parent_expr(cx, expr);
if let hir::ExprKind::Unary(op, _) = parent.kind;
if op == hir::UnOp::Not;
then {
lint_unary = "!";
verb = "denies";
help_unary = "";
span = parent.span;
} else {
lint_unary = "";
verb = "covers";
help_unary = "!";
span = expr.span;
}
}
let lint_msg = format!("`{}FileType::is_file()` only {} regular files", lint_unary, verb);
let help_msg = format!("use `{}FileType::is_dir()` instead", help_unary);
span_lint_and_help(cx, FILETYPE_IS_FILE, span, &lint_msg, None, &help_msg);
}

21
clippy_lints/src/methods/filter_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().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().flat_map()` is an Iterator
if match_trait_method(cx, expr, &paths::ITERATOR) {
let msg = "called `filter(..).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);
}
}

85
clippy_lints/src/methods/filter_map.rs Normal file
View file

@ -0,0 +1,85 @@
use crate::utils::{match_trait_method, path_to_local_id, paths, snippet, span_lint_and_sugg, SpanlessEq};
use if_chain::if_chain;
use rustc_errors::Applicability;
use rustc_hir as hir;
use rustc_hir::{Expr, ExprKind, PatKind, UnOp};
use rustc_lint::LateContext;
use rustc_middle::ty::TyS;
use rustc_span::symbol::sym;
use super::MANUAL_FILTER_MAP;
use super::MANUAL_FIND_MAP;
/// lint use of `filter().map()` or `find().map()` for `Iterators`
pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'_>, is_find: bool) {
if_chain! {
if let ExprKind::MethodCall(_, _, [map_recv, map_arg], map_span) = expr.kind;
if let ExprKind::MethodCall(_, _, [_, filter_arg], filter_span) = map_recv.kind;
if match_trait_method(cx, map_recv, &paths::ITERATOR);
// filter(|x| ...is_some())...
if let ExprKind::Closure(_, _, filter_body_id, ..) = filter_arg.kind;
let filter_body = cx.tcx.hir().body(filter_body_id);
if let [filter_param] = filter_body.params;
// optional ref pattern: `filter(|&x| ..)`
let (filter_pat, is_filter_param_ref) = if let PatKind::Ref(ref_pat, _) = filter_param.pat.kind {
(ref_pat, true)
} else {
(filter_param.pat, false)
};
// closure ends with is_some() or is_ok()
if let PatKind::Binding(_, filter_param_id, _, None) = filter_pat.kind;
if let ExprKind::MethodCall(path, _, [filter_arg], _) = filter_body.value.kind;
if let Some(opt_ty) = cx.typeck_results().expr_ty(filter_arg).ty_adt_def();
if let Some(is_result) = if cx.tcx.is_diagnostic_item(sym::option_type, opt_ty.did) {
Some(false)
} else if cx.tcx.is_diagnostic_item(sym::result_type, opt_ty.did) {
Some(true)
} else {
None
};
if path.ident.name.as_str() == if is_result { "is_ok" } else { "is_some" };
// ...map(|x| ...unwrap())
if let ExprKind::Closure(_, _, map_body_id, ..) = map_arg.kind;
let map_body = cx.tcx.hir().body(map_body_id);
if let [map_param] = map_body.params;
if let PatKind::Binding(_, map_param_id, map_param_ident, None) = map_param.pat.kind;
// closure ends with expect() or unwrap()
if let ExprKind::MethodCall(seg, _, [map_arg, ..], _) = map_body.value.kind;
if matches!(seg.ident.name, sym::expect | sym::unwrap | sym::unwrap_or);
let eq_fallback = |a: &Expr<'_>, b: &Expr<'_>| {
// in `filter(|x| ..)`, replace `*x` with `x`
let a_path = if_chain! {
if !is_filter_param_ref;
if let ExprKind::Unary(UnOp::Deref, expr_path) = a.kind;
then { expr_path } else { a }
};
// let the filter closure arg and the map closure arg be equal
if_chain! {
if path_to_local_id(a_path, filter_param_id);
if path_to_local_id(b, map_param_id);
if TyS::same_type(cx.typeck_results().expr_ty_adjusted(a), cx.typeck_results().expr_ty_adjusted(b));
then {
return true;
}
}
false
};
if SpanlessEq::new(cx).expr_fallback(eq_fallback).eq_expr(filter_arg, map_arg);
then {
let span = filter_span.to(map_span);
let (filter_name, lint) = if is_find {
("find", MANUAL_FIND_MAP)
} else {
("filter", MANUAL_FILTER_MAP)
};
let msg = format!("`{}(..).map(..)` can be simplified as `{0}_map(..)`", filter_name);
let to_opt = if is_result { ".ok()" } else { "" };
let sugg = format!("{}_map(|{}| {}{})", filter_name, map_param_ident,
snippet(cx, map_arg.span, ".."), to_opt);
span_lint_and_sugg(cx, lint, span, &msg, "try", sugg, Applicability::MachineApplicable);
}
}
}

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);
}
}

20
clippy_lints/src/methods/filter_map_map.rs Normal file
View file

@ -0,0 +1,20 @@
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().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().map()` is an Iterator
if match_trait_method(cx, expr, &paths::ITERATOR) {
let msg = "called `filter_map(..).map(..)` on an `Iterator`";
let hint = "this is more succinctly expressed by only calling `.filter_map(..)` instead";
span_lint_and_help(cx, FILTER_MAP, expr.span, msg, None, hint);
}
}

40
clippy_lints/src/methods/filter_map_next.rs Normal file
View file

@ -0,0 +1,40 @@
use crate::utils::{match_trait_method, meets_msrv, paths, snippet, span_lint, span_lint_and_sugg};
use rustc_errors::Applicability;
use rustc_hir as hir;
use rustc_lint::LateContext;
use rustc_semver::RustcVersion;
use super::FILTER_MAP_NEXT;
const FILTER_MAP_NEXT_MSRV: RustcVersion = RustcVersion::new(1, 30, 0);
pub(super) fn check<'tcx>(
cx: &LateContext<'tcx>,
expr: &'tcx hir::Expr<'_>,
filter_args: &'tcx [hir::Expr<'_>],
msrv: Option<&RustcVersion>,
) {
if match_trait_method(cx, expr, &paths::ITERATOR) {
if !meets_msrv(msrv, &FILTER_MAP_NEXT_MSRV) {
return;
}
let msg = "called `filter_map(..).next()` on an `Iterator`. This is more succinctly expressed by calling \
`.find_map(..)` instead";
let filter_snippet = snippet(cx, filter_args[1].span, "..");
if filter_snippet.lines().count() <= 1 {
let iter_snippet = snippet(cx, filter_args[0].span, "..");
span_lint_and_sugg(
cx,
FILTER_MAP_NEXT,
expr.span,
msg,
"try this",
format!("{}.find_map({})", iter_snippet, filter_snippet),
Applicability::MachineApplicable,
);
} else {
span_lint(cx, FILTER_MAP_NEXT, expr.span, msg);
}
}
}

31
clippy_lints/src/methods/filter_next.rs Normal file
View file

@ -0,0 +1,31 @@
use crate::utils::{match_trait_method, paths, snippet, span_lint, span_lint_and_sugg};
use rustc_errors::Applicability;
use rustc_hir as hir;
use rustc_lint::LateContext;
use super::FILTER_NEXT;
/// lint use of `filter().next()` for `Iterators`
pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'_>, filter_args: &'tcx [hir::Expr<'_>]) {
// lint if caller of `.filter().next()` is an Iterator
if match_trait_method(cx, expr, &paths::ITERATOR) {
let msg = "called `filter(..).next()` on an `Iterator`. This is more succinctly expressed by calling \
`.find(..)` instead";
let filter_snippet = snippet(cx, filter_args[1].span, "..");
if filter_snippet.lines().count() <= 1 {
let iter_snippet = snippet(cx, filter_args[0].span, "..");
// add note if not multi-line
span_lint_and_sugg(
cx,
FILTER_NEXT,
expr.span,
msg,
"try this",
format!("{}.find({})", iter_snippet, filter_snippet),
Applicability::MachineApplicable,
);
} else {
span_lint(cx, FILTER_NEXT, expr.span, msg);
}
}
}

57
clippy_lints/src/methods/flat_map_identity.rs Normal file
View file

@ -0,0 +1,57 @@
use crate::utils::{match_qpath, match_trait_method, paths, span_lint_and_sugg};
use if_chain::if_chain;
use rustc_errors::Applicability;
use rustc_hir as hir;
use rustc_lint::LateContext;
use rustc_span::source_map::Span;
use super::FLAT_MAP_IDENTITY;
/// lint use of `flat_map` for `Iterators` where `flatten` would be sufficient
pub(super) fn check<'tcx>(
cx: &LateContext<'tcx>,
expr: &'tcx hir::Expr<'_>,
flat_map_args: &'tcx [hir::Expr<'_>],
flat_map_span: Span,
) {
if match_trait_method(cx, expr, &paths::ITERATOR) {
let arg_node = &flat_map_args[1].kind;
let apply_lint = |message: &str| {
span_lint_and_sugg(
cx,
FLAT_MAP_IDENTITY,
flat_map_span.with_hi(expr.span.hi()),
message,
"try",
"flatten()".to_string(),
Applicability::MachineApplicable,
);
};
if_chain! {
if let hir::ExprKind::Closure(_, _, body_id, _, _) = arg_node;
let body = cx.tcx.hir().body(*body_id);
if let hir::PatKind::Binding(_, _, binding_ident, _) = body.params[0].pat.kind;
if let hir::ExprKind::Path(hir::QPath::Resolved(_, ref path)) = body.value.kind;
if path.segments.len() == 1;
if path.segments[0].ident.name == binding_ident.name;
then {
apply_lint("called `flat_map(|x| x)` on an `Iterator`");
}
}
if_chain! {
if let hir::ExprKind::Path(ref qpath) = arg_node;
if match_qpath(qpath, &paths::STD_CONVERT_IDENTITY);
then {
apply_lint("called `flat_map(std::convert::identity)` on an `Iterator`");
}
}
}
}

67
clippy_lints/src/methods/from_iter_instead_of_collect.rs Normal file
View file

@ -0,0 +1,67 @@
use crate::utils::{get_trait_def_id, implements_trait, paths, span_lint_and_sugg, sugg};
use if_chain::if_chain;
use rustc_errors::Applicability;
use rustc_hir as hir;
use rustc_lint::{LateContext, LintContext};
use rustc_middle::ty::Ty;
use super::FROM_ITER_INSTEAD_OF_COLLECT;
pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, args: &[hir::Expr<'_>]) {
let ty = cx.typeck_results().expr_ty(expr);
let arg_ty = cx.typeck_results().expr_ty(&args[0]);
if_chain! {
if let Some(from_iter_id) = get_trait_def_id(cx, &paths::FROM_ITERATOR);
if let Some(iter_id) = get_trait_def_id(cx, &paths::ITERATOR);
if implements_trait(cx, ty, from_iter_id, &[]) && implements_trait(cx, arg_ty, iter_id, &[]);
then {
// `expr` implements `FromIterator` trait
let iter_expr = sugg::Sugg::hir(cx, &args[0], "..").maybe_par();
let turbofish = extract_turbofish(cx, expr, ty);
let sugg = format!("{}.collect::<{}>()", iter_expr, turbofish);
span_lint_and_sugg(
cx,
FROM_ITER_INSTEAD_OF_COLLECT,
expr.span,
"usage of `FromIterator::from_iter`",
"use `.collect()` instead of `::from_iter()`",
sugg,
Applicability::MaybeIncorrect,
);
}
}
}
fn extract_turbofish(cx: &LateContext<'_>, expr: &hir::Expr<'_>, ty: Ty<'tcx>) -> String {
if_chain! {
let call_site = expr.span.source_callsite();
if let Ok(snippet) = cx.sess().source_map().span_to_snippet(call_site);
let snippet_split = snippet.split("::").collect::<Vec<_>>();
if let Some((_, elements)) = snippet_split.split_last();
then {
// is there a type specifier? (i.e.: like `<u32>` in `collections::BTreeSet::<u32>::`)
if let Some(type_specifier) = snippet_split.iter().find(|e| e.starts_with('<') && e.ends_with('>')) {
// remove the type specifier from the path elements
let without_ts = elements.iter().filter_map(|e| {
if e == type_specifier { None } else { Some((*e).to_string()) }
}).collect::<Vec<_>>();
// join and add the type specifier at the end (i.e.: `collections::BTreeSet<u32>`)
format!("{}{}", without_ts.join("::"), type_specifier)
} else {
// type is not explicitly specified so wildcards are needed
// i.e.: 2 wildcards in `std::collections::BTreeMap<&i32, &char>`
let ty_str = ty.to_string();
let start = ty_str.find('<').unwrap_or(0);
let end = ty_str.find('>').unwrap_or_else(|| ty_str.len());
let nb_wildcard = ty_str[start..end].split(',').count();
let wildcards = format!("_{}", ", _".repeat(nb_wildcard - 1));
format!("{}<{}>", elements.join("::"), wildcards)
}
} else {
ty.to_string()
}
}
}

84
clippy_lints/src/methods/get_unwrap.rs Normal file
View file

@ -0,0 +1,84 @@
use crate::methods::derefs_to_slice;
use crate::utils::{
get_parent_expr, is_type_diagnostic_item, match_type, paths, snippet_with_applicability, span_lint_and_sugg,
};
use if_chain::if_chain;
use rustc_errors::Applicability;
use rustc_hir as hir;
use rustc_lint::LateContext;
use rustc_span::sym;
use super::GET_UNWRAP;
pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &hir::Expr<'_>, get_args: &'tcx [hir::Expr<'_>], is_mut: bool) {
// Note: we don't want to lint `get_mut().unwrap` for `HashMap` or `BTreeMap`,
// because they do not implement `IndexMut`
let mut applicability = Applicability::MachineApplicable;
let expr_ty = cx.typeck_results().expr_ty(&get_args[0]);
let get_args_str = if get_args.len() > 1 {
snippet_with_applicability(cx, get_args[1].span, "..", &mut applicability)
} else {
return; // not linting on a .get().unwrap() chain or variant
};
let mut needs_ref;
let caller_type = if derefs_to_slice(cx, &get_args[0], expr_ty).is_some() {
needs_ref = get_args_str.parse::<usize>().is_ok();
"slice"
} else if is_type_diagnostic_item(cx, expr_ty, sym::vec_type) {
needs_ref = get_args_str.parse::<usize>().is_ok();
"Vec"
} else if is_type_diagnostic_item(cx, expr_ty, sym::vecdeque_type) {
needs_ref = get_args_str.parse::<usize>().is_ok();
"VecDeque"
} else if !is_mut && is_type_diagnostic_item(cx, expr_ty, sym::hashmap_type) {
needs_ref = true;
"HashMap"
} else if !is_mut && match_type(cx, expr_ty, &paths::BTREEMAP) {
needs_ref = true;
"BTreeMap"
} else {
return; // caller is not a type that we want to lint
};
let mut span = expr.span;
// Handle the case where the result is immediately dereferenced
// by not requiring ref and pulling the dereference into the
// suggestion.
if_chain! {
if needs_ref;
if let Some(parent) = get_parent_expr(cx, expr);
if let hir::ExprKind::Unary(hir::UnOp::Deref, _) = parent.kind;
then {
needs_ref = false;
span = parent.span;
}
}
let mut_str = if is_mut { "_mut" } else { "" };
let borrow_str = if !needs_ref {
""
} else if is_mut {
"&mut "
} else {
"&"
};
span_lint_and_sugg(
cx,
GET_UNWRAP,
span,
&format!(
"called `.get{0}().unwrap()` on a {1}. Using `[]` is more clear and more concise",
mut_str, caller_type
),
"try this",
format!(
"{}{}[{}]",
borrow_str,
snippet_with_applicability(cx, get_args[0].span, "..", &mut applicability),
get_args_str
),
applicability,
);
}

2
clippy_lints/src/methods/inefficient_to_string.rs
View file

@ -10,7 +10,7 @@ use rustc_middle::ty::{self, Ty};
use rustc_span::sym;
/// Checks for the `INEFFICIENT_TO_STRING` lint
pub fn lint<'tcx>(cx: &LateContext<'tcx>, expr: &hir::Expr<'_>, arg: &hir::Expr<'_>, arg_ty: Ty<'tcx>) {
pub fn check<'tcx>(cx: &LateContext<'tcx>, expr: &hir::Expr<'_>, arg: &hir::Expr<'_>, arg_ty: Ty<'tcx>) {
if_chain! {
if let Some(to_string_meth_did) = cx.typeck_results().type_dependent_def_id(expr.hir_id);
if match_def_path(cx, to_string_meth_did, &paths::TO_STRING_METHOD);

2
clippy_lints/src/methods/inspect_for_each.rs
View file

@ -7,7 +7,7 @@ use crate::utils::{match_trait_method, paths, span_lint_and_help};
use super::INSPECT_FOR_EACH;
/// lint use of `inspect().for_each()` for `Iterators`
pub(super) fn lint<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'_>, inspect_span: Span) {
pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'_>, inspect_span: Span) {
if match_trait_method(cx, expr, &paths::ITERATOR) {
let msg = "called `inspect(..).for_each(..)` on an `Iterator`";
let hint = "move the code from `inspect(..)` to `for_each(..)` and remove the `inspect(..)`";

43
clippy_lints/src/methods/into_iter_on_ref.rs Normal file
View file

@ -0,0 +1,43 @@
use crate::utils::{has_iter_method, match_trait_method, paths, span_lint_and_sugg};
use rustc_errors::Applicability;
use rustc_hir as hir;
use rustc_lint::LateContext;
use rustc_middle::ty::{self, Ty};
use rustc_span::source_map::Span;
use rustc_span::symbol::Symbol;
use super::INTO_ITER_ON_REF;
pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, self_ref_ty: Ty<'_>, method_span: Span) {
if !match_trait_method(cx, expr, &paths::INTO_ITERATOR) {
return;
}
if let Some((kind, method_name)) = ty_has_iter_method(cx, self_ref_ty) {
span_lint_and_sugg(
cx,
INTO_ITER_ON_REF,
method_span,
&format!(
"this `.into_iter()` call is equivalent to `.{}()` and will not consume the `{}`",
method_name, kind,
),
"call directly",
method_name.to_string(),
Applicability::MachineApplicable,
);
}
}
fn ty_has_iter_method(cx: &LateContext<'_>, self_ref_ty: Ty<'_>) -> Option<(Symbol, &'static str)> {
has_iter_method(cx, self_ref_ty).map(|ty_name| {
let mutbl = match self_ref_ty.kind() {
ty::Ref(_, _, mutbl) => mutbl,
_ => unreachable!(),
};
let method_name = match mutbl {
hir::Mutability::Not => "iter",
hir::Mutability::Mut => "iter_mut",
};
(ty_name, method_name)
})
}

30
clippy_lints/src/methods/iter_cloned_collect.rs Normal file
View file

@ -0,0 +1,30 @@
use crate::methods::derefs_to_slice;
use crate::utils::{is_type_diagnostic_item, span_lint_and_sugg};
use if_chain::if_chain;
use rustc_errors::Applicability;
use rustc_hir as hir;
use rustc_lint::LateContext;
use rustc_span::sym;
use super::ITER_CLONED_COLLECT;
pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &hir::Expr<'_>, iter_args: &'tcx [hir::Expr<'_>]) {
if_chain! {
if is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(expr), sym::vec_type);
if let Some(slice) = derefs_to_slice(cx, &iter_args[0], cx.typeck_results().expr_ty(&iter_args[0]));
if let Some(to_replace) = expr.span.trim_start(slice.span.source_callsite());
then {
span_lint_and_sugg(
cx,
ITER_CLONED_COLLECT,
to_replace,
"called `iter().cloned().collect()` on a slice to create a `Vec`. Calling `to_vec()` is both faster and \
more readable",
"try",
".to_vec()".to_string(),
Applicability::MachineApplicable,
);
}
}
}

2
clippy_lints/src/methods/iter_count.rs
View file

@ -8,7 +8,7 @@ use rustc_span::sym;
use super::ITER_COUNT;
pub(crate) fn lints<'tcx>(cx: &LateContext<'tcx>, expr: &Expr<'_>, iter_args: &'tcx [Expr<'tcx>], iter_method: &str) {
pub(crate) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &Expr<'_>, iter_args: &'tcx [Expr<'tcx>], iter_method: &str) {
let ty = cx.typeck_results().expr_ty(&iter_args[0]);
let caller_type = if derefs_to_slice(cx, &iter_args[0], ty).is_some() {
"slice"

68
clippy_lints/src/methods/iter_next_slice.rs Normal file
View file

@ -0,0 +1,68 @@
use crate::methods::derefs_to_slice;
use crate::utils::{get_parent_expr, higher, is_type_diagnostic_item, snippet_with_applicability, span_lint_and_sugg};
use if_chain::if_chain;
use rustc_ast::ast;
use rustc_errors::Applicability;
use rustc_hir as hir;
use rustc_lint::LateContext;
use rustc_middle::ty;
use rustc_span::symbol::sym;
use super::ITER_NEXT_SLICE;
pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'_>, iter_args: &'tcx [hir::Expr<'_>]) {
let caller_expr = &iter_args[0];
// Skip lint if the `iter().next()` expression is a for loop argument,
// since it is already covered by `&loops::ITER_NEXT_LOOP`
let mut parent_expr_opt = get_parent_expr(cx, expr);
while let Some(parent_expr) = parent_expr_opt {
if higher::for_loop(parent_expr).is_some() {
return;
}
parent_expr_opt = get_parent_expr(cx, parent_expr);
}
if derefs_to_slice(cx, caller_expr, cx.typeck_results().expr_ty(caller_expr)).is_some() {
// caller is a Slice
if_chain! {
if let hir::ExprKind::Index(ref caller_var, ref index_expr) = &caller_expr.kind;
if let Some(higher::Range { start: Some(start_expr), end: None, limits: ast::RangeLimits::HalfOpen })
= higher::range(index_expr);
if let hir::ExprKind::Lit(ref start_lit) = &start_expr.kind;
if let ast::LitKind::Int(start_idx, _) = start_lit.node;
then {
let mut applicability = Applicability::MachineApplicable;
span_lint_and_sugg(
cx,
ITER_NEXT_SLICE,
expr.span,
"using `.iter().next()` on a Slice without end index",
"try calling",
format!("{}.get({})", snippet_with_applicability(cx, caller_var.span, "..", &mut applicability), start_idx),
applicability,
);
}
}
} else if is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(caller_expr), sym::vec_type)
|| matches!(
&cx.typeck_results().expr_ty(caller_expr).peel_refs().kind(),
ty::Array(_, _)
)
{
// caller is a Vec or an Array
let mut applicability = Applicability::MachineApplicable;
span_lint_and_sugg(
cx,
ITER_NEXT_SLICE,
expr.span,
"using `.iter().next()` on an array",
"try calling",
format!(
"{}.get(0)",
snippet_with_applicability(cx, caller_expr.span, "..", &mut applicability)
),
applicability,
);
}
}

38
clippy_lints/src/methods/iter_nth.rs Normal file
View file

@ -0,0 +1,38 @@
use crate::methods::derefs_to_slice;
use crate::methods::iter_nth_zero;
use crate::utils::{is_type_diagnostic_item, span_lint_and_help};
use rustc_hir as hir;
use rustc_lint::LateContext;
use rustc_span::symbol::sym;
use super::ITER_NTH;
pub(super) fn check<'tcx>(
cx: &LateContext<'tcx>,
expr: &hir::Expr<'_>,
nth_and_iter_args: &[&'tcx [hir::Expr<'tcx>]],
is_mut: bool,
) {
let iter_args = nth_and_iter_args[1];
let mut_str = if is_mut { "_mut" } else { "" };
let caller_type = if derefs_to_slice(cx, &iter_args[0], cx.typeck_results().expr_ty(&iter_args[0])).is_some() {
"slice"
} else if is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(&iter_args[0]), sym::vec_type) {
"Vec"
} else if is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(&iter_args[0]), sym::vecdeque_type) {
"VecDeque"
} else {
let nth_args = nth_and_iter_args[0];
iter_nth_zero::check(cx, expr, &nth_args);
return; // caller is not a type that we want to lint
};
span_lint_and_help(
cx,
ITER_NTH,
expr.span,
&format!("called `.iter{0}().nth()` on a {1}", mut_str, caller_type),
None,
&format!("calling `.get{}()` is both faster and more readable", mut_str),
);
}

27
clippy_lints/src/methods/iter_nth_zero.rs Normal file
View file

@ -0,0 +1,27 @@
use crate::consts::{constant, Constant};
use crate::utils::{match_trait_method, paths, snippet_with_applicability, span_lint_and_sugg};
use if_chain::if_chain;
use rustc_errors::Applicability;
use rustc_hir as hir;
use rustc_lint::LateContext;
use super::ITER_NTH_ZERO;
pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &hir::Expr<'_>, nth_args: &'tcx [hir::Expr<'_>]) {
if_chain! {
if match_trait_method(cx, expr, &paths::ITERATOR);
if let Some((Constant::Int(0), _)) = constant(cx, cx.typeck_results(), &nth_args[1]);
then {
let mut applicability = Applicability::MachineApplicable;
span_lint_and_sugg(
cx,
ITER_NTH_ZERO,
expr.span,
"called `.nth(0)` on a `std::iter::Iterator`, when `.next()` is equivalent",
"try calling `.next()` instead of `.nth(0)`",
format!("{}.next()", snippet_with_applicability(cx, nth_args[0].span, "..", &mut applicability)),
applicability,
);
}
}
}

24
clippy_lints/src/methods/iter_skip_next.rs Normal file
View file

@ -0,0 +1,24 @@
use crate::utils::{match_trait_method, paths, snippet, span_lint_and_sugg};
use rustc_errors::Applicability;
use rustc_hir as hir;
use rustc_lint::LateContext;
use super::ITER_SKIP_NEXT;
pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, skip_args: &[hir::Expr<'_>]) {
// lint if caller of skip is an Iterator
if match_trait_method(cx, expr, &paths::ITERATOR) {
if let [caller, n] = skip_args {
let hint = format!(".nth({})", snippet(cx, n.span, ".."));
span_lint_and_sugg(
cx,
ITER_SKIP_NEXT,
expr.span.trim_start(caller.span).unwrap(),
"called `skip(..).next()` on an iterator",
"use `nth` instead",
hint,
Applicability::MachineApplicable,
);
}
}
}

19
clippy_lints/src/methods/iterator_step_by_zero.rs Normal file
View file

@ -0,0 +1,19 @@
use crate::consts::{constant, Constant};
use crate::utils::{match_trait_method, paths, span_lint};
use rustc_hir as hir;
use rustc_lint::LateContext;
use super::ITERATOR_STEP_BY_ZERO;
pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &hir::Expr<'_>, args: &'tcx [hir::Expr<'_>]) {
if match_trait_method(cx, expr, &paths::ITERATOR) {
if let Some((Constant::Int(0), _)) = constant(cx, cx.typeck_results(), &args[1]) {
span_lint(
cx,
ITERATOR_STEP_BY_ZERO,
expr.span,
"`Iterator::step_by(0)` will panic at runtime",
);
}
}
}

2
clippy_lints/src/methods/manual_saturating_arithmetic.rs
View file

@ -6,7 +6,7 @@ use rustc_hir as hir;
use rustc_lint::LateContext;
use rustc_target::abi::LayoutOf;
pub fn lint(cx: &LateContext<'_>, expr: &hir::Expr<'_>, args: &[&[hir::Expr<'_>]], arith: &str) {
pub fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, args: &[&[hir::Expr<'_>]], arith: &str) {
let unwrap_arg = &args[0][1];
let arith_lhs = &args[1][0];
let arith_rhs = &args[1][1];

45
clippy_lints/src/methods/map_collect_result_unit.rs Normal file
View file

@ -0,0 +1,45 @@
use crate::utils::{is_type_diagnostic_item, match_trait_method, paths, snippet, span_lint_and_sugg};
use if_chain::if_chain;
use rustc_errors::Applicability;
use rustc_hir as hir;
use rustc_lint::LateContext;
use rustc_middle::ty;
use rustc_span::symbol::sym;
use super::MAP_COLLECT_RESULT_UNIT;
pub(super) fn check(
cx: &LateContext<'_>,
expr: &hir::Expr<'_>,
map_args: &[hir::Expr<'_>],
collect_args: &[hir::Expr<'_>],
) {
if_chain! {
// called on Iterator
if let [map_expr] = collect_args;
if match_trait_method(cx, map_expr, &paths::ITERATOR);
// return of collect `Result<(),_>`
let collect_ret_ty = cx.typeck_results().expr_ty(expr);
if is_type_diagnostic_item(cx, collect_ret_ty, sym::result_type);
if let ty::Adt(_, substs) = collect_ret_ty.kind();
if let Some(result_t) = substs.types().next();
if result_t.is_unit();
// get parts for snippet
if let [iter, map_fn] = map_args;
then {
span_lint_and_sugg(
cx,
MAP_COLLECT_RESULT_UNIT,
expr.span,
"`.map().collect()` can be replaced with `.try_for_each()`",
"try this",
format!(
"{}.try_for_each({})",
snippet(cx, iter.span, ".."),
snippet(cx, map_fn.span, "..")
),
Applicability::MachineApplicable,
);
}
}
}

61
clippy_lints/src/methods/map_flatten.rs Normal file
View file

@ -0,0 +1,61 @@
use crate::utils::{is_type_diagnostic_item, match_trait_method, paths, snippet, span_lint_and_sugg};
use rustc_errors::Applicability;
use rustc_hir as hir;
use rustc_lint::LateContext;
use rustc_middle::ty;
use rustc_span::symbol::sym;
use super::MAP_FLATTEN;
/// lint use of `map().flatten()` for `Iterators` and 'Options'
pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'_>, map_args: &'tcx [hir::Expr<'_>]) {
// lint if caller of `.map().flatten()` is an Iterator
if match_trait_method(cx, expr, &paths::ITERATOR) {
let map_closure_ty = cx.typeck_results().expr_ty(&map_args[1]);
let is_map_to_option = match map_closure_ty.kind() {
ty::Closure(_, _) | ty::FnDef(_, _) | ty::FnPtr(_) => {
let map_closure_sig = match map_closure_ty.kind() {
ty::Closure(_, substs) => substs.as_closure().sig(),
_ => map_closure_ty.fn_sig(cx.tcx),
};
let map_closure_return_ty = cx.tcx.erase_late_bound_regions(map_closure_sig.output());
is_type_diagnostic_item(cx, map_closure_return_ty, sym::option_type)
},
_ => false,
};
let method_to_use = if is_map_to_option {
// `(...).map(...)` has type `impl Iterator<Item=Option<...>>
"filter_map"
} else {
// `(...).map(...)` has type `impl Iterator<Item=impl Iterator<...>>
"flat_map"
};
let func_snippet = snippet(cx, map_args[1].span, "..");
let hint = format!(".{0}({1})", method_to_use, func_snippet);
span_lint_and_sugg(
cx,
MAP_FLATTEN,
expr.span.with_lo(map_args[0].span.hi()),
"called `map(..).flatten()` on an `Iterator`",
&format!("try using `{}` instead", method_to_use),
hint,
Applicability::MachineApplicable,
);
}
// lint if caller of `.map().flatten()` is an Option
if is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(&map_args[0]), sym::option_type) {
let func_snippet = snippet(cx, map_args[1].span, "..");
let hint = format!(".and_then({})", func_snippet);
span_lint_and_sugg(
cx,
MAP_FLATTEN,
expr.span.with_lo(map_args[0].span.hi()),
"called `map(..).flatten()` on an `Option`",
"try using `and_then` instead",
hint,
Applicability::MachineApplicable,
);
}
}

76
clippy_lints/src/methods/map_unwrap_or.rs Normal file
View file

@ -0,0 +1,76 @@
use crate::utils::usage::mutated_variables;
use crate::utils::{is_type_diagnostic_item, meets_msrv, snippet, span_lint, span_lint_and_sugg};
use rustc_errors::Applicability;
use rustc_hir as hir;
use rustc_lint::LateContext;
use rustc_semver::RustcVersion;
use rustc_span::symbol::sym;
use super::MAP_UNWRAP_OR;
const MAP_UNWRAP_OR_MSRV: RustcVersion = RustcVersion::new(1, 41, 0);
/// lint use of `map().unwrap_or_else()` for `Option`s and `Result`s
/// Return true if lint triggered
pub(super) fn check<'tcx>(
cx: &LateContext<'tcx>,
expr: &'tcx hir::Expr<'_>,
map_args: &'tcx [hir::Expr<'_>],
unwrap_args: &'tcx [hir::Expr<'_>],
msrv: Option<&RustcVersion>,
) -> bool {
if !meets_msrv(msrv, &MAP_UNWRAP_OR_MSRV) {
return false;
}
// lint if the caller of `map()` is an `Option`
let is_option = is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(&map_args[0]), sym::option_type);
let is_result = is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(&map_args[0]), sym::result_type);
if is_option || is_result {
// Don't make a suggestion that may fail to compile due to mutably borrowing
// the same variable twice.
let map_mutated_vars = mutated_variables(&map_args[0], cx);
let unwrap_mutated_vars = mutated_variables(&unwrap_args[1], cx);
if let (Some(map_mutated_vars), Some(unwrap_mutated_vars)) = (map_mutated_vars, unwrap_mutated_vars) {
if map_mutated_vars.intersection(&unwrap_mutated_vars).next().is_some() {
return false;
}
} else {
return false;
}
// lint message
let msg = if is_option {
"called `map(<f>).unwrap_or_else(<g>)` on an `Option` value. This can be done more directly by calling \
`map_or_else(<g>, <f>)` instead"
} else {
"called `map(<f>).unwrap_or_else(<g>)` on a `Result` value. This can be done more directly by calling \
`.map_or_else(<g>, <f>)` instead"
};
// get snippets for args to map() and unwrap_or_else()
let map_snippet = snippet(cx, map_args[1].span, "..");
let unwrap_snippet = snippet(cx, unwrap_args[1].span, "..");
// lint, with note if neither arg is > 1 line and both map() and
// unwrap_or_else() have the same span
let multiline = map_snippet.lines().count() > 1 || unwrap_snippet.lines().count() > 1;
let same_span = map_args[1].span.ctxt() == unwrap_args[1].span.ctxt();
if same_span && !multiline {
let var_snippet = snippet(cx, map_args[0].span, "..");
span_lint_and_sugg(
cx,
MAP_UNWRAP_OR,
expr.span,
msg,
"try this",
format!("{}.map_or_else({}, {})", var_snippet, unwrap_snippet, map_snippet),
Applicability::MachineApplicable,
);
return true;
} else if same_span && multiline {
span_lint(cx, MAP_UNWRAP_OR, expr.span, msg);
return true;
}
}
false
}

2134
clippy_lints/src/methods/mod.rs
View file

File diff suppressed because it is too large Load diff

45
clippy_lints/src/methods/ok_expect.rs Normal file
View file

@ -0,0 +1,45 @@
use crate::utils::{implements_trait, is_type_diagnostic_item, span_lint_and_help};
use if_chain::if_chain;
use rustc_hir as hir;
use rustc_lint::LateContext;
use rustc_middle::ty::{self, Ty};
use rustc_span::sym;
use super::OK_EXPECT;
/// lint use of `ok().expect()` for `Result`s
pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, ok_args: &[hir::Expr<'_>]) {
if_chain! {
// lint if the caller of `ok()` is a `Result`
if is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(&ok_args[0]), sym::result_type);
let result_type = cx.typeck_results().expr_ty(&ok_args[0]);
if let Some(error_type) = get_error_type(cx, result_type);
if has_debug_impl(error_type, cx);
then {
span_lint_and_help(
cx,
OK_EXPECT,
expr.span,
"called `ok().expect()` on a `Result` value",
None,
"you can call `expect()` directly on the `Result`",
);
}
}
}
/// Given a `Result<T, E>` type, return its error type (`E`).
fn get_error_type<'a>(cx: &LateContext<'_>, ty: Ty<'a>) -> Option<Ty<'a>> {
match ty.kind() {
ty::Adt(_, substs) if is_type_diagnostic_item(cx, ty, sym::result_type) => substs.types().nth(1),
_ => None,
}
}
/// This checks whether a given type is known to implement Debug.
fn has_debug_impl<'tcx>(ty: Ty<'tcx>, cx: &LateContext<'tcx>) -> bool {
cx.tcx
.get_diagnostic_item(sym::debug_trait)
.map_or(false, |debug| implements_trait(cx, ty, debug, &[]))
}

122
clippy_lints/src/methods/option_as_ref_deref.rs Normal file
View file

@ -0,0 +1,122 @@
use crate::utils::{
is_type_diagnostic_item, match_def_path, meets_msrv, path_to_local_id, paths, remove_blocks, snippet,
span_lint_and_sugg,
};
use if_chain::if_chain;
use rustc_errors::Applicability;
use rustc_hir as hir;
use rustc_lint::LateContext;
use rustc_middle::ty;
use rustc_semver::RustcVersion;
use rustc_span::sym;
use super::OPTION_AS_REF_DEREF;
const OPTION_AS_REF_DEREF_MSRV: RustcVersion = RustcVersion::new(1, 40, 0);
/// lint use of `_.as_ref().map(Deref::deref)` for `Option`s
pub(super) fn check<'tcx>(
cx: &LateContext<'tcx>,
expr: &hir::Expr<'_>,
as_ref_args: &[hir::Expr<'_>],
map_args: &[hir::Expr<'_>],
is_mut: bool,
msrv: Option<&RustcVersion>,
) {
if !meets_msrv(msrv, &OPTION_AS_REF_DEREF_MSRV) {
return;
}
let same_mutability = |m| (is_mut && m == &hir::Mutability::Mut) || (!is_mut && m == &hir::Mutability::Not);
let option_ty = cx.typeck_results().expr_ty(&as_ref_args[0]);
if !is_type_diagnostic_item(cx, option_ty, sym::option_type) {
return;
}
let deref_aliases: [&[&str]; 9] = [
&paths::DEREF_TRAIT_METHOD,
&paths::DEREF_MUT_TRAIT_METHOD,
&paths::CSTRING_AS_C_STR,
&paths::OS_STRING_AS_OS_STR,
&paths::PATH_BUF_AS_PATH,
&paths::STRING_AS_STR,
&paths::STRING_AS_MUT_STR,
&paths::VEC_AS_SLICE,
&paths::VEC_AS_MUT_SLICE,
];
let is_deref = match map_args[1].kind {
hir::ExprKind::Path(ref expr_qpath) => cx
.qpath_res(expr_qpath, map_args[1].hir_id)
.opt_def_id()
.map_or(false, |fun_def_id| {
deref_aliases.iter().any(|path| match_def_path(cx, fun_def_id, path))
}),
hir::ExprKind::Closure(_, _, body_id, _, _) => {
let closure_body = cx.tcx.hir().body(body_id);
let closure_expr = remove_blocks(&closure_body.value);
match &closure_expr.kind {
hir::ExprKind::MethodCall(_, _, args, _) => {
if_chain! {
if args.len() == 1;
if path_to_local_id(&args[0], closure_body.params[0].pat.hir_id);
let adj = cx
.typeck_results()
.expr_adjustments(&args[0])
.iter()
.map(|x| &x.kind)
.collect::<Box<[_]>>();
if let [ty::adjustment::Adjust::Deref(None), ty::adjustment::Adjust::Borrow(_)] = *adj;
then {
let method_did = cx.typeck_results().type_dependent_def_id(closure_expr.hir_id).unwrap();
deref_aliases.iter().any(|path| match_def_path(cx, method_did, path))
} else {
false
}
}
},
hir::ExprKind::AddrOf(hir::BorrowKind::Ref, m, ref inner) if same_mutability(m) => {
if_chain! {
if let hir::ExprKind::Unary(hir::UnOp::Deref, ref inner1) = inner.kind;
if let hir::ExprKind::Unary(hir::UnOp::Deref, ref inner2) = inner1.kind;
then {
path_to_local_id(inner2, closure_body.params[0].pat.hir_id)
} else {
false
}
}
},
_ => false,
}
},
_ => false,
};
if is_deref {
let current_method = if is_mut {
format!(".as_mut().map({})", snippet(cx, map_args[1].span, ".."))
} else {
format!(".as_ref().map({})", snippet(cx, map_args[1].span, ".."))
};
let method_hint = if is_mut { "as_deref_mut" } else { "as_deref" };
let hint = format!("{}.{}()", snippet(cx, as_ref_args[0].span, ".."), method_hint);
let suggestion = format!("try using {} instead", method_hint);
let msg = format!(
"called `{0}` on an Option value. This can be done more directly \
by calling `{1}` instead",
current_method, hint
);
span_lint_and_sugg(
cx,
OPTION_AS_REF_DEREF,
expr.span,
&msg,
&suggestion,
hint,
Applicability::MachineApplicable,
);
}
}

78
clippy_lints/src/methods/option_map_or_none.rs Normal file
View file

@ -0,0 +1,78 @@
use crate::utils::{is_type_diagnostic_item, match_qpath, paths, snippet, span_lint_and_sugg};
use rustc_errors::Applicability;
use rustc_hir as hir;
use rustc_lint::LateContext;
use rustc_span::symbol::sym;
use super::OPTION_MAP_OR_NONE;
use super::RESULT_MAP_OR_INTO_OPTION;
/// lint use of `_.map_or(None, _)` for `Option`s and `Result`s
pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'_>, map_or_args: &'tcx [hir::Expr<'_>]) {
let is_option = is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(&map_or_args[0]), sym::option_type);
let is_result = is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(&map_or_args[0]), sym::result_type);
// There are two variants of this `map_or` lint:
// (1) using `map_or` as an adapter from `Result<T,E>` to `Option<T>`
// (2) using `map_or` as a combinator instead of `and_then`
//
// (For this lint) we don't care if any other type calls `map_or`
if !is_option && !is_result {
return;
}
let (lint_name, msg, instead, hint) = {
let default_arg_is_none = if let hir::ExprKind::Path(ref qpath) = map_or_args[1].kind {
match_qpath(qpath, &paths::OPTION_NONE)
} else {
return;
};
if !default_arg_is_none {
// nothing to lint!
return;
}
let f_arg_is_some = if let hir::ExprKind::Path(ref qpath) = map_or_args[2].kind {
match_qpath(qpath, &paths::OPTION_SOME)
} else {
false
};
if is_option {
let self_snippet = snippet(cx, map_or_args[0].span, "..");
let func_snippet = snippet(cx, map_or_args[2].span, "..");
let msg = "called `map_or(None, ..)` on an `Option` value. This can be done more directly by calling \
`and_then(..)` instead";
(
OPTION_MAP_OR_NONE,
msg,
"try using `and_then` instead",
format!("{0}.and_then({1})", self_snippet, func_snippet),
)
} else if f_arg_is_some {
let msg = "called `map_or(None, Some)` on a `Result` value. This can be done more directly by calling \
`ok()` instead";
let self_snippet = snippet(cx, map_or_args[0].span, "..");
(
RESULT_MAP_OR_INTO_OPTION,
msg,
"try using `ok` instead",
format!("{0}.ok()", self_snippet),
)
} else {
// nothing to lint!
return;
}
};
span_lint_and_sugg(
cx,
lint_name,
expr.span,
msg,
instead,
hint,
Applicability::MachineApplicable,
);
}

2
clippy_lints/src/methods/option_map_unwrap_or.rs
View file

@ -12,7 +12,7 @@ use rustc_span::{sym, Symbol};
use super::MAP_UNWRAP_OR;
/// lint use of `map().unwrap_or()` for `Option`s
pub(super) fn lint<'tcx>(
pub(super) fn check<'tcx>(
cx: &LateContext<'tcx>,
expr: &rustc_hir::Expr<'_>,
map_args: &'tcx [rustc_hir::Expr<'_>],

173
clippy_lints/src/methods/or_fun_call.rs Normal file
View file

@ -0,0 +1,173 @@
use crate::utils::eager_or_lazy::is_lazyness_candidate;
use crate::utils::{
contains_return, get_trait_def_id, implements_trait, is_type_diagnostic_item, last_path_segment, match_type, paths,
snippet, snippet_with_applicability, snippet_with_macro_callsite, span_lint_and_sugg,
};
use if_chain::if_chain;
use rustc_errors::Applicability;
use rustc_hir as hir;
use rustc_lint::LateContext;
use rustc_middle::ty;
use rustc_span::source_map::Span;
use rustc_span::symbol::sym;
use std::borrow::Cow;
use super::OR_FUN_CALL;
/// Checks for the `OR_FUN_CALL` lint.
#[allow(clippy::too_many_lines)]
pub(super) fn check<'tcx>(
cx: &LateContext<'tcx>,
expr: &hir::Expr<'_>,
method_span: Span,
name: &str,
args: &'tcx [hir::Expr<'_>],
) {
/// Checks for `unwrap_or(T::new())` or `unwrap_or(T::default())`.
fn check_unwrap_or_default(
cx: &LateContext<'_>,
name: &str,
fun: &hir::Expr<'_>,
self_expr: &hir::Expr<'_>,
arg: &hir::Expr<'_>,
or_has_args: bool,
span: Span,
) -> bool {
if_chain! {
if !or_has_args;
if name == "unwrap_or";
if let hir::ExprKind::Path(ref qpath) = fun.kind;
let path = &*last_path_segment(qpath).ident.as_str();
if ["default", "new"].contains(&path);
let arg_ty = cx.typeck_results().expr_ty(arg);
if let Some(default_trait_id) = get_trait_def_id(cx, &paths::DEFAULT_TRAIT);
if implements_trait(cx, arg_ty, default_trait_id, &[]);
then {
let mut applicability = Applicability::MachineApplicable;
span_lint_and_sugg(
cx,
OR_FUN_CALL,
span,
&format!("use of `{}` followed by a call to `{}`", name, path),
"try this",
format!(
"{}.unwrap_or_default()",
snippet_with_applicability(cx, self_expr.span, "..", &mut applicability)
),
applicability,
);
true
} else {
false
}
}
}
/// Checks for `*or(foo())`.
#[allow(clippy::too_many_arguments)]
fn check_general_case<'tcx>(
cx: &LateContext<'tcx>,
name: &str,
method_span: Span,
self_expr: &hir::Expr<'_>,
arg: &'tcx hir::Expr<'_>,
span: Span,
// None if lambda is required
fun_span: Option<Span>,
) {
// (path, fn_has_argument, methods, suffix)
static KNOW_TYPES: [(&[&str], bool, &[&str], &str); 4] = [
(&paths::BTREEMAP_ENTRY, false, &["or_insert"], "with"),
(&paths::HASHMAP_ENTRY, false, &["or_insert"], "with"),
(&paths::OPTION, false, &["map_or", "ok_or", "or", "unwrap_or"], "else"),
(&paths::RESULT, true, &["or", "unwrap_or"], "else"),
];
if let hir::ExprKind::MethodCall(ref path, _, ref args, _) = &arg.kind {
if path.ident.as_str() == "len" {
let ty = cx.typeck_results().expr_ty(&args[0]).peel_refs();
match ty.kind() {
ty::Slice(_) | ty::Array(_, _) => return,
_ => (),
}
if is_type_diagnostic_item(cx, ty, sym::vec_type) {
return;
}
}
}
if_chain! {
if KNOW_TYPES.iter().any(|k| k.2.contains(&name));
if is_lazyness_candidate(cx, arg);
if !contains_return(&arg);
let self_ty = cx.typeck_results().expr_ty(self_expr);
if let Some(&(_, fn_has_arguments, poss, suffix)) =
KNOW_TYPES.iter().find(|&&i| match_type(cx, self_ty, i.0));
if poss.contains(&name);
then {
let macro_expanded_snipped;
let sugg: Cow<'_, str> = {
let (snippet_span, use_lambda) = match (fn_has_arguments, fun_span) {
(false, Some(fun_span)) => (fun_span, false),
_ => (arg.span, true),
};
let snippet = {
let not_macro_argument_snippet = snippet_with_macro_callsite(cx, snippet_span, "..");
if not_macro_argument_snippet == "vec![]" {
macro_expanded_snipped = snippet(cx, snippet_span, "..");
match macro_expanded_snipped.strip_prefix("$crate::vec::") {
Some(stripped) => Cow::from(stripped),
None => macro_expanded_snipped
}
}
else {
not_macro_argument_snippet
}
};
if use_lambda {
let l_arg = if fn_has_arguments { "_" } else { "" };
format!("|{}| {}", l_arg, snippet).into()
} else {
snippet
}
};
let span_replace_word = method_span.with_hi(span.hi());
span_lint_and_sugg(
cx,
OR_FUN_CALL,
span_replace_word,
&format!("use of `{}` followed by a function call", name),
"try this",
format!("{}_{}({})", name, suffix, sugg),
Applicability::HasPlaceholders,
);
}
}
}
if args.len() == 2 {
match args[1].kind {
hir::ExprKind::Call(ref fun, ref or_args) => {
let or_has_args = !or_args.is_empty();
if !check_unwrap_or_default(cx, name, fun, &args[0], &args[1], or_has_args, expr.span) {
let fun_span = if or_has_args { None } else { Some(fun.span) };
check_general_case(cx, name, method_span, &args[0], &args[1], expr.span, fun_span);
}
},
hir::ExprKind::Index(..) | hir::ExprKind::MethodCall(..) => {
check_general_case(cx, name, method_span, &args[0], &args[1], expr.span, None);
},
_ => {},
}
}
}

101
clippy_lints/src/methods/search_is_some.rs Normal file
View file

@ -0,0 +1,101 @@
use crate::utils::{
is_type_diagnostic_item, match_trait_method, paths, snippet, snippet_with_applicability, span_lint_and_help,
span_lint_and_sugg, strip_pat_refs,
};
use if_chain::if_chain;
use rustc_errors::Applicability;
use rustc_hir as hir;
use rustc_hir::PatKind;
use rustc_lint::LateContext;
use rustc_middle::ty;
use rustc_span::source_map::Span;
use rustc_span::symbol::sym;
use super::SEARCH_IS_SOME;
/// lint searching an Iterator followed by `is_some()`
/// or calling `find()` on a string followed by `is_some()`
pub(super) fn check<'tcx>(
cx: &LateContext<'tcx>,
expr: &'tcx hir::Expr<'_>,
search_method: &str,
search_args: &'tcx [hir::Expr<'_>],
is_some_args: &'tcx [hir::Expr<'_>],
method_span: Span,
) {
// lint if caller of search is an Iterator
if match_trait_method(cx, &is_some_args[0], &paths::ITERATOR) {
let msg = format!(
"called `is_some()` after searching an `Iterator` with `{}`",
search_method
);
let hint = "this is more succinctly expressed by calling `any()`";
let search_snippet = snippet(cx, search_args[1].span, "..");
if search_snippet.lines().count() <= 1 {
// suggest `any(|x| ..)` instead of `any(|&x| ..)` for `find(|&x| ..).is_some()`
// suggest `any(|..| *..)` instead of `any(|..| **..)` for `find(|..| **..).is_some()`
let any_search_snippet = if_chain! {
if search_method == "find";
if let hir::ExprKind::Closure(_, _, body_id, ..) = search_args[1].kind;
let closure_body = cx.tcx.hir().body(body_id);
if let Some(closure_arg) = closure_body.params.get(0);
then {
if let hir::PatKind::Ref(..) = closure_arg.pat.kind {
Some(search_snippet.replacen('&', "", 1))
} else if let PatKind::Binding(_, _, ident, _) = strip_pat_refs(&closure_arg.pat).kind {
let name = &*ident.name.as_str();
Some(search_snippet.replace(&format!("*{}", name), name))
} else {
None
}
} else {
None
}
};
// add note if not multi-line
span_lint_and_sugg(
cx,
SEARCH_IS_SOME,
method_span.with_hi(expr.span.hi()),
&msg,
"use `any()` instead",
format!(
"any({})",
any_search_snippet.as_ref().map_or(&*search_snippet, String::as_str)
),
Applicability::MachineApplicable,
);
} else {
span_lint_and_help(cx, SEARCH_IS_SOME, expr.span, &msg, None, hint);
}
}
// lint if `find()` is called by `String` or `&str`
else if search_method == "find" {
let is_string_or_str_slice = |e| {
let self_ty = cx.typeck_results().expr_ty(e).peel_refs();
if is_type_diagnostic_item(cx, self_ty, sym::string_type) {
true
} else {
*self_ty.kind() == ty::Str
}
};
if_chain! {
if is_string_or_str_slice(&search_args[0]);
if is_string_or_str_slice(&search_args[1]);
then {
let msg = "called `is_some()` after calling `find()` on a string";
let mut applicability = Applicability::MachineApplicable;
let find_arg = snippet_with_applicability(cx, search_args[1].span, "..", &mut applicability);
span_lint_and_sugg(
cx,
SEARCH_IS_SOME,
method_span.with_hi(expr.span.hi()),
msg,
"use `contains()` instead",
format!("contains({})", find_arg),
applicability,
);
}
}
}
}

27
clippy_lints/src/methods/single_char_insert_string.rs Normal file
View file

@ -0,0 +1,27 @@
use crate::methods::get_hint_if_single_char_arg;
use crate::utils::{snippet_with_applicability, span_lint_and_sugg};
use rustc_errors::Applicability;
use rustc_hir as hir;
use rustc_lint::LateContext;
use super::SINGLE_CHAR_ADD_STR;
/// lint for length-1 `str`s as argument for `insert_str`
pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, args: &[hir::Expr<'_>]) {
let mut applicability = Applicability::MachineApplicable;
if let Some(extension_string) = get_hint_if_single_char_arg(cx, &args[2], &mut applicability) {
let base_string_snippet =
snippet_with_applicability(cx, args[0].span.source_callsite(), "_", &mut applicability);
let pos_arg = snippet_with_applicability(cx, args[1].span, "..", &mut applicability);
let sugg = format!("{}.insert({}, {})", base_string_snippet, pos_arg, extension_string);
span_lint_and_sugg(
cx,
SINGLE_CHAR_ADD_STR,
expr.span,
"calling `insert_str()` using a single-character string literal",
"consider using `insert` with a character literal",
sugg,
applicability,
);
}
}

23
clippy_lints/src/methods/single_char_pattern.rs Normal file
View file

@ -0,0 +1,23 @@
use crate::methods::get_hint_if_single_char_arg;
use crate::utils::span_lint_and_sugg;
use rustc_errors::Applicability;
use rustc_hir as hir;
use rustc_lint::LateContext;
use super::SINGLE_CHAR_PATTERN;
/// lint for length-1 `str`s for methods in `PATTERN_METHODS`
pub(super) fn check(cx: &LateContext<'_>, _expr: &hir::Expr<'_>, arg: &hir::Expr<'_>) {
let mut applicability = Applicability::MachineApplicable;
if let Some(hint) = get_hint_if_single_char_arg(cx, arg, &mut applicability) {
span_lint_and_sugg(
cx,
SINGLE_CHAR_PATTERN,
arg.span,
"single-character string constant used as pattern",
"try using a `char` instead",
hint,
applicability,
);
}
}

26
clippy_lints/src/methods/single_char_push_string.rs Normal file
View file

@ -0,0 +1,26 @@
use crate::methods::get_hint_if_single_char_arg;
use crate::utils::{snippet_with_applicability, span_lint_and_sugg};
use rustc_errors::Applicability;
use rustc_hir as hir;
use rustc_lint::LateContext;
use super::SINGLE_CHAR_ADD_STR;
/// lint for length-1 `str`s as argument for `push_str`
pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, args: &[hir::Expr<'_>]) {
let mut applicability = Applicability::MachineApplicable;
if let Some(extension_string) = get_hint_if_single_char_arg(cx, &args[1], &mut applicability) {
let base_string_snippet =
snippet_with_applicability(cx, args[0].span.source_callsite(), "..", &mut applicability);
let sugg = format!("{}.push({})", base_string_snippet, extension_string);
span_lint_and_sugg(
cx,
SINGLE_CHAR_ADD_STR,
expr.span,
"calling `push_str()` using a single-character string literal",
"consider using `push` with a character literal",
sugg,
applicability,
);
}
}

20
clippy_lints/src/methods/skip_while_next.rs Normal file
View file

@ -0,0 +1,20 @@
use crate::utils::{match_trait_method, paths, span_lint_and_help};
use rustc_hir as hir;
use rustc_lint::LateContext;
use super::SKIP_WHILE_NEXT;
/// lint use of `skip_while().next()` for `Iterators`
pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'_>, _skip_while_args: &'tcx [hir::Expr<'_>]) {
// lint if caller of `.skip_while().next()` is an Iterator
if match_trait_method(cx, expr, &paths::ITERATOR) {
span_lint_and_help(
cx,
SKIP_WHILE_NEXT,
expr.span,
"called `skip_while(<p>).next()` on an `Iterator`",
None,
"this is more succinctly expressed by calling `.find(!<p>)` instead",
);
}
}

42
clippy_lints/src/methods/string_extend_chars.rs Normal file
View file

@ -0,0 +1,42 @@
use crate::utils::{is_type_diagnostic_item, method_chain_args, snippet_with_applicability, span_lint_and_sugg};
use rustc_errors::Applicability;
use rustc_hir as hir;
use rustc_lint::LateContext;
use rustc_middle::ty;
use rustc_span::symbol::sym;
use super::STRING_EXTEND_CHARS;
pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, args: &[hir::Expr<'_>]) {
let obj_ty = cx.typeck_results().expr_ty(&args[0]).peel_refs();
if is_type_diagnostic_item(cx, obj_ty, sym::string_type) {
let arg = &args[1];
if let Some(arglists) = method_chain_args(arg, &["chars"]) {
let target = &arglists[0][0];
let self_ty = cx.typeck_results().expr_ty(target).peel_refs();
let ref_str = if *self_ty.kind() == ty::Str {
""
} else if is_type_diagnostic_item(cx, self_ty, sym::string_type) {
"&"
} else {
return;
};
let mut applicability = Applicability::MachineApplicable;
span_lint_and_sugg(
cx,
STRING_EXTEND_CHARS,
expr.span,
"calling `.extend(_.chars())`",
"try this",
format!(
"{}.push_str({}{})",
snippet_with_applicability(cx, args[0].span, "..", &mut applicability),
ref_str,
snippet_with_applicability(cx, target.span, "..", &mut applicability)
),
applicability,
);
}
}
}

16
clippy_lints/src/methods/suspicious_map.rs Normal file
View file

@ -0,0 +1,16 @@
use crate::utils::span_lint_and_help;
use rustc_hir as hir;
use rustc_lint::LateContext;
use super::SUSPICIOUS_MAP;
pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>) {
span_lint_and_help(
cx,
SUSPICIOUS_MAP,
expr.span,
"this call to `map()` won't have an effect on the call to `count()`",
None,
"make sure you did not confuse `map` with `filter` or `for_each`",
);
}

35
clippy_lints/src/methods/uninit_assumed_init.rs Normal file
View file

@ -0,0 +1,35 @@
use crate::utils::{match_def_path, match_qpath, paths, span_lint};
use if_chain::if_chain;
use rustc_hir as hir;
use rustc_lint::LateContext;
use rustc_middle::ty::{self, Ty};
use super::UNINIT_ASSUMED_INIT;
/// lint for `MaybeUninit::uninit().assume_init()` (we already have the latter)
pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, outer: &hir::Expr<'_>) {
if_chain! {
if let hir::ExprKind::Call(ref callee, ref args) = expr.kind;
if args.is_empty();
if let hir::ExprKind::Path(ref path) = callee.kind;
if match_qpath(path, &paths::MEM_MAYBEUNINIT_UNINIT);
if !is_maybe_uninit_ty_valid(cx, cx.typeck_results().expr_ty_adjusted(outer));
then {
span_lint(
cx,
UNINIT_ASSUMED_INIT,
outer.span,
"this call for this type may be undefined behavior"
);
}
}
}
fn is_maybe_uninit_ty_valid(cx: &LateContext<'_>, ty: Ty<'_>) -> bool {
match ty.kind() {
ty::Array(ref component, _) => is_maybe_uninit_ty_valid(cx, component),
ty::Tuple(ref types) => types.types().all(|ty| is_maybe_uninit_ty_valid(cx, ty)),
ty::Adt(ref adt, _) => match_def_path(cx, adt.did, &paths::MEM_MAYBEUNINIT),
_ => false,
}
}

2
clippy_lints/src/methods/unnecessary_filter_map.rs
View file

@ -9,7 +9,7 @@ use if_chain::if_chain;
use super::UNNECESSARY_FILTER_MAP;
pub(super) fn lint(cx: &LateContext<'_>, expr: &hir::Expr<'_>, args: &[hir::Expr<'_>]) {
pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, args: &[hir::Expr<'_>]) {
if !match_trait_method(cx, expr, &paths::ITERATOR) {
return;
}

101
clippy_lints/src/methods/unnecessary_fold.rs Normal file
View file

@ -0,0 +1,101 @@
use crate::utils::{
match_trait_method, path_to_local_id, paths, remove_blocks, snippet_with_applicability, span_lint_and_sugg,
strip_pat_refs,
};
use if_chain::if_chain;
use rustc_ast::ast;
use rustc_errors::Applicability;
use rustc_hir as hir;
use rustc_hir::PatKind;
use rustc_lint::LateContext;
use rustc_span::source_map::Span;
use super::UNNECESSARY_FOLD;
pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, fold_args: &[hir::Expr<'_>], fold_span: Span) {
fn check_fold_with_op(
cx: &LateContext<'_>,
expr: &hir::Expr<'_>,
fold_args: &[hir::Expr<'_>],
fold_span: Span,
op: hir::BinOpKind,
replacement_method_name: &str,
replacement_has_args: bool,
) {
if_chain! {
// Extract the body of the closure passed to fold
if let hir::ExprKind::Closure(_, _, body_id, _, _) = fold_args[2].kind;
let closure_body = cx.tcx.hir().body(body_id);
let closure_expr = remove_blocks(&closure_body.value);
// Check if the closure body is of the form `acc <op> some_expr(x)`
if let hir::ExprKind::Binary(ref bin_op, ref left_expr, ref right_expr) = closure_expr.kind;
if bin_op.node == op;
// Extract the names of the two arguments to the closure
if let [param_a, param_b] = closure_body.params;
if let PatKind::Binding(_, first_arg_id, ..) = strip_pat_refs(&param_a.pat).kind;
if let PatKind::Binding(_, second_arg_id, second_arg_ident, _) = strip_pat_refs(&param_b.pat).kind;
if path_to_local_id(left_expr, first_arg_id);
if replacement_has_args || path_to_local_id(right_expr, second_arg_id);
then {
let mut applicability = Applicability::MachineApplicable;
let sugg = if replacement_has_args {
format!(
"{replacement}(|{s}| {r})",
replacement = replacement_method_name,
s = second_arg_ident,
r = snippet_with_applicability(cx, right_expr.span, "EXPR", &mut applicability),
)
} else {
format!(
"{replacement}()",
replacement = replacement_method_name,
)
};
span_lint_and_sugg(
cx,
UNNECESSARY_FOLD,
fold_span.with_hi(expr.span.hi()),
// TODO #2371 don't suggest e.g., .any(|x| f(x)) if we can suggest .any(f)
"this `.fold` can be written more succinctly using another method",
"try",
sugg,
applicability,
);
}
}
}
// Check that this is a call to Iterator::fold rather than just some function called fold
if !match_trait_method(cx, expr, &paths::ITERATOR) {
return;
}
assert!(
fold_args.len() == 3,
"Expected fold_args to have three entries - the receiver, the initial value and the closure"
);
// Check if the first argument to .fold is a suitable literal
if let hir::ExprKind::Lit(ref lit) = fold_args[1].kind {
match lit.node {
ast::LitKind::Bool(false) => {
check_fold_with_op(cx, expr, fold_args, fold_span, hir::BinOpKind::Or, "any", true)
},
ast::LitKind::Bool(true) => {
check_fold_with_op(cx, expr, fold_args, fold_span, hir::BinOpKind::And, "all", true)
},
ast::LitKind::Int(0, _) => {
check_fold_with_op(cx, expr, fold_args, fold_span, hir::BinOpKind::Add, "sum", false)
},
ast::LitKind::Int(1, _) => {
check_fold_with_op(cx, expr, fold_args, fold_span, hir::BinOpKind::Mul, "product", false)
},
_ => (),
}
}
}

2
clippy_lints/src/methods/unnecessary_lazy_eval.rs
View file

@ -9,7 +9,7 @@ use super::UNNECESSARY_LAZY_EVALUATIONS;
/// lint use of `<fn>_else(simple closure)` for `Option`s and `Result`s that can be
/// replaced with `<fn>(return value of simple closure)`
pub(super) fn lint<'tcx>(
pub(super) fn check<'tcx>(
cx: &LateContext<'tcx>,
expr: &'tcx hir::Expr<'_>,
args: &'tcx [hir::Expr<'_>],

34
clippy_lints/src/methods/unwrap_used.rs Normal file
View file

@ -0,0 +1,34 @@
use crate::utils::{is_type_diagnostic_item, span_lint_and_help};
use rustc_hir as hir;
use rustc_lint::LateContext;
use rustc_span::sym;
use super::UNWRAP_USED;
/// lint use of `unwrap()` for `Option`s and `Result`s
pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, unwrap_args: &[hir::Expr<'_>]) {
let obj_ty = cx.typeck_results().expr_ty(&unwrap_args[0]).peel_refs();
let mess = if is_type_diagnostic_item(cx, obj_ty, sym::option_type) {
Some((UNWRAP_USED, "an Option", "None"))
} else if is_type_diagnostic_item(cx, obj_ty, sym::result_type) {
Some((UNWRAP_USED, "a Result", "Err"))
} else {
None
};
if let Some((lint, kind, none_value)) = mess {
span_lint_and_help(
cx,
lint,
expr.span,
&format!("used `unwrap()` on `{}` value", kind,),
None,
&format!(
"if you don't want to handle the `{}` case gracefully, consider \
using `expect()` to provide a better panic message",
none_value,
),
);
}
}

45
clippy_lints/src/methods/useless_asref.rs Normal file
View file

@ -0,0 +1,45 @@
use crate::utils::{
get_parent_expr, match_trait_method, paths, snippet_with_applicability, span_lint_and_sugg, walk_ptrs_ty_depth,
};
use if_chain::if_chain;
use rustc_errors::Applicability;
use rustc_hir as hir;
use rustc_lint::LateContext;
use super::USELESS_ASREF;
/// Checks for the `USELESS_ASREF` lint.
pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, call_name: &str, as_ref_args: &[hir::Expr<'_>]) {
// when we get here, we've already checked that the call name is "as_ref" or "as_mut"
// check if the call is to the actual `AsRef` or `AsMut` trait
if match_trait_method(cx, expr, &paths::ASREF_TRAIT) || match_trait_method(cx, expr, &paths::ASMUT_TRAIT) {
// check if the type after `as_ref` or `as_mut` is the same as before
let recvr = &as_ref_args[0];
let rcv_ty = cx.typeck_results().expr_ty(recvr);
let res_ty = cx.typeck_results().expr_ty(expr);
let (base_res_ty, res_depth) = walk_ptrs_ty_depth(res_ty);
let (base_rcv_ty, rcv_depth) = walk_ptrs_ty_depth(rcv_ty);
if base_rcv_ty == base_res_ty && rcv_depth >= res_depth {
// allow the `as_ref` or `as_mut` if it is followed by another method call
if_chain! {
if let Some(parent) = get_parent_expr(cx, expr);
if let hir::ExprKind::MethodCall(_, ref span, _, _) = parent.kind;
if span != &expr.span;
then {
return;
}
}
let mut applicability = Applicability::MachineApplicable;
span_lint_and_sugg(
cx,
USELESS_ASREF,
expr.span,
&format!("this call to `{}` does nothing", call_name),
"try this",
snippet_with_applicability(cx, recvr.span, "..", &mut applicability).to_string(),
applicability,
);
}
}
}

76
clippy_lints/src/methods/wrong_self_convention.rs Normal file
View file

@ -0,0 +1,76 @@
use crate::methods::SelfKind;
use crate::utils::span_lint;
use rustc_lint::LateContext;
use rustc_middle::ty::TyS;
use rustc_span::source_map::Span;
use std::fmt;
use super::WRONG_PUB_SELF_CONVENTION;
use super::WRONG_SELF_CONVENTION;
#[rustfmt::skip]
const CONVENTIONS: [(Convention, &[SelfKind]); 7] = [
(Convention::Eq("new"), &[SelfKind::No]),
(Convention::StartsWith("as_"), &[SelfKind::Ref, SelfKind::RefMut]),
(Convention::StartsWith("from_"), &[SelfKind::No]),
(Convention::StartsWith("into_"), &[SelfKind::Value]),
(Convention::StartsWith("is_"), &[SelfKind::Ref, SelfKind::No]),
(Convention::Eq("to_mut"), &[SelfKind::RefMut]),
(Convention::StartsWith("to_"), &[SelfKind::Ref]),
];
enum Convention {
Eq(&'static str),
StartsWith(&'static str),
}
impl Convention {
#[must_use]
fn check(&self, other: &str) -> bool {
match *self {
Self::Eq(this) => this == other,
Self::StartsWith(this) => other.starts_with(this) && this != other,
}
}
}
impl fmt::Display for Convention {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
match *self {
Self::Eq(this) => this.fmt(f),
Self::StartsWith(this) => this.fmt(f).and_then(|_| '*'.fmt(f)),
}
}
}
pub(super) fn check<'tcx>(
cx: &LateContext<'tcx>,
item_name: &str,
is_pub: bool,
self_ty: &'tcx TyS<'tcx>,
first_arg_ty: &'tcx TyS<'tcx>,
first_arg_span: Span,
) {
let lint = if is_pub {
WRONG_PUB_SELF_CONVENTION
} else {
WRONG_SELF_CONVENTION
};
if let Some((ref conv, self_kinds)) = &CONVENTIONS.iter().find(|(ref conv, _)| conv.check(item_name)) {
if !self_kinds.iter().any(|k| k.matches(cx, self_ty, first_arg_ty)) {
span_lint(
cx,
lint,
first_arg_span,
&format!(
"methods called `{}` usually take {}; consider choosing a less ambiguous name",
conv,
&self_kinds
.iter()
.map(|k| k.description())
.collect::<Vec<_>>()
.join(" or ")
),
);
}
}
}

19
clippy_lints/src/methods/zst_offset.rs Normal file
View file

@ -0,0 +1,19 @@
use crate::utils::span_lint;
use if_chain::if_chain;
use rustc_hir as hir;
use rustc_lint::LateContext;
use rustc_middle::ty;
use super::ZST_OFFSET;
pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, args: &[hir::Expr<'_>]) {
if_chain! {
if args.len() == 2;
if let ty::RawPtr(ty::TypeAndMut { ref ty, .. }) = cx.typeck_results().expr_ty(&args[0]).kind();
if let Ok(layout) = cx.tcx.layout_of(cx.param_env.and(ty));
if layout.is_zst();
then {
span_lint(cx, ZST_OFFSET, expr.span, "offset calculation on zero-sized value");
}
}
}