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Simplify check_for_loop_arg

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This commit is contained in:
Yoshitomo Nakanishi 2021-03-02 12:41:06 +09:00
parent eaf63d6df7
commit 74bd806b05
4 changed files with 90 additions and 67 deletions
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11
clippy_lints/src/loops/explicit_into_iter_loop.rs
View File

@ -3,10 +3,17 @@
use rustc_errors::Applicability;
use rustc_hir::Expr;
use rustc_lint::LateContext;
use rustc_middle::ty::TyS;
pub(super) fn check(cx: &LateContext<'_>, args: &'hir [Expr<'hir>], arg: &Expr<'_>) {
let receiver_ty = cx.typeck_results().expr_ty(&args[0]);
let receiver_ty_adjusted = cx.typeck_results().expr_ty_adjusted(&args[0]);
if !TyS::same_type(receiver_ty, receiver_ty_adjusted) {
return;
}
pub(super) fn check(cx: &LateContext<'_>, method_args: &'hir [Expr<'hir>], arg: &Expr<'_>) {
let mut applicability = Applicability::MachineApplicable;
let object = snippet_with_applicability(cx, method_args[0].span, "_", &mut applicability);
let object = snippet_with_applicability(cx, args[0].span, "_", &mut applicability);
span_lint_and_sugg(
cx,
EXPLICIT_INTO_ITER_LOOP,

57
clippy_lints/src/loops/explicit_iter_loop.rs
View File

@ -1,10 +1,35 @@
use super::EXPLICIT_ITER_LOOP;
use crate::utils::{snippet_with_applicability, span_lint_and_sugg};
use crate::utils::{match_trait_method, snippet_with_applicability, span_lint_and_sugg};
use rustc_errors::Applicability;
use rustc_hir::Expr;
use rustc_hir::{Expr, Mutability};
use rustc_lint::LateContext;
use rustc_middle::ty::{self, Ty, TyS};
use rustc_span::symbol::sym;
use crate::utils::{is_type_diagnostic_item, match_type, paths};
pub(super) fn check(cx: &LateContext<'_>, args: &[Expr<'_>], arg: &Expr<'_>, method_name: &str) {
let should_lint = match method_name {
"iter" | "iter_mut" => is_ref_iterable_type(cx, &args[0]),
"into_iter" if match_trait_method(cx, arg, &paths::INTO_ITERATOR) => {
let receiver_ty = cx.typeck_results().expr_ty(&args[0]);
let receiver_ty_adjusted = cx.typeck_results().expr_ty_adjusted(&args[0]);
let ref_receiver_ty = cx.tcx.mk_ref(
cx.tcx.lifetimes.re_erased,
ty::TypeAndMut {
ty: receiver_ty,
mutbl: Mutability::Not,
},
);
TyS::same_type(receiver_ty_adjusted, ref_receiver_ty)
},
_ => false,
};
if !should_lint {
return;
}
let mut applicability = Applicability::MachineApplicable;
let object = snippet_with_applicability(cx, args[0].span, "_", &mut applicability);
let muta = if method_name == "iter_mut" { "mut " } else { "" };
@ -19,3 +44,31 @@ pub(super) fn check(cx: &LateContext<'_>, args: &[Expr<'_>], arg: &Expr<'_>, met
applicability,
)
}
/// Returns `true` if the type of expr is one that provides `IntoIterator` impls
/// for `&T` and `&mut T`, such as `Vec`.
#[rustfmt::skip]
fn is_ref_iterable_type(cx: &LateContext<'_>, e: &Expr<'_>) -> bool {
// no walk_ptrs_ty: calling iter() on a reference can make sense because it
// will allow further borrows afterwards
let ty = cx.typeck_results().expr_ty(e);
is_iterable_array(ty, cx) ||
is_type_diagnostic_item(cx, ty, sym::vec_type) ||
match_type(cx, ty, &paths::LINKED_LIST) ||
is_type_diagnostic_item(cx, ty, sym!(hashmap_type)) ||
is_type_diagnostic_item(cx, ty, sym!(hashset_type)) ||
is_type_diagnostic_item(cx, ty, sym!(vecdeque_type)) ||
match_type(cx, ty, &paths::BINARY_HEAP) ||
match_type(cx, ty, &paths::BTREEMAP) ||
match_type(cx, ty, &paths::BTREESET)
}
fn is_iterable_array<'tcx>(ty: Ty<'tcx>, cx: &LateContext<'tcx>) -> bool {
// IntoIterator is currently only implemented for array sizes <= 32 in rustc
match ty.kind() {
ty::Array(_, n) => n
.try_eval_usize(cx.tcx, cx.param_env)
.map_or(false, |val| (0..=32).contains(&val)),
_ => false,
}
}

23
clippy_lints/src/loops/iter_next_loop.rs
View File

@ -1,14 +1,19 @@
use super::ITER_NEXT_LOOP;
use crate::utils::span_lint;
use crate::utils::{match_trait_method, paths, span_lint};
use rustc_hir::Expr;
use rustc_lint::LateContext;
pub(super) fn check(cx: &LateContext<'_>, expr: &Expr<'_>) {
span_lint(
cx,
ITER_NEXT_LOOP,
expr.span,
"you are iterating over `Iterator::next()` which is an Option; this will compile but is \
probably not what you want",
);
pub(super) fn check(cx: &LateContext<'_>, arg: &Expr<'_>, expr: &Expr<'_>) -> bool {
if match_trait_method(cx, arg, &paths::ITERATOR) {
span_lint(
cx,
ITER_NEXT_LOOP,
expr.span,
"you are iterating over `Iterator::next()` which is an Option; this will compile but is \
probably not what you want",
);
true
} else {
false
}
}

66
clippy_lints/src/loops/mod.rs
View File

@ -18,13 +18,11 @@
mod while_let_loop;
mod while_let_on_iterator;
use crate::utils::{higher, is_type_diagnostic_item, match_trait_method, match_type, paths};
use rustc_hir::{Expr, ExprKind, LoopSource, Mutability, Pat};
use crate::utils::higher;
use rustc_hir::{Expr, ExprKind, LoopSource, Pat};
use rustc_lint::{LateContext, LateLintPass};
use rustc_middle::ty::{self, Ty, TyS};
use rustc_session::{declare_lint_pass, declare_tool_lint};
use rustc_span::source_map::Span;
use rustc_span::symbol::sym;
use utils::{get_span_of_entire_for_loop, make_iterator_snippet, IncrementVisitor, InitializeVisitor};
declare_clippy_lint! {
@ -603,67 +601,27 @@ fn check_for_loop<'tcx>(
fn check_for_loop_arg(cx: &LateContext<'_>, pat: &Pat<'_>, arg: &Expr<'_>, expr: &Expr<'_>) {
let mut next_loop_linted = false; // whether or not ITER_NEXT_LOOP lint was used
if let ExprKind::MethodCall(ref method, _, ref args, _) = arg.kind {
// just the receiver, no arguments
if args.len() == 1 {
let method_name = &*method.ident.as_str();
// check for looping over x.iter() or x.iter_mut(), could use &x or &mut x
if method_name == "iter" || method_name == "iter_mut" {
if is_ref_iterable_type(cx, &args[0]) {
match method_name {
"iter" | "iter_mut" => explicit_iter_loop::check(cx, args, arg, method_name),
"into_iter" => {
explicit_iter_loop::check(cx, args, arg, method_name);
}
} else if method_name == "into_iter" && match_trait_method(cx, arg, &paths::INTO_ITERATOR) {
let receiver_ty = cx.typeck_results().expr_ty(&args[0]);
let receiver_ty_adjusted = cx.typeck_results().expr_ty_adjusted(&args[0]);
if TyS::same_type(receiver_ty, receiver_ty_adjusted) {
explicit_into_iter_loop::check(cx, args, arg);
} else {
let ref_receiver_ty = cx.tcx.mk_ref(
cx.tcx.lifetimes.re_erased,
ty::TypeAndMut {
ty: receiver_ty,
mutbl: Mutability::Not,
},
);
if TyS::same_type(receiver_ty_adjusted, ref_receiver_ty) {
explicit_iter_loop::check(cx, args, arg, method_name)
}
}
} else if method_name == "next" && match_trait_method(cx, arg, &paths::ITERATOR) {
iter_next_loop::check(cx, expr);
next_loop_linted = true;
},
"next" => {
next_loop_linted = iter_next_loop::check(cx, arg, expr);
},
_ => {},
}
}
}
if !next_loop_linted {
for_loops_over_fallibles::check(cx, pat, arg);
}
}
/// Returns `true` if the type of expr is one that provides `IntoIterator` impls
/// for `&T` and `&mut T`, such as `Vec`.
#[rustfmt::skip]
fn is_ref_iterable_type(cx: &LateContext<'_>, e: &Expr<'_>) -> bool {
// no walk_ptrs_ty: calling iter() on a reference can make sense because it
// will allow further borrows afterwards
let ty = cx.typeck_results().expr_ty(e);
is_iterable_array(ty, cx) ||
is_type_diagnostic_item(cx, ty, sym::vec_type) ||
match_type(cx, ty, &paths::LINKED_LIST) ||
is_type_diagnostic_item(cx, ty, sym!(hashmap_type)) ||
is_type_diagnostic_item(cx, ty, sym!(hashset_type)) ||
is_type_diagnostic_item(cx, ty, sym!(vecdeque_type)) ||
match_type(cx, ty, &paths::BINARY_HEAP) ||
match_type(cx, ty, &paths::BTREEMAP) ||
match_type(cx, ty, &paths::BTREESET)
}
fn is_iterable_array<'tcx>(ty: Ty<'tcx>, cx: &LateContext<'tcx>) -> bool {
// IntoIterator is currently only implemented for array sizes <= 32 in rustc
match ty.kind() {
ty::Array(_, n) => n
.try_eval_usize(cx.tcx, cx.param_env)
.map_or(false, |val| (0..=32).contains(&val)),
_ => false,
}
}