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use visitors to support full block
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@Jacherr
Jacherr committed Mar 13, 2024
1 parent e12409d commit a6f952b
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Showing 7 changed files with 214 additions and 123 deletions.
4 changes: 2 additions & 2 deletions clippy_lints/src/manual_strip.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -95,7 +95,7 @@ impl<'tcx> LateLintPass<'tcx> for ManualStrip {
}

let strippings = find_stripping(cx, strip_kind, target_res, pattern, then);
if !strippings.is_empty() {
if let Some(first_stripping) = strippings.first() {
let kind_word = match strip_kind {
StripKind::Prefix => "prefix",
StripKind::Suffix => "suffix",
Expand All @@ -105,7 +105,7 @@ impl<'tcx> LateLintPass<'tcx> for ManualStrip {
span_lint_and_then(
cx,
MANUAL_STRIP,
strippings[0],
*first_stripping,
&format!("stripping a {kind_word} manually"),
|diag| {
diag.span_note(test_span, format!("the {kind_word} was tested here"));
Expand Down
206 changes: 102 additions & 104 deletions clippy_lints/src/unnecessary_indexing.rs
View file
Original file line number Diff line number Diff line change
@@ -1,13 +1,16 @@
use std::ops::ControlFlow;

use clippy_utils::diagnostics::span_lint_and_then;
use clippy_utils::eq_expr_value;
use clippy_utils::source::snippet;
use clippy_utils::ty::is_type_diagnostic_item;
use clippy_utils::visitors::for_each_expr;
use rustc_ast::LitKind;
use rustc_errors::Applicability;
use rustc_hir::{ExprKind, Local, StmtKind, UnOp};
use rustc_hir::{Expr, ExprKind, Local, Node, UnOp};
use rustc_lint::{LateContext, LateLintPass};
use rustc_session::declare_lint_pass;
use rustc_span::{sym, Span};
use rustc_span::sym;

declare_clippy_lint! {
/// ### What it does
Expand Down Expand Up @@ -53,111 +56,106 @@ impl LateLintPass<'_> for UnnecessaryIndexing {
&& (expr_ty.is_array_slice() || expr_ty.is_array() || is_type_diagnostic_item(cx, expr_ty, sym::Vec))
&& let ExprKind::Block(block, _) = if_expr.then.kind
{
// checked if conditional is calling `is_empty` on a sequence, now check if the first
// statement inside the 'if' statement does unchecked get of first element
// the receiver for the index operation
let mut index_receiver: Option<&Expr<'_>> = None;
// first local in the block - used as pattern for `Some(pat)`
let mut first_local: Option<&Local<'_>> = None;
// any other locals to be aware of, these are set to the value of `pat`
let mut extra_locals: Vec<&Local<'_>> = vec![];
// any other index expressions to replace with `pat` (or "element" if no local exists)
let mut extra_exprs: Vec<&Expr<'_>> = vec![];

// if calling a function on the indexing - local
if let Some(first) = block.stmts.first()
&& let StmtKind::Local(local) = first.kind
&& let Some(init) = local.init
&& let ExprKind::Call(_, args) | ExprKind::MethodCall(_, _, args, _) = init.kind
{
for arg_expr in args {
if check_arg_stmt(cx, expr, arg_expr, conditional_receiver, if_expr.cond.span) {
break;
}
}
// if calling a function on the indexing - statement or expression
} else if let Some(first) = block.stmts.first()
&& let StmtKind::Expr(stmt_expr) | StmtKind::Semi(stmt_expr) = first.kind
&& let ExprKind::Call(_, args) | ExprKind::MethodCall(_, _, args, _) = stmt_expr.kind
{
for arg_expr in args {
if check_arg_stmt(cx, expr, arg_expr, conditional_receiver, if_expr.cond.span) {
break;
}
}
// if calling on a local which is not in itself a call or methodcall
} else if let Some(first) = block.stmts.first()
&& let StmtKind::Local(local) = first.kind
&& let Some(_) = local.init
{
check_local_stmt(cx, expr, local, conditional_receiver, if_expr.cond.span);
}
}
}
}
for_each_expr(block.stmts, |x| {
if let ExprKind::Index(receiver, index, _) = x.kind
&& let ExprKind::Lit(lit) = index.kind
&& let LitKind::Int(val, _) = lit.node
&& eq_expr_value(cx, receiver, conditional_receiver)
&& val.0 == 0
{
index_receiver = Some(receiver);
if let Node::Local(local) = cx.tcx.parent_hir_node(x.hir_id) {
if first_local.is_none() {
first_local = Some(local);
} else {
extra_locals.push(local);
};
} else {
extra_exprs.push(x);
};
};

fn check_local_stmt(
cx: &LateContext<'_>,
expr: &'_ rustc_hir::Expr<'_>,
local: &Local<'_>,
conditional_receiver: &'_ rustc_hir::Expr<'_>,
cond_span: Span,
) {
if let ExprKind::Index(receiver, index, _) = local.init.unwrap().kind
&& let ExprKind::Lit(lit) = index.kind
&& let LitKind::Int(val, _) = lit.node
&& eq_expr_value(cx, receiver, conditional_receiver)
&& val.0 == 0
{
span_lint_and_then(
cx,
UNNECESSARY_INDEXING,
expr.span,
"condition can be simplified with if..let syntax",
|x| {
x.span_suggestion(
cond_span,
"consider using if..let syntax (variable may need to be dereferenced)",
format!(
"let Some({}) = {}.first()",
snippet(cx, local.pat.span, ".."),
snippet(cx, receiver.span, "..")
),
Applicability::Unspecified,
);
x.span_suggestion(local.span, "remove this line", "", Applicability::MachineApplicable);
},
);
}
}
ControlFlow::Continue::<()>(())
});

fn check_arg_stmt(
cx: &LateContext<'_>,
expr: &'_ rustc_hir::Expr<'_>,
arg_expr: &'_ rustc_hir::Expr<'_>,
conditional_receiver: &'_ rustc_hir::Expr<'_>,
cond_span: Span,
) -> bool {
if let ExprKind::Index(receiver, index, _) = arg_expr.kind
&& let ExprKind::Lit(lit) = index.kind
&& let LitKind::Int(val, _) = lit.node
&& eq_expr_value(cx, receiver, conditional_receiver)
&& val.0 == 0
{
span_lint_and_then(
cx,
UNNECESSARY_INDEXING,
expr.span,
"condition can be simplified with if..let syntax",
|x| {
x.multipart_suggestion(
"consider using if..let syntax (variable may need to be dereferenced)",
vec![
(
cond_span,
format!("let Some(element) = {}.first()", snippet(cx, receiver.span, "..")),
),
(arg_expr.span, "element".to_owned()),
],
Applicability::Unspecified,
);
},
);
if let Some(receiver) = index_receiver {
span_lint_and_then(
cx,
UNNECESSARY_INDEXING,
expr.span,
"condition can be simplified with if..let syntax",
|x| {
if let Some(first_local) = first_local {
x.span_suggestion(
if_expr.cond.span,
"consider using if..let syntax (variable may need to be dereferenced)",
format!(
"let Some({}) = {}.first()",
snippet(cx, first_local.pat.span, ".."),
snippet(cx, receiver.span, "..")
),
Applicability::Unspecified,
);
x.span_suggestion(
first_local.span,
"remove this line",
"",
Applicability::MachineApplicable,
);
if !extra_locals.is_empty() {
let extra_local_suggestions = extra_locals
.iter()
.map(|x| {
(
x.init.unwrap().span,
snippet(cx, first_local.pat.span, "..").to_string(),
)
})
.collect::<Vec<_>>();

return true;
}
x.multipart_suggestion(
"initialize this variable to be the `Some` variant (may need dereferencing)",
extra_local_suggestions,
Applicability::Unspecified,
);
}
if !extra_exprs.is_empty() {
let index_accesses = extra_exprs
.iter()
.map(|x| (x.span, snippet(cx, first_local.pat.span, "..").to_string()))
.collect::<Vec<_>>();

false
x.multipart_suggestion(
"set this index to be the `Some` variant (may need dereferencing)",
index_accesses,
Applicability::Unspecified,
);
}
} else {
let mut index_accesses = vec![(
if_expr.cond.span,
format!("let Some(element) = {}.first()", snippet(cx, receiver.span, "..")),
)];
index_accesses.extend(extra_exprs.iter().map(|x| (x.span, "element".to_owned())));

x.multipart_suggestion(
"consider using if..let syntax (variable may need to be dereferenced)",
index_accesses,
Applicability::Unspecified,
);
}
},
);
}
}
}
}
1 change: 1 addition & 0 deletions tests/ui/index_refutable_slice/if_let_slice_binding.fixed
View file
Original file line number Diff line number Diff line change
@@ -1,5 +1,6 @@
#![deny(clippy::index_refutable_slice)]
#![allow(clippy::uninlined_format_args)]
#![allow(clippy::unnecessary_indexing)]

enum SomeEnum<T> {
One(T),
Expand Down
1 change: 1 addition & 0 deletions tests/ui/index_refutable_slice/if_let_slice_binding.rs
View file
Original file line number Diff line number Diff line change
@@ -1,5 +1,6 @@
#![deny(clippy::index_refutable_slice)]
#![allow(clippy::uninlined_format_args)]
#![allow(clippy::unnecessary_indexing)]

enum SomeEnum<T> {
One(T),
Expand Down
20 changes: 10 additions & 10 deletions tests/ui/index_refutable_slice/if_let_slice_binding.stderr
View file
Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
error: this binding can be a slice pattern to avoid indexing
--> tests/ui/index_refutable_slice/if_let_slice_binding.rs:14:17
--> tests/ui/index_refutable_slice/if_let_slice_binding.rs:15:17
|
LL | if let Some(slice) = slice {
| ^^^^^
Expand All @@ -19,7 +19,7 @@ LL | println!("{}", slice_0);
| ~~~~~~~

error: this binding can be a slice pattern to avoid indexing
--> tests/ui/index_refutable_slice/if_let_slice_binding.rs:21:17
--> tests/ui/index_refutable_slice/if_let_slice_binding.rs:22:17
|
LL | if let Some(slice) = slice {
| ^^^^^
Expand All @@ -34,7 +34,7 @@ LL | println!("{}", slice_0);
| ~~~~~~~

error: this binding can be a slice pattern to avoid indexing
--> tests/ui/index_refutable_slice/if_let_slice_binding.rs:28:17
--> tests/ui/index_refutable_slice/if_let_slice_binding.rs:29:17
|
LL | if let Some(slice) = slice {
| ^^^^^
Expand All @@ -50,7 +50,7 @@ LL ~ println!("{}", slice_0);
|

error: this binding can be a slice pattern to avoid indexing
--> tests/ui/index_refutable_slice/if_let_slice_binding.rs:36:26
--> tests/ui/index_refutable_slice/if_let_slice_binding.rs:37:26
|
LL | if let SomeEnum::One(slice) | SomeEnum::Three(slice) = slice_wrapped {
| ^^^^^
Expand All @@ -65,7 +65,7 @@ LL | println!("{}", slice_0);
| ~~~~~~~

error: this binding can be a slice pattern to avoid indexing
--> tests/ui/index_refutable_slice/if_let_slice_binding.rs:44:29
--> tests/ui/index_refutable_slice/if_let_slice_binding.rs:45:29
|
LL | if let (SomeEnum::Three(a), Some(b)) = (a_wrapped, b_wrapped) {
| ^
Expand All @@ -80,7 +80,7 @@ LL | println!("{} -> {}", a_2, b[1]);
| ~~~

error: this binding can be a slice pattern to avoid indexing
--> tests/ui/index_refutable_slice/if_let_slice_binding.rs:44:38
--> tests/ui/index_refutable_slice/if_let_slice_binding.rs:45:38
|
LL | if let (SomeEnum::Three(a), Some(b)) = (a_wrapped, b_wrapped) {
| ^
Expand All @@ -95,7 +95,7 @@ LL | println!("{} -> {}", a[2], b_1);
| ~~~

error: this binding can be a slice pattern to avoid indexing
--> tests/ui/index_refutable_slice/if_let_slice_binding.rs:53:21
--> tests/ui/index_refutable_slice/if_let_slice_binding.rs:54:21
|
LL | if let Some(ref slice) = slice {
| ^^^^^
Expand All @@ -110,7 +110,7 @@ LL | println!("{:?}", slice_1);
| ~~~~~~~

error: this binding can be a slice pattern to avoid indexing
--> tests/ui/index_refutable_slice/if_let_slice_binding.rs:62:17
--> tests/ui/index_refutable_slice/if_let_slice_binding.rs:63:17
|
LL | if let Some(slice) = &slice {
| ^^^^^
Expand All @@ -125,7 +125,7 @@ LL | println!("{:?}", slice_0);
| ~~~~~~~

error: this binding can be a slice pattern to avoid indexing
--> tests/ui/index_refutable_slice/if_let_slice_binding.rs:132:17
--> tests/ui/index_refutable_slice/if_let_slice_binding.rs:133:17
|
LL | if let Some(slice) = wrap.inner {
| ^^^^^
Expand All @@ -140,7 +140,7 @@ LL | println!("This is awesome! {}", slice_0);
| ~~~~~~~

error: this binding can be a slice pattern to avoid indexing
--> tests/ui/index_refutable_slice/if_let_slice_binding.rs:140:17
--> tests/ui/index_refutable_slice/if_let_slice_binding.rs:141:17
|
LL | if let Some(slice) = wrap.inner {
| ^^^^^
Expand Down
25 changes: 25 additions & 0 deletions tests/ui/unnecessary_indexing.rs
View file
Original file line number Diff line number Diff line change
@@ -1,5 +1,6 @@
//@no-rustfix
#![allow(unused)]
#![allow(dropping_copy_types)]
#![warn(clippy::unnecessary_indexing)]

fn c(x: i32) -> i32 {
Expand Down Expand Up @@ -52,6 +53,30 @@ fn main() {
let b = a[0];
}

// lint when access is not first line
let a: &[i32] = &[1];
if !a.is_empty() {
dbg!(a);
let b = a[0];
}

// lint on multiple accesses/locals
let a: &[i32] = &[1];
if !a.is_empty() {
dbg!(a);
let b = a[0];
let c = a[0];
drop(a[0]);
}

// lint on multiple accesses
let a: &[i32] = &[1];
if !a.is_empty() {
dbg!(a);
drop(a[0]);
drop(a[0]);
}

// dont lint when not accessing [0]
let a: &[i32] = &[1, 2];
if !a.is_empty() {
Expand Down
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