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Auto merge of #10785 - Centri3:diverting_sub_expression, r=Jarcho

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Fix `diverging_sub_expression` not checking body of block

Fixes #10776

This also adds a warning to the test `ui/never_loop.rs`, not sure if this is correct or not.

changelog: [`diverging_sub_expression`]: Fix false negatives with body of block
This commit is contained in:
bors 2023-06-10 00:16:43 +00:00
commit d44ea7c5c5
4 changed files with 75 additions and 9 deletions
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12
clippy_lints/src/mixed_read_write_in_expression.rs
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@ -114,7 +114,7 @@ struct DivergenceVisitor<'a, 'tcx> {
impl<'a, 'tcx> DivergenceVisitor<'a, 'tcx> {
fn maybe_walk_expr(&mut self, e: &'tcx Expr<'_>) {
match e.kind {
ExprKind::Closure { .. } => {},
ExprKind::Closure(..) | ExprKind::If(..) | ExprKind::Loop(..) => {},
ExprKind::Match(e, arms, _) => {
self.visit_expr(e);
for arm in arms {
@ -128,6 +128,7 @@ impl<'a, 'tcx> DivergenceVisitor<'a, 'tcx> {
_ => walk_expr(self, e),
}
}
fn report_diverging_sub_expr(&mut self, e: &Expr<'_>) {
span_lint(self.cx, DIVERGING_SUB_EXPRESSION, e.span, "sub-expression diverges");
}
@ -136,6 +137,15 @@ impl<'a, 'tcx> DivergenceVisitor<'a, 'tcx> {
impl<'a, 'tcx> Visitor<'tcx> for DivergenceVisitor<'a, 'tcx> {
fn visit_expr(&mut self, e: &'tcx Expr<'_>) {
match e.kind {
// fix #10776
ExprKind::Block(block, ..) => match (block.stmts, block.expr) {
([], Some(e)) => self.visit_expr(e),
([stmt], None) => match stmt.kind {
StmtKind::Expr(e) | StmtKind::Semi(e) => self.visit_expr(e),
_ => {},
},
_ => {},
},
ExprKind::Continue(_) | ExprKind::Break(_, _) | ExprKind::Ret(_) => self.report_diverging_sub_expr(e),
ExprKind::Call(func, _) => {
let typ = self.cx.typeck_results().expr_ty(func);

16
tests/ui/diverging_sub_expression.rs
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@ -1,5 +1,6 @@
#![warn(clippy::diverging_sub_expression)]
#![allow(clippy::match_same_arms, clippy::overly_complex_bool_expr)]
#![allow(clippy::nonminimal_bool)]
#[allow(clippy::empty_loop)]
fn diverge() -> ! {
loop {}
@ -21,6 +22,7 @@ fn main() {
}
#[allow(dead_code, unused_variables)]
#[rustfmt::skip]
fn foobar() {
loop {
let x = match 5 {
@ -35,6 +37,20 @@ fn foobar() {
99 => return,
_ => true || panic!("boo"),
},
// lint blocks as well
15 => true || { return; },
16 => false || { return; },
// ... and when it's a single expression
17 => true || { return },
18 => false || { return },
// ... but not when there's both an expression and a statement
19 => true || { _ = 1; return },
20 => false || { _ = 1; return },
// ... or multiple statements
21 => true || { _ = 1; return; },
22 => false || { _ = 1; return; },
23 => true || { return; true },
24 => true || { return; true },
_ => true || break,
};
}

46
tests/ui/diverging_sub_expression.stderr
View File

@ -1,5 +1,5 @@
error: sub-expression diverges
--> $DIR/diverging_sub_expression.rs:19:10
--> $DIR/diverging_sub_expression.rs:20:10
|
LL | b || diverge();
| ^^^^^^^^^
@ -7,34 +7,66 @@ LL | b || diverge();
= note: `-D clippy::diverging-sub-expression` implied by `-D warnings`
error: sub-expression diverges
--> $DIR/diverging_sub_expression.rs:20:10
--> $DIR/diverging_sub_expression.rs:21:10
|
LL | b || A.foo();
| ^^^^^^^
error: sub-expression diverges
--> $DIR/diverging_sub_expression.rs:29:26
--> $DIR/diverging_sub_expression.rs:31:26
|
LL | 6 => true || return,
| ^^^^^^
error: sub-expression diverges
--> $DIR/diverging_sub_expression.rs:30:26
--> $DIR/diverging_sub_expression.rs:32:26
|
LL | 7 => true || continue,
| ^^^^^^^^
error: sub-expression diverges
--> $DIR/diverging_sub_expression.rs:33:26
--> $DIR/diverging_sub_expression.rs:35:26
|
LL | 3 => true || diverge(),
| ^^^^^^^^^
error: sub-expression diverges
--> $DIR/diverging_sub_expression.rs:38:26
--> $DIR/diverging_sub_expression.rs:38:30
|
LL | _ => true || panic!("boo"),
| ^^^^^^^^^^^^^
|
= note: this error originates in the macro `$crate::panic::panic_2021` which comes from the expansion of the macro `panic` (in Nightly builds, run with -Z macro-backtrace for more info)
error: sub-expression diverges
--> $DIR/diverging_sub_expression.rs:41:29
|
LL | 15 => true || { return; },
| ^^^^^^
error: sub-expression diverges
--> $DIR/diverging_sub_expression.rs:42:30
|
LL | 16 => false || { return; },
| ^^^^^^
error: sub-expression diverges
--> $DIR/diverging_sub_expression.rs:44:29
|
LL | 17 => true || { return },
| ^^^^^^
error: sub-expression diverges
--> $DIR/diverging_sub_expression.rs:45:30
|
LL | 18 => false || { return },
| ^^^^^^
error: sub-expression diverges
--> $DIR/diverging_sub_expression.rs:54:26
|
LL | _ => true || break,
| ^^^^^
error: aborting due to 6 previous errors
error: aborting due to 11 previous errors

10
tests/ui/never_loop.stderr
View File

@ -126,6 +126,14 @@ LL | | }
LL | | }
| |_____^
error: sub-expression diverges
--> $DIR/never_loop.rs:247:17
|
LL | break 'a;
| ^^^^^^^^
|
= note: `-D clippy::diverging-sub-expression` implied by `-D warnings`
error: this loop never actually loops
--> $DIR/never_loop.rs:278:13
|
@ -139,5 +147,5 @@ help: if you need the first element of the iterator, try writing
LL | if let Some(_) = (0..20).next() {
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
error: aborting due to 12 previous errors
error: aborting due to 13 previous errors