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Fix dbg_macro ICE when used iterated by for loop #16011

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Fix dbg_macro ICE when used iterated by for loop #16011

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119 changes: 70 additions & 49 deletions clippy_lints/src/dbg_macro.rs
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Original file line number Diff line number Diff line change
@@ -1,14 +1,17 @@
use std::ops::ControlFlow;

use clippy_config::Conf;
use clippy_utils::diagnostics::span_lint_and_then;
use clippy_utils::is_in_test;
use clippy_utils::macros::{MacroCall, macro_backtrace};
use clippy_utils::source::snippet_with_applicability;
use clippy_utils::visitors::for_each_expr;
use rustc_data_structures::fx::FxHashSet;
use rustc_errors::Applicability;
use rustc_hir::{Closure, ClosureKind, CoroutineKind, Expr, ExprKind, LetStmt, LocalSource, Node, Stmt, StmtKind};
use rustc_lint::{LateContext, LateLintPass, LintContext};
use rustc_session::impl_lint_pass;
use rustc_span::{Span, SyntaxContext, sym};
use rustc_span::{BytePos, Span, SyntaxContext, sym};

declare_clippy_lint! {
/// ### What it does
Expand Down Expand Up @@ -53,8 +56,8 @@ impl DbgMacro {
}
}

impl LateLintPass<'_> for DbgMacro {
fn check_expr(&mut self, cx: &LateContext<'_>, expr: &Expr<'_>) {
impl<'tcx> LateLintPass<'tcx> for DbgMacro {
fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) {
let cur_syntax_ctxt = expr.span.ctxt();

if cur_syntax_ctxt != self.prev_ctxt &&
Expand All @@ -66,60 +69,76 @@ impl LateLintPass<'_> for DbgMacro {
// allows `dbg!` in test code if allow-dbg-in-test is set to true in clippy.toml
!(self.allow_dbg_in_tests && is_in_test(cx.tcx, expr.hir_id))
{
self.prev_ctxt = cur_syntax_ctxt;

span_lint_and_then(
cx,
DBG_MACRO,
macro_call.span,
"the `dbg!` macro is intended as a debugging tool",
|diag| {
let mut applicability = Applicability::MachineApplicable;
let (sugg_span, suggestion) =
match is_async_move_desugar(expr).unwrap_or(expr).peel_drop_temps().kind {
// dbg!()
ExprKind::Block(..) => {
// If the `dbg!` macro is a "free" statement and not contained within other expressions,
// remove the whole statement.
if let Node::Stmt(_) = cx.tcx.parent_hir_node(expr.hir_id)
&& let Some(semi_span) =
cx.sess().source_map().mac_call_stmt_semi_span(macro_call.span)
{
(macro_call.span.to(semi_span), String::new())
} else {
(macro_call.span, String::from("()"))
let expr = is_async_move_desugar(expr).unwrap_or(expr).peel_drop_temps();
let (sugg_span, suggestion) = match expr.kind {
// dbg!()
ExprKind::Block(..) => {
// If the `dbg!` macro is a "free" statement and not contained within other expressions,
// remove the whole statement.
if let Node::Stmt(_) = cx.tcx.parent_hir_node(expr.hir_id)
&& let Some(semi_span) = cx.sess().source_map().mac_call_stmt_semi_span(macro_call.span)
{
(macro_call.span.to(semi_span), String::new())
} else {
(macro_call.span, String::from("()"))
}
},
// dbg!(1)
ExprKind::Match(val, ..) => (
macro_call.span,
snippet_with_applicability(cx, val.span.source_callsite(), "..", &mut applicability)
.to_string(),
),
// dbg!(2, 3)
ExprKind::Tup(
[
Expr {
kind: ExprKind::Match(first, ..),
..
},
..,
Expr {
kind: ExprKind::Match(last, ..),
..
},
],
) => {
let snippet = snippet_with_applicability(
cx,
first.span.source_callsite().to(last.span.source_callsite()),
"..",
&mut applicability,
);
(macro_call.span, format!("({snippet})"))
},
_ => {
let macro_arg_span = if let Some(sub_expr_span) = for_each_expr(cx, expr, |sub_expr| {
if sub_expr.span.ctxt() == self.prev_ctxt {
return ControlFlow::Break(sub_expr.span);
}
},
// dbg!(1)
ExprKind::Match(val, ..) => (
macro_call.span,
snippet_with_applicability(cx, val.span.source_callsite(), "..", &mut applicability)
.to_string(),
),
// dbg!(2, 3)
ExprKind::Tup(
[
Expr {
kind: ExprKind::Match(first, ..),
..
},
..,
Expr {
kind: ExprKind::Match(last, ..),
..
},
],
) => {
let snippet = snippet_with_applicability(
cx,
first.span.source_callsite().to(last.span.source_callsite()),
"..",
&mut applicability,
);
(macro_call.span, format!("({snippet})"))
},
_ => unreachable!(),
};
ControlFlow::Continue(())
}) {
// Find the first sub-expression with the previous syntax context.
sub_expr_span
} else {
// Fallback: unwrap the argument span from the `dbg!` macro call manually.
macro_call
.span
.source_callsite()
.with_lo(macro_call.span.lo() + BytePos(5)) // after `dbg!(`
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@ada4a ada4a Nov 3, 2025

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what if the expression is poorly formatted, something like dbg ! { 0}?

.with_hi(macro_call.span.hi() - BytePos(1))
};
let snippet = snippet_with_applicability(cx, macro_arg_span, "..", &mut applicability);
(macro_call.span, snippet.to_string())
},
};

diag.span_suggestion(
sugg_span,
Expand All @@ -129,6 +148,8 @@ impl LateLintPass<'_> for DbgMacro {
);
},
);

self.prev_ctxt = cur_syntax_ctxt;
}
}

Expand Down
5 changes: 5 additions & 0 deletions tests/ui/dbg_macro/dbg_macro.fixed
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Original file line number Diff line number Diff line change
Expand Up @@ -139,3 +139,8 @@ mod issue14914 {
//~^ dbg_macro
}
}

fn issue16008() {
for _ in [1, 2] {}
//~^ dbg_macro
}
5 changes: 5 additions & 0 deletions tests/ui/dbg_macro/dbg_macro.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -139,3 +139,8 @@ mod issue14914 {
//~^ dbg_macro
}
}

fn issue16008() {
for _ in dbg!([1, 2]) {}
//~^ dbg_macro
}
14 changes: 13 additions & 1 deletion tests/ui/dbg_macro/dbg_macro.stderr
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Original file line number Diff line number Diff line change
Expand Up @@ -242,5 +242,17 @@ LL - takes_async_fn(async |val| dbg!(val));
LL + takes_async_fn(async |val| val);
|

error: aborting due to 20 previous errors
error: the `dbg!` macro is intended as a debugging tool
--> tests/ui/dbg_macro/dbg_macro.rs:144:14
|
LL | for _ in dbg!([1, 2]) {}
| ^^^^^^^^^^^^
|
help: remove the invocation before committing it to a version control system
|
LL - for _ in dbg!([1, 2]) {}
LL + for _ in [1, 2] {}
|

error: aborting due to 21 previous errors

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