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Fix dbg_macro fail to handle async coroutine desugar #14937

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Merged
merged 1 commit into from
May 31, 2025
Merged

Fix dbg_macro fail to handle async coroutine desugar #14937

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122 changes: 77 additions & 45 deletions clippy_lints/src/dbg_macro.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -5,7 +5,7 @@ use clippy_utils::macros::{MacroCall, macro_backtrace};
use clippy_utils::source::snippet_with_applicability;
use rustc_data_structures::fx::FxHashSet;
use rustc_errors::Applicability;
use rustc_hir::{Expr, ExprKind, Node};
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};
Expand Down Expand Up @@ -60,6 +60,8 @@ impl LateLintPass<'_> for DbgMacro {
if cur_syntax_ctxt != self.prev_ctxt &&
let Some(macro_call) = first_dbg_macro_in_expansion(cx, expr.span) &&
!macro_call.span.in_external_macro(cx.sess().source_map()) &&
// avoids exprs generated by the desugaring of coroutines
!is_coroutine_desugar(expr) &&
self.checked_dbg_call_site.insert(macro_call.span) &&
// 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))
Expand All @@ -73,50 +75,51 @@ impl LateLintPass<'_> for DbgMacro {
"the `dbg!` macro is intended as a debugging tool",
|diag| {
let mut applicability = Applicability::MachineApplicable;

let (sugg_span, suggestion) = match 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("()"))
}
},
// 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!(),
};
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("()"))
}
},
// 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!(),
};

diag.span_suggestion(
sugg_span,
Expand All @@ -134,6 +137,35 @@ impl LateLintPass<'_> for DbgMacro {
}
}

fn is_coroutine_desugar(expr: &Expr<'_>) -> bool {
matches!(
expr.kind,
ExprKind::Closure(Closure {
kind: ClosureKind::Coroutine(CoroutineKind::Desugared(..)) | ClosureKind::CoroutineClosure(..),
..
})
)
}

fn is_async_move_desugar<'tcx>(expr: &'tcx Expr<'tcx>) -> Option<&'tcx Expr<'tcx>> {
if let ExprKind::Block(block, _) = expr.kind
&& let [
Stmt {
kind:
StmtKind::Let(LetStmt {
source: LocalSource::AsyncFn,
..
}),
..
},
] = block.stmts
{
return block.expr;
}

None
}

fn first_dbg_macro_in_expansion(cx: &LateContext<'_>, span: Span) -> Option<MacroCall> {
macro_backtrace(span).find(|mc| cx.tcx.is_diagnostic_item(sym::dbg_macro, mc.def_id))
}
16 changes: 16 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 @@ -123,3 +123,19 @@ mod issue12131 {
//~^ dbg_macro
}
}

mod issue14914 {
use std::future::Future;

fn takes_async_fn<F, Fut>(_f: F)
where
F: FnOnce(i32) -> Fut,
Fut: Future<Output = i32>,
{
}

fn should_not_panic() {
takes_async_fn(async |val| val);
//~^ dbg_macro
}
}
16 changes: 16 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 @@ -123,3 +123,19 @@ mod issue12131 {
//~^ dbg_macro
}
}

mod issue14914 {
use std::future::Future;

fn takes_async_fn<F, Fut>(_f: F)
where
F: FnOnce(i32) -> Fut,
Fut: Future<Output = i32>,
{
}

fn should_not_panic() {
takes_async_fn(async |val| dbg!(val));
//~^ dbg_macro
}
}
14 changes: 13 additions & 1 deletion tests/ui/dbg_macro/dbg_macro.stderr
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Expand Up @@ -230,5 +230,17 @@ LL - print!("{}", dbg!(s));
LL + print!("{}", s);
|

error: aborting due to 19 previous errors
error: the `dbg!` macro is intended as a debugging tool
--> tests/ui/dbg_macro/dbg_macro.rs:138:36
|
LL | takes_async_fn(async |val| dbg!(val));
| ^^^^^^^^^
|
help: remove the invocation before committing it to a version control system
|
LL - takes_async_fn(async |val| dbg!(val));
LL + takes_async_fn(async |val| val);
|

error: aborting due to 20 previous errors