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Avoid invalid NaN lint machine-applicable suggestion in const context #114486

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Merged
merged 2 commits into from
Aug 6, 2023
Merged

Avoid invalid NaN lint machine-applicable suggestion in const context #114486

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b71f2be
Avoid invalid NaN lint machine-applicable suggestion in const context
Urgau Aug 4, 2023
3b3e466
Add FIXME as reminder to restore suggestion later
compiler-errors Aug 6, 2023
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2 changes: 1 addition & 1 deletion compiler/rustc_lint/src/lints.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -1467,7 +1467,7 @@ pub enum InvalidNanComparisons {
#[diag(lint_invalid_nan_comparisons_eq_ne)]
EqNe {
#[subdiagnostic]
suggestion: InvalidNanComparisonsSuggestion,
suggestion: Option<InvalidNanComparisonsSuggestion>,
},
#[diag(lint_invalid_nan_comparisons_lt_le_gt_ge)]
LtLeGtGe,
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14 changes: 9 additions & 5 deletions compiler/rustc_lint/src/types.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -572,32 +572,36 @@ fn lint_nan<'tcx>(
}

fn eq_ne(
cx: &LateContext<'_>,
e: &hir::Expr<'_>,
l: &hir::Expr<'_>,
r: &hir::Expr<'_>,
f: impl FnOnce(Span, Span) -> InvalidNanComparisonsSuggestion,
) -> InvalidNanComparisons {
let suggestion =
// FIXME(#72505): This suggestion can be restored if `f{32,64}::is_nan` is made const.
let suggestion = (!cx.tcx.hir().is_inside_const_context(e.hir_id)).then(|| {
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nit: this is a somewhat confusing way of avoiding an if statement 😅

if let Some(l_span) = l.span.find_ancestor_inside(e.span) &&
let Some(r_span) = r.span.find_ancestor_inside(e.span) {
let Some(r_span) = r.span.find_ancestor_inside(e.span)
{
f(l_span, r_span)
} else {
InvalidNanComparisonsSuggestion::Spanless
};
}
});

InvalidNanComparisons::EqNe { suggestion }
}

let lint = match binop.node {
hir::BinOpKind::Eq | hir::BinOpKind::Ne if is_nan(cx, l) => {
eq_ne(e, l, r, |l_span, r_span| InvalidNanComparisonsSuggestion::Spanful {
eq_ne(cx, e, l, r, |l_span, r_span| InvalidNanComparisonsSuggestion::Spanful {
nan_plus_binop: l_span.until(r_span),
float: r_span.shrink_to_hi(),
neg: (binop.node == hir::BinOpKind::Ne).then(|| r_span.shrink_to_lo()),
})
}
hir::BinOpKind::Eq | hir::BinOpKind::Ne if is_nan(cx, r) => {
eq_ne(e, l, r, |l_span, r_span| InvalidNanComparisonsSuggestion::Spanful {
eq_ne(cx, e, l, r, |l_span, r_span| InvalidNanComparisonsSuggestion::Spanful {
nan_plus_binop: l_span.shrink_to_hi().to(r_span),
float: l_span.shrink_to_hi(),
neg: (binop.node == hir::BinOpKind::Ne).then(|| l_span.shrink_to_lo()),
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5 changes: 0 additions & 5 deletions tests/ui/lint/invalid-nan-comparison.stderr
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Expand Up @@ -5,11 +5,6 @@ LL | const TEST: bool = 5f32 == f32::NAN;
| ^^^^^^^^^^^^^^^^
|
= note: `#[warn(invalid_nan_comparisons)]` on by default
help: use `f32::is_nan()` or `f64::is_nan()` instead
|
LL - const TEST: bool = 5f32 == f32::NAN;
LL + const TEST: bool = 5f32.is_nan();
|

warning: incorrect NaN comparison, NaN cannot be directly compared to itself
--> $DIR/invalid-nan-comparison.rs:14:5
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