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Slightly tweak comments wrt lint_overflowing_range_endpoint #102602

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merged 1 commit into from
Oct 22, 2022
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Slightly tweak comments wrt lint_overflowing_range_endpoint #102602

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78 changes: 40 additions & 38 deletions compiler/rustc_lint/src/types.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -116,8 +116,8 @@ impl TypeLimits {
}
}

/// Attempts to special-case the overflowing literal lint when it occurs as a range endpoint.
/// Returns `true` iff the lint was overridden.
/// Attempts to special-case the overflowing literal lint when it occurs as a range endpoint (`expr..MAX+1`).
/// Returns `true` iff the lint was emitted.
fn lint_overflowing_range_endpoint<'tcx>(
cx: &LateContext<'tcx>,
lit: &hir::Lit,
Expand All @@ -140,44 +140,46 @@ fn lint_overflowing_range_endpoint<'tcx>(
return false;
}

let mut overwritten = false;
// We can suggest using an inclusive range
// (`..=`) instead only if it is the `end` that is
// overflowing and only by 1.
if eps[1].expr.hir_id == expr.hir_id && lit_val - 1 == max
&& let Ok(start) = cx.sess().source_map().span_to_snippet(eps[0].span)
{
cx.struct_span_lint(
OVERFLOWING_LITERALS,
struct_expr.span,
fluent::lint::range_endpoint_out_of_range,
|lint| {
use ast::{LitIntType, LitKind};

lint.set_arg("ty", ty);

// We need to preserve the literal's suffix,
// as it may determine typing information.
let suffix = match lit.node {
LitKind::Int(_, LitIntType::Signed(s)) => s.name_str(),
LitKind::Int(_, LitIntType::Unsigned(s)) => s.name_str(),
LitKind::Int(_, LitIntType::Unsuffixed) => "",
_ => bug!(),
};
let suggestion = format!("{}..={}{}", start, lit_val - 1, suffix);
lint.span_suggestion(
struct_expr.span,
fluent::lint::suggestion,
suggestion,
Applicability::MachineApplicable,
);
overwritten = true;
if !(eps[1].expr.hir_id == expr.hir_id && lit_val - 1 == max) {
return false;
};
let Ok(start) = cx.sess().source_map().span_to_snippet(eps[0].span) else { return false };

lint
},
);
}
overwritten
cx.struct_span_lint(
OVERFLOWING_LITERALS,
struct_expr.span,
fluent::lint::range_endpoint_out_of_range,
|lint| {
use ast::{LitIntType, LitKind};

lint.set_arg("ty", ty);

// We need to preserve the literal's suffix,
// as it may determine typing information.
let suffix = match lit.node {
LitKind::Int(_, LitIntType::Signed(s)) => s.name_str(),
LitKind::Int(_, LitIntType::Unsigned(s)) => s.name_str(),
LitKind::Int(_, LitIntType::Unsuffixed) => "",
_ => bug!(),
};
let suggestion = format!("{}..={}{}", start, lit_val - 1, suffix);
lint.span_suggestion(
struct_expr.span,
fluent::lint::suggestion,
suggestion,
Applicability::MachineApplicable,
);

lint
},
);

// We've just emitted a lint, special cased for `(...)..MAX+1` ranges,
// return `true` so the callers don't also emit a lint
true
}

// For `isize` & `usize`, be conservative with the warnings, so that the
Expand Down Expand Up @@ -358,7 +360,7 @@ fn lint_int_literal<'tcx>(
}

if lint_overflowing_range_endpoint(cx, lit, v, max, e, t.name_str()) {
// The overflowing literal lint was overridden.
// The overflowing literal lint was emited by `lint_overflowing_range_endpoint`.
return;
}

Expand Down Expand Up @@ -427,7 +429,7 @@ fn lint_uint_literal<'tcx>(
}
}
if lint_overflowing_range_endpoint(cx, lit, lit_val, max, e, t.name_str()) {
// The overflowing literal lint was overridden.
// The overflowing literal lint was emited by `lint_overflowing_range_endpoint`.
return;
}
if let Some(repr_str) = get_bin_hex_repr(cx, lit) {
Expand Down