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Auto merge of #116623 - Nadrieril:validate-range-endpoints, r=oli-obk

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Fix overflow checking in range patterns

When a range pattern contains an overflowing literal, if we're not careful we might not notice the overflow and use the wrapped value. This makes for confusing error messages because linting against overflowing literals is only done in a later pass. So when a range is invalid we check for overflows to provide a better error.

This check didn't use to handle negative types; this PR fixes that. First commit adds tests, second cleans up without changing behavior, third does the fix.

EDIT: while I was at it, I fixed a small annoyance about the span of the overflow lint on negated literals.

Fixes https://github.com/rust-lang/rust/issues/94239
This commit is contained in:
bors 2023-10-11 10:07:19 +00:00
commit 71704c4f84
11 changed files with 318 additions and 168 deletions
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17
compiler/rustc_lint/src/types.rs
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@ -140,13 +140,15 @@ declare_lint! {
pub struct TypeLimits {
/// Id of the last visited negated expression
negated_expr_id: Option<hir::HirId>,
/// Span of the last visited negated expression
negated_expr_span: Option<Span>,
}
impl_lint_pass!(TypeLimits => [UNUSED_COMPARISONS, OVERFLOWING_LITERALS, INVALID_NAN_COMPARISONS]);
impl TypeLimits {
pub fn new() -> TypeLimits {
TypeLimits { negated_expr_id: None }
TypeLimits { negated_expr_id: None, negated_expr_span: None }
}
}
@ -426,17 +428,15 @@ fn lint_int_literal<'tcx>(
return;
}
let lit = cx
.sess()
.source_map()
.span_to_snippet(lit.span)
.expect("must get snippet from literal");
let span = if negative { type_limits.negated_expr_span.unwrap() } else { e.span };
let lit =
cx.sess().source_map().span_to_snippet(span).expect("must get snippet from literal");
let help = get_type_suggestion(cx.typeck_results().node_type(e.hir_id), v, negative)
.map(|suggestion_ty| OverflowingIntHelp { suggestion_ty });
cx.emit_spanned_lint(
OVERFLOWING_LITERALS,
e.span,
span,
OverflowingInt { ty: t.name_str(), lit, min, max, help },
);
}
@ -622,9 +622,10 @@ impl<'tcx> LateLintPass<'tcx> for TypeLimits {
fn check_expr(&mut self, cx: &LateContext<'tcx>, e: &'tcx hir::Expr<'tcx>) {
match e.kind {
hir::ExprKind::Unary(hir::UnOp::Neg, ref expr) => {
// propagate negation, if the negation itself isn't negated
// Propagate negation, if the negation itself isn't negated
if self.negated_expr_id != Some(e.hir_id) {
self.negated_expr_id = Some(expr.hir_id);
self.negated_expr_span = Some(e.span);
}
}
hir::ExprKind::Binary(binop, ref l, ref r) => {