bjoernager/rust
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Suggest ..= when someone tries to create an overflowing range

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This commit is contained in:
Mu42 2023-03-24 14:24:25 +08:00
parent cf073ec2cb
commit 8e56c2c5f1
3 changed files with 35 additions and 7 deletions
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27
compiler/rustc_lint/src/types.rs
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@ -136,6 +136,13 @@ fn lint_overflowing_range_endpoint<'tcx>(
expr: &'tcx hir::Expr<'tcx>,
ty: &str,
) -> bool {
let (expr, cast_ty) = if let Node::Expr(par_expr) = cx.tcx.hir().get(cx.tcx.hir().parent_id(expr.hir_id))
&& let ExprKind::Cast(_, ty) = par_expr.kind {
(par_expr, Some(ty))
} else {
(expr, None)
};
// We only want to handle exclusive (`..`) ranges,
// which are represented as `ExprKind::Struct`.
let par_id = cx.tcx.hir().parent_id(expr.hir_id);
@ -157,13 +164,19 @@ fn lint_overflowing_range_endpoint<'tcx>(
};
let Ok(start) = cx.sess().source_map().span_to_snippet(eps[0].span) else { return false };
use rustc_ast::{LitIntType, LitKind};
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 suffix = if let Some(cast_ty) = cast_ty {
let Ok(ty) = cx.sess().source_map().span_to_snippet(cast_ty.span) else { return false };
format!(" as {}", ty)
} else {
use rustc_ast::{LitIntType, LitKind};
match lit.node {
LitKind::Int(_, LitIntType::Signed(s)) => s.name_str().to_owned(),
LitKind::Int(_, LitIntType::Unsigned(s)) => s.name_str().to_owned(),
LitKind::Int(_, LitIntType::Unsuffixed) => "".to_owned(),
_ => bug!(),
}
};
cx.emit_spanned_lint(
OVERFLOWING_LITERALS,
struct_expr.span,
@ -172,7 +185,7 @@ fn lint_overflowing_range_endpoint<'tcx>(
suggestion: struct_expr.span,
start,
literal: lit_val - 1,
suffix,
suffix: &suffix,
},
);