62a82b361c
In the updated nightly version, it seems that rustfmt now supports formatting let-chains. Since we're using them a lot, it's a lot of reformatting.
51 lines
1.7 KiB
Rust
51 lines
1.7 KiB
Rust
use clippy_utils::consts::{constant, Constant};
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use clippy_utils::diagnostics::span_lint;
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use clippy_utils::{is_integer_literal, is_path_diagnostic_item};
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use rustc_hir::{Expr, ExprKind};
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use rustc_lint::LateContext;
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use rustc_middle::ty::Ty;
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use rustc_span::symbol::sym;
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use super::TRANSMUTING_NULL;
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const LINT_MSG: &str = "transmuting a known null pointer into a reference";
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pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, arg: &'tcx Expr<'_>, to_ty: Ty<'tcx>) -> bool {
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if !to_ty.is_ref() {
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return false;
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}
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// Catching transmute over constants that resolve to `null`.
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if let ExprKind::Path(ref _qpath) = arg.kind
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&& let Some(Constant::RawPtr(0)) = constant(cx, cx.typeck_results(), arg)
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{
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span_lint(cx, TRANSMUTING_NULL, expr.span, LINT_MSG);
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return true;
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}
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// Catching:
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// `std::mem::transmute(0 as *const i32)`
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if let ExprKind::Cast(inner_expr, _cast_ty) = arg.kind
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&& is_integer_literal(inner_expr, 0)
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{
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span_lint(cx, TRANSMUTING_NULL, expr.span, LINT_MSG);
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return true;
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}
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// Catching:
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// `std::mem::transmute(std::ptr::null::<i32>())`
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if let ExprKind::Call(func1, []) = arg.kind
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&& is_path_diagnostic_item(cx, func1, sym::ptr_null)
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{
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span_lint(cx, TRANSMUTING_NULL, expr.span, LINT_MSG);
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return true;
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}
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// FIXME:
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// Also catch transmutations of variables which are known nulls.
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// To do this, MIR const propagation seems to be the better tool.
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// Whenever MIR const prop routines are more developed, this will
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// become available. As of this writing (25/03/19) it is not yet.
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false
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}
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