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Extend check for UnsafeCell in consts to cover unions

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A validity companion to changes from #90373.
This commit is contained in:
Tomasz Miąsko 2021-10-28 00:00:00 +00:00
parent 8baeddfe8f
commit 2eb637a9f2
4 changed files with 100 additions and 1 deletions
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9
compiler/rustc_const_eval/src/interpret/validity.rs
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@ -14,6 +14,7 @@ use rustc_middle::mir::interpret::InterpError;
use rustc_middle::ty;
use rustc_middle::ty::layout::{LayoutOf, TyAndLayout};
use rustc_span::symbol::{sym, Symbol};
use rustc_span::DUMMY_SP;
use rustc_target::abi::{Abi, Scalar as ScalarAbi, Size, VariantIdx, Variants, WrappingRange};
use std::hash::Hash;
@ -736,9 +737,15 @@ impl<'rt, 'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> ValueVisitor<'mir, 'tcx, M>
#[inline(always)]
fn visit_union(
&mut self,
_op: &OpTy<'tcx, M::PointerTag>,
op: &OpTy<'tcx, M::PointerTag>,
_fields: NonZeroUsize,
) -> InterpResult<'tcx> {
// Special check preventing `UnsafeCell` inside unions in the inner part of constants.
if matches!(self.ctfe_mode, Some(CtfeValidationMode::Const { inner: true, .. })) {
if !op.layout.ty.is_freeze(self.ecx.tcx.at(DUMMY_SP), self.ecx.param_env) {
throw_validation_failure!(self.path, { "`UnsafeCell` in a `const`" });
}
}
Ok(())
}