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implement const_evaluatable_checked feature MVP

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This commit is contained in:
Bastian Kauschke 2020-09-10 08:52:02 +02:00
parent a1894e4afe
commit 8667f93040
7 changed files with 122 additions and 17 deletions
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51
compiler/rustc_trait_selection/src/traits/const_evaluatable.rs
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@ -14,6 +14,24 @@ pub fn is_const_evaluatable<'cx, 'tcx>(
param_env: ty::ParamEnv<'tcx>,
span: Span,
) -> Result<(), ErrorHandled> {
debug!("is_const_evaluatable({:?}, {:?})", def, substs);
if infcx.tcx.features().const_evaluatable_checked {
// FIXME(const_evaluatable_checked): Actually look into generic constants to
// implement const equality.
for pred in param_env.caller_bounds() {
match pred.skip_binders() {
ty::PredicateAtom::ConstEvaluatable(b_def, b_substs) => {
debug!("is_const_evaluatable: caller_bound={:?}, {:?}", b_def, b_substs);
if b_def == def && b_substs == substs {
debug!("is_const_evaluatable: caller_bound ~~> ok");
return Ok(());
}
}
_ => {} // don't care
}
}
}
let future_compat_lint = || {
if let Some(local_def_id) = def.did.as_local() {
infcx.tcx.struct_span_lint_hir(
@ -38,24 +56,27 @@ pub fn is_const_evaluatable<'cx, 'tcx>(
// See #74595 for more details about this.
let concrete = infcx.const_eval_resolve(param_env, def, substs, None, Some(span));
let def_kind = infcx.tcx.def_kind(def.did);
match def_kind {
DefKind::AnonConst => {
let mir_body = if let Some(def) = def.as_const_arg() {
infcx.tcx.optimized_mir_of_const_arg(def)
} else {
infcx.tcx.optimized_mir(def.did)
};
if mir_body.is_polymorphic && concrete.is_ok() {
future_compat_lint();
}
}
_ => {
if substs.has_param_types_or_consts() && concrete.is_ok() {
future_compat_lint();
if concrete.is_ok() && substs.has_param_types_or_consts() {
match infcx.tcx.def_kind(def.did) {
DefKind::AnonConst => {
let mir_body = if let Some(def) = def.as_const_arg() {
infcx.tcx.optimized_mir_of_const_arg(def)
} else {
infcx.tcx.optimized_mir(def.did)
};
if mir_body.is_polymorphic {
future_compat_lint();
}
}
_ => future_compat_lint(),
}
}
if concrete.is_ok() {
debug!("is_const_evaluatable: concrete ~~> ok");
} else {
debug!("is_const_evaluatable: concrete ~~> err");
}
concrete.map(drop)
}