polymorphize: don't normalize self-ty need substs

`characteristic_def_id_of_type` was being invoked during partitioning
for self types of impl blocks which had projections that depended on the
value of unused generic parameters of a function, resulting in an ICE in
the 'generic-names' debuginfo test. If partitioning is enabled and the
instance needs substitution then this is now skipped.

Signed-off-by: David Wood <david.wood@huawei.com>
This commit is contained in:
David Wood 2021-10-04 09:50:10 +00:00
parent 76b05531ca
commit b39e915981

View file

@ -9,7 +9,7 @@ use rustc_middle::middle::exported_symbols::SymbolExportLevel;
use rustc_middle::mir::mono::{CodegenUnit, CodegenUnitNameBuilder, Linkage, Visibility};
use rustc_middle::mir::mono::{InstantiationMode, MonoItem};
use rustc_middle::ty::print::characteristic_def_id_of_type;
use rustc_middle::ty::{self, DefIdTree, InstanceDef, TyCtxt};
use rustc_middle::ty::{self, fold::TypeFoldable, DefIdTree, InstanceDef, TyCtxt};
use rustc_span::symbol::Symbol;
use super::PartitioningCx;
@ -300,14 +300,21 @@ fn characteristic_def_id_of_mono_item<'tcx>(
// call it.
return None;
}
// This is a method within an impl, find out what the self-type is:
let impl_self_ty = tcx.subst_and_normalize_erasing_regions(
instance.substs,
ty::ParamEnv::reveal_all(),
tcx.type_of(impl_def_id),
);
if let Some(def_id) = characteristic_def_id_of_type(impl_self_ty) {
return Some(def_id);
// When polymorphization is enabled, methods which do not depend on their generic
// parameters, but the self-type of their impl block do will fail to normalize.
if !tcx.sess.opts.debugging_opts.polymorphize
|| !instance.definitely_needs_subst(tcx)
{
// This is a method within an impl, find out what the self-type is:
let impl_self_ty = tcx.subst_and_normalize_erasing_regions(
instance.substs,
ty::ParamEnv::reveal_all(),
tcx.type_of(impl_def_id),
);
if let Some(def_id) = characteristic_def_id_of_type(impl_self_ty) {
return Some(def_id);
}
}
}