From 9220558c246d6d1610e7a9b20bd031559b868236 Mon Sep 17 00:00:00 2001
From: varkor <github@varkor.com>
Date: Tue, 22 Oct 2019 14:00:19 +0100
Subject: [PATCH 1/5] Fix an issue with const inference variables sticking
around under Chalk + NLL
---
src/librustc/infer/combine.rs | 14 ++++------
src/librustc/infer/nll_relate/mod.rs | 41 ++++++++++++++++------------
2 files changed, 28 insertions(+), 27 deletions(-)
diff --git a/src/librustc/infer/combine.rs b/src/librustc/infer/combine.rs
index f06dbc72cd9..2e724ac56ee 100644
--- a/src/librustc/infer/combine.rs
+++ b/src/librustc/infer/combine.rs
@@ -602,19 +602,15 @@ impl TypeRelation<'tcx> for Generalizer<'_, 'tcx> {
) -> RelateResult<'tcx, &'tcx ty::Const<'tcx>> {
assert_eq!(c, c2); // we are abusing TypeRelation here; both LHS and RHS ought to be ==
- match c {
- ty::Const { val: ConstValue::Infer(InferConst::Var(vid)), .. } => {
+ match c.val {
+ ConstValue::Infer(InferConst::Var(vid)) => {
let mut variable_table = self.infcx.const_unification_table.borrow_mut();
- match variable_table.probe_value(*vid).val.known() {
- Some(u) => {
- self.relate(&u, &u)
- }
+ match variable_table.probe_value(vid).val.known() {
+ Some(u) => self.relate(&u, &u),
None => Ok(c),
}
}
- _ => {
- relate::super_relate_consts(self, c, c)
- }
+ _ => relate::super_relate_consts(self, c, c),
}
}
}
diff --git a/src/librustc/infer/nll_relate/mod.rs b/src/librustc/infer/nll_relate/mod.rs
index 64ef0421808..8d59f455cbb 100644
--- a/src/librustc/infer/nll_relate/mod.rs
+++ b/src/librustc/infer/nll_relate/mod.rs
@@ -27,7 +27,7 @@ use crate::ty::error::TypeError;
use crate::ty::fold::{TypeFoldable, TypeVisitor};
use crate::ty::relate::{self, Relate, RelateResult, TypeRelation};
use crate::ty::subst::GenericArg;
-use crate::ty::{self, Ty, TyCtxt};
+use crate::ty::{self, Ty, TyCtxt, InferConst};
use crate::mir::interpret::ConstValue;
use rustc_data_structures::fx::FxHashMap;
use std::fmt::Debug;
@@ -616,15 +616,20 @@ where
fn consts(
&mut self,
a: &'tcx ty::Const<'tcx>,
- b: &'tcx ty::Const<'tcx>,
+ mut b: &'tcx ty::Const<'tcx>,
) -> RelateResult<'tcx, &'tcx ty::Const<'tcx>> {
- if let ty::Const { val: ConstValue::Bound(..), .. } = a {
- // FIXME(const_generics): I'm unsure how this branch should actually be handled,
- // so this is probably not correct.
- self.infcx.super_combine_consts(self, a, b)
- } else {
- debug!("consts(a={:?}, b={:?}, variance={:?})", a, b, self.ambient_variance);
- relate::super_relate_consts(self, a, b)
+ let a = self.infcx.shallow_resolve(a);
+
+ if !D::forbid_inference_vars() {
+ b = self.infcx.shallow_resolve(b);
+ }
+
+ match b.val {
+ ConstValue::Infer(InferConst::Var(_)) if D::forbid_inference_vars() => {
+ // Forbid inference variables in the RHS.
+ bug!("unexpected inference var {:?}", b)
+ }
+ _ => self.infcx.super_combine_consts(self, a, b)
}
}
@@ -991,15 +996,15 @@ where
a: &'tcx ty::Const<'tcx>,
_: &'tcx ty::Const<'tcx>,
) -> RelateResult<'tcx, &'tcx ty::Const<'tcx>> {
- debug!("TypeGeneralizer::consts(a={:?})", a);
-
- if let ty::Const { val: ConstValue::Bound(..), .. } = a {
- bug!(
- "unexpected inference variable encountered in NLL generalization: {:?}",
- a
- );
- } else {
- relate::super_relate_consts(self, a, a)
+ match a.val {
+ ConstValue::Infer(InferConst::Var(vid)) => {
+ let mut variable_table = self.infcx.const_unification_table.borrow_mut();
+ match variable_table.probe_value(vid).val.known() {
+ Some(u) => self.relate(&u, &u),
+ None => Ok(a),
+ }
+ }
+ _ => relate::super_relate_consts(self, a, a),
}
}
From 51c687446d65fe271972f6371639334bb10da6db Mon Sep 17 00:00:00 2001
From: varkor <github@varkor.com>
Date: Tue, 22 Oct 2019 14:07:20 +0100
Subject: [PATCH 2/5] Add regression test for #65675
---
src/test/ui/const-generics/issues/issue-65675.rs | 10 ++++++++++
src/test/ui/const-generics/issues/issue-65675.stderr | 8 ++++++++
2 files changed, 18 insertions(+)
create mode 100644 src/test/ui/const-generics/issues/issue-65675.rs
create mode 100644 src/test/ui/const-generics/issues/issue-65675.stderr
diff --git a/src/test/ui/const-generics/issues/issue-65675.rs b/src/test/ui/const-generics/issues/issue-65675.rs
new file mode 100644
index 00000000000..3ca527313f9
--- /dev/null
+++ b/src/test/ui/const-generics/issues/issue-65675.rs
@@ -0,0 +1,10 @@
+// run-pass
+// compile-flags: -Z chalk
+
+#![feature(const_generics)]
+//~^ WARN the feature `const_generics` is incomplete and may cause the compiler to crash
+
+pub struct Foo<T, const N: usize>([T; N]);
+impl<T, const N: usize> Foo<T, {N}> {}
+
+fn main() {}
diff --git a/src/test/ui/const-generics/issues/issue-65675.stderr b/src/test/ui/const-generics/issues/issue-65675.stderr
new file mode 100644
index 00000000000..60b388e6278
--- /dev/null
+++ b/src/test/ui/const-generics/issues/issue-65675.stderr
@@ -0,0 +1,8 @@
+warning: the feature `const_generics` is incomplete and may cause the compiler to crash
+ --> $DIR/issue-65675.rs:4:12
+ |
+LL | #![feature(const_generics)]
+ | ^^^^^^^^^^^^^^
+ |
+ = note: `#[warn(incomplete_features)]` on by default
+
From cc7294c751fd700b77c3556eaae8507661f08f22 Mon Sep 17 00:00:00 2001
From: varkor <github@varkor.com>
Date: Wed, 23 Oct 2019 17:09:56 +0100
Subject: [PATCH 3/5] Add regression test for #62579
---
.../const-generics/issues/issue-62579-no-match.rs | 15 +++++++++++++++
.../issues/issue-62579-no-match.stderr | 8 ++++++++
2 files changed, 23 insertions(+)
create mode 100644 src/test/ui/const-generics/issues/issue-62579-no-match.rs
create mode 100644 src/test/ui/const-generics/issues/issue-62579-no-match.stderr
diff --git a/src/test/ui/const-generics/issues/issue-62579-no-match.rs b/src/test/ui/const-generics/issues/issue-62579-no-match.rs
new file mode 100644
index 00000000000..0ff7ddc41fe
--- /dev/null
+++ b/src/test/ui/const-generics/issues/issue-62579-no-match.rs
@@ -0,0 +1,15 @@
+// run-pass
+
+#![feature(const_generics)]
+//~^ WARN the feature `const_generics` is incomplete and may cause the compiler to crash
+
+#[derive(PartialEq, Eq)]
+struct NoMatch;
+
+fn foo<const T: NoMatch>() -> bool {
+ true
+}
+
+fn main() {
+ foo::<{NoMatch}>();
+}
diff --git a/src/test/ui/const-generics/issues/issue-62579-no-match.stderr b/src/test/ui/const-generics/issues/issue-62579-no-match.stderr
new file mode 100644
index 00000000000..759d5fdeb4c
--- /dev/null
+++ b/src/test/ui/const-generics/issues/issue-62579-no-match.stderr
@@ -0,0 +1,8 @@
+warning: the feature `const_generics` is incomplete and may cause the compiler to crash
+ --> $DIR/issue-62579-no-match.rs:3:12
+ |
+LL | #![feature(const_generics)]
+ | ^^^^^^^^^^^^^^
+ |
+ = note: `#[warn(incomplete_features)]` on by default
+
From 12f68e6987c4669b90a6cdac1643b99b6c677aea Mon Sep 17 00:00:00 2001
From: varkor <github@varkor.com>
Date: Wed, 23 Oct 2019 17:40:18 +0100
Subject: [PATCH 4/5] Account for const generalisation in combine
---
src/librustc/infer/combine.rs | 18 +++++++++++++++---
1 file changed, 15 insertions(+), 3 deletions(-)
diff --git a/src/librustc/infer/combine.rs b/src/librustc/infer/combine.rs
index 2e724ac56ee..a6c3c2de139 100644
--- a/src/librustc/infer/combine.rs
+++ b/src/librustc/infer/combine.rs
@@ -605,9 +605,21 @@ impl TypeRelation<'tcx> for Generalizer<'_, 'tcx> {
match c.val {
ConstValue::Infer(InferConst::Var(vid)) => {
let mut variable_table = self.infcx.const_unification_table.borrow_mut();
- match variable_table.probe_value(vid).val.known() {
- Some(u) => self.relate(&u, &u),
- None => Ok(c),
+ let var_value = variable_table.probe_value(vid);
+ match var_value.val {
+ ConstVariableValue::Known { value: u } => self.relate(&u, &u),
+ ConstVariableValue::Unknown { universe } => {
+ if self.for_universe.can_name(universe) {
+ Ok(c)
+ } else {
+ let new_var_id = variable_table.new_key(ConstVarValue {
+ origin: var_value.origin,
+ val: ConstVariableValue::Unknown { universe: self.for_universe },
+ });
+ let u = self.tcx().mk_const_var(new_var_id, c.ty);
+ return Ok(u);
+ }
+ }
}
}
_ => relate::super_relate_consts(self, c, c),
From 624e34a5d02d47b807bad3a81aa7ce0c088d2452 Mon Sep 17 00:00:00 2001
From: varkor <github@varkor.com>
Date: Wed, 23 Oct 2019 18:00:35 +0100
Subject: [PATCH 5/5] Account for const generalisation in nll_relate
---
src/librustc/infer/combine.rs | 7 +++----
src/librustc/infer/nll_relate/mod.rs | 21 ++++++++++++++++++---
2 files changed, 21 insertions(+), 7 deletions(-)
diff --git a/src/librustc/infer/combine.rs b/src/librustc/infer/combine.rs
index a6c3c2de139..51ae4e49493 100644
--- a/src/librustc/infer/combine.rs
+++ b/src/librustc/infer/combine.rs
@@ -494,7 +494,7 @@ impl TypeRelation<'tcx> for Generalizer<'_, 'tcx> {
if sub_vid == self.for_vid_sub_root {
// If sub-roots are equal, then `for_vid` and
// `vid` are related via subtyping.
- return Err(TypeError::CyclicTy(self.root_ty));
+ Err(TypeError::CyclicTy(self.root_ty))
} else {
match variables.probe(vid) {
TypeVariableValue::Known { value: u } => {
@@ -527,7 +527,7 @@ impl TypeRelation<'tcx> for Generalizer<'_, 'tcx> {
let u = self.tcx().mk_ty_var(new_var_id);
debug!("generalize: replacing original vid={:?} with new={:?}",
vid, u);
- return Ok(u);
+ Ok(u)
}
}
}
@@ -616,8 +616,7 @@ impl TypeRelation<'tcx> for Generalizer<'_, 'tcx> {
origin: var_value.origin,
val: ConstVariableValue::Unknown { universe: self.for_universe },
});
- let u = self.tcx().mk_const_var(new_var_id, c.ty);
- return Ok(u);
+ Ok(self.tcx().mk_const_var(new_var_id, c.ty))
}
}
}
diff --git a/src/librustc/infer/nll_relate/mod.rs b/src/librustc/infer/nll_relate/mod.rs
index 8d59f455cbb..d6f76e9ee34 100644
--- a/src/librustc/infer/nll_relate/mod.rs
+++ b/src/librustc/infer/nll_relate/mod.rs
@@ -28,6 +28,7 @@ use crate::ty::fold::{TypeFoldable, TypeVisitor};
use crate::ty::relate::{self, Relate, RelateResult, TypeRelation};
use crate::ty::subst::GenericArg;
use crate::ty::{self, Ty, TyCtxt, InferConst};
+use crate::infer::{ConstVariableValue, ConstVarValue};
use crate::mir::interpret::ConstValue;
use rustc_data_structures::fx::FxHashMap;
use std::fmt::Debug;
@@ -324,7 +325,7 @@ where
let vid = pair.vid();
let value_ty = pair.value_ty();
- // FIXME -- this logic assumes invariance, but that is wrong.
+ // FIXME(invariance) -- this logic assumes invariance, but that is wrong.
// This only presently applies to chalk integration, as NLL
// doesn't permit type variables to appear on both sides (and
// doesn't use lazy norm).
@@ -629,6 +630,7 @@ where
// Forbid inference variables in the RHS.
bug!("unexpected inference var {:?}", b)
}
+ // FIXME(invariance): see the related FIXME above.
_ => self.infcx.super_combine_consts(self, a, b)
}
}
@@ -997,11 +999,24 @@ where
_: &'tcx ty::Const<'tcx>,
) -> RelateResult<'tcx, &'tcx ty::Const<'tcx>> {
match a.val {
+ ConstValue::Infer(InferConst::Var(_)) if D::forbid_inference_vars() => {
+ bug!(
+ "unexpected inference variable encountered in NLL generalization: {:?}",
+ a
+ );
+ }
ConstValue::Infer(InferConst::Var(vid)) => {
let mut variable_table = self.infcx.const_unification_table.borrow_mut();
- match variable_table.probe_value(vid).val.known() {
+ let var_value = variable_table.probe_value(vid);
+ match var_value.val.known() {
Some(u) => self.relate(&u, &u),
- None => Ok(a),
+ None => {
+ let new_var_id = variable_table.new_key(ConstVarValue {
+ origin: var_value.origin,
+ val: ConstVariableValue::Unknown { universe: self.universe },
+ });
+ Ok(self.tcx().mk_const_var(new_var_id, a.ty))
+ }
}
}
_ => relate::super_relate_consts(self, a, a),