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Simplify eager normalization of constants #63820

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Merged
merged 1 commit into from
Aug 28, 2019
Merged

Simplify eager normalization of constants #63820

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36 changes: 1 addition & 35 deletions src/librustc/traits/project.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -15,7 +15,6 @@ use super::util;
use crate::hir::def_id::DefId;
use crate::infer::{InferCtxt, InferOk, LateBoundRegionConversionTime};
use crate::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
use crate::mir::interpret::{GlobalId, ConstValue};
use rustc_data_structures::snapshot_map::{Snapshot, SnapshotMap};
use rustc_macros::HashStable;
use syntax::ast::Ident;
Expand Down Expand Up @@ -397,40 +396,7 @@ impl<'a, 'b, 'tcx> TypeFolder<'tcx> for AssocTypeNormalizer<'a, 'b, 'tcx> {
}

fn fold_const(&mut self, constant: &'tcx ty::Const<'tcx>) -> &'tcx ty::Const<'tcx> {
if let ConstValue::Unevaluated(def_id, substs) = constant.val {
let tcx = self.selcx.tcx().global_tcx();
let param_env = self.param_env;
if !param_env.has_local_value() {
if substs.needs_infer() || substs.has_placeholders() {
let identity_substs = InternalSubsts::identity_for_item(tcx, def_id);
let instance = ty::Instance::resolve(tcx, param_env, def_id, identity_substs);
if let Some(instance) = instance {
let cid = GlobalId {
instance,
promoted: None
};
if let Ok(evaluated) = tcx.const_eval(param_env.and(cid)) {
let evaluated = evaluated.subst(tcx, substs);
return evaluated;
}
}
} else {
if !substs.has_local_value() {
let instance = ty::Instance::resolve(tcx, param_env, def_id, substs);
if let Some(instance) = instance {
let cid = GlobalId {
instance,
promoted: None
};
if let Ok(evaluated) = tcx.const_eval(param_env.and(cid)) {
return evaluated;
}
}
}
}
}
}
constant
constant.eval(self.selcx.tcx(), self.param_env)
}
}

Expand Down
38 changes: 2 additions & 36 deletions src/librustc/traits/query/normalize.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -5,11 +5,10 @@
use crate::infer::at::At;
use crate::infer::canonical::OriginalQueryValues;
use crate::infer::{InferCtxt, InferOk};
use crate::mir::interpret::{GlobalId, ConstValue};
use crate::traits::project::Normalized;
use crate::traits::{Obligation, ObligationCause, PredicateObligation, Reveal};
use crate::ty::fold::{TypeFoldable, TypeFolder};
use crate::ty::subst::{Subst, InternalSubsts};
use crate::ty::subst::Subst;
use crate::ty::{self, Ty, TyCtxt};

use super::NoSolution;
Expand Down Expand Up @@ -191,40 +190,7 @@ impl<'cx, 'tcx> TypeFolder<'tcx> for QueryNormalizer<'cx, 'tcx> {
}

fn fold_const(&mut self, constant: &'tcx ty::Const<'tcx>) -> &'tcx ty::Const<'tcx> {
if let ConstValue::Unevaluated(def_id, substs) = constant.val {
let tcx = self.infcx.tcx.global_tcx();
let param_env = self.param_env;
if !param_env.has_local_value() {
if substs.needs_infer() || substs.has_placeholders() {
let identity_substs = InternalSubsts::identity_for_item(tcx, def_id);
let instance = ty::Instance::resolve(tcx, param_env, def_id, identity_substs);
if let Some(instance) = instance {
let cid = GlobalId {
instance,
promoted: None,
};
if let Ok(evaluated) = tcx.const_eval(param_env.and(cid)) {
let evaluated = evaluated.subst(tcx, substs);
return evaluated;
}
}
} else {
if !substs.has_local_value() {
let instance = ty::Instance::resolve(tcx, param_env, def_id, substs);
if let Some(instance) = instance {
let cid = GlobalId {
instance,
promoted: None,
};
if let Ok(evaluated) = tcx.const_eval(param_env.and(cid)) {
return evaluated;
}
}
}
}
}
}
constant
constant.eval(self.infcx.tcx, self.param_env)
}
}

Expand Down
10 changes: 5 additions & 5 deletions src/test/ui/consts/const-size_of-cycle.stderr
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Expand Up @@ -4,18 +4,18 @@ error[E0391]: cycle detected when const-evaluating + checking `Foo::bytes::{{con
LL | bytes: [u8; std::mem::size_of::<Foo>()]
| ^^^^^^^^^^^^^^^^^^^^^^^^^^
|
note: ...which requires const-evaluating + checking `Foo::bytes::{{constant}}#0`...
--> $DIR/const-size_of-cycle.rs:6:17
|
LL | bytes: [u8; std::mem::size_of::<Foo>()]
| ^^^^^^^^^^^^^^^^^^^^^^^^^^
note: ...which requires const-evaluating `Foo::bytes::{{constant}}#0`...
--> $SRC_DIR/libcore/mem/mod.rs:LL:COL
|
LL | intrinsics::size_of::<T>()
| ^^^^^^^^^^^^^^^^^^^^^^^^^^
= note: ...which requires computing layout of `Foo`...
= note: ...which requires normalizing `ParamEnvAnd { param_env: ParamEnv { caller_bounds: [], reveal: All, def_id: None }, value: [u8; _] }`...
note: ...which requires const-evaluating + checking `Foo::bytes::{{constant}}#0`...
--> $DIR/const-size_of-cycle.rs:6:17
|
LL | bytes: [u8; std::mem::size_of::<Foo>()]
| ^^^^^^^^^^^^^^^^^^^^^^^^^^
= note: ...which again requires const-evaluating + checking `Foo::bytes::{{constant}}#0`, completing the cycle
note: cycle used when processing `Foo`
--> $DIR/const-size_of-cycle.rs:5:1
Expand Down
10 changes: 5 additions & 5 deletions src/test/ui/issues/issue-44415.stderr
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Expand Up @@ -4,18 +4,18 @@ error[E0391]: cycle detected when const-evaluating + checking `Foo::bytes::{{con
LL | bytes: [u8; unsafe { intrinsics::size_of::<Foo>() }],
| ^^^^^^
|
note: ...which requires const-evaluating + checking `Foo::bytes::{{constant}}#0`...
--> $DIR/issue-44415.rs:6:17
|
LL | bytes: [u8; unsafe { intrinsics::size_of::<Foo>() }],
| ^^^^^^
note: ...which requires const-evaluating `Foo::bytes::{{constant}}#0`...
--> $DIR/issue-44415.rs:6:26
|
LL | bytes: [u8; unsafe { intrinsics::size_of::<Foo>() }],
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
= note: ...which requires computing layout of `Foo`...
= note: ...which requires normalizing `ParamEnvAnd { param_env: ParamEnv { caller_bounds: [], reveal: All, def_id: None }, value: [u8; _] }`...
note: ...which requires const-evaluating + checking `Foo::bytes::{{constant}}#0`...
--> $DIR/issue-44415.rs:6:17
|
LL | bytes: [u8; unsafe { intrinsics::size_of::<Foo>() }],
| ^^^^^^
= note: ...which again requires const-evaluating + checking `Foo::bytes::{{constant}}#0`, completing the cycle
note: cycle used when processing `Foo`
--> $DIR/issue-44415.rs:5:1
Expand Down