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//! Propagates constants for early reporting of statically known
//! assertion failures
use std::cell::Cell;
use rustc::hir::def::DefKind;
use rustc::mir::{
AggregateKind, Constant, Location, Place, PlaceBase, Body, Operand, Rvalue,
Local, NullOp, UnOp, StatementKind, Statement, LocalKind, Static, StaticKind,
TerminatorKind, Terminator, ClearCrossCrate, SourceInfo, BinOp, ProjectionElem,
SourceScope, SourceScopeLocalData, LocalDecl, Promoted,
};
use rustc::mir::visit::{
Visitor, PlaceContext, MutatingUseContext, MutVisitor, NonMutatingUseContext,
};
use rustc::mir::interpret::{Scalar, GlobalId, InterpResult, PanicInfo};
use rustc::ty::{self, Instance, ParamEnv, Ty, TyCtxt};
use syntax_pos::{Span, DUMMY_SP};
use rustc::ty::subst::InternalSubsts;
use rustc_data_structures::indexed_vec::IndexVec;
use rustc::ty::layout::{
LayoutOf, TyLayout, LayoutError, HasTyCtxt, TargetDataLayout, HasDataLayout,
};
use crate::interpret::{
self, InterpCx, ScalarMaybeUndef, Immediate, OpTy,
ImmTy, MemoryKind, StackPopCleanup, LocalValue, LocalState,
};
use crate::const_eval::{
CompileTimeInterpreter, error_to_const_error, eval_promoted, mk_eval_cx,
};
use crate::transform::{MirPass, MirSource};
pub struct ConstProp;
impl MirPass for ConstProp {
fn run_pass<'tcx>(&self, tcx: TyCtxt<'tcx>, source: MirSource<'tcx>, body: &mut Body<'tcx>) {
// will be evaluated by miri and produce its errors there
if source.promoted.is_some() {
return;
}
use rustc::hir::map::blocks::FnLikeNode;
let hir_id = tcx.hir().as_local_hir_id(source.def_id())
.expect("Non-local call to local provider is_const_fn");
let is_fn_like = FnLikeNode::from_node(tcx.hir().get(hir_id)).is_some();
let is_assoc_const = match tcx.def_kind(source.def_id()) {
Some(DefKind::AssocConst) => true,
_ => false,
};
// Only run const prop on functions, methods, closures and associated constants
if !is_fn_like && !is_assoc_const {
// skip anon_const/statics/consts because they'll be evaluated by miri anyway
trace!("ConstProp skipped for {:?}", source.def_id());
return
}
trace!("ConstProp starting for {:?}", source.def_id());
// Steal some data we need from `body`.
let source_scope_local_data = std::mem::replace(
&mut body.source_scope_local_data,
ClearCrossCrate::Clear
);
let promoted = std::mem::replace(
&mut body.promoted,
IndexVec::new()
);
let dummy_body =
&Body::new(
body.basic_blocks().clone(),
Default::default(),
ClearCrossCrate::Clear,
Default::default(),
None,
body.local_decls.clone(),
Default::default(),
body.arg_count,
Default::default(),
tcx.def_span(source.def_id()),
Default::default(),
);
// FIXME(oli-obk, eddyb) Optimize locals (or even local paths) to hold
// constants, instead of just checking for const-folding succeeding.
// That would require an uniform one-def no-mutation analysis
// and RPO (or recursing when needing the value of a local).
let mut optimization_finder = ConstPropagator::new(
body,
dummy_body,
source_scope_local_data,
promoted,
tcx,
source
);
optimization_finder.visit_body(body);
// put back the data we stole from `mir`
let (source_scope_local_data, promoted) = optimization_finder.release_stolen_data();
std::mem::replace(
&mut body.source_scope_local_data,
source_scope_local_data
);
std::mem::replace(
&mut body.promoted,
promoted
);
trace!("ConstProp done for {:?}", source.def_id());
}
}
type Const<'tcx> = OpTy<'tcx>;
/// Finds optimization opportunities on the MIR.
struct ConstPropagator<'mir, 'tcx> {
ecx: InterpCx<'mir, 'tcx, CompileTimeInterpreter<'mir, 'tcx>>,
tcx: TyCtxt<'tcx>,
source: MirSource<'tcx>,
can_const_prop: IndexVec<Local, bool>,
param_env: ParamEnv<'tcx>,
source_scope_local_data: ClearCrossCrate<IndexVec<SourceScope, SourceScopeLocalData>>,
local_decls: IndexVec<Local, LocalDecl<'tcx>>,
promoted: IndexVec<Promoted, Body<'tcx>>,
}
impl<'mir, 'tcx> LayoutOf for ConstPropagator<'mir, 'tcx> {
type Ty = Ty<'tcx>;
type TyLayout = Result<TyLayout<'tcx>, LayoutError<'tcx>>;
fn layout_of(&self, ty: Ty<'tcx>) -> Self::TyLayout {
self.tcx.layout_of(self.param_env.and(ty))
}
}
impl<'mir, 'tcx> HasDataLayout for ConstPropagator<'mir, 'tcx> {
#[inline]
fn data_layout(&self) -> &TargetDataLayout {
&self.tcx.data_layout
}
}
impl<'mir, 'tcx> HasTyCtxt<'tcx> for ConstPropagator<'mir, 'tcx> {
#[inline]
fn tcx(&self) -> TyCtxt<'tcx> {
self.tcx
}
}
impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
fn new(
body: &Body<'tcx>,
dummy_body: &'mir Body<'tcx>,
source_scope_local_data: ClearCrossCrate<IndexVec<SourceScope, SourceScopeLocalData>>,
promoted: IndexVec<Promoted, Body<'tcx>>,
tcx: TyCtxt<'tcx>,
source: MirSource<'tcx>,
) -> ConstPropagator<'mir, 'tcx> {
let def_id = source.def_id();
let param_env = tcx.param_env(def_id);
let span = tcx.def_span(def_id);
let mut ecx = mk_eval_cx(tcx, span, param_env);
let can_const_prop = CanConstProp::check(body);
ecx.push_stack_frame(
Instance::new(def_id, &InternalSubsts::identity_for_item(tcx, def_id)),
span,
dummy_body,
None,
StackPopCleanup::None {
cleanup: false,
},
).expect("failed to push initial stack frame");
ConstPropagator {
ecx,
tcx,
source,
param_env,
can_const_prop,
source_scope_local_data,
//FIXME(wesleywiser) we can't steal this because `Visitor::super_visit_body()` needs it
local_decls: body.local_decls.clone(),
promoted,
}
}
fn release_stolen_data(
self,
) -> (
ClearCrossCrate<IndexVec<SourceScope, SourceScopeLocalData>>,
IndexVec<Promoted, Body<'tcx>>,
) {
(self.source_scope_local_data, self.promoted)
}
fn get_const(&self, local: Local) -> Option<Const<'tcx>> {
let l = &self.ecx.frame().locals[local];
// If the local is `Unitialized` or `Dead` then we haven't propagated a value into it.
//
// `InterpCx::access_local()` mostly takes care of this for us however, for ZSTs,
// it will synthesize a value for us. In doing so, that will cause the
// `get_const(l).is_empty()` assert right before we call `set_const()` in `visit_statement`
// to fail.
if let LocalValue::Uninitialized | LocalValue::Dead = l.value {
return None;
}
self.ecx.access_local(self.ecx.frame(), local, None).ok()
}
fn set_const(&mut self, local: Local, c: Const<'tcx>) {
let frame = self.ecx.frame_mut();
if let Some(layout) = frame.locals[local].layout.get() {
debug_assert_eq!(c.layout, layout);
}
frame.locals[local] = LocalState {
value: LocalValue::Live(*c),
layout: Cell::new(Some(c.layout)),
};
}
fn remove_const(&mut self, local: Local) {
self.ecx.frame_mut().locals[local] = LocalState {
value: LocalValue::Uninitialized,
layout: Cell::new(None),
};
}
fn use_ecx<F, T>(
&mut self,
source_info: SourceInfo,
f: F
) -> Option<T>
where
F: FnOnce(&mut Self) -> InterpResult<'tcx, T>,
{
self.ecx.tcx.span = source_info.span;
let lint_root = match self.source_scope_local_data {
ClearCrossCrate::Set(ref ivs) => {
//FIXME(#51314): remove this check
if source_info.scope.index() >= ivs.len() {
return None;
}
ivs[source_info.scope].lint_root
},
ClearCrossCrate::Clear => return None,
};
let r = match f(self) {
Ok(val) => Some(val),
Err(error) => {
let diagnostic = error_to_const_error(&self.ecx, error);
use rustc::mir::interpret::InterpError::*;
match diagnostic.error {
Exit(_) => bug!("the CTFE program cannot exit"),
Unsupported(_)
| UndefinedBehavior(_)
| InvalidProgram(_)
| ResourceExhaustion(_) => {
// Ignore these errors.
}
Panic(_) => {
diagnostic.report_as_lint(
self.ecx.tcx,
"this expression will panic at runtime",
lint_root,
None,
);
}
}
None
},
};
self.ecx.tcx.span = DUMMY_SP;
r
}
fn eval_constant(
&mut self,
c: &Constant<'tcx>,
) -> Option<Const<'tcx>> {
self.ecx.tcx.span = c.span;
match self.ecx.eval_const_to_op(c.literal, None) {
Ok(op) => {
Some(op)
},
Err(error) => {
let err = error_to_const_error(&self.ecx, error);
err.report_as_error(self.ecx.tcx, "erroneous constant used");
None
},
}
}
fn eval_place(&mut self, place: &Place<'tcx>, source_info: SourceInfo) -> Option<Const<'tcx>> {
trace!("eval_place(place={:?})", place);
place.iterate(|place_base, place_projection| {
let mut eval = match place_base {
PlaceBase::Local(loc) => self.get_const(*loc).clone()?,
PlaceBase::Static(box Static {kind: StaticKind::Promoted(promoted), ..}) => {
let generics = self.tcx.generics_of(self.source.def_id());
if generics.requires_monomorphization(self.tcx) {
// FIXME: can't handle code with generics
return None;
}
let substs = InternalSubsts::identity_for_item(self.tcx, self.source.def_id());
let instance = Instance::new(self.source.def_id(), substs);
let cid = GlobalId {
instance,
promoted: Some(*promoted),
};
// cannot use `const_eval` here, because that would require having the MIR
// for the current function available, but we're producing said MIR right now
let res = self.use_ecx(source_info, |this| {
let body = &this.promoted[*promoted];
eval_promoted(this.tcx, cid, body, this.param_env)
})?;
trace!("evaluated promoted {:?} to {:?}", promoted, res);
res.into()
}
_ => return None,
};
for proj in place_projection {
match proj.elem {
ProjectionElem::Field(field, _) => {
trace!("field proj on {:?}", proj.base);
eval = self.use_ecx(source_info, |this| {
this.ecx.operand_field(eval, field.index() as u64)
})?;
},
ProjectionElem::Deref => {
trace!("processing deref");
eval = self.use_ecx(source_info, |this| {
this.ecx.deref_operand(eval)
})?.into();
}
// We could get more projections by using e.g., `operand_projection`,
// but we do not even have the stack frame set up properly so
// an `Index` projection would throw us off-track.
_ => return None,
}
}
Some(eval)
})
}
fn eval_operand(&mut self, op: &Operand<'tcx>, source_info: SourceInfo) -> Option<Const<'tcx>> {
match *op {
Operand::Constant(ref c) => self.eval_constant(c),
| Operand::Move(ref place)
| Operand::Copy(ref place) => self.eval_place(place, source_info),
}
}
fn const_prop(
&mut self,
rvalue: &Rvalue<'tcx>,
place_layout: TyLayout<'tcx>,
source_info: SourceInfo,
) -> Option<Const<'tcx>> {
let span = source_info.span;
match *rvalue {
Rvalue::Use(ref op) => {
self.eval_operand(op, source_info)
},
Rvalue::Ref(_, _, ref place) => {
let src = self.eval_place(place, source_info)?;
let mplace = src.try_as_mplace().ok()?;
Some(ImmTy::from_scalar(mplace.ptr.into(), place_layout).into())
},
Rvalue::Repeat(..) |
Rvalue::Aggregate(..) |
Rvalue::NullaryOp(NullOp::Box, _) |
Rvalue::Discriminant(..) => None,
Rvalue::Cast(kind, ref operand, _) => {
let op = self.eval_operand(operand, source_info)?;
self.use_ecx(source_info, |this| {
let dest = this.ecx.allocate(place_layout, MemoryKind::Stack);
this.ecx.cast(op, kind, dest.into())?;
Ok(dest.into())
})
},
Rvalue::Len(ref place) => {
let place = self.eval_place(&place, source_info)?;
let mplace = place.try_as_mplace().ok()?;
if let ty::Slice(_) = mplace.layout.ty.sty {
let len = mplace.meta.unwrap().to_usize(&self.ecx).unwrap();
Some(ImmTy::from_uint(
len,
self.tcx.layout_of(self.param_env.and(self.tcx.types.usize)).ok()?,
).into())
} else {
trace!("not slice: {:?}", mplace.layout.ty.sty);
None
}
},
Rvalue::NullaryOp(NullOp::SizeOf, ty) => {
type_size_of(self.tcx, self.param_env, ty).and_then(|n| Some(
ImmTy::from_uint(
n,
self.tcx.layout_of(self.param_env.and(self.tcx.types.usize)).ok()?,
).into()
))
}
Rvalue::UnaryOp(op, ref arg) => {
let def_id = if self.tcx.is_closure(self.source.def_id()) {
self.tcx.closure_base_def_id(self.source.def_id())
} else {
self.source.def_id()
};
let generics = self.tcx.generics_of(def_id);
if generics.requires_monomorphization(self.tcx) {
// FIXME: can't handle code with generics
return None;
}
let arg = self.eval_operand(arg, source_info)?;
let val = self.use_ecx(source_info, |this| {
let prim = this.ecx.read_immediate(arg)?;
match op {
UnOp::Neg => {
// Need to do overflow check here: For actual CTFE, MIR
// generation emits code that does this before calling the op.
if prim.to_bits()? == (1 << (prim.layout.size.bits() - 1)) {
throw_panic!(OverflowNeg)
}
}
UnOp::Not => {
// Cannot overflow
}
}
// Now run the actual operation.
this.ecx.unary_op(op, prim)
})?;
Some(val.into())
}
Rvalue::CheckedBinaryOp(op, ref left, ref right) |
Rvalue::BinaryOp(op, ref left, ref right) => {
trace!("rvalue binop {:?} for {:?} and {:?}", op, left, right);
let right = self.eval_operand(right, source_info)?;
let def_id = if self.tcx.is_closure(self.source.def_id()) {
self.tcx.closure_base_def_id(self.source.def_id())
} else {
self.source.def_id()
};
let generics = self.tcx.generics_of(def_id);
if generics.requires_monomorphization(self.tcx) {
// FIXME: can't handle code with generics
return None;
}
let r = self.use_ecx(source_info, |this| {
this.ecx.read_immediate(right)
})?;
if op == BinOp::Shr || op == BinOp::Shl {
let left_ty = left.ty(&self.local_decls, self.tcx);
let left_bits = self
.tcx
.layout_of(self.param_env.and(left_ty))
.unwrap()
.size
.bits();
let right_size = right.layout.size;
let r_bits = r.to_scalar().and_then(|r| r.to_bits(right_size));
if r_bits.ok().map_or(false, |b| b >= left_bits as u128) {
let source_scope_local_data = match self.source_scope_local_data {
ClearCrossCrate::Set(ref data) => data,
ClearCrossCrate::Clear => return None,
};
let dir = if op == BinOp::Shr {
"right"
} else {
"left"
};
let hir_id = source_scope_local_data[source_info.scope].lint_root;
self.tcx.lint_hir(
::rustc::lint::builtin::EXCEEDING_BITSHIFTS,
hir_id,
span,
&format!("attempt to shift {} with overflow", dir));
return None;
}
}
let left = self.eval_operand(left, source_info)?;
let l = self.use_ecx(source_info, |this| {
this.ecx.read_immediate(left)
})?;
trace!("const evaluating {:?} for {:?} and {:?}", op, left, right);
let (val, overflow, _ty) = self.use_ecx(source_info, |this| {
this.ecx.overflowing_binary_op(op, l, r)
})?;
let val = if let Rvalue::CheckedBinaryOp(..) = *rvalue {
Immediate::ScalarPair(
val.into(),
Scalar::from_bool(overflow).into(),
)
} else {
if overflow {
let err = err_panic!(Overflow(op)).into();
let _: Option<()> = self.use_ecx(source_info, |_| Err(err));
return None;
}
Immediate::Scalar(val.into())
};
let res = ImmTy {
imm: val,
layout: place_layout,
};
Some(res.into())
},
}
}
fn operand_from_scalar(&self, scalar: Scalar, ty: Ty<'tcx>, span: Span) -> Operand<'tcx> {
Operand::Constant(Box::new(
Constant {
span,
user_ty: None,
literal: self.tcx.mk_const(*ty::Const::from_scalar(
self.tcx,
scalar,
ty,
))
}
))
}
fn replace_with_const(
&mut self,
rval: &mut Rvalue<'tcx>,
value: Const<'tcx>,
source_info: SourceInfo,
) {
trace!("attepting to replace {:?} with {:?}", rval, value);
if let Err(e) = self.ecx.validate_operand(
value,
vec![],
// FIXME: is ref tracking too expensive?
Some(&mut interpret::RefTracking::empty()),
) {
trace!("validation error, attempt failed: {:?}", e);
return;
}
// FIXME> figure out what tho do when try_read_immediate fails
let imm = self.use_ecx(source_info, |this| {
this.ecx.try_read_immediate(value)
});
if let Some(Ok(imm)) = imm {
match *imm {
interpret::Immediate::Scalar(ScalarMaybeUndef::Scalar(scalar)) => {
*rval = Rvalue::Use(
self.operand_from_scalar(scalar, value.layout.ty, source_info.span));
},
Immediate::ScalarPair(
ScalarMaybeUndef::Scalar(one),
ScalarMaybeUndef::Scalar(two)
) => {
let ty = &value.layout.ty.sty;
if let ty::Tuple(substs) = ty {
*rval = Rvalue::Aggregate(
Box::new(AggregateKind::Tuple),
vec![
self.operand_from_scalar(
one, substs[0].expect_ty(), source_info.span
),
self.operand_from_scalar(
two, substs[1].expect_ty(), source_info.span
),
],
);
}
},
_ => { }
}
}
}
fn should_const_prop(&self) -> bool {
self.tcx.sess.opts.debugging_opts.mir_opt_level >= 2
}
}
fn type_size_of<'tcx>(
tcx: TyCtxt<'tcx>,
param_env: ty::ParamEnv<'tcx>,
ty: Ty<'tcx>,
) -> Option<u64> {
tcx.layout_of(param_env.and(ty)).ok().map(|layout| layout.size.bytes())
}
struct CanConstProp {
can_const_prop: IndexVec<Local, bool>,
// false at the beginning, once set, there are not allowed to be any more assignments
found_assignment: IndexVec<Local, bool>,
}
impl CanConstProp {
/// returns true if `local` can be propagated
fn check(body: &Body<'_>) -> IndexVec<Local, bool> {
let mut cpv = CanConstProp {
can_const_prop: IndexVec::from_elem(true, &body.local_decls),
found_assignment: IndexVec::from_elem(false, &body.local_decls),
};
for (local, val) in cpv.can_const_prop.iter_enumerated_mut() {
// cannot use args at all
// cannot use locals because if x < y { y - x } else { x - y } would
// lint for x != y
// FIXME(oli-obk): lint variables until they are used in a condition
// FIXME(oli-obk): lint if return value is constant
*val = body.local_kind(local) == LocalKind::Temp;
if !*val {
trace!("local {:?} can't be propagated because it's not a temporary", local);
}
}
cpv.visit_body(body);
cpv.can_const_prop
}
}
impl<'tcx> Visitor<'tcx> for CanConstProp {
fn visit_local(
&mut self,
&local: &Local,
context: PlaceContext,
_: Location,
) {
use rustc::mir::visit::PlaceContext::*;
match context {
// Constants must have at most one write
// FIXME(oli-obk): we could be more powerful here, if the multiple writes
// only occur in independent execution paths
MutatingUse(MutatingUseContext::Store) => if self.found_assignment[local] {
trace!("local {:?} can't be propagated because of multiple assignments", local);
self.can_const_prop[local] = false;
} else {
self.found_assignment[local] = true
},
// Reading constants is allowed an arbitrary number of times
NonMutatingUse(NonMutatingUseContext::Copy) |
NonMutatingUse(NonMutatingUseContext::Move) |
NonMutatingUse(NonMutatingUseContext::Inspect) |
NonMutatingUse(NonMutatingUseContext::Projection) |
MutatingUse(MutatingUseContext::Projection) |
NonUse(_) => {},
_ => {
trace!("local {:?} can't be propagaged because it's used: {:?}", local, context);
self.can_const_prop[local] = false;
},
}
}
}
impl<'mir, 'tcx> MutVisitor<'tcx> for ConstPropagator<'mir, 'tcx> {
fn visit_constant(
&mut self,
constant: &mut Constant<'tcx>,
location: Location,
) {
trace!("visit_constant: {:?}", constant);
self.super_constant(constant, location);
self.eval_constant(constant);
}
fn visit_statement(
&mut self,
statement: &mut Statement<'tcx>,
location: Location,
) {
trace!("visit_statement: {:?}", statement);
if let StatementKind::Assign(ref place, ref mut rval) = statement.kind {
let place_ty: Ty<'tcx> = place
.ty(&self.local_decls, self.tcx)
.ty;
if let Ok(place_layout) = self.tcx.layout_of(self.param_env.and(place_ty)) {
if let Some(value) = self.const_prop(rval, place_layout, statement.source_info) {
if let Place {
base: PlaceBase::Local(local),
projection: None,
} = *place {
trace!("checking whether {:?} can be stored to {:?}", value, local);
if self.can_const_prop[local] {
trace!("storing {:?} to {:?}", value, local);
assert!(self.get_const(local).is_none());
self.set_const(local, value);
if self.should_const_prop() {
self.replace_with_const(
rval,
value,
statement.source_info,
);
}
}
}
}
}
}
self.super_statement(statement, location);
}
fn visit_terminator(
&mut self,
terminator: &mut Terminator<'tcx>,
location: Location,
) {
self.super_terminator(terminator, location);
let source_info = terminator.source_info;
match &mut terminator.kind {
TerminatorKind::Assert { expected, ref msg, ref mut cond, .. } => {
if let Some(value) = self.eval_operand(&cond, source_info) {
trace!("assertion on {:?} should be {:?}", value, expected);
let expected = ScalarMaybeUndef::from(Scalar::from_bool(*expected));
let value_const = self.ecx.read_scalar(value).unwrap();
if expected != value_const {
// poison all places this operand references so that further code
// doesn't use the invalid value
match cond {
Operand::Move(ref place) | Operand::Copy(ref place) => {
if let PlaceBase::Local(local) = place.base {
self.remove_const(local);
}
},
Operand::Constant(_) => {}
}
let span = terminator.source_info.span;
let hir_id = self
.tcx
.hir()
.as_local_hir_id(self.source.def_id())
.expect("some part of a failing const eval must be local");
let msg = match msg {
PanicInfo::Overflow(_) |
PanicInfo::OverflowNeg |
PanicInfo::DivisionByZero |
PanicInfo::RemainderByZero =>
msg.description().to_owned(),
PanicInfo::BoundsCheck { ref len, ref index } => {
let len = self
.eval_operand(len, source_info)
.expect("len must be const");
let len = match self.ecx.read_scalar(len) {
Ok(ScalarMaybeUndef::Scalar(Scalar::Raw {
data, ..
})) => data,
other => bug!("const len not primitive: {:?}", other),
};
let index = self
.eval_operand(index, source_info)
.expect("index must be const");
let index = match self.ecx.read_scalar(index) {
Ok(ScalarMaybeUndef::Scalar(Scalar::Raw {
data, ..
})) => data,
other => bug!("const index not primitive: {:?}", other),
};
format!(
"index out of bounds: \
the len is {} but the index is {}",
len,
index,
)
},
// Need proper const propagator for these
_ => return,
};
self.tcx.lint_hir(
::rustc::lint::builtin::CONST_ERR,
hir_id,
span,
&msg,
);
} else {
if self.should_const_prop() {
if let ScalarMaybeUndef::Scalar(scalar) = value_const {
*cond = self.operand_from_scalar(
scalar,
self.tcx.types.bool,
source_info.span,
);
}
}
}
}
},
TerminatorKind::SwitchInt { ref mut discr, switch_ty, .. } => {
if self.should_const_prop() {
if let Some(value) = self.eval_operand(&discr, source_info) {
if let ScalarMaybeUndef::Scalar(scalar) =
self.ecx.read_scalar(value).unwrap() {
*discr = self.operand_from_scalar(scalar, switch_ty, source_info.span);
}
}
}
},
//none of these have Operands to const-propagate
TerminatorKind::Goto { .. } |
TerminatorKind::Resume |
TerminatorKind::Abort |
TerminatorKind::Return |
TerminatorKind::Unreachable |
TerminatorKind::Drop { .. } |
TerminatorKind::DropAndReplace { .. } |
TerminatorKind::Yield { .. } |
TerminatorKind::GeneratorDrop |
TerminatorKind::FalseEdges { .. } |
TerminatorKind::FalseUnwind { .. } => { }
//FIXME(wesleywiser) Call does have Operands that could be const-propagated
TerminatorKind::Call { .. } => { }
}
}
}
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