use rustc::middle::const_val::ConstVal::*;
use rustc::middle::const_val::ConstVal;
use self::ErrKind::*;
-use self::EvalHint::*;
use rustc::hir::map as hir_map;
use rustc::hir::map::blocks::FnLikeNode;
use rustc::hir::def_id::DefId;
use rustc::ty::{self, Ty, TyCtxt};
use rustc::ty::util::IntTypeExt;
-use rustc::ty::subst::Substs;
+use rustc::ty::subst::{Substs, Subst};
use rustc::traits::Reveal;
use rustc::util::common::ErrorReported;
use rustc::util::nodemap::DefIdMap;
use graphviz::IntoCow;
use syntax::ast;
use rustc::hir::{self, Expr};
-use syntax::attr::IntType;
-use syntax_pos::Span;
+use syntax_pos::{Span, DUMMY_SP};
use std::borrow::Cow;
use std::cmp::Ordering;
use rustc_const_math::*;
use rustc_errors::DiagnosticBuilder;
+macro_rules! signal {
+ ($e:expr, $exn:expr) => {
+ return Err(ConstEvalErr { span: $e.span, kind: $exn })
+ }
+}
+
macro_rules! math {
($e:expr, $op:expr) => {
match $op {
Ok(val) => val,
- Err(e) => signal!($e, Math(e)),
+ Err(e) => signal!($e, ErrKind::from(e)),
}
}
}
fn lookup_variant_by_id<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
variant_def: DefId)
- -> Option<(&'tcx Expr, Option<&'a ty::TypeckTables<'tcx>>)> {
+ -> Option<(&'tcx Expr, &'a ty::TypeckTables<'tcx>)> {
if let Some(variant_node_id) = tcx.hir.as_local_node_id(variant_def) {
let enum_node_id = tcx.hir.get_parent(variant_node_id);
if let Some(hir_map::NodeItem(it)) = tcx.hir.find(enum_node_id) {
return variant.node.disr_expr.map(|e| {
let def_id = tcx.hir.body_owner_def_id(e);
(&tcx.hir.body(e).value,
- tcx.tables.borrow().get(&def_id).cloned())
+ tcx.item_tables(def_id))
});
}
}
/// This generally happens in late/trans const evaluation.
pub fn lookup_const_by_id<'a, 'tcx: 'a>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
def_id: DefId,
- substs: Option<&'tcx Substs<'tcx>>)
+ substs: &'tcx Substs<'tcx>)
-> Option<(&'tcx Expr,
- Option<&'a ty::TypeckTables<'tcx>>,
- Option<ty::Ty<'tcx>>)> {
+ &'a ty::TypeckTables<'tcx>)> {
if let Some(node_id) = tcx.hir.as_local_node_id(def_id) {
match tcx.hir.find(node_id) {
None => None,
Some(hir_map::NodeItem(&hir::Item {
- node: hir::ItemConst(ref ty, body), ..
+ node: hir::ItemConst(_, body), ..
})) |
Some(hir_map::NodeImplItem(&hir::ImplItem {
- node: hir::ImplItemKind::Const(ref ty, body), ..
+ node: hir::ImplItemKind::Const(_, body), ..
})) => {
Some((&tcx.hir.body(body).value,
- tcx.tables.borrow().get(&def_id).cloned(),
- tcx.ast_ty_to_prim_ty(ty)))
+ tcx.item_tables(def_id)))
}
Some(hir_map::NodeTraitItem(ti)) => match ti.node {
- hir::TraitItemKind::Const(ref ty, default) => {
- if let Some(substs) = substs {
- // If we have a trait item and the substitutions for it,
- // `resolve_trait_associated_const` will select an impl
- // or the default.
- let trait_id = tcx.hir.get_parent(node_id);
- let trait_id = tcx.hir.local_def_id(trait_id);
- let default_value = default.map(|body| {
- (&tcx.hir.body(body).value,
- tcx.tables.borrow().get(&def_id).cloned(),
- tcx.ast_ty_to_prim_ty(ty))
- });
- resolve_trait_associated_const(tcx, def_id, default_value, trait_id, substs)
- } else {
- // Technically, without knowing anything about the
- // expression that generates the obligation, we could
- // still return the default if there is one. However,
- // it's safer to return `None` than to return some value
- // that may differ from what you would get from
- // correctly selecting an impl.
- None
- }
+ hir::TraitItemKind::Const(_, default) => {
+ // If we have a trait item and the substitutions for it,
+ // `resolve_trait_associated_const` will select an impl
+ // or the default.
+ let trait_id = tcx.hir.get_parent(node_id);
+ let trait_id = tcx.hir.local_def_id(trait_id);
+ let default_value = default.map(|body| {
+ (&tcx.hir.body(body).value,
+ tcx.item_tables(def_id))
+ });
+ resolve_trait_associated_const(tcx, def_id, default_value, trait_id, substs)
}
_ => None
},
Some(_) => None
}
} else {
- let expr_tables_ty = tcx.sess.cstore.maybe_get_item_body(tcx, def_id).map(|body| {
- (&body.value, Some(tcx.item_tables(def_id)),
- Some(tcx.sess.cstore.item_type(tcx, def_id)))
+ let expr_and_tables = tcx.sess.cstore.maybe_get_item_body(tcx, def_id).map(|body| {
+ (&body.value, tcx.item_tables(def_id))
});
match tcx.sess.cstore.describe_def(def_id) {
Some(Def::AssociatedConst(_)) => {
// trait-associated const if the caller gives us the
// substitutions for the reference to it.
if let Some(trait_id) = trait_id {
- if let Some(substs) = substs {
- resolve_trait_associated_const(tcx, def_id, expr_tables_ty,
- trait_id, substs)
- } else {
- None
- }
+ resolve_trait_associated_const(tcx, def_id, expr_and_tables,
+ trait_id, substs)
} else {
- expr_tables_ty
+ expr_and_tables
}
},
- Some(Def::Const(..)) => expr_tables_ty,
+ Some(Def::Const(..)) => expr_and_tables,
_ => None
}
}
}
fn lookup_const_fn_by_id<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId)
- -> Option<(&'tcx hir::Body, Option<&'a ty::TypeckTables<'tcx>>)>
+ -> Option<(&'tcx hir::Body, &'a ty::TypeckTables<'tcx>)>
{
if let Some(node_id) = tcx.hir.as_local_node_id(def_id) {
FnLikeNode::from_node(tcx.hir.get(node_id)).and_then(|fn_like| {
if fn_like.constness() == hir::Constness::Const {
Some((tcx.hir.body(fn_like.body()),
- tcx.tables.borrow().get(&def_id).cloned()))
+ tcx.item_tables(def_id)))
} else {
None
}
} else {
if tcx.sess.cstore.is_const_fn(def_id) {
tcx.sess.cstore.maybe_get_item_body(tcx, def_id).map(|body| {
- (body, Some(tcx.item_tables(def_id)))
+ (body, tcx.item_tables(def_id))
})
} else {
None
}
}
-pub fn report_const_eval_err<'a, 'tcx>(
+fn build_const_eval_err<'a, 'tcx>(
tcx: TyCtxt<'a, 'tcx, 'tcx>,
err: &ConstEvalErr,
primary_span: Span,
diag
}
+pub fn report_const_eval_err<'a, 'tcx>(
+ tcx: TyCtxt<'a, 'tcx, 'tcx>,
+ err: &ConstEvalErr,
+ primary_span: Span,
+ primary_kind: &str)
+{
+ if let TypeckError = err.kind {
+ return;
+ }
+ build_const_eval_err(tcx, err, primary_span, primary_kind).emit();
+}
+
pub fn fatal_const_eval_err<'a, 'tcx>(
tcx: TyCtxt<'a, 'tcx, 'tcx>,
err: &ConstEvalErr,
primary_kind: &str)
-> !
{
- report_const_eval_err(tcx, err, primary_span, primary_kind).emit();
+ report_const_eval_err(tcx, err, primary_span, primary_kind);
tcx.sess.abort_if_errors();
unreachable!()
}
pub struct ConstContext<'a, 'tcx: 'a> {
tcx: TyCtxt<'a, 'tcx, 'tcx>,
- tables: Option<&'a ty::TypeckTables<'tcx>>,
- fn_args: Option<DefIdMap<ConstVal>>
+ tables: &'a ty::TypeckTables<'tcx>,
+ substs: &'tcx Substs<'tcx>,
+ fn_args: Option<DefIdMap<ConstVal<'tcx>>>
}
impl<'a, 'tcx> ConstContext<'a, 'tcx> {
pub fn new(tcx: TyCtxt<'a, 'tcx, 'tcx>, body: hir::BodyId) -> Self {
let def_id = tcx.hir.body_owner_def_id(body);
- ConstContext {
- tcx: tcx,
- tables: tcx.tables.borrow().get(&def_id).cloned(),
- fn_args: None
- }
+ ty::queries::mir_const_qualif::get(tcx, DUMMY_SP, def_id);
+ ConstContext::with_tables(tcx, tcx.item_tables(def_id))
}
pub fn with_tables(tcx: TyCtxt<'a, 'tcx, 'tcx>, tables: &'a ty::TypeckTables<'tcx>) -> Self {
ConstContext {
tcx: tcx,
- tables: Some(tables),
+ tables: tables,
+ substs: tcx.intern_substs(&[]),
fn_args: None
}
}
/// Evaluate a constant expression in a context where the expression isn't
- /// guaranteed to be evaluatable. `ty_hint` is usually ExprTypeChecked,
- /// but a few places need to evaluate constants during type-checking, like
- /// computing the length of an array. (See also the FIXME above EvalHint.)
- pub fn eval(&self, e: &Expr, ty_hint: EvalHint<'tcx>) -> EvalResult {
- eval_const_expr_partial(self, e, ty_hint)
+ /// guaranteed to be evaluatable.
+ pub fn eval(&self, e: &Expr) -> EvalResult<'tcx> {
+ if self.tables.tainted_by_errors {
+ signal!(e, TypeckError);
+ }
+ eval_const_expr_partial(self, e)
}
}
#[derive(Clone, Debug)]
-pub struct ConstEvalErr {
+pub struct ConstEvalErr<'tcx> {
pub span: Span,
- pub kind: ErrKind,
+ pub kind: ErrKind<'tcx>,
}
#[derive(Clone, Debug)]
-pub enum ErrKind {
+pub enum ErrKind<'tcx> {
CannotCast,
- CannotCastTo(&'static str),
- InvalidOpForInts(hir::BinOp_),
- InvalidOpForBools(hir::BinOp_),
- InvalidOpForFloats(hir::BinOp_),
- InvalidOpForIntUint(hir::BinOp_),
- InvalidOpForUintInt(hir::BinOp_),
- NegateOn(ConstVal),
- NotOn(ConstVal),
- CallOn(ConstVal),
-
MissingStructField,
+ NegateOn(ConstVal<'tcx>),
+ NotOn(ConstVal<'tcx>),
+ CallOn(ConstVal<'tcx>),
+
NonConstPath,
UnimplementedConstVal(&'static str),
- UnresolvedPath,
ExpectedConstTuple,
ExpectedConstStruct,
- TupleIndexOutOfBounds,
IndexedNonVec,
- IndexNegative,
- IndexNotInt,
+ IndexNotUsize,
IndexOutOfBounds { len: u64, index: u64 },
- RepeatCountNotNatural,
- RepeatCountNotInt,
MiscBinaryOp,
MiscCatchAll,
IndexOpFeatureGated,
Math(ConstMathErr),
- IntermediateUnsignedNegative,
- /// Expected, Got
- TypeMismatch(String, ConstInt),
+ ErroneousReferencedConstant(Box<ConstEvalErr<'tcx>>),
- BadType(ConstVal),
- ErroneousReferencedConstant(Box<ConstEvalErr>),
- CharCast(ConstInt),
+ TypeckError
}
-impl From<ConstMathErr> for ErrKind {
- fn from(err: ConstMathErr) -> ErrKind {
- Math(err)
+impl<'tcx> From<ConstMathErr> for ErrKind<'tcx> {
+ fn from(err: ConstMathErr) -> ErrKind<'tcx> {
+ match err {
+ ConstMathErr::UnsignedNegation => TypeckError,
+ _ => Math(err)
+ }
}
}
}
}
-impl ConstEvalErr {
+impl<'tcx> ConstEvalErr<'tcx> {
pub fn description(&self) -> ConstEvalErrDescription {
use self::ErrKind::*;
use self::ConstEvalErrDescription::*;
match self.kind {
CannotCast => simple!("can't cast this type"),
- CannotCastTo(s) => simple!("can't cast this type to {}", s),
- InvalidOpForInts(_) => simple!("can't do this op on integrals"),
- InvalidOpForBools(_) => simple!("can't do this op on bools"),
- InvalidOpForFloats(_) => simple!("can't do this op on floats"),
- InvalidOpForIntUint(..) => simple!("can't do this op on an isize and usize"),
- InvalidOpForUintInt(..) => simple!("can't do this op on a usize and isize"),
NegateOn(ref const_val) => simple!("negate on {}", const_val.description()),
NotOn(ref const_val) => simple!("not on {}", const_val.description()),
CallOn(ref const_val) => simple!("call on {}", const_val.description()),
NonConstPath => simple!("non-constant path in constant expression"),
UnimplementedConstVal(what) =>
simple!("unimplemented constant expression: {}", what),
- UnresolvedPath => simple!("unresolved path in constant expression"),
ExpectedConstTuple => simple!("expected constant tuple"),
ExpectedConstStruct => simple!("expected constant struct"),
- TupleIndexOutOfBounds => simple!("tuple index out of bounds"),
IndexedNonVec => simple!("indexing is only supported for arrays"),
- IndexNegative => simple!("indices must be non-negative integers"),
- IndexNotInt => simple!("indices must be integers"),
+ IndexNotUsize => simple!("indices must be of type `usize`"),
IndexOutOfBounds { len, index } => {
simple!("index out of bounds: the len is {} but the index is {}",
len, index)
}
- RepeatCountNotNatural => simple!("repeat count must be a natural number"),
- RepeatCountNotInt => simple!("repeat count must be integers"),
MiscBinaryOp => simple!("bad operands for binary"),
MiscCatchAll => simple!("unsupported constant expr"),
IndexOpFeatureGated => simple!("the index operation on const values is unstable"),
Math(ref err) => Simple(err.description().into_cow()),
- IntermediateUnsignedNegative => simple!(
- "during the computation of an unsigned a negative \
- number was encountered. This is most likely a bug in\
- the constant evaluator"),
-
- TypeMismatch(ref expected, ref got) => {
- simple!("expected {}, found {}", expected, got.description())
- },
- BadType(ref i) => simple!("value of wrong type: {:?}", i),
ErroneousReferencedConstant(_) => simple!("could not evaluate referenced constant"),
- CharCast(ref got) => {
- simple!("only `u8` can be cast as `char`, not `{}`", got.description())
- },
- }
- }
-}
-pub type EvalResult = Result<ConstVal, ConstEvalErr>;
-pub type CastResult = Result<ConstVal, ErrKind>;
-
-// FIXME: Long-term, this enum should go away: trying to evaluate
-// an expression which hasn't been type-checked is a recipe for
-// disaster. That said, it's not clear how to fix ast_ty_to_ty
-// to avoid the ordering issue.
-
-/// Hint to determine how to evaluate constant expressions which
-/// might not be type-checked.
-#[derive(Copy, Clone, Debug)]
-pub enum EvalHint<'tcx> {
- /// We have a type-checked expression.
- ExprTypeChecked,
- /// We have an expression which hasn't been type-checked, but we have
- /// an idea of what the type will be because of the context. For example,
- /// the length of an array is always `usize`. (This is referred to as
- /// a hint because it isn't guaranteed to be consistent with what
- /// type-checking would compute.)
- UncheckedExprHint(Ty<'tcx>),
- /// We have an expression which has not yet been type-checked, and
- /// and we have no clue what the type will be.
- UncheckedExprNoHint,
-}
-
-impl<'tcx> EvalHint<'tcx> {
- fn erase_hint(&self) -> EvalHint<'tcx> {
- match *self {
- ExprTypeChecked => ExprTypeChecked,
- UncheckedExprHint(_) | UncheckedExprNoHint => UncheckedExprNoHint,
- }
- }
- fn checked_or(&self, ty: Ty<'tcx>) -> EvalHint<'tcx> {
- match *self {
- ExprTypeChecked => ExprTypeChecked,
- _ => UncheckedExprHint(ty),
+ TypeckError => simple!("type-checking failed"),
}
}
}
-macro_rules! signal {
- ($e:expr, $exn:expr) => {
- return Err(ConstEvalErr { span: $e.span, kind: $exn })
- }
-}
+pub type EvalResult<'tcx> = Result<ConstVal<'tcx>, ConstEvalErr<'tcx>>;
+pub type CastResult<'tcx> = Result<ConstVal<'tcx>, ErrKind<'tcx>>;
fn eval_const_expr_partial<'a, 'tcx>(cx: &ConstContext<'a, 'tcx>,
- e: &Expr,
- ty_hint: EvalHint<'tcx>) -> EvalResult {
+ e: &Expr) -> EvalResult<'tcx> {
let tcx = cx.tcx;
- // Try to compute the type of the expression based on the EvalHint.
- // (See also the definition of EvalHint, and the FIXME above EvalHint.)
- let ety = match ty_hint {
- ExprTypeChecked => {
- // After type-checking, expr_ty is guaranteed to succeed.
- cx.tables.map(|tables| tables.expr_ty(e))
- }
- UncheckedExprHint(ty) => {
- // Use the type hint; it's not guaranteed to be right, but it's
- // usually good enough.
- Some(ty)
- }
- UncheckedExprNoHint => {
- // This expression might not be type-checked, and we have no hint.
- // Try to query the context for a type anyway; we might get lucky
- // (for example, if the expression was imported from another crate).
- cx.tables.and_then(|tables| tables.expr_ty_opt(e))
- }
+ let ety = cx.tables.expr_ty(e);
+
+ // Avoid applying substitutions if they're empty, that'd ICE.
+ let ety = if cx.substs.is_empty() {
+ ety
+ } else {
+ ety.subst(tcx, cx.substs)
};
+
let result = match e.node {
hir::ExprUnary(hir::UnNeg, ref inner) => {
// unary neg literals already got their sign during creation
const I32_OVERFLOW: u128 = i32::min_value() as u32 as u128;
const I64_OVERFLOW: u128 = i64::min_value() as u64 as u128;
const I128_OVERFLOW: u128 = i128::min_value() as u128;
- match (&lit.node, ety.map(|t| &t.sty)) {
- (&LitKind::Int(I8_OVERFLOW, _), Some(&ty::TyInt(IntTy::I8))) |
+ match (&lit.node, &ety.sty) {
+ (&LitKind::Int(I8_OVERFLOW, _), &ty::TyInt(IntTy::I8)) |
(&LitKind::Int(I8_OVERFLOW, Signed(IntTy::I8)), _) => {
return Ok(Integral(I8(i8::min_value())))
},
- (&LitKind::Int(I16_OVERFLOW, _), Some(&ty::TyInt(IntTy::I16))) |
+ (&LitKind::Int(I16_OVERFLOW, _), &ty::TyInt(IntTy::I16)) |
(&LitKind::Int(I16_OVERFLOW, Signed(IntTy::I16)), _) => {
return Ok(Integral(I16(i16::min_value())))
},
- (&LitKind::Int(I32_OVERFLOW, _), Some(&ty::TyInt(IntTy::I32))) |
+ (&LitKind::Int(I32_OVERFLOW, _), &ty::TyInt(IntTy::I32)) |
(&LitKind::Int(I32_OVERFLOW, Signed(IntTy::I32)), _) => {
return Ok(Integral(I32(i32::min_value())))
},
- (&LitKind::Int(I64_OVERFLOW, _), Some(&ty::TyInt(IntTy::I64))) |
+ (&LitKind::Int(I64_OVERFLOW, _), &ty::TyInt(IntTy::I64)) |
(&LitKind::Int(I64_OVERFLOW, Signed(IntTy::I64)), _) => {
return Ok(Integral(I64(i64::min_value())))
},
- (&LitKind::Int(I128_OVERFLOW, _), Some(&ty::TyInt(IntTy::I128))) |
+ (&LitKind::Int(I128_OVERFLOW, _), &ty::TyInt(IntTy::I128)) |
(&LitKind::Int(I128_OVERFLOW, Signed(IntTy::I128)), _) => {
return Ok(Integral(I128(i128::min_value())))
},
- (&LitKind::Int(n, _), Some(&ty::TyInt(IntTy::Is))) |
+ (&LitKind::Int(n, _), &ty::TyInt(IntTy::Is)) |
(&LitKind::Int(n, Signed(IntTy::Is)), _) => {
match tcx.sess.target.int_type {
IntTy::I16 => if n == I16_OVERFLOW {
IntTy::I64 => if n == I64_OVERFLOW {
return Ok(Integral(Isize(Is64(i64::min_value()))));
},
- _ => bug!(),
+ _ => span_bug!(e.span, "typeck error")
}
},
_ => {},
}
}
- match cx.eval(inner, ty_hint)? {
+ match cx.eval(inner)? {
Float(f) => Float(-f),
Integral(i) => Integral(math!(e, -i)),
const_val => signal!(e, NegateOn(const_val)),
}
}
hir::ExprUnary(hir::UnNot, ref inner) => {
- match cx.eval(inner, ty_hint)? {
+ match cx.eval(inner)? {
Integral(i) => Integral(math!(e, !i)),
Bool(b) => Bool(!b),
const_val => signal!(e, NotOn(const_val)),
}
hir::ExprUnary(hir::UnDeref, _) => signal!(e, UnimplementedConstVal("deref operation")),
hir::ExprBinary(op, ref a, ref b) => {
- let b_ty = match op.node {
- hir::BiShl | hir::BiShr => ty_hint.erase_hint(),
- _ => ty_hint
- };
// technically, if we don't have type hints, but integral eval
// gives us a type through a type-suffix, cast or const def type
// we need to re-eval the other value of the BinOp if it was
// not inferred
- match (cx.eval(a, ty_hint)?,
- cx.eval(b, b_ty)?) {
+ match (cx.eval(a)?, cx.eval(b)?) {
(Float(a), Float(b)) => {
use std::cmp::Ordering::*;
match op.node {
hir::BiNe => Bool(math!(e, a.try_cmp(b)) != Equal),
hir::BiGe => Bool(math!(e, a.try_cmp(b)) != Less),
hir::BiGt => Bool(math!(e, a.try_cmp(b)) == Greater),
- _ => signal!(e, InvalidOpForFloats(op.node)),
+ _ => span_bug!(e.span, "typeck error"),
}
}
(Integral(a), Integral(b)) => {
hir::BiNe => Bool(math!(e, a.try_cmp(b)) != Equal),
hir::BiGe => Bool(math!(e, a.try_cmp(b)) != Less),
hir::BiGt => Bool(math!(e, a.try_cmp(b)) == Greater),
- _ => signal!(e, InvalidOpForInts(op.node)),
+ _ => span_bug!(e.span, "typeck error"),
}
}
(Bool(a), Bool(b)) => {
hir::BiLe => a <= b,
hir::BiGe => a >= b,
hir::BiGt => a > b,
- _ => signal!(e, InvalidOpForBools(op.node)),
+ _ => span_bug!(e.span, "typeck error"),
+ })
+ }
+ (Char(a), Char(b)) => {
+ Bool(match op.node {
+ hir::BiEq => a == b,
+ hir::BiNe => a != b,
+ hir::BiLt => a < b,
+ hir::BiLe => a <= b,
+ hir::BiGe => a >= b,
+ hir::BiGt => a > b,
+ _ => span_bug!(e.span, "typeck error"),
})
}
_ => signal!(e, MiscBinaryOp),
}
}
- hir::ExprCast(ref base, ref target_ty) => {
- let ety = tcx.ast_ty_to_prim_ty(&target_ty).or(ety)
- .unwrap_or_else(|| {
- tcx.sess.span_fatal(target_ty.span,
- "target type not found for const cast")
- });
-
- let base_hint = if let ExprTypeChecked = ty_hint {
- ExprTypeChecked
- } else {
- match cx.tables.and_then(|tables| tables.expr_ty_opt(&base)) {
- Some(t) => UncheckedExprHint(t),
- None => ty_hint
- }
- };
-
- let val = match cx.eval(base, base_hint) {
- Ok(val) => val,
- Err(ConstEvalErr { kind: ErroneousReferencedConstant(
- box ConstEvalErr { kind: TypeMismatch(_, val), .. }), .. }) |
- Err(ConstEvalErr { kind: TypeMismatch(_, val), .. }) => {
- // Something like `5i8 as usize` doesn't need a type hint for the base
- // instead take the type hint from the inner value
- let hint = match val.int_type() {
- Some(IntType::UnsignedInt(ty)) => ty_hint.checked_or(tcx.mk_mach_uint(ty)),
- Some(IntType::SignedInt(ty)) => ty_hint.checked_or(tcx.mk_mach_int(ty)),
- // we had a type hint, so we can't have an unknown type
- None => bug!(),
- };
- cx.eval(base, hint)?
- },
- Err(e) => return Err(e),
- };
- match cast_const(tcx, val, ety) {
+ hir::ExprCast(ref base, _) => {
+ match cast_const(tcx, cx.eval(base)?, ety) {
Ok(val) => val,
Err(kind) => return Err(ConstEvalErr { span: e.span, kind: kind }),
}
}
hir::ExprPath(ref qpath) => {
- let def = cx.tables.map(|tables| tables.qpath_def(qpath, e.id)).unwrap_or_else(|| {
- // There are no tables so we can only handle already-resolved HIR.
- match *qpath {
- hir::QPath::Resolved(_, ref path) => path.def,
- hir::QPath::TypeRelative(..) => Def::Err
- }
- });
- match def {
+ let substs = cx.tables.node_id_item_substs(e.id)
+ .unwrap_or_else(|| tcx.intern_substs(&[]));
+
+ // Avoid applying substitutions if they're empty, that'd ICE.
+ let substs = if cx.substs.is_empty() {
+ substs
+ } else {
+ substs.subst(tcx, cx.substs)
+ };
+
+ match cx.tables.qpath_def(qpath, e.id) {
Def::Const(def_id) |
Def::AssociatedConst(def_id) => {
- let substs = if let ExprTypeChecked = ty_hint {
- Some(cx.tables.and_then(|tables| tables.node_id_item_substs(e.id))
- .unwrap_or_else(|| tcx.intern_substs(&[])))
- } else {
- None
- };
- if let Some((expr, tables, ty)) = lookup_const_by_id(tcx, def_id, substs) {
- let item_hint = match ty {
- Some(ty) => ty_hint.checked_or(ty),
- None => ty_hint,
- };
- let cx = ConstContext { tcx: tcx, tables: tables, fn_args: None };
- match cx.eval(expr, item_hint) {
+ if let Some((expr, tables)) = lookup_const_by_id(tcx, def_id, substs) {
+ let cx = ConstContext::with_tables(tcx, tables);
+ match cx.eval(expr) {
Ok(val) => val,
+ Err(ConstEvalErr { kind: TypeckError, .. }) => {
+ signal!(e, TypeckError);
+ }
Err(err) => {
debug!("bad reference: {:?}, {:?}", err.description(), err.span);
signal!(e, ErroneousReferencedConstant(box err))
},
}
} else {
- signal!(e, NonConstPath);
+ signal!(e, TypeckError);
}
},
Def::VariantCtor(variant_def, ..) => {
if let Some((expr, tables)) = lookup_variant_by_id(tcx, variant_def) {
- let cx = ConstContext { tcx: tcx, tables: tables, fn_args: None };
- match cx.eval(expr, ty_hint) {
+ let cx = ConstContext::with_tables(tcx, tables);
+ match cx.eval(expr) {
Ok(val) => val,
+ Err(ConstEvalErr { kind: TypeckError, .. }) => {
+ signal!(e, TypeckError);
+ }
Err(err) => {
debug!("bad reference: {:?}, {:?}", err.description(), err.span);
signal!(e, ErroneousReferencedConstant(box err))
signal!(e, NonConstPath);
}
},
- Def::Method(id) | Def::Fn(id) => Function(id),
- Def::Err => signal!(e, UnresolvedPath),
+ Def::Method(id) | Def::Fn(id) => Function(id, substs),
+ Def::Err => span_bug!(e.span, "typeck error"),
_ => signal!(e, NonConstPath),
}
}
hir::ExprCall(ref callee, ref args) => {
- let sub_ty_hint = ty_hint.erase_hint();
- let callee_val = cx.eval(callee, sub_ty_hint)?;
- let did = match callee_val {
- Function(did) => did,
+ let (did, substs) = match cx.eval(callee)? {
+ Function(did, substs) => (did, substs),
Struct(_) => signal!(e, UnimplementedConstVal("tuple struct constructors")),
callee => signal!(e, CallOn(callee)),
};
let mut call_args = DefIdMap();
for (arg, arg_expr) in arg_defs.into_iter().zip(args.iter()) {
- let arg_hint = ty_hint.erase_hint();
- let arg_val = cx.eval(arg_expr, arg_hint)?;
+ let arg_val = cx.eval(arg_expr)?;
debug!("const call arg: {:?}", arg);
if let Some(def_id) = arg {
assert!(call_args.insert(def_id, arg_val).is_none());
let callee_cx = ConstContext {
tcx: tcx,
tables: tables,
+ substs: substs,
fn_args: Some(call_args)
};
- callee_cx.eval(&body.value, ty_hint)?
+ callee_cx.eval(&body.value)?
},
hir::ExprLit(ref lit) => match lit_to_const(&lit.node, tcx, ety) {
Ok(val) => val,
},
hir::ExprBlock(ref block) => {
match block.expr {
- Some(ref expr) => cx.eval(expr, ty_hint)?,
- None => signal!(e, UnimplementedConstVal("empty block")),
+ Some(ref expr) => cx.eval(expr)?,
+ None => Tuple(vec![]),
}
}
- hir::ExprType(ref e, _) => cx.eval(e, ty_hint)?,
+ hir::ExprType(ref e, _) => cx.eval(e)?,
hir::ExprTup(ref fields) => {
- let field_hint = ty_hint.erase_hint();
- Tuple(fields.iter().map(|e| cx.eval(e, field_hint)).collect::<Result<_, _>>()?)
+ Tuple(fields.iter().map(|e| cx.eval(e)).collect::<Result<_, _>>()?)
}
hir::ExprStruct(_, ref fields, _) => {
- let field_hint = ty_hint.erase_hint();
Struct(fields.iter().map(|f| {
- cx.eval(&f.expr, field_hint).map(|v| (f.name.node, v))
+ cx.eval(&f.expr).map(|v| (f.name.node, v))
}).collect::<Result<_, _>>()?)
}
hir::ExprIndex(ref arr, ref idx) => {
if !tcx.sess.features.borrow().const_indexing {
signal!(e, IndexOpFeatureGated);
}
- let arr_hint = ty_hint.erase_hint();
- let arr = cx.eval(arr, arr_hint)?;
- let idx_hint = ty_hint.checked_or(tcx.types.usize);
- let idx = match cx.eval(idx, idx_hint)? {
+ let arr = cx.eval(arr)?;
+ let idx = match cx.eval(idx)? {
Integral(Usize(i)) => i.as_u64(tcx.sess.target.uint_type),
- Integral(_) => bug!(),
- _ => signal!(idx, IndexNotInt),
+ _ => signal!(idx, IndexNotUsize),
};
assert_eq!(idx as usize as u64, idx);
match arr {
}
}
hir::ExprArray(ref v) => {
- let elem_hint = ty_hint.erase_hint();
- Array(v.iter().map(|e| cx.eval(e, elem_hint)).collect::<Result<_, _>>()?)
+ Array(v.iter().map(|e| cx.eval(e)).collect::<Result<_, _>>()?)
}
- hir::ExprRepeat(ref elem, count) => {
- let elem_hint = ty_hint.erase_hint();
- let len_hint = ty_hint.checked_or(tcx.types.usize);
- let n = if let Some(ty) = ety {
- // For cross-crate constants, we have the type already,
- // but not the body for `count`, so use the type.
- match ty.sty {
- ty::TyArray(_, n) => n as u64,
- _ => bug!()
- }
- } else {
- let n = &tcx.hir.body(count).value;
- match ConstContext::new(tcx, count).eval(n, len_hint)? {
- Integral(Usize(i)) => i.as_u64(tcx.sess.target.uint_type),
- Integral(_) => signal!(e, RepeatCountNotNatural),
- _ => signal!(e, RepeatCountNotInt),
- }
+ hir::ExprRepeat(ref elem, _) => {
+ let n = match ety.sty {
+ ty::TyArray(_, n) => n as u64,
+ _ => span_bug!(e.span, "typeck error")
};
- Repeat(Box::new(cx.eval(elem, elem_hint)?), n)
+ Repeat(Box::new(cx.eval(elem)?), n)
},
hir::ExprTupField(ref base, index) => {
- let base_hint = ty_hint.erase_hint();
- let c = cx.eval(base, base_hint)?;
+ let c = cx.eval(base)?;
if let Tuple(ref fields) = c {
- if let Some(elem) = fields.get(index.node) {
- elem.clone()
- } else {
- signal!(e, TupleIndexOutOfBounds);
- }
+ fields[index.node].clone()
} else {
signal!(base, ExpectedConstTuple);
}
}
hir::ExprField(ref base, field_name) => {
- let base_hint = ty_hint.erase_hint();
- let c = cx.eval(base, base_hint)?;
+ let c = cx.eval(base)?;
if let Struct(ref fields) = c {
if let Some(f) = fields.get(&field_name.node) {
f.clone()
_ => signal!(e, MiscCatchAll)
};
- match (ety.map(|t| &t.sty), result) {
- (Some(ref ty_hint), Integral(i)) => match infer(i, tcx, ty_hint) {
- Ok(inferred) => Ok(Integral(inferred)),
- Err(err) => signal!(e, err),
- },
- (_, result) => Ok(result),
- }
-}
-
-fn infer<'a, 'tcx>(i: ConstInt,
- tcx: TyCtxt<'a, 'tcx, 'tcx>,
- ty_hint: &ty::TypeVariants<'tcx>)
- -> Result<ConstInt, ErrKind> {
- use syntax::ast::*;
-
- match (ty_hint, i) {
- (&ty::TyInt(IntTy::I8), result @ I8(_)) => Ok(result),
- (&ty::TyInt(IntTy::I16), result @ I16(_)) => Ok(result),
- (&ty::TyInt(IntTy::I32), result @ I32(_)) => Ok(result),
- (&ty::TyInt(IntTy::I64), result @ I64(_)) => Ok(result),
- (&ty::TyInt(IntTy::I128), result @ I128(_)) => Ok(result),
- (&ty::TyInt(IntTy::Is), result @ Isize(_)) => Ok(result),
-
- (&ty::TyUint(UintTy::U8), result @ U8(_)) => Ok(result),
- (&ty::TyUint(UintTy::U16), result @ U16(_)) => Ok(result),
- (&ty::TyUint(UintTy::U32), result @ U32(_)) => Ok(result),
- (&ty::TyUint(UintTy::U64), result @ U64(_)) => Ok(result),
- (&ty::TyUint(UintTy::U128), result @ U128(_)) => Ok(result),
- (&ty::TyUint(UintTy::Us), result @ Usize(_)) => Ok(result),
-
- (&ty::TyInt(IntTy::I8), Infer(i)) => Ok(I8(i as i128 as i8)),
- (&ty::TyInt(IntTy::I16), Infer(i)) => Ok(I16(i as i128 as i16)),
- (&ty::TyInt(IntTy::I32), Infer(i)) => Ok(I32(i as i128 as i32)),
- (&ty::TyInt(IntTy::I64), Infer(i)) => Ok(I64(i as i128 as i64)),
- (&ty::TyInt(IntTy::I128), Infer(i)) => Ok(I128(i as i128)),
- (&ty::TyInt(IntTy::Is), Infer(i)) => {
- Ok(Isize(ConstIsize::new_truncating(i as i128, tcx.sess.target.int_type)))
- },
-
- (&ty::TyInt(IntTy::I8), InferSigned(i)) => Ok(I8(i as i8)),
- (&ty::TyInt(IntTy::I16), InferSigned(i)) => Ok(I16(i as i16)),
- (&ty::TyInt(IntTy::I32), InferSigned(i)) => Ok(I32(i as i32)),
- (&ty::TyInt(IntTy::I64), InferSigned(i)) => Ok(I64(i as i64)),
- (&ty::TyInt(IntTy::I128), InferSigned(i)) => Ok(I128(i)),
- (&ty::TyInt(IntTy::Is), InferSigned(i)) => {
- Ok(Isize(ConstIsize::new_truncating(i, tcx.sess.target.int_type)))
- },
-
- (&ty::TyUint(UintTy::U8), Infer(i)) => Ok(U8(i as u8)),
- (&ty::TyUint(UintTy::U16), Infer(i)) => Ok(U16(i as u16)),
- (&ty::TyUint(UintTy::U32), Infer(i)) => Ok(U32(i as u32)),
- (&ty::TyUint(UintTy::U64), Infer(i)) => Ok(U64(i as u64)),
- (&ty::TyUint(UintTy::U128), Infer(i)) => Ok(U128(i)),
- (&ty::TyUint(UintTy::Us), Infer(i)) => {
- Ok(Usize(ConstUsize::new_truncating(i, tcx.sess.target.uint_type)))
- },
- (&ty::TyUint(_), InferSigned(_)) => Err(IntermediateUnsignedNegative),
-
- (&ty::TyInt(ity), i) => Err(TypeMismatch(ity.to_string(), i)),
- (&ty::TyUint(ity), i) => Err(TypeMismatch(ity.to_string(), i)),
-
- (&ty::TyAdt(adt, _), i) if adt.is_enum() => {
- let hints = tcx.lookup_repr_hints(adt.did);
- let int_ty = tcx.enum_repr_type(hints.iter().next());
- infer(i, tcx, &int_ty.to_ty(tcx).sty)
- },
- (_, i) => Err(BadType(ConstVal::Integral(i))),
- }
+ Ok(result)
}
fn resolve_trait_associated_const<'a, 'tcx: 'a>(
tcx: TyCtxt<'a, 'tcx, 'tcx>,
trait_item_id: DefId,
- default_value: Option<(&'tcx Expr, Option<&'a ty::TypeckTables<'tcx>>, Option<ty::Ty<'tcx>>)>,
+ default_value: Option<(&'tcx Expr, &'a ty::TypeckTables<'tcx>)>,
trait_id: DefId,
rcvr_substs: &'tcx Substs<'tcx>
-) -> Option<(&'tcx Expr, Option<&'a ty::TypeckTables<'tcx>>, Option<ty::Ty<'tcx>>)>
+) -> Option<(&'tcx Expr, &'a ty::TypeckTables<'tcx>)>
{
let trait_ref = ty::Binder(ty::TraitRef::new(trait_id, rcvr_substs));
debug!("resolve_trait_associated_const: trait_ref={:?}",
trait_ref);
tcx.populate_implementations_for_trait_if_necessary(trait_id);
- tcx.infer_ctxt((), Reveal::NotSpecializable).enter(|infcx| {
+ tcx.infer_ctxt((), Reveal::UserFacing).enter(|infcx| {
let mut selcx = traits::SelectionContext::new(&infcx);
let obligation = traits::Obligation::new(traits::ObligationCause::dummy(),
trait_ref.to_poly_trait_predicate());
let ac = tcx.associated_items(impl_data.impl_def_id)
.find(|item| item.kind == ty::AssociatedKind::Const && item.name == name);
match ac {
- Some(ic) => lookup_const_by_id(tcx, ic.def_id, None),
+ Some(ic) => lookup_const_by_id(tcx, ic.def_id, Substs::empty()),
None => default_value,
}
}
})
}
-fn cast_const_int<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, val: ConstInt, ty: ty::Ty) -> CastResult {
+fn cast_const_int<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
+ val: ConstInt,
+ ty: Ty<'tcx>)
+ -> CastResult<'tcx> {
let v = val.to_u128_unchecked();
match ty.sty {
ty::TyBool if v == 0 => Ok(Bool(false)),
ty::TyUint(ast::UintTy::Us) => {
Ok(Integral(Usize(ConstUsize::new_truncating(v, tcx.sess.target.uint_type))))
},
- ty::TyFloat(ast::FloatTy::F64) => match val.erase_type() {
- Infer(u) => Ok(Float(F64(u as f64))),
- InferSigned(i) => Ok(Float(F64(i as f64))),
- _ => bug!("ConstInt::erase_type returned something other than Infer/InferSigned"),
- },
- ty::TyFloat(ast::FloatTy::F32) => match val.erase_type() {
- Infer(u) => Ok(Float(F32(u as f32))),
- InferSigned(i) => Ok(Float(F32(i as f32))),
- _ => bug!("ConstInt::erase_type returned something other than Infer/InferSigned"),
- },
+ ty::TyFloat(ast::FloatTy::F64) => Ok(Float(F64(val.to_f64()))),
+ ty::TyFloat(ast::FloatTy::F32) => Ok(Float(F32(val.to_f32()))),
ty::TyRawPtr(_) => Err(ErrKind::UnimplementedConstVal("casting an address to a raw ptr")),
- ty::TyChar => match infer(val, tcx, &ty::TyUint(ast::UintTy::U8)) {
- Ok(U8(u)) => Ok(Char(u as char)),
- // can only occur before typeck, typeck blocks `T as char` for `T` != `u8`
- _ => Err(CharCast(val)),
+ ty::TyChar => match val {
+ U8(u) => Ok(Char(u as char)),
+ _ => bug!(),
},
- _ => Err(CannotCast),
+ _ => bug!(),
}
}
fn cast_const_float<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
val: ConstFloat,
- ty: ty::Ty) -> CastResult {
+ ty: Ty<'tcx>) -> CastResult<'tcx> {
match ty.sty {
ty::TyInt(_) | ty::TyUint(_) => {
let i = match val {
- F32(f) if f >= 0.0 => Infer(f as u128),
- FInfer { f64: f, .. } |
- F64(f) if f >= 0.0 => Infer(f as u128),
+ F32(f) if f >= 0.0 => U128(f as u128),
+ F64(f) if f >= 0.0 => U128(f as u128),
- F32(f) => InferSigned(f as i128),
- FInfer { f64: f, .. } |
- F64(f) => InferSigned(f as i128)
+ F32(f) => I128(f as i128),
+ F64(f) => I128(f as i128)
};
- if let (InferSigned(_), &ty::TyUint(_)) = (i, &ty.sty) {
+ if let (I128(_), &ty::TyUint(_)) = (i, &ty.sty) {
return Err(CannotCast);
}
}
ty::TyFloat(ast::FloatTy::F64) => Ok(Float(F64(match val {
F32(f) => f as f64,
- FInfer { f64: f, .. } | F64(f) => f
+ F64(f) => f
}))),
ty::TyFloat(ast::FloatTy::F32) => Ok(Float(F32(match val {
F64(f) => f as f32,
- FInfer { f32: f, .. } | F32(f) => f
+ F32(f) => f
}))),
_ => Err(CannotCast),
}
}
-fn cast_const<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, val: ConstVal, ty: ty::Ty) -> CastResult {
+fn cast_const<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
+ val: ConstVal<'tcx>,
+ ty: Ty<'tcx>)
+ -> CastResult<'tcx> {
match val {
Integral(i) => cast_const_int(tcx, i, ty),
- Bool(b) => cast_const_int(tcx, Infer(b as u128), ty),
+ Bool(b) => cast_const_int(tcx, U8(b as u8), ty),
Float(f) => cast_const_float(tcx, f, ty),
- Char(c) => cast_const_int(tcx, Infer(c as u128), ty),
- Function(_) => Err(UnimplementedConstVal("casting fn pointers")),
+ Char(c) => cast_const_int(tcx, U32(c as u32), ty),
+ Function(..) => Err(UnimplementedConstVal("casting fn pointers")),
ByteStr(b) => match ty.sty {
ty::TyRawPtr(_) => {
Err(ErrKind::UnimplementedConstVal("casting a bytestr to a raw ptr"))
fn lit_to_const<'a, 'tcx>(lit: &ast::LitKind,
tcx: TyCtxt<'a, 'tcx, 'tcx>,
- ty_hint: Option<Ty<'tcx>>)
- -> Result<ConstVal, ErrKind> {
+ mut ty: Ty<'tcx>)
+ -> Result<ConstVal<'tcx>, ErrKind<'tcx>> {
use syntax::ast::*;
use syntax::ast::LitIntType::*;
+
+ if let ty::TyAdt(adt, _) = ty.sty {
+ if adt.is_enum() {
+ ty = adt.repr.discr_type().to_ty(tcx)
+ }
+ }
+
match *lit {
LitKind::Str(ref s, _) => Ok(Str(s.as_str())),
LitKind::ByteStr(ref data) => Ok(ByteStr(data.clone())),
LitKind::Byte(n) => Ok(Integral(U8(n))),
- LitKind::Int(n, Signed(ity)) => {
- infer(InferSigned(n as i128), tcx, &ty::TyInt(ity)).map(Integral)
- },
-
- // FIXME: this should become u128.
- LitKind::Int(n, Unsuffixed) => {
- match ty_hint.map(|t| &t.sty) {
- Some(&ty::TyInt(ity)) => {
- infer(InferSigned(n as i128), tcx, &ty::TyInt(ity)).map(Integral)
- },
- Some(&ty::TyUint(uty)) => {
- infer(Infer(n as u128), tcx, &ty::TyUint(uty)).map(Integral)
- },
- None => Ok(Integral(Infer(n as u128))),
- Some(&ty::TyAdt(adt, _)) => {
- let hints = tcx.lookup_repr_hints(adt.did);
- let int_ty = tcx.enum_repr_type(hints.iter().next());
- infer(Infer(n as u128), tcx, &int_ty.to_ty(tcx).sty).map(Integral)
- },
- Some(ty_hint) => bug!("bad ty_hint: {:?}, {:?}", ty_hint, lit),
+ LitKind::Int(n, hint) => {
+ match (&ty.sty, hint) {
+ (&ty::TyInt(ity), _) |
+ (_, Signed(ity)) => {
+ Ok(Integral(ConstInt::new_signed_truncating(n as i128,
+ ity, tcx.sess.target.int_type)))
+ }
+ (&ty::TyUint(uty), _) |
+ (_, Unsigned(uty)) => {
+ Ok(Integral(ConstInt::new_unsigned_truncating(n as u128,
+ uty, tcx.sess.target.uint_type)))
+ }
+ _ => bug!()
}
- },
- LitKind::Int(n, Unsigned(ity)) => {
- infer(Infer(n as u128), tcx, &ty::TyUint(ity)).map(Integral)
- },
-
+ }
LitKind::Float(n, fty) => {
- parse_float(&n.as_str(), Some(fty)).map(Float)
+ parse_float(&n.as_str(), fty).map(Float)
}
LitKind::FloatUnsuffixed(n) => {
- let fty_hint = match ty_hint.map(|t| &t.sty) {
- Some(&ty::TyFloat(fty)) => Some(fty),
- _ => None
+ let fty = match ty.sty {
+ ty::TyFloat(fty) => fty,
+ _ => bug!()
};
- parse_float(&n.as_str(), fty_hint).map(Float)
+ parse_float(&n.as_str(), fty).map(Float)
}
LitKind::Bool(b) => Ok(Bool(b)),
LitKind::Char(c) => Ok(Char(c)),
}
}
-fn parse_float(num: &str, fty_hint: Option<ast::FloatTy>)
- -> Result<ConstFloat, ErrKind> {
- let val = match fty_hint {
- Some(ast::FloatTy::F32) => num.parse::<f32>().map(F32),
- Some(ast::FloatTy::F64) => num.parse::<f64>().map(F64),
- None => {
- num.parse::<f32>().and_then(|f32| {
- num.parse::<f64>().map(|f64| {
- FInfer { f32: f32, f64: f64 }
- })
- })
- }
+fn parse_float<'tcx>(num: &str, fty: ast::FloatTy)
+ -> Result<ConstFloat, ErrKind<'tcx>> {
+ let val = match fty {
+ ast::FloatTy::F32 => num.parse::<f32>().map(F32),
+ ast::FloatTy::F64 => num.parse::<f64>().map(F64)
};
val.map_err(|_| {
// FIXME(#31407) this is only necessary because float parsing is buggy
a: &Expr,
b: &Expr) -> Result<Ordering, ErrorReported> {
let tcx = self.tcx;
- let a = match self.eval(a, ExprTypeChecked) {
+ let a = match self.eval(a) {
Ok(a) => a,
Err(e) => {
- report_const_eval_err(tcx, &e, a.span, "expression").emit();
+ report_const_eval_err(tcx, &e, a.span, "expression");
return Err(ErrorReported);
}
};
- let b = match self.eval(b, ExprTypeChecked) {
+ let b = match self.eval(b) {
Ok(b) => b,
Err(e) => {
- report_const_eval_err(tcx, &e, b.span, "expression").emit();
+ report_const_eval_err(tcx, &e, b.span, "expression");
return Err(ErrorReported);
}
};
reason: &str)
-> Result<usize, ErrorReported>
{
- let hint = UncheckedExprHint(tcx.types.usize);
let count_expr = &tcx.hir.body(count).value;
- match ConstContext::new(tcx, count).eval(count_expr, hint) {
+ match ConstContext::new(tcx, count).eval(count_expr) {
Ok(Integral(Usize(count))) => {
let val = count.as_u64(tcx.sess.target.uint_type);
assert_eq!(val as usize as u64, val);
Ok(val as usize)
},
- Ok(const_val) => {
- struct_span_err!(tcx.sess, count_expr.span, E0306,
- "expected `usize` for {}, found {}",
- reason,
- const_val.description())
- .span_label(count_expr.span, &format!("expected `usize`"))
- .emit();
-
- Err(ErrorReported)
- }
+ Ok(_) |
+ Err(ConstEvalErr { kind: TypeckError, .. }) => Err(ErrorReported),
Err(err) => {
- let mut diag = report_const_eval_err(
+ let mut diag = build_const_eval_err(
tcx, &err, count_expr.span, reason);
if let hir::ExprPath(hir::QPath::Resolved(None, ref path)) = count_expr.node {
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