Merge ConstMathError into EvalErrorKind

12 files changed, 65 insertions, 115 deletions

diff --git a/src/librustc/ich/impls_ty.rs b/src/librustc/ich/impls_ty.rs
index 92a8ee28168..a5447a3145a 100644
--- a/src/librustc/ich/impls_ty.rs
+++ b/src/librustc/ich/impls_ty.rs
@@ -525,16 +525,26 @@ impl_stable_hash_for!(struct ty::GenericPredicates<'tcx> {
     predicates
 });
 
+
 impl<'a, 'gcx> HashStable<StableHashingContext<'a>>
 for ::mir::interpret::EvalError<'gcx> {
     fn hash_stable<W: StableHasherResult>(&self,
                                           hcx: &mut StableHashingContext<'a>,
                                           hasher: &mut StableHasher<W>) {
+        self.kind.hash_stable(hcx, hasher)
+    }
+}
+
+impl<'a, 'gcx> HashStable<StableHashingContext<'a>>
+for ::mir::interpret::EvalErrorKind<'gcx> {
+    fn hash_stable<W: StableHasherResult>(&self,
+                                          hcx: &mut StableHashingContext<'a>,
+                                          hasher: &mut StableHasher<W>) {
         use mir::interpret::EvalErrorKind::*;
 
-        mem::discriminant(&self.kind).hash_stable(hcx, hasher);
+        mem::discriminant(&self).hash_stable(hcx, hasher);
 
-        match self.kind {
+        match *self {
             DanglingPointerDeref |
             DoubleFree |
             InvalidMemoryAccess |
@@ -565,8 +575,10 @@ for ::mir::interpret::EvalError<'gcx> {
             TypeckError |
             DerefFunctionPointer |
             ExecuteMemory |
-            ReferencedConstant |
-            OverflowingMath => {}
+            OverflowNeg |
+            RemainderByZero |
+            DivisionByZero |
+            ReferencedConstant => {}
             MachineError(ref err) => err.hash_stable(hcx, hasher),
             FunctionPointerTyMismatch(a, b) => {
                 a.hash_stable(hcx, hasher);
@@ -590,10 +602,6 @@ for ::mir::interpret::EvalError<'gcx> {
                 a.hash_stable(hcx, hasher);
                 b.hash_stable(hcx, hasher)
             },
-            Math(sp, ref err) => {
-                sp.hash_stable(hcx, hasher);
-                err.hash_stable(hcx, hasher)
-            },
             Intrinsic(ref s) => s.hash_stable(hcx, hasher),
             InvalidChar(c) => c.hash_stable(hcx, hasher),
             AbiViolation(ref s) => s.hash_stable(hcx, hasher),
@@ -665,27 +673,11 @@ for ::mir::interpret::EvalError<'gcx> {
             Layout(lay) => lay.hash_stable(hcx, hasher),
             HeapAllocNonPowerOfTwoAlignment(n) => n.hash_stable(hcx, hasher),
             PathNotFound(ref v) => v.hash_stable(hcx, hasher),
+            Overflow(op) => op.hash_stable(hcx, hasher),
         }
     }
 }
 
-impl_stable_hash_for!(enum mir::interpret::ConstMathErr {
-    Overflow(op),
-    DivisionByZero,
-    RemainderByZero,
-});
-
-impl_stable_hash_for!(enum mir::interpret::Op {
-    Add,
-    Sub,
-    Mul,
-    Div,
-    Rem,
-    Shr,
-    Shl,
-    Neg,
-});
-
 impl_stable_hash_for!(enum mir::interpret::Lock {
     NoLock,
     WriteLock(dl),
diff --git a/src/librustc/mir/interpret/error.rs b/src/librustc/mir/interpret/error.rs
index fff555a8976..022b82841bc 100644
--- a/src/librustc/mir/interpret/error.rs
+++ b/src/librustc/mir/interpret/error.rs
@@ -1,4 +1,3 @@
-use std::error::Error;
 use std::{fmt, env};
 
 use mir;
@@ -30,7 +29,7 @@ impl<'tcx> From<EvalErrorKind<'tcx>> for EvalError<'tcx> {
     }
 }
 
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, RustcEncodable, RustcDecodable)]
 pub enum EvalErrorKind<'tcx> {
     /// This variant is used by machines to signal their own errors that do not
     /// match an existing variant
@@ -60,9 +59,11 @@ pub enum EvalErrorKind<'tcx> {
     DerefFunctionPointer,
     ExecuteMemory,
     ArrayIndexOutOfBounds(Span, u64, u64),
-    Math(Span, ConstMathErr),
+    Overflow(mir::BinOp),
+    OverflowNeg,
+    DivisionByZero,
+    RemainderByZero,
     Intrinsic(String),
-    OverflowingMath,
     InvalidChar(u128),
     StackFrameLimitReached,
     OutOfTls,
@@ -124,10 +125,10 @@ pub enum EvalErrorKind<'tcx> {
 
 pub type EvalResult<'tcx, T = ()> = Result<T, EvalError<'tcx>>;
 
-impl<'tcx> Error for EvalError<'tcx> {
-    fn description(&self) -> &str {
+impl<'tcx> EvalErrorKind<'tcx> {
+    pub fn description(&self) -> &str {
         use self::EvalErrorKind::*;
-        match self.kind {
+        match *self {
             MachineError(ref inner) => inner,
             FunctionPointerTyMismatch(..) =>
                 "tried to call a function through a function pointer of a different type",
@@ -176,12 +177,8 @@ impl<'tcx> Error for EvalError<'tcx> {
                 "tried to treat a memory pointer as a function pointer",
             ArrayIndexOutOfBounds(..) =>
                 "array index out of bounds",
-            Math(..) =>
-                "mathematical operation failed",
             Intrinsic(..) =>
                 "intrinsic failed",
-            OverflowingMath =>
-                "attempted to do overflowing math",
             NoMirFor(..) =>
                 "mir not found",
             InvalidChar(..) =>
@@ -239,6 +236,17 @@ impl<'tcx> Error for EvalError<'tcx> {
                 "encountered constants with type errors, stopping evaluation",
             ReferencedConstant =>
                 "referenced constant has errors",
+            Overflow(mir::BinOp::Add) => "attempt to add with overflow",
+            Overflow(mir::BinOp::Sub) => "attempt to subtract with overflow",
+            Overflow(mir::BinOp::Mul) => "attempt to multiply with overflow",
+            Overflow(mir::BinOp::Div) => "attempt to divide with overflow",
+            Overflow(mir::BinOp::Rem) => "attempt to calculate the remainder with overflow",
+            OverflowNeg => "attempt to negate with overflow",
+            Overflow(mir::BinOp::Shr) => "attempt to shift right with overflow",
+            Overflow(mir::BinOp::Shl) => "attempt to shift left with overflow",
+            Overflow(op) => bug!("{:?} cannot overflow", op),
+            DivisionByZero => "attempt to divide by zero",
+            RemainderByZero => "attempt to calculate the remainder with a divisor of zero",
         }
     }
 }
@@ -280,8 +288,6 @@ impl<'tcx> fmt::Display for EvalError<'tcx> {
                 write!(f, "tried to reallocate memory from {} to {}", old, new),
             DeallocatedWrongMemoryKind(ref old, ref new) =>
                 write!(f, "tried to deallocate {} memory but gave {} as the kind", old, new),
-            Math(_, ref err) =>
-                write!(f, "{}", err.description()),
             Intrinsic(ref err) =>
                 write!(f, "{}", err),
             InvalidChar(c) =>
@@ -299,45 +305,7 @@ impl<'tcx> fmt::Display for EvalError<'tcx> {
                 write!(f, "{}", inner),
             IncorrectAllocationInformation(size, size2, align, align2) =>
                 write!(f, "incorrect alloc info: expected size {} and align {}, got size {} and align {}", size, align, size2, align2),
-            _ => write!(f, "{}", self.description()),
-        }
-    }
-}
-
-#[derive(Debug, PartialEq, Eq, Clone, RustcEncodable, RustcDecodable)]
-pub enum ConstMathErr {
-    Overflow(Op),
-    DivisionByZero,
-    RemainderByZero,
-}
-pub use self::ConstMathErr::*;
-
-#[derive(Debug, PartialEq, Eq, Clone, RustcEncodable, RustcDecodable)]
-pub enum Op {
-    Add,
-    Sub,
-    Mul,
-    Div,
-    Rem,
-    Shr,
-    Shl,
-    Neg,
-}
-
-impl ConstMathErr {
-    pub fn description(&self) -> &'static str {
-        use self::Op::*;
-        match *self {
-            Overflow(Add) => "attempt to add with overflow",
-            Overflow(Sub) => "attempt to subtract with overflow",
-            Overflow(Mul) => "attempt to multiply with overflow",
-            Overflow(Div) => "attempt to divide with overflow",
-            Overflow(Rem) => "attempt to calculate the remainder with overflow",
-            Overflow(Neg) => "attempt to negate with overflow",
-            Overflow(Shr) => "attempt to shift right with overflow",
-            Overflow(Shl) => "attempt to shift left with overflow",
-            DivisionByZero => "attempt to divide by zero",
-            RemainderByZero => "attempt to calculate the remainder with a divisor of zero",
+            _ => write!(f, "{}", self.kind.description()),
         }
     }
 }
diff --git a/src/librustc/mir/interpret/mod.rs b/src/librustc/mir/interpret/mod.rs
index fe29222e883..a521caf4fda 100644
--- a/src/librustc/mir/interpret/mod.rs
+++ b/src/librustc/mir/interpret/mod.rs
@@ -8,7 +8,7 @@ macro_rules! err {
 mod error;
 mod value;
 
-pub use self::error::{EvalError, EvalResult, EvalErrorKind, Op, ConstMathErr};
+pub use self::error::{EvalError, EvalResult, EvalErrorKind};
 
 pub use self::value::{PrimVal, PrimValKind, Value, Pointer};
 
@@ -23,7 +23,7 @@ use std::iter;
 use syntax::ast::Mutability;
 use rustc_serialize::{Encoder, Decoder, Decodable, Encodable};
 
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Clone, Debug, PartialEq, RustcEncodable, RustcDecodable)]
 pub enum Lock {
     NoLock,
     WriteLock(DynamicLifetime),
@@ -31,13 +31,13 @@ pub enum Lock {
     ReadLock(Vec<DynamicLifetime>),
 }
 
-#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
+#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
 pub struct DynamicLifetime {
     pub frame: usize,
     pub region: Option<region::Scope>, // "None" indicates "until the function ends"
 }
 
-#[derive(Copy, Clone, Debug, PartialEq, Eq)]
+#[derive(Copy, Clone, Debug, PartialEq, Eq, RustcEncodable, RustcDecodable)]
 pub enum AccessKind {
     Read,
     Write,
@@ -88,12 +88,12 @@ pub trait PointerArithmetic: layout::HasDataLayout {
 
     fn signed_offset<'tcx>(self, val: u64, i: i64) -> EvalResult<'tcx, u64> {
         let (res, over) = self.overflowing_signed_offset(val, i as i128);
-        if over { err!(OverflowingMath) } else { Ok(res) }
+        if over { err!(Overflow(mir::BinOp::Add)) } else { Ok(res) }
     }
 
     fn offset<'tcx>(self, val: u64, i: u64) -> EvalResult<'tcx, u64> {
         let (res, over) = self.overflowing_offset(val, i);
-        if over { err!(OverflowingMath) } else { Ok(res) }
+        if over { err!(Overflow(mir::BinOp::Add)) } else { Ok(res) }
     }
 
     fn wrapping_signed_offset(self, val: u64, i: i64) -> u64 {
diff --git a/src/librustc/mir/mod.rs b/src/librustc/mir/mod.rs
index 3c4b9ae3351..0b56dbda42c 100644
--- a/src/librustc/mir/mod.rs
+++ b/src/librustc/mir/mod.rs
@@ -25,7 +25,7 @@ use rustc_serialize as serialize;
 use hir::def::CtorKind;
 use hir::def_id::DefId;
 use mir::visit::MirVisitable;
-use mir::interpret::{Value, PrimVal, ConstMathErr};
+use mir::interpret::{Value, PrimVal, EvalErrorKind};
 use ty::subst::{Subst, Substs};
 use ty::{self, AdtDef, CanonicalTy, ClosureSubsts, Region, Ty, TyCtxt, GeneratorInterior};
 use ty::fold::{TypeFoldable, TypeFolder, TypeVisitor};
@@ -1211,7 +1211,7 @@ pub enum AssertMessage<'tcx> {
         len: Operand<'tcx>,
         index: Operand<'tcx>
     },
-    Math(ConstMathErr),
+    Math(EvalErrorKind<'tcx>),
     GeneratorResumedAfterReturn,
     GeneratorResumedAfterPanic,
 }
@@ -1920,9 +1920,9 @@ pub fn print_miri_value<W: Write>(value: Value, ty: Ty, f: &mut W) -> fmt::Resul
         (Value::ByVal(PrimVal::Bytes(0)), &TyBool) => write!(f, "false"),
         (Value::ByVal(PrimVal::Bytes(1)), &TyBool) => write!(f, "true"),
         (Value::ByVal(PrimVal::Bytes(bits)), &TyFloat(ast::FloatTy::F32)) =>
-            write!(f, "{}", Single::from_bits(bits)),
+            write!(f, "{}f32", Single::from_bits(bits)),
         (Value::ByVal(PrimVal::Bytes(bits)), &TyFloat(ast::FloatTy::F64)) =>
-            write!(f, "{}", Double::from_bits(bits)),
+            write!(f, "{}f64", Double::from_bits(bits)),
         (Value::ByVal(PrimVal::Bytes(n)), &TyUint(ui)) => write!(f, "{:?}{}", n, ui),
         (Value::ByVal(PrimVal::Bytes(n)), &TyInt(i)) => write!(f, "{:?}{}", n as i128, i),
         (Value::ByVal(PrimVal::Bytes(n)), &TyChar) =>
diff --git a/src/librustc/ty/layout.rs b/src/librustc/ty/layout.rs
index 55137e28911..92cea61bae5 100644
--- a/src/librustc/ty/layout.rs
+++ b/src/librustc/ty/layout.rs
@@ -149,7 +149,7 @@ pub const FAT_PTR_ADDR: usize = 0;
 /// - For a slice, this is the length.
 pub const FAT_PTR_EXTRA: usize = 1;
 
-#[derive(Copy, Clone, Debug)]
+#[derive(Copy, Clone, Debug, RustcEncodable, RustcDecodable)]
 pub enum LayoutError<'tcx> {
     Unknown(Ty<'tcx>),
     SizeOverflow(Ty<'tcx>)
diff --git a/src/librustc/ty/structural_impls.rs b/src/librustc/ty/structural_impls.rs
index f81617a3795..bae91d064a5 100644
--- a/src/librustc/ty/structural_impls.rs
+++ b/src/librustc/ty/structural_impls.rs
@@ -505,9 +505,7 @@ impl<'a, 'tcx> Lift<'tcx> for interpret::EvalError<'a> {
             DerefFunctionPointer => DerefFunctionPointer,
             ExecuteMemory => ExecuteMemory,
             ArrayIndexOutOfBounds(sp, a, b) => ArrayIndexOutOfBounds(sp, a, b),
-            Math(sp, ref err) => Math(sp, err.clone()),
             Intrinsic(ref s) => Intrinsic(s.clone()),
-            OverflowingMath => OverflowingMath,
             InvalidChar(c) => InvalidChar(c),
             StackFrameLimitReached => StackFrameLimitReached,
             OutOfTls => OutOfTls,
@@ -568,6 +566,10 @@ impl<'a, 'tcx> Lift<'tcx> for interpret::EvalError<'a> {
             UnimplementedTraitSelection => UnimplementedTraitSelection,
             TypeckError => TypeckError,
             ReferencedConstant => ReferencedConstant,
+            OverflowNeg => OverflowNeg,
+            Overflow(op) => Overflow(op),
+            DivisionByZero => DivisionByZero,
+            RemainderByZero => RemainderByZero,
         };
         Some(interpret::EvalError {
             kind: kind,
diff --git a/src/librustc_mir/build/expr/as_rvalue.rs b/src/librustc_mir/build/expr/as_rvalue.rs
index a3798f3ed4c..33c80ab22a3 100644
--- a/src/librustc_mir/build/expr/as_rvalue.rs
+++ b/src/librustc_mir/build/expr/as_rvalue.rs
@@ -20,7 +20,7 @@ use rustc::middle::const_val::ConstVal;
 use rustc::middle::region;
 use rustc::ty::{self, Ty};
 use rustc::mir::*;
-use rustc::mir::interpret::{Value, PrimVal, ConstMathErr, Op};
+use rustc::mir::interpret::{Value, PrimVal, EvalErrorKind};
 use syntax_pos::Span;
 
 impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
@@ -85,7 +85,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
                     this.cfg.push_assign(block, source_info, &is_min,
                                          Rvalue::BinaryOp(BinOp::Eq, arg.to_copy(), minval));
 
-                    let err = ConstMathErr::Overflow(Op::Neg);
+                    let err = EvalErrorKind::OverflowNeg;
                     block = this.assert(block, Operand::Move(is_min), false,
                                         AssertMessage::Math(err), expr_span);
                 }
@@ -310,16 +310,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
             let val = result_value.clone().field(val_fld, ty);
             let of = result_value.field(of_fld, bool_ty);
 
-            let err = ConstMathErr::Overflow(match op {
-                BinOp::Add => Op::Add,
-                BinOp::Sub => Op::Sub,
-                BinOp::Mul => Op::Mul,
-                BinOp::Shl => Op::Shl,
-                BinOp::Shr => Op::Shr,
-                _ => {
-                    bug!("MIR build_binary_op: {:?} is not checkable", op)
-                }
-            });
+            let err = EvalErrorKind::Overflow(op);
 
             block = self.assert(block, Operand::Move(of), false,
                                 AssertMessage::Math(err), span);
@@ -331,11 +322,11 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
                 // and 2. there are two possible failure cases, divide-by-zero and overflow.
 
                 let (zero_err, overflow_err) = if op == BinOp::Div {
-                    (ConstMathErr::DivisionByZero,
-                     ConstMathErr::Overflow(Op::Div))
+                    (EvalErrorKind::DivisionByZero,
+                     EvalErrorKind::Overflow(op))
                 } else {
-                    (ConstMathErr::RemainderByZero,
-                     ConstMathErr::Overflow(Op::Rem))
+                    (EvalErrorKind::RemainderByZero,
+                     EvalErrorKind::Overflow(op))
                 };
 
                 // Check for / 0
diff --git a/src/librustc_mir/interpret/eval_context.rs b/src/librustc_mir/interpret/eval_context.rs
index f6e9994b5da..d055c979d11 100644
--- a/src/librustc_mir/interpret/eval_context.rs
+++ b/src/librustc_mir/interpret/eval_context.rs
@@ -513,7 +513,7 @@ impl<'a, 'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M
                     // it emits in debug mode) is performance, but it doesn't cost us any performance in miri.
                     // If, however, the compiler ever starts transforming unchecked intrinsics into unchecked binops,
                     // we have to go back to just ignoring the overflow here.
-                    return err!(OverflowingMath);
+                    return err!(Overflow(bin_op));
                 }
             }
 
diff --git a/src/librustc_mir/interpret/operator.rs b/src/librustc_mir/interpret/operator.rs
index 5a815e0dc67..6e7a37c2228 100644
--- a/src/librustc_mir/interpret/operator.rs
+++ b/src/librustc_mir/interpret/operator.rs
@@ -269,7 +269,7 @@ impl<'a, 'mir, 'tcx, M: Machine<'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M> {
             (Neg, ty::TyFloat(FloatTy::F32)) => Single::to_bits(-Single::from_bits(bytes)),
             (Neg, ty::TyFloat(FloatTy::F64)) => Double::to_bits(-Double::from_bits(bytes)),
 
-            (Neg, _) if bytes == (1 << (size - 1)) => return err!(OverflowingMath),
+            (Neg, _) if bytes == (1 << (size - 1)) => return err!(OverflowNeg),
             (Neg, _) => (-(bytes as i128)) as u128,
         };
 
diff --git a/src/librustc_mir/interpret/terminator/mod.rs b/src/librustc_mir/interpret/terminator/mod.rs
index aa80ee7af18..4f0e97f6e1a 100644
--- a/src/librustc_mir/interpret/terminator/mod.rs
+++ b/src/librustc_mir/interpret/terminator/mod.rs
@@ -160,9 +160,7 @@ impl<'a, 'mir, 'tcx, M: Machine<'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M> {
                                 .to_u64()?;
                             err!(ArrayIndexOutOfBounds(span, len, index))
                         }
-                        Math(ref err) => {
-                            err!(Math(terminator.source_info.span, err.clone()))
-                        }
+                        Math(ref err) => Err(err.clone().into()),
                         GeneratorResumedAfterReturn |
                         GeneratorResumedAfterPanic => unimplemented!(),
                     };
diff --git a/src/librustc_mir/transform/const_prop.rs b/src/librustc_mir/transform/const_prop.rs
index 47b2f430bc7..192ab6e17e7 100644
--- a/src/librustc_mir/transform/const_prop.rs
+++ b/src/librustc_mir/transform/const_prop.rs
@@ -328,7 +328,7 @@ impl<'b, 'a, 'tcx:'b> ConstPropagator<'b, 'a, 'tcx> {
                         } else {
                             if overflow {
                                 use rustc::mir::interpret::EvalErrorKind;
-                                let mut err = EvalErrorKind::OverflowingMath.into();
+                                let mut err = EvalErrorKind::Overflow(op).into();
                                 ecx.report(&mut err, false, Some(span));
                                 return None;
                             }
diff --git a/src/librustc_trans/mir/block.rs b/src/librustc_trans/mir/block.rs
index 7c854ef04b7..32cb6c72d58 100644
--- a/src/librustc_trans/mir/block.rs
+++ b/src/librustc_trans/mir/block.rs
@@ -311,10 +311,9 @@ impl<'a, 'tcx> FunctionCx<'a, 'tcx> {
                 // checked operation, just a comparison with the minimum
                 // value, so we have to check for the assert message.
                 if !bx.cx.check_overflow {
-                    use rustc::mir::interpret::ConstMathErr::Overflow;
-                    use rustc::mir::interpret::Op::Neg;
+                    use rustc::mir::interpret::EvalErrorKind::OverflowNeg;
 
-                    if let mir::AssertMessage::Math(Overflow(Neg)) = *msg {
+                    if let mir::AssertMessage::Math(OverflowNeg) = *msg {
                         const_cond = Some(expected);
                     }
                 }