Eliminate old CTFE's `ErrKind`

10 files changed, 50 insertions, 114 deletions

diff --git a/src/librustc/ich/impls_ty.rs b/src/librustc/ich/impls_ty.rs
index 684a1d29658..0d3ac8edbd3 100644
--- a/src/librustc/ich/impls_ty.rs
+++ b/src/librustc/ich/impls_ty.rs
@@ -505,7 +505,7 @@ impl_stable_hash_for!(struct ty::Const<'tcx> {
 
 impl_stable_hash_for!(struct ::middle::const_val::ConstEvalErr<'tcx> {
     span,
-    kind
+    data
 });
 
 impl_stable_hash_for!(struct ::middle::const_val::FrameInfo {
@@ -514,29 +514,6 @@ impl_stable_hash_for!(struct ::middle::const_val::FrameInfo {
     location
 });
 
-impl<'a, 'gcx> HashStable<StableHashingContext<'a>>
-for ::middle::const_val::ErrKind<'gcx> {
-    fn hash_stable<W: StableHasherResult>(&self,
-                                          hcx: &mut StableHashingContext<'a>,
-                                          hasher: &mut StableHasher<W>) {
-        use middle::const_val::ErrKind::*;
-
-        mem::discriminant(self).hash_stable(hcx, hasher);
-
-        match *self {
-            TypeckError |
-            CouldNotResolve |
-            CheckMatchError => {
-                // nothing to do
-            }
-            Miri(ref err, ref trace) => {
-                err.hash_stable(hcx, hasher);
-                trace.hash_stable(hcx, hasher);
-            },
-        }
-    }
-}
-
 impl_stable_hash_for!(struct ty::ClosureSubsts<'tcx> { substs });
 impl_stable_hash_for!(struct ty::GeneratorSubsts<'tcx> { substs });
 
@@ -593,6 +570,8 @@ for ::mir::interpret::EvalErrorKind<'gcx, O> {
             ReadFromReturnPointer |
             UnimplementedTraitSelection |
             TypeckError |
+            ResolutionFailed |
+            CheckMatchError |
             DerefFunctionPointer |
             ExecuteMemory |
             OverflowNeg |
diff --git a/src/librustc/middle/const_val.rs b/src/librustc/middle/const_val.rs
index 8a824c66ec4..588265dffa7 100644
--- a/src/librustc/middle/const_val.rs
+++ b/src/librustc/middle/const_val.rs
@@ -33,16 +33,7 @@ pub enum ConstVal<'tcx> {
 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
 pub struct ConstEvalErr<'tcx> {
     pub span: Span,
-    pub kind: Lrc<ErrKind<'tcx>>,
-}
-
-#[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
-pub enum ErrKind<'tcx> {
-
-    CouldNotResolve,
-    TypeckError,
-    CheckMatchError,
-    Miri(::mir::interpret::EvalError<'tcx>, Vec<FrameInfo>),
+    pub data: Lrc<(::mir::interpret::EvalError<'tcx>, Vec<FrameInfo>)>,
 }
 
 #[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
@@ -69,25 +60,6 @@ impl<'a, 'tcx> ConstEvalErrDescription<'a, 'tcx> {
 }
 
 impl<'a, 'gcx, 'tcx> ConstEvalErr<'tcx> {
-    pub fn description(&'a self) -> ConstEvalErrDescription<'a, 'tcx> {
-        use self::ErrKind::*;
-        use self::ConstEvalErrDescription::*;
-
-        macro_rules! simple {
-            ($msg:expr) => ({ Simple($msg.into_cow()) });
-            ($fmt:expr, $($arg:tt)+) => ({
-                Simple(format!($fmt, $($arg)+).into_cow())
-            })
-        }
-
-        match *self.kind {
-            CouldNotResolve => simple!("could not resolve"),
-            TypeckError => simple!("type-checking failed"),
-            CheckMatchError => simple!("match-checking failed"),
-            Miri(ref err, ref trace) => Backtrace(err, trace),
-        }
-    }
-
     pub fn struct_error(&self,
         tcx: TyCtxtAt<'a, 'gcx, 'tcx>,
         message: &str)
@@ -127,24 +99,19 @@ impl<'a, 'gcx, 'tcx> ConstEvalErr<'tcx> {
         message: &str,
         lint_root: Option<ast::NodeId>,
     ) -> Option<DiagnosticBuilder<'tcx>> {
-        let (msg, frames): (_, &[_]) = match *self.kind {
-            ErrKind::TypeckError | ErrKind::CheckMatchError => return None,
-            ErrKind::Miri(ref miri, ref frames) => {
-                match miri.kind {
-                    ::mir::interpret::EvalErrorKind::TypeckError |
-                    ::mir::interpret::EvalErrorKind::Layout(_) => return None,
-                    ::mir::interpret::EvalErrorKind::ReferencedConstant(ref inner) => {
-                        inner.struct_generic(tcx, "referenced constant", lint_root)?.emit();
-                        (miri.to_string(), frames)
-                    },
-                    _ => (miri.to_string(), frames),
-                }
-            }
-            _ => (self.description().into_oneline().to_string(), &[]),
-        };
+        match self.data.0.kind {
+            ::mir::interpret::EvalErrorKind::TypeckError |
+            ::mir::interpret::EvalErrorKind::ResolutionFailed |
+            ::mir::interpret::EvalErrorKind::CheckMatchError |
+            ::mir::interpret::EvalErrorKind::Layout(_) => return None,
+            ::mir::interpret::EvalErrorKind::ReferencedConstant(ref inner) => {
+                inner.struct_generic(tcx, "referenced constant", lint_root)?.emit();
+            },
+            _ => {},
+        }
         trace!("reporting const eval failure at {:?}", self.span);
         let mut err = if let Some(lint_root) = lint_root {
-            let node_id = frames
+            let node_id = self.data.1
                 .iter()
                 .rev()
                 .filter_map(|frame| frame.lint_root)
@@ -159,8 +126,8 @@ impl<'a, 'gcx, 'tcx> ConstEvalErr<'tcx> {
         } else {
             struct_error(tcx, message)
         };
-        err.span_label(self.span, msg);
-        for FrameInfo { span, location, .. } in frames {
+        err.span_label(self.span, self.data.0.to_string());
+        for FrameInfo { span, location, .. } in &self.data.1 {
             err.span_label(*span, format!("inside call to `{}`", location));
         }
         Some(err)
diff --git a/src/librustc/mir/interpret/error.rs b/src/librustc/mir/interpret/error.rs
index bf5bae6b20c..4771875760d 100644
--- a/src/librustc/mir/interpret/error.rs
+++ b/src/librustc/mir/interpret/error.rs
@@ -150,6 +150,9 @@ pub enum EvalErrorKind<'tcx, O> {
     UnimplementedTraitSelection,
     /// Abort in case type errors are reached
     TypeckError,
+    /// Resolution can fail if we are in a too generic context
+    ResolutionFailed,
+    CheckMatchError,
     /// Cannot compute this constant because it depends on another one
     /// which already produced an error
     ReferencedConstant(ConstEvalErr<'tcx>),
@@ -268,6 +271,10 @@ impl<'tcx, O> EvalErrorKind<'tcx, O> {
                 "there were unresolved type arguments during trait selection",
             TypeckError =>
                 "encountered constants with type errors, stopping evaluation",
+            ResolutionFailed =>
+                "encountered overly generic constant",
+            CheckMatchError =>
+                "match checking failed",
             ReferencedConstant(_) =>
                 "referenced constant has errors",
             Overflow(mir::BinOp::Add) => "attempt to add with overflow",
diff --git a/src/librustc/traits/fulfill.rs b/src/librustc/traits/fulfill.rs
index b3f56d4de65..288634a800c 100644
--- a/src/librustc/traits/fulfill.rs
+++ b/src/librustc/traits/fulfill.rs
@@ -16,7 +16,8 @@ use rustc_data_structures::obligation_forest::{Error, ForestObligation, Obligati
 use rustc_data_structures::obligation_forest::{ObligationProcessor, ProcessResult};
 use std::marker::PhantomData;
 use hir::def_id::DefId;
-use middle::const_val::{ConstEvalErr, ErrKind};
+use middle::const_val::ConstEvalErr;
+use mir::interpret::EvalErrorKind;
 
 use super::CodeAmbiguity;
 use super::CodeProjectionError;
@@ -498,10 +499,11 @@ impl<'a, 'b, 'gcx, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'b, 'gcx,
                                             CodeSelectionError(ConstEvalFailure(err)))
                                     }
                                 } else {
+                                    let err = EvalErrorKind::ResolutionFailed.into();
                                     ProcessResult::Error(
                                         CodeSelectionError(ConstEvalFailure(ConstEvalErr {
                                             span: obligation.cause.span,
-                                            kind: ErrKind::CouldNotResolve.into(),
+                                            data: (err, Vec::new()).into(),
                                         }))
                                     )
                                 }
diff --git a/src/librustc/ty/structural_impls.rs b/src/librustc/ty/structural_impls.rs
index 79a63111850..2bc4698c44a 100644
--- a/src/librustc/ty/structural_impls.rs
+++ b/src/librustc/ty/structural_impls.rs
@@ -13,7 +13,7 @@
 //! hand, though we've recently added some macros (e.g.,
 //! `BraceStructLiftImpl!`) to help with the tedium.
 
-use middle::const_val::{self, ConstVal, ConstEvalErr};
+use middle::const_val::{ConstVal, ConstEvalErr};
 use ty::{self, Lift, Ty, TyCtxt};
 use ty::fold::{TypeFoldable, TypeFolder, TypeVisitor};
 use rustc_data_structures::accumulate_vec::AccumulateVec;
@@ -462,10 +462,10 @@ impl<'a, 'tcx> Lift<'tcx> for ty::error::TypeError<'a> {
 impl<'a, 'tcx> Lift<'tcx> for ConstEvalErr<'a> {
     type Lifted = ConstEvalErr<'tcx>;
     fn lift_to_tcx<'b, 'gcx>(&self, tcx: TyCtxt<'b, 'gcx, 'tcx>) -> Option<Self::Lifted> {
-        tcx.lift(&*self.kind).map(|kind| {
+        tcx.lift(&self.data.0).map(|data| {
             ConstEvalErr {
                 span: self.span,
-                kind: Lrc::new(kind),
+                data: Lrc::new((data, self.data.1.clone())),
             }
         })
     }
@@ -577,6 +577,8 @@ impl<'a, 'tcx, O: Lift<'tcx>> Lift<'tcx> for interpret::EvalErrorKind<'a, O> {
             PathNotFound(ref v) => PathNotFound(v.clone()),
             UnimplementedTraitSelection => UnimplementedTraitSelection,
             TypeckError => TypeckError,
+            ResolutionFailed => ResolutionFailed,
+            CheckMatchError => CheckMatchError,
             ReferencedConstant(ref err) => ReferencedConstant(tcx.lift(err)?),
             OverflowNeg => OverflowNeg,
             Overflow(op) => Overflow(op),
@@ -588,20 +590,6 @@ impl<'a, 'tcx, O: Lift<'tcx>> Lift<'tcx> for interpret::EvalErrorKind<'a, O> {
     }
 }
 
-impl<'a, 'tcx> Lift<'tcx> for const_val::ErrKind<'a> {
-    type Lifted = const_val::ErrKind<'tcx>;
-    fn lift_to_tcx<'b, 'gcx>(&self, tcx: TyCtxt<'b, 'gcx, 'tcx>) -> Option<Self::Lifted> {
-        use middle::const_val::ErrKind::*;
-
-        Some(match *self {
-            CouldNotResolve => CouldNotResolve,
-            TypeckError => TypeckError,
-            CheckMatchError => CheckMatchError,
-            Miri(ref e, ref frames) => return tcx.lift(e).map(|e| Miri(e, frames.clone())),
-        })
-    }
-}
-
 impl<'a, 'tcx> Lift<'tcx> for ty::layout::LayoutError<'a> {
     type Lifted = ty::layout::LayoutError<'tcx>;
     fn lift_to_tcx<'b, 'gcx>(&self, tcx: TyCtxt<'b, 'gcx, 'tcx>) -> Option<Self::Lifted> {
diff --git a/src/librustc_mir/interpret/const_eval.rs b/src/librustc_mir/interpret/const_eval.rs
index 592c9dbe6ff..831b3bfd8d1 100644
--- a/src/librustc_mir/interpret/const_eval.rs
+++ b/src/librustc_mir/interpret/const_eval.rs
@@ -1,6 +1,5 @@
 use rustc::hir;
-use rustc::middle::const_val::{ConstEvalErr, ErrKind};
-use rustc::middle::const_val::ErrKind::{TypeckError, CheckMatchError};
+use rustc::middle::const_val::{ConstEvalErr};
 use rustc::mir;
 use rustc::ty::{self, TyCtxt, Ty, Instance};
 use rustc::ty::layout::{self, LayoutOf, Primitive};
@@ -18,7 +17,6 @@ use super::{Place, EvalContext, StackPopCleanup, ValTy, PlaceExtra, Memory, Memo
 
 use std::fmt;
 use std::error::Error;
-use rustc_data_structures::sync::Lrc;
 
 pub fn mk_borrowck_eval_cx<'a, 'mir, 'tcx>(
     tcx: TyCtxt<'a, 'tcx, 'tcx>,
@@ -106,7 +104,7 @@ pub fn value_to_const_value<'tcx>(
             let (frames, span) = ecx.generate_stacktrace(None);
             let err = ConstEvalErr {
                 span,
-                kind: ErrKind::Miri(err, frames).into(),
+                data: (err, frames).into(),
             };
             err.report_as_error(
                 ecx.tcx,
@@ -467,9 +465,8 @@ pub fn const_val_field<'a, 'tcx>(
     })();
     result.map_err(|err| {
         let (trace, span) = ecx.generate_stacktrace(None);
-        let err = ErrKind::Miri(err, trace);
         ConstEvalErr {
-            kind: err.into(),
+            data: (err, trace).into(),
             span,
         }
     })
@@ -540,7 +537,7 @@ pub fn const_eval_provider<'a, 'tcx>(
         // Do match-check before building MIR
         if tcx.check_match(def_id).is_err() {
             return Err(ConstEvalErr {
-                kind: Lrc::new(CheckMatchError),
+                data: (EvalErrorKind::CheckMatchError.into(), Vec::new()).into(),
                 span,
             });
         }
@@ -552,7 +549,7 @@ pub fn const_eval_provider<'a, 'tcx>(
         // Do not continue into miri if typeck errors occurred; it will fail horribly
         if tables.tainted_by_errors {
             return Err(ConstEvalErr {
-                kind: Lrc::new(TypeckError),
+                data: (EvalErrorKind::TypeckError.into(), Vec::new()).into(),
                 span,
             });
         }
@@ -566,9 +563,8 @@ pub fn const_eval_provider<'a, 'tcx>(
         Ok(value_to_const_value(&ecx, val, miri_ty))
     }).map_err(|err| {
         let (trace, span) = ecx.generate_stacktrace(None);
-        let err = ErrKind::Miri(err, trace);
         let err = ConstEvalErr {
-            kind: err.into(),
+            data: (err, trace).into(),
             span,
         };
         if tcx.is_static(def_id).is_some() {
diff --git a/src/librustc_mir/interpret/eval_context.rs b/src/librustc_mir/interpret/eval_context.rs
index ea667273ece..32ec48e15b4 100644
--- a/src/librustc_mir/interpret/eval_context.rs
+++ b/src/librustc_mir/interpret/eval_context.rs
@@ -280,7 +280,7 @@ impl<'a, 'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M
             self.param_env,
             def_id,
             substs,
-        ).ok_or_else(|| EvalErrorKind::TypeckError.into()) // turn error prop into a panic to expose associated type in const issue
+        ).ok_or_else(|| EvalErrorKind::ResolutionFailed.into())
     }
 
     pub(super) fn type_is_sized(&self, ty: Ty<'tcx>) -> bool {
@@ -739,7 +739,7 @@ impl<'a, 'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> EvalContext<'a, 'mir, 'tcx, M
                                     self.param_env,
                                     def_id,
                                     substs,
-                                ).ok_or_else(|| EvalErrorKind::TypeckError.into());
+                                ).ok_or_else(|| EvalErrorKind::ResolutionFailed.into());
                                 let fn_ptr = self.memory.create_fn_alloc(instance?);
                                 let valty = ValTy {
                                     value: Value::Scalar(fn_ptr.into()),
diff --git a/src/librustc_mir/interpret/memory.rs b/src/librustc_mir/interpret/memory.rs
index ad571fbe90d..3810aedb90c 100644
--- a/src/librustc_mir/interpret/memory.rs
+++ b/src/librustc_mir/interpret/memory.rs
@@ -285,10 +285,10 @@ impl<'a, 'mir, 'tcx, M: Machine<'mir, 'tcx>> Memory<'a, 'mir, 'tcx, M> {
             instance,
             promoted: None,
         };
-        self.tcx.const_eval(ParamEnv::reveal_all().and(gid)).map_err(|_| {
+        self.tcx.const_eval(ParamEnv::reveal_all().and(gid)).map_err(|err| {
             // no need to report anything, the const_eval call takes care of that for statics
             assert!(self.tcx.is_static(def_id).is_some());
-            EvalErrorKind::TypeckError.into()
+            EvalErrorKind::ReferencedConstant(err).into()
         }).map(|val| {
             let const_val = match val.val {
                 ConstVal::Value(val) => val,
diff --git a/src/librustc_mir/monomorphize/collector.rs b/src/librustc_mir/monomorphize/collector.rs
index ef69cb574e0..8e13ac3d415 100644
--- a/src/librustc_mir/monomorphize/collector.rs
+++ b/src/librustc_mir/monomorphize/collector.rs
@@ -1209,15 +1209,12 @@ fn collect_neighbours<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
         match tcx.const_eval(param_env.and(cid)) {
             Ok(val) => collect_const(tcx, val, instance.substs, output),
             Err(err) => {
-                use rustc::middle::const_val::ErrKind;
                 use rustc::mir::interpret::EvalErrorKind;
-                if let ErrKind::Miri(ref miri, ..) = *err.kind {
-                    if let EvalErrorKind::ReferencedConstant(_) = miri.kind {
-                        err.report_as_error(
-                            tcx.at(mir.promoted[i].span),
-                            "erroneous constant used",
-                        );
-                    }
+                if let EvalErrorKind::ReferencedConstant(_) = err.data.0.kind {
+                    err.report_as_error(
+                        tcx.at(mir.promoted[i].span),
+                        "erroneous constant used",
+                    );
                 }
             },
         }
diff --git a/src/librustc_mir/transform/const_prop.rs b/src/librustc_mir/transform/const_prop.rs
index 24382815084..ee53cfb7b6b 100644
--- a/src/librustc_mir/transform/const_prop.rs
+++ b/src/librustc_mir/transform/const_prop.rs
@@ -17,7 +17,7 @@ use rustc::mir::{Constant, Literal, Location, Place, Mir, Operand, Rvalue, Local
 use rustc::mir::{NullOp, StatementKind, Statement, BasicBlock, LocalKind};
 use rustc::mir::{TerminatorKind, ClearCrossCrate, SourceInfo, BinOp, ProjectionElem};
 use rustc::mir::visit::{Visitor, PlaceContext};
-use rustc::middle::const_val::{ConstVal, ConstEvalErr, ErrKind};
+use rustc::middle::const_val::{ConstVal, ConstEvalErr};
 use rustc::ty::{TyCtxt, self, Instance};
 use rustc::mir::interpret::{Value, Scalar, GlobalId, EvalResult};
 use interpret::EvalContext;
@@ -145,7 +145,7 @@ impl<'b, 'a, 'tcx:'b> ConstPropagator<'b, 'a, 'tcx> {
                 let (frames, span) = self.ecx.generate_stacktrace(None);
                 let err = ConstEvalErr {
                     span,
-                    kind: ErrKind::Miri(err, frames).into(),
+                    data: (err, frames).into(),
                 };
                 err.report_as_lint(
                     self.ecx.tcx,