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use hir::def_id::DefId;
use ty;
use ty::subst::Substs;
use ty::query::TyCtxtAt;
use mir::interpret::ConstValue;
use errors::DiagnosticBuilder;
use graphviz::IntoCow;
use syntax_pos::Span;
use syntax::ast;
use std::borrow::Cow;
use rustc_data_structures::sync::Lrc;
pub type EvalResult<'tcx> = Result<&'tcx ty::Const<'tcx>, ConstEvalErr<'tcx>>;
#[derive(Copy, Clone, Debug, Hash, RustcEncodable, RustcDecodable, Eq, PartialEq, Ord, PartialOrd)]
pub enum ConstVal<'tcx> {
Unevaluated(DefId, &'tcx Substs<'tcx>),
Value(ConstValue<'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>),
}
#[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
pub struct FrameInfo {
pub span: Span,
pub location: String,
pub lint_root: Option<ast::NodeId>,
}
#[derive(Clone, Debug)]
pub enum ConstEvalErrDescription<'a, 'tcx: 'a> {
Simple(Cow<'a, str>),
Backtrace(&'a ::mir::interpret::EvalError<'tcx>, &'a [FrameInfo]),
}
impl<'a, 'tcx> ConstEvalErrDescription<'a, 'tcx> {
pub fn into_oneline(self) -> Cow<'a, str> {
match self {
ConstEvalErrDescription::Simple(simple) => simple,
ConstEvalErrDescription::Backtrace(miri, _) => format!("{}", miri).into_cow(),
}
}
}
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)
-> Option<DiagnosticBuilder<'tcx>>
{
self.struct_generic(tcx, message, None, true)
}
pub fn report_as_error(&self,
tcx: TyCtxtAt<'a, 'gcx, 'tcx>,
message: &str
) {
let err = self.struct_generic(tcx, message, None, true);
if let Some(mut err) = err {
err.emit();
}
}
pub fn report_as_lint(&self,
tcx: TyCtxtAt<'a, 'gcx, 'tcx>,
message: &str,
lint_root: ast::NodeId,
) {
let lint = self.struct_generic(
tcx,
message,
Some(lint_root),
false,
);
if let Some(mut lint) = lint {
lint.emit();
}
}
fn struct_generic(
&self,
tcx: TyCtxtAt<'a, 'gcx, 'tcx>,
message: &str,
lint_root: Option<ast::NodeId>,
as_err: bool,
) -> 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, as_err)?.emit();
(miri.to_string(), frames)
},
_ => (miri.to_string(), frames),
}
}
_ => (self.description().into_oneline().to_string(), &[]),
};
trace!("reporting const eval failure at {:?}", self.span);
let mut err = if as_err {
struct_error(tcx, message)
} else {
let node_id = frames
.iter()
.rev()
.filter_map(|frame| frame.lint_root)
.next()
.or(lint_root)
.expect("some part of a failing const eval must be local");
tcx.struct_span_lint_node(
::rustc::lint::builtin::CONST_ERR,
node_id,
tcx.span,
message,
)
};
err.span_label(self.span, msg);
for FrameInfo { span, location, .. } in frames {
err.span_label(*span, format!("inside call to `{}`", location));
}
Some(err)
}
}
pub fn struct_error<'a, 'gcx, 'tcx>(
tcx: TyCtxtAt<'a, 'gcx, 'tcx>,
msg: &str,
) -> DiagnosticBuilder<'tcx> {
struct_span_err!(tcx.sess, tcx.span, E0080, "{}", msg)
}