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ICE more gracefully in constant evaluation when float parsing fails

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Ideally float parsing wouldn't fail at all, but for the moment let's give a helpful message.

Fixes #31109
This commit is contained in:
Robin Kruppe 2016-02-04 16:18:20 +01:00
parent 33713bca49
commit a76cb45e34
2 changed files with 24 additions and 3 deletions
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12
src/librustc/middle/const_eval.rs
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@ -26,6 +26,7 @@ use middle::ty::{self, Ty};
use middle::astconv_util::ast_ty_to_prim_ty;
use util::num::ToPrimitive;
use util::nodemap::NodeMap;
use session::Session;
use graphviz::IntoCow;
use syntax::ast;
@ -1117,7 +1118,7 @@ pub fn eval_const_expr_partial<'tcx>(tcx: &ty::ctxt<'tcx>,
debug!("const call({:?})", call_args);
try!(eval_const_expr_partial(tcx, &**result, ty_hint, Some(&call_args)))
},
hir::ExprLit(ref lit) => lit_to_const(&**lit, ety),
hir::ExprLit(ref lit) => lit_to_const(tcx.sess, e.span, &**lit, ety),
hir::ExprBlock(ref block) => {
match block.expr {
Some(ref expr) => try!(eval_const_expr_partial(tcx, &**expr, ty_hint, fn_args)),
@ -1319,7 +1320,7 @@ fn cast_const<'tcx>(tcx: &ty::ctxt<'tcx>, val: ConstVal, ty: Ty) -> CastResult {
}
}
fn lit_to_const(lit: &ast::Lit, ty_hint: Option<Ty>) -> ConstVal {
fn lit_to_const(sess: &Session, span: Span, lit: &ast::Lit, ty_hint: Option<Ty>) -> ConstVal {
match lit.node {
ast::LitStr(ref s, _) => Str((*s).clone()),
ast::LitByteStr(ref data) => {
@ -1339,7 +1340,12 @@ fn lit_to_const(lit: &ast::Lit, ty_hint: Option<Ty>) -> ConstVal {
ast::LitInt(n, ast::UnsignedIntLit(_)) => Uint(n),
ast::LitFloat(ref n, _) |
ast::LitFloatUnsuffixed(ref n) => {
Float(n.parse::<f64>().unwrap() as f64)
if let Ok(x) = n.parse::<f64>() {
Float(x)
} else {
// FIXME(#31407) this is only necessary because float parsing is buggy
sess.span_bug(span, "could not evaluate float literal (see issue #31407)");
}
}
ast::LitBool(b) => Bool(b)
}