use rustc::mir::*;
use rustc::mir::transform::{MirSuite, MirPassIndex, MirSource};
use rustc::ty::TyCtxt;
+use rustc::ty::item_path;
use rustc_data_structures::fx::FxHashMap;
use rustc_data_structures::indexed_vec::{Idx};
use std::fmt::Display;
return;
}
- let node_path = tcx.item_path_str(tcx.hir.local_def_id(source.item_id()));
+ let node_path = item_path::with_forced_impl_filename_line(|| { // see notes on #41697 below
+ tcx.item_path_str(tcx.hir.local_def_id(source.item_id()))
+ });
dump_matched_mir_node(tcx, pass_num, pass_name, &node_path,
disambiguator, source, mir);
for (index, promoted_mir) in mir.promoted.iter_enumerated() {
Some(ref filters) => filters,
};
let node_id = source.item_id();
- let node_path = tcx.item_path_str(tcx.hir.local_def_id(node_id));
+ let node_path = item_path::with_forced_impl_filename_line(|| { // see notes on #41697 below
+ tcx.item_path_str(tcx.hir.local_def_id(node_id))
+ });
filters.split("&")
.any(|filter| {
filter == "all" ||
})
}
+// #41697 -- we use `with_forced_impl_filename_line()` because
+// `item_path_str()` would otherwise trigger `type_of`, and this can
+// run while we are already attempting to evaluate `type_of`.
+
fn dump_matched_mir_node<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
pass_num: Option<(MirSuite, MirPassIndex)>,
pass_name: &str,
--- /dev/null
+// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// compile-flags:-Zdump-mir=NEVER_MATCHED
+
+// Regression test for #41697. Using dump-mir was triggering
+// artificial cycles: during type-checking, we had to get the MIR for
+// the constant expressions in `[u8; 2]`, which in turn would trigger
+// an attempt to get the item-path, which in turn would request the
+// types of the impl, which would trigger a cycle. We supressed this
+// cycle now by forcing mir-dump to avoid asking for types of an impl.
+
+#![feature(rustc_attrs)]
+
+use std::sync::Arc;
+
+trait Foo {
+ fn get(&self) -> [u8; 2];
+}
+
+impl Foo for [u8; 2] {
+ fn get(&self) -> [u8; 2] {
+ *self
+ }
+}
+
+struct Bar<T: ?Sized>(T);
+
+fn unsize_fat_ptr<'a>(x: &'a Bar<Foo + Send + 'a>) -> &'a Bar<Foo + 'a> {
+ x
+}
+
+fn unsize_nested_fat_ptr(x: Arc<Foo + Send>) -> Arc<Foo> {
+ x
+}
+
+fn main() {
+ let x: Box<Bar<Foo + Send>> = Box::new(Bar([1,2]));
+ assert_eq!(unsize_fat_ptr(&*x).0.get(), [1, 2]);
+
+ let x: Arc<Foo + Send> = Arc::new([3, 4]);
+ assert_eq!(unsize_nested_fat_ptr(x).get(), [3, 4]);
+}