From 81cc4822653b1f80729e8d50f9527c1fd0e5394f Mon Sep 17 00:00:00 2001
From: "Felix S. Klock II" <pnkfelix@pnkfx.org>
Date: Mon, 8 Jul 2019 22:26:15 +0200
Subject: [PATCH 1/2] Avoid infinite looping in `print_def_path`.
---
src/librustc/ty/print/pretty.rs | 26 +++++++++++++++++++++++++-
1 file changed, 25 insertions(+), 1 deletion(-)
diff --git a/src/librustc/ty/print/pretty.rs b/src/librustc/ty/print/pretty.rs
index cb0ac0f07f287..e889f2edef2bb 100644
--- a/src/librustc/ty/print/pretty.rs
+++ b/src/librustc/ty/print/pretty.rs
@@ -228,8 +228,27 @@ pub trait PrettyPrinter<'tcx>:
/// from at least one local module and returns true. If the crate defining `def_id` is
/// declared with an `extern crate`, the path is guaranteed to use the `extern crate`.
fn try_print_visible_def_path(
+ self,
+ def_id: DefId,
+ ) -> Result<(Self, bool), Self::Error> {
+ let mut callers = Vec::new();
+ self.try_print_visible_def_path_recur(def_id, &mut callers)
+ }
+
+ /// Does the work of `try_print_visible_def_path`, building the
+ /// full definition path recursively before attempting to
+ /// post-process it into the valid and visible version that
+ /// accounts for re-exports.
+ ///
+ /// This method should only be callled by itself or
+ /// `try_print_visible_def_path`.
+ ///
+ /// `callers` is a chain of visible_parent's leading to `def_id`,
+ /// to support cycle detection during recursion.
+ fn try_print_visible_def_path_recur(
mut self,
def_id: DefId,
+ callers: &mut Vec<DefId>,
) -> Result<(Self, bool), Self::Error> {
define_scoped_cx!(self);
@@ -302,14 +321,19 @@ pub trait PrettyPrinter<'tcx>:
Some(parent) => parent,
None => return Ok((self, false)),
};
+ if callers.contains(&visible_parent) {
+ return Ok((self, false));
+ }
+ callers.push(visible_parent);
// HACK(eddyb) this bypasses `path_append`'s prefix printing to avoid
// knowing ahead of time whether the entire path will succeed or not.
// To support printers that do not implement `PrettyPrinter`, a `Vec` or
// linked list on the stack would need to be built, before any printing.
- match self.try_print_visible_def_path(visible_parent)? {
+ match self.try_print_visible_def_path_recur(visible_parent, callers)? {
(cx, false) => return Ok((cx, false)),
(cx, true) => self = cx,
}
+ callers.pop();
let actual_parent = self.tcx().parent(def_id);
debug!(
"try_print_visible_def_path: visible_parent={:?} actual_parent={:?}",
From 4c58b29285015f6d7739e342e09bf3be7eea3b12 Mon Sep 17 00:00:00 2001
From: "Felix S. Klock II" <pnkfelix@pnkfx.org>
Date: Mon, 8 Jul 2019 17:04:02 +0200
Subject: [PATCH 2/2] regression test.
---
src/test/ui/issues/auxiliary/xcrate-issue-61711-b.rs | 5 +++++
.../issues/issue-61711-once-caused-rustc-inf-loop.rs | 11 +++++++++++
2 files changed, 16 insertions(+)
create mode 100644 src/test/ui/issues/auxiliary/xcrate-issue-61711-b.rs
create mode 100644 src/test/ui/issues/issue-61711-once-caused-rustc-inf-loop.rs
diff --git a/src/test/ui/issues/auxiliary/xcrate-issue-61711-b.rs b/src/test/ui/issues/auxiliary/xcrate-issue-61711-b.rs
new file mode 100644
index 0000000000000..88a040529e709
--- /dev/null
+++ b/src/test/ui/issues/auxiliary/xcrate-issue-61711-b.rs
@@ -0,0 +1,5 @@
+// edition:2018
+#![crate_type="lib"]
+#![crate_name="xcrate_issue_61711_b"]
+pub struct Struct;
+pub use crate as alias;
diff --git a/src/test/ui/issues/issue-61711-once-caused-rustc-inf-loop.rs b/src/test/ui/issues/issue-61711-once-caused-rustc-inf-loop.rs
new file mode 100644
index 0000000000000..8fc09c89f786b
--- /dev/null
+++ b/src/test/ui/issues/issue-61711-once-caused-rustc-inf-loop.rs
@@ -0,0 +1,11 @@
+// Issue 61711: A crate pub re-exporting `crate` was causing an
+// infinite loop.
+
+// edition:2018
+// aux-build:xcrate-issue-61711-b.rs
+// compile-flags:--extern xcrate_issue_61711_b
+
+// run-pass
+
+fn f<F: Fn(xcrate_issue_61711_b::Struct)>(_: F) { }
+fn main() { }