From 29fe07641f67c78c0f305a8cd4dbe816e8dafd7b Mon Sep 17 00:00:00 2001
From: Vadim Petrochenkov <vadim.petrochenkov@gmail.com>
Date: Mon, 19 Aug 2019 23:10:07 +0300
Subject: [PATCH] Add a test for an opaque macro eagerly expanding its
 arguments

---
 src/test/ui/hygiene/eager-from-opaque.rs     | 18 ++++++++++++++++++
 src/test/ui/hygiene/eager-from-opaque.stderr |  8 ++++++++
 2 files changed, 26 insertions(+)
 create mode 100644 src/test/ui/hygiene/eager-from-opaque.rs
 create mode 100644 src/test/ui/hygiene/eager-from-opaque.stderr

diff --git a/src/test/ui/hygiene/eager-from-opaque.rs b/src/test/ui/hygiene/eager-from-opaque.rs
new file mode 100644
index 000000000000..57925d626b9d
--- /dev/null
+++ b/src/test/ui/hygiene/eager-from-opaque.rs
@@ -0,0 +1,18 @@
+// Opaque macro can eagerly expand its input without breaking its resolution.
+// Regression test for issue #63685.
+
+macro_rules! foo {
+    () => {
+        "foo"
+    };
+}
+
+macro_rules! bar {
+    () => {
+        foo!() //~ ERROR cannot find macro `foo!` in this scope
+    };
+}
+
+fn main() {
+    format_args!(bar!());
+}
diff --git a/src/test/ui/hygiene/eager-from-opaque.stderr b/src/test/ui/hygiene/eager-from-opaque.stderr
new file mode 100644
index 000000000000..8db96e6ac95e
--- /dev/null
+++ b/src/test/ui/hygiene/eager-from-opaque.stderr
@@ -0,0 +1,8 @@
+error: cannot find macro `foo!` in this scope
+  --> $DIR/eager-from-opaque.rs:12:9
+   |
+LL |         foo!()
+   |         ^^^
+
+error: aborting due to previous error
+