From 80929e17ae4806a1d2fb5cf282f430c5e34f7796 Mon Sep 17 00:00:00 2001
From: Ralf Jung <post@ralfj.de>
Date: Mon, 10 Aug 2020 09:04:37 +0200
Subject: [PATCH] add test for unused ill-formed constant

also use better span in TopFrameInfo
---
 src/diagnostics.rs                    |  2 +-
 tests/compile-fail/erroneous_const.rs | 19 +++++++++++++++++++
 2 files changed, 20 insertions(+), 1 deletion(-)
 create mode 100644 tests/compile-fail/erroneous_const.rs

diff --git a/src/diagnostics.rs b/src/diagnostics.rs
index ca3dd4dd66f..eed60c2696e 100644
--- a/src/diagnostics.rs
+++ b/src/diagnostics.rs
@@ -227,7 +227,7 @@ fn preprocess_diagnostics(&self) -> TopFrameInfo<'tcx> {
         TopFrameInfo {
             stack_size: this.active_thread_stack().len(),
             instance: Some(frame.instance),
-            span: frame.current_source_info().map_or(DUMMY_SP, |si| si.span),
+            span: frame.current_span(),
         }
     }
 
diff --git a/tests/compile-fail/erroneous_const.rs b/tests/compile-fail/erroneous_const.rs
new file mode 100644
index 00000000000..287e0735814
--- /dev/null
+++ b/tests/compile-fail/erroneous_const.rs
@@ -0,0 +1,19 @@
+//! Make sure we detect erroneous constants post-monomorphization even when they are unused.
+//! (https://github.com/rust-lang/miri/issues/1382)
+#![feature(const_panic)]
+#![feature(never_type)]
+#![warn(warnings, const_err)]
+
+struct PrintName<T>(T);
+impl<T> PrintName<T> {
+    const VOID: ! = panic!(); //~WARN any use of this value will cause an error
+}
+
+fn no_codegen<T>() {
+    if false {
+        let _ = PrintName::<T>::VOID; //~ERROR referenced constant has errors
+    }
+}
+fn main() {
+    no_codegen::<i32>();
+}
-- 
2.44.0