1 files changed, 25 insertions, 13 deletions
diff --git a/samples/test/gcc5_codegen_bug.rs b/samples/test/gcc5_codegen_bug.rs
index fde709b6..60a54ea9 100644
--- a/samples/test/gcc5_codegen_bug.rs
+++ b/samples/test/gcc5_codegen_bug.rs
@@ -1,24 +1,36 @@
 // compile-flags: -O
+extern crate test;
 
 // A reduction of issue #63, where gcc5 (but not 6) will generate invalid code for the following iterator adapter's
 // `next` function (seen in librustc)
 // ::"core"::iter::Map<::"core"::iter::Chain<::"core"::iter::sources::Once<::"syntax"::ast::NodeId/*S*/,>/*S*/,::"core"::iter::Map<::"core"::slice::Iter<::"syntax"::codemap::Spanned<::"syntax"::ast::PathListItem_/*S*/,>/*S*/,>/*S*/,::"rustc"::closure_I_82<::"rustc"::hir::lowering::LoweringContext/*S*/,>/*S*/,>/*S*/,>/*S*/,::"rustc"::closure_I_83<::"rustc"::hir::lowering::LoweringContext/*S*/,>/*S*/,>
 //
-//
-
-fn main()
-{
-    // The function call is kinda needed to trigger the bug
-    // - Probably because of how it sets up `rbx` to be non-zero
-    println!("{:?}", foo(0, &[]));
-}
+// Symptom is an abort due to bad enum tag on Option<u32> when handling the second call to `it.next()`
 
-// Has to have the second map - even if it's just identity
-fn foo(n: u32, list: &[u32]) -> Vec<u32> {
-    Iterator::chain(
+fn main() {
+    let n = 0;
+    let list: &[u32] = &[1]; // List can be zero length, it's appears to be the _last_ result that leads to a bad tag.
+    // Has to have the second map - even if it's just identity, first map probably needs to exist
+    let mut it = Iterator::chain(
             ::std::iter::once(0u32),
             list.iter().map(|v| *v)
-        ).map(|id| id)
-        .collect()
+        ).map(|id| id);
+
+    // First works, and Foo is printed
+    it.next();
+    println!("Foo");
+    // Second one will crash with an abort (used in condition to avoid it being optimised out)
+    if it.next().is_none() {
+        println!("Bar");
+    }
+    else {
+        println!("Not-Bar");
+    }
+    if it.next().is_none() {
+        println!("Bar");
+    }
+    else {
+        println!("Not-Bar");
+    }
 }