Add codegen tests for the genericity of fold closures

2 files changed, 24 insertions, 0 deletions

diff --git a/src/test/codegen/iter-fold-closure-no-dupes.rs b/src/test/codegen/iter-fold-closure-no-dupes.rs
new file mode 100644
index 00000000000..ec58f7068ab
--- /dev/null
+++ b/src/test/codegen/iter-fold-closure-no-dupes.rs
@@ -0,0 +1,14 @@
+//! Check that fold closures aren't duplicated for each iterator type.
+// compile-flags: -C opt-level=0
+
+fn main() {
+    (0i32..10).by_ref().count();
+    (0i32..=10).by_ref().count();
+}
+
+// `count` calls `fold`, which calls `try_fold` -- find the `fold` closure:
+// CHECK: {{^define.*Iterator::fold::.*closure}}
+//
+// Only one closure is needed for both `count` calls, even from different
+// monomorphized iterator types, as it's only generic over the item type.
+// CHECK-NOT: {{^define.*Iterator::fold::.*closure}}
diff --git a/src/test/codegen/iter-fold-closure-no-iterator.rs b/src/test/codegen/iter-fold-closure-no-iterator.rs
new file mode 100644
index 00000000000..fbeafd5f395
--- /dev/null
+++ b/src/test/codegen/iter-fold-closure-no-iterator.rs
@@ -0,0 +1,10 @@
+//! Check that fold closures aren't generic in the iterator type.
+// compile-flags: -C opt-level=0
+
+fn main() {
+    (0i32..10).by_ref().count();
+}
+
+// `count` calls `fold`, which calls `try_fold` -- that `fold` closure should
+// not be generic in the iterator type, only in the item type.
+// CHECK-NOT: {{^define.*Iterator::fold::.*closure.*Range}}