From 1b0af1ee6030b233eba7d29629c5ea995d5df944 Mon Sep 17 00:00:00 2001
From: Steven Schveighoffer <schveiguy@yahoo.com>
Date: Mon, 18 Jun 2018 09:34:22 -0400
Subject: [PATCH] Fix issue 18996 - ProtoGC should support removing roots and
 ranges that were not originally added. Behavior is now consistent with
 conservative GC.

---
 src/gc/impl/proto/gc.d         |  2 --
 test/init_fini/Makefile        |  2 +-
 test/init_fini/src/test18996.d | 13 +++++++++++++
 3 files changed, 14 insertions(+), 3 deletions(-)
 create mode 100644 test/init_fini/src/test18996.d

diff --git a/src/gc/impl/proto/gc.d b/src/gc/impl/proto/gc.d
index fa879a88c7..e23e38f7f9 100644
--- a/src/gc/impl/proto/gc.d
+++ b/src/gc/impl/proto/gc.d
@@ -177,7 +177,6 @@ class ProtoGC : GC
                 return;
             }
         }
-        assert(false);
     }
 
     @property RootIterator rootIter() return @nogc
@@ -211,7 +210,6 @@ class ProtoGC : GC
                 return;
             }
         }
-        assert(false);
     }
 
     @property RangeIterator rangeIter() return @nogc
diff --git a/test/init_fini/Makefile b/test/init_fini/Makefile
index 20ccdbd8a6..6f01a13cd0 100644
--- a/test/init_fini/Makefile
+++ b/test/init_fini/Makefile
@@ -1,6 +1,6 @@
 include ../common.mak
 
-TESTS:=thread_join runtime_args
+TESTS:=thread_join runtime_args test18996
 
 .PHONY: all clean
 all: $(addprefix $(ROOT)/,$(addsuffix .done,$(TESTS)))
diff --git a/test/init_fini/src/test18996.d b/test/init_fini/src/test18996.d
new file mode 100644
index 0000000000..01d514cd56
--- /dev/null
+++ b/test/init_fini/src/test18996.d
@@ -0,0 +1,13 @@
+// Issue https://issues.dlang.org/show_bug.cgi?id=18996
+// Array!string calls removeRange without first adding the range, but never
+// initializes the GC. The behavior of the default GC is to ignore removing
+// ranges when the range wasn't added. The ProtoGC originally would crash when
+// this happened.
+
+import core.memory;
+
+void main()
+{
+    GC.removeRange(null);
+    GC.removeRoot(null);
+}