diff --git a/dstep/translator/HeaderIndex.d b/dstep/translator/HeaderIndex.d
index ae1b2531..78ee27c7 100644
--- a/dstep/translator/HeaderIndex.d
+++ b/dstep/translator/HeaderIndex.d
@@ -68,6 +68,10 @@ class IncludeGraph
 
                 auto pair = Inclusion(headers_[includedPath], headers_[path]);
                 directInclusions.add(pair);
+            } else if (includedPath != "" && includedPath !in headers_)
+            {
+                reverse_[headers_.length] = includedPath;
+                headers_[includedPath] = headers_.length;
             }
         }
 
diff --git a/tests/functional/graph/include_known.h b/tests/functional/graph/include_known.h
new file mode 100644
index 00000000..339f4fc1
--- /dev/null
+++ b/tests/functional/graph/include_known.h
@@ -0,0 +1 @@
+#include <errno.h>
diff --git a/tests/unit/IncludeGraphTests.d b/tests/unit/IncludeGraphTests.d
index 8fcf78e5..ef37d832 100644
--- a/tests/unit/IncludeGraphTests.d
+++ b/tests/unit/IncludeGraphTests.d
@@ -90,3 +90,14 @@ unittest
 
     new HeaderIndex(translationUnit);
 }
+
+unittest
+{
+    const string file = "tests/functional/graph/subfile1.h".asAbsNormPath();
+
+    auto translationUnit = makeTranslationUnit(
+        "tests/functional/graph/include_known.h",
+        ["-Wno-missing-declarations", "-Itests/functional", "-include", file]);
+
+    new HeaderIndex(translationUnit);
+}