diff --git a/validation-test/compiler_crashers/28237-swift-archetypebuilder-addgenericparameter.swift b/validation-test/compiler_crashers/28237-swift-archetypebuilder-addgenericparameter.swift
new file mode 100644
index 0000000000000..02d5602683a1d
--- /dev/null
+++ b/validation-test/compiler_crashers/28237-swift-archetypebuilder-addgenericparameter.swift
@@ -0,0 +1,8 @@
+// RUN: not --crash %target-swift-frontend %s -parse
+// REQUIRES: asserts
+
+// Distributed under the terms of the MIT license
+// Test case submitted to project by https://github.com/practicalswift (practicalswift)
+// Test case found by fuzzing
+
+{<f}class B<a{protocol a{enum S<A{extension{protocol a{func<