diff --git a/swift/downgrades/e646f9e0308ec7135c83c0fdf96896d2737a8013/type_alias_decls.ql b/swift/downgrades/e646f9e0308ec7135c83c0fdf96896d2737a8013/type_alias_decls.ql
new file mode 100644
index 00000000000..72f89e3946d
--- /dev/null
+++ b/swift/downgrades/e646f9e0308ec7135c83c0fdf96896d2737a8013/type_alias_decls.ql
@@ -0,0 +1,6 @@
+class TypeAliasDecl extends @type_alias_decl {
+  string toString() { result = "TypeAliasDecl" }
+}
+
+from TypeAliasDecl id
+select id
diff --git a/swift/downgrades/e646f9e0308ec7135c83c0fdf96896d2737a8013/upgrade.properties b/swift/downgrades/e646f9e0308ec7135c83c0fdf96896d2737a8013/upgrade.properties
index 64da53384a5..31ffe35bf1c 100644
--- a/swift/downgrades/e646f9e0308ec7135c83c0fdf96896d2737a8013/upgrade.properties
+++ b/swift/downgrades/e646f9e0308ec7135c83c0fdf96896d2737a8013/upgrade.properties
@@ -1,2 +1,3 @@
-description: <INSERT DESCRIPTION HERE>
-compatibility: full|backwards|partial|breaking
+description: Revert adding TypeAliasDecl.getAliasedType()
+compatibility: full
+type_alias_decls.rel: run type_alias_decls.qlo
diff --git a/swift/ql/lib/upgrades/c2f01f2beb67e5a57e9df9b6d1c51e35e8d5b0a2/type_alias_decls.ql b/swift/ql/lib/upgrades/c2f01f2beb67e5a57e9df9b6d1c51e35e8d5b0a2/type_alias_decls.ql
new file mode 100644
index 00000000000..4b5ecd00925
--- /dev/null
+++ b/swift/ql/lib/upgrades/c2f01f2beb67e5a57e9df9b6d1c51e35e8d5b0a2/type_alias_decls.ql
@@ -0,0 +1,14 @@
+class TypeAliasDecl extends @type_alias_decl {
+  string toString() { result = "TypeAliasDecl" }
+}
+
+class Type extends @type_or_none {
+  string toString() { result = "Type" }
+}
+
+// use the canonical type as an approximation of the aliased type
+from TypeAliasDecl td, Type t, Type canonical
+where
+  type_alias_types(t, td) and // td is the declaration of t
+  types(t, _, canonical) // canonical is the canonical type of t
+select td, canonical
diff --git a/swift/ql/lib/upgrades/c2f01f2beb67e5a57e9df9b6d1c51e35e8d5b0a2/upgrade.properties b/swift/ql/lib/upgrades/c2f01f2beb67e5a57e9df9b6d1c51e35e8d5b0a2/upgrade.properties
index 64da53384a5..301f7bb8899 100644
--- a/swift/ql/lib/upgrades/c2f01f2beb67e5a57e9df9b6d1c51e35e8d5b0a2/upgrade.properties
+++ b/swift/ql/lib/upgrades/c2f01f2beb67e5a57e9df9b6d1c51e35e8d5b0a2/upgrade.properties
@@ -1,2 +1,3 @@
-description: <INSERT DESCRIPTION HERE>
-compatibility: full|backwards|partial|breaking
+description: Add TypeAliasDecl.getAliasedType()
+compatibility: backwards
+type_alias_decls.rel: run type_alias_decls.qlo