diff --git a/swift/ql/src/queries/Security/CWE-079/UnsafeWebViewFetch.ql b/swift/ql/src/queries/Security/CWE-079/UnsafeWebViewFetch.ql
index 455cd7e3751..3009f0d0d03 100644
--- a/swift/ql/src/queries/Security/CWE-079/UnsafeWebViewFetch.ql
+++ b/swift/ql/src/queries/Security/CWE-079/UnsafeWebViewFetch.ql
@@ -31,7 +31,7 @@ class Sink extends DataFlow::Node {
       int baseUrlArg
     |
       // arguments to method calls...
-      exists(string className, ClassDecl c |
+      exists(string className, ClassOrStructDecl c |
         (
           // `loadHTMLString`
           className = ["UIWebView", "WKWebView"] and
diff --git a/swift/ql/src/queries/Security/CWE-135/StringLengthConflation.ql b/swift/ql/src/queries/Security/CWE-135/StringLengthConflation.ql
index 397d5826fe5..5e4bcbf3ffa 100644
--- a/swift/ql/src/queries/Security/CWE-135/StringLengthConflation.ql
+++ b/swift/ql/src/queries/Security/CWE-135/StringLengthConflation.ql
@@ -99,7 +99,7 @@ class StringLengthConflationConfiguration extends DataFlow::Configuration {
     |
       (
         // arguments to method calls...
-        exists(string className, ClassDecl c |
+        exists(string className, ClassOrStructDecl c |
           (
             // `NSRange.init`
             className = "NSRange" and
@@ -127,7 +127,7 @@ class StringLengthConflationConfiguration extends DataFlow::Configuration {
             paramName = "at"
           ) and
           c.getName() = className and
-          c.getABaseTypeDecl*().(ClassDecl).getAMember() = funcDecl and
+          c.getABaseTypeDecl*().(ClassOrStructDecl).getAMember() = funcDecl and
           call.getStaticTarget() = funcDecl and
           flowstate = "NSString"
         )
diff --git a/swift/ql/src/queries/Security/CWE-311/CleartextStorageDatabase.ql b/swift/ql/src/queries/Security/CWE-311/CleartextStorageDatabase.ql
index 5e655c0dc90..49f4e6ab7e9 100644
--- a/swift/ql/src/queries/Security/CWE-311/CleartextStorageDatabase.ql
+++ b/swift/ql/src/queries/Security/CWE-311/CleartextStorageDatabase.ql
@@ -28,7 +28,7 @@ abstract class Stored extends DataFlow::Node { }
 class CoreDataStore extends Stored {
   CoreDataStore() {
     // `content` arg to `NWConnection.send` is a sink
-    exists(ClassDecl c, AbstractFunctionDecl f, CallExpr call |
+    exists(ClassOrStructDecl c, AbstractFunctionDecl f, CallExpr call |
       c.getName() = "NSManagedObject" and
       c.getAMember() = f and
       f.getName() = ["setValue(_:forKey:)", "setPrimitiveValue(_:forKey:)"] and
@@ -47,7 +47,7 @@ class RealmStore extends Stored instanceof DataFlow::PostUpdateNode {
     // any write into a class derived from `RealmSwiftObject` is a sink. For
     // example in `realmObj.data = sensitive` the post-update node corresponding
     // with `realmObj.data` is a sink.
-    exists(ClassDecl cd, Expr e |
+    exists(ClassOrStructDecl cd, Expr e |
       cd.getABaseTypeDecl*().getName() = "RealmSwiftObject" and
       this.getPreUpdateNode().asExpr() = e and
       e.getFullyConverted().getType() = cd.getType() and
@@ -81,7 +81,7 @@ class CleartextStorageConfig extends TaintTracking::Configuration {
     // flow out from fields of a `RealmSwiftObject` at the sink, for example in
     // `realmObj.data = sensitive`.
     isSink(node) and
-    exists(ClassDecl cd |
+    exists(ClassOrStructDecl cd |
       c.getAReadContent().(DataFlow::Content::FieldContent).getField() = cd.getAMember() and
       cd.getABaseTypeDecl*().getName() = "RealmSwiftObject"
     )
diff --git a/swift/ql/src/queries/Security/CWE-311/CleartextTransmission.ql b/swift/ql/src/queries/Security/CWE-311/CleartextTransmission.ql
index ba2d2a17807..d2dec5a104a 100644
--- a/swift/ql/src/queries/Security/CWE-311/CleartextTransmission.ql
+++ b/swift/ql/src/queries/Security/CWE-311/CleartextTransmission.ql
@@ -28,7 +28,7 @@ abstract class Transmitted extends Expr { }
 class NWConnectionSend extends Transmitted {
   NWConnectionSend() {
     // `content` arg to `NWConnection.send` is a sink
-    exists(ClassDecl c, AbstractFunctionDecl f, CallExpr call |
+    exists(ClassOrStructDecl c, AbstractFunctionDecl f, CallExpr call |
       c.getName() = "NWConnection" and
       c.getAMember() = f and
       f.getName() = "send(content:contentContext:isComplete:completion:)" and
@@ -46,7 +46,7 @@ class Url extends Transmitted {
   Url() {
     // `string` arg in `URL.init` is a sink
     // (we assume here that the URL goes on to be used in a network operation)
-    exists(StructDecl c, AbstractFunctionDecl f, CallExpr call |
+    exists(ClassOrStructDecl c, AbstractFunctionDecl f, CallExpr call |
       c.getName() = "URL" and
       c.getAMember() = f and
       f.getName() = ["init(string:)", "init(string:relativeTo:)"] and
diff --git a/swift/ql/src/queries/Security/CWE-328/WeakSensitiveDataHashing.ql b/swift/ql/src/queries/Security/CWE-328/WeakSensitiveDataHashing.ql
index b697a9a01dd..5a6fc396257 100755
--- a/swift/ql/src/queries/Security/CWE-328/WeakSensitiveDataHashing.ql
+++ b/swift/ql/src/queries/Security/CWE-328/WeakSensitiveDataHashing.ql
@@ -42,7 +42,7 @@ module WeakHashingConfig {
         call.getAnArgument().getExpr() = this.asExpr() and
         call.getStaticTarget() = func and
         func.getName().matches(["hash(%", "update(%"]) and
-        algorithm = func.getEnclosingDecl().(StructDecl).getName() and
+        algorithm = func.getEnclosingDecl().(ClassOrStructDecl).getName() and
         algorithm = ["MD5", "SHA1"]
       )
     }
diff --git a/swift/ql/src/queries/Security/ECB-Encryption/ECBEncryption.ql b/swift/ql/src/queries/Security/ECB-Encryption/ECBEncryption.ql
index d0170d84237..cb531c1a4b8 100644
--- a/swift/ql/src/queries/Security/ECB-Encryption/ECBEncryption.ql
+++ b/swift/ql/src/queries/Security/ECB-Encryption/ECBEncryption.ql
@@ -26,7 +26,7 @@ abstract class BlockMode extends Expr { }
 class AES extends BlockMode {
   AES() {
     // `blockMode` arg in `AES.init` is a sink
-    exists(ClassDecl c, AbstractFunctionDecl f, CallExpr call |
+    exists(ClassOrStructDecl c, AbstractFunctionDecl f, CallExpr call |
       c.getName() = "AES" and
       c.getAMember() = f and
       f.getName() = ["init(key:blockMode:)", "init(key:blockMode:padding:)"] and
@@ -42,7 +42,7 @@ class AES extends BlockMode {
 class Blowfish extends BlockMode {
   Blowfish() {
     // `blockMode` arg in `Blowfish.init` is a sink
-    exists(ClassDecl c, AbstractFunctionDecl f, CallExpr call |
+    exists(ClassOrStructDecl c, AbstractFunctionDecl f, CallExpr call |
       c.getName() = "Blowfish" and
       c.getAMember() = f and
       f.getName() = "init(key:blockMode:padding:)" and
@@ -60,7 +60,7 @@ class EcbEncryptionConfig extends DataFlow::Configuration {
   EcbEncryptionConfig() { this = "EcbEncryptionConfig" }
 
   override predicate isSource(DataFlow::Node node) {
-    exists(StructDecl s, AbstractFunctionDecl f, CallExpr call |
+    exists(ClassOrStructDecl s, AbstractFunctionDecl f, CallExpr call |
       s.getName() = "ECB" and
       s.getAMember() = f and
       f.getName() = "init()" and
diff --git a/swift/ql/test/query-tests/Security/CWE-311/testSend.swift b/swift/ql/test/query-tests/Security/CWE-311/testSend.swift
index 87d140b1eea..506b3a921e3 100644
--- a/swift/ql/test/query-tests/Security/CWE-311/testSend.swift
+++ b/swift/ql/test/query-tests/Security/CWE-311/testSend.swift
@@ -1,7 +1,7 @@
 
 // --- stubs ---
 
-class Data {
+struct Data {
     init<S>(_ elements: S) {}
 }
 
@@ -13,7 +13,7 @@ class NWConnection {
 	class ContentContext {
         static let defaultMessage = ContentContext()
     }
-	
+
 	func send(content: Data?, contentContext: NWConnection.ContentContext = .defaultMessage, isComplete: Bool = true, completion: NWConnection.SendCompletion) { }
 	func send<Content>(content: Content?, contentContext: NWConnection.ContentContext = .defaultMessage, isComplete: Bool = true, completion: NWConnection.SendCompletion) { }
 }