diff --git a/hilti/toolchain/src/compiler/optimizer.cc b/hilti/toolchain/src/compiler/optimizer.cc
index d2cb43ec2..ea922a700 100644
--- a/hilti/toolchain/src/compiler/optimizer.cc
+++ b/hilti/toolchain/src/compiler/optimizer.cc
@@ -1477,6 +1477,18 @@ struct MemberVisitor : OptimizerVisitor, visitor::PreOrder<bool, MemberVisitor>
     }
 };
 
+// Helper function to detect whether a struct has lifecycle hooks attached.
+bool hasLifecycleHooks(const type::Struct& s) {
+    // NOLINTNEXTLINE(readability-use-anyofallof)
+    for ( const auto& f : s.fields() ) {
+        // Currently the only lifecycle hook we have is `~finally`.
+        if ( f.id().str() == "~finally" )
+            return true;
+    }
+
+    return false;
+};
+
 // Optimizer pass which removes dead store and variable declarations.
 struct DeadStoreVisitor : OptimizerVisitor, visitor::PreOrder<bool, DeadStoreVisitor> {
     // We use decl identities here instead of their canonical IDs since for
@@ -1546,10 +1558,9 @@ struct DeadStoreVisitor : OptimizerVisitor, visitor::PreOrder<bool, DeadStoreVis
         if ( ! decl.isA<declaration::LocalVariable>() && ! decl.isA<declaration::GlobalVariable>() )
             return false;
 
-        // Do not work on assignments to values of struct types since structs
-        // can have hooks attached which could make the assignment result
-        // visible non-locally.
-        if ( target->type().isA<type::Struct>() )
+        // Do not work on assignments to values of struct types which have
+        // lifecycle hooks attached.
+        if ( auto s = target->type().tryAs<type::Struct>(); s && hasLifecycleHooks(*s) )
             return false;
 
         switch ( _stage ) {
@@ -1614,9 +1625,9 @@ struct DeadStoreVisitor : OptimizerVisitor, visitor::PreOrder<bool, DeadStoreVis
                 const auto& decl = x.declaration();
 
                 if ( const auto& local = decl.tryAs<declaration::LocalVariable>() ) {
-                    // Do not attempt to remove declarations of structs since
-                    // they might have additional state attached via hooks.
-                    if ( local->type().isA<type::Struct>() )
+                    // Do not attempt to remove declarations of structs with
+                    // lifecycle hooks.
+                    if ( auto s = local->type().tryAs<type::Struct>(); s && hasLifecycleHooks(*s) )
                         break;
 
                     // If the local is initialized do not remove it to still
@@ -1805,10 +1816,8 @@ struct DeadCodeVisitor : OptimizerVisitor, visitor::PreOrder<bool, DeadCodeVisit
                 if ( fn->flavor() == type::function::Flavor::Hook )
                     return true;
 
-                // If the function returns a struct type there might be hooks
-                // like `finally` attached to the type so calling the function
-                // has side effects.
-                if ( fn->result().type().isA<type::Struct>() )
+                // If the function returns a struct type with lifecycle hooks it has side effects.
+                if ( auto s = fn->result().type().tryAs<type::Struct>(); s && hasLifecycleHooks(*s) )
                     return true;
 
                 // If the function is not marked pure it has side effects.
@@ -1834,17 +1843,6 @@ struct DeadCodeVisitor : OptimizerVisitor, visitor::PreOrder<bool, DeadCodeVisit
     }
 };
 
-bool hasLifecycleHooks(const type::Struct& s) {
-    // NOLINTNEXTLINE(readability-use-anyofallof)
-    for ( const auto& f : s.fields() ) {
-        // Currently the only lifecycle hook we have is `~finally`.
-        if ( f.id().str() == "~finally" )
-            return true;
-    }
-
-    return false;
-};
-
 // An optimizer pass which annotates pure functions. This
 // information can be used by other passes to remove dead code.
 struct PureFunctionVisitor : OptimizerVisitor, visitor::PreOrder<bool, PureFunctionVisitor> {