diff --git a/src/Expr.cc b/src/Expr.cc
index bcd9ac96ae..3183743043 100644
--- a/src/Expr.cc
+++ b/src/Expr.cc
@@ -4726,7 +4726,7 @@ bool LambdaExpr::CheckCaptures(StmtPtr when_parent)
 
 	for ( const auto& c : *captures )
 		{
-		auto cid = c.id.get();
+		auto cid = c.Id().get();
 
 		if ( ! cid )
 			// This happens for undefined/inappropriate
@@ -4768,7 +4768,7 @@ bool LambdaExpr::CheckCaptures(StmtPtr when_parent)
 
 	for ( const auto& c : *captures )
 		{
-		auto cid = c.id.get();
+		auto cid = c.Id().get();
 		if ( cid && capture_is_matched.count(cid) == 0 )
 			{
 			auto msg = util::fmt("%s is captured but not used inside %s", cid->Name(), desc);
diff --git a/src/Stmt.cc b/src/Stmt.cc
index 5cfb7bb914..0f6bd043f0 100644
--- a/src/Stmt.cc
+++ b/src/Stmt.cc
@@ -2018,7 +2018,7 @@ WhenInfo::WhenInfo(ExprPtr arg_cond, FuncType::CaptureList* arg_cl, bool arg_is_
 		bool is_present = false;
 
 		for ( auto& c : *cl )
-			if ( c.id == wl )
+			if ( c.Id() == wl )
 				{
 				is_present = true;
 				break;
diff --git a/src/Type.cc b/src/Type.cc
index 469a7ba6fd..2bb7279c10 100644
--- a/src/Type.cc
+++ b/src/Type.cc
@@ -699,6 +699,12 @@ TypePtr SetType::ShallowClone()
 
 SetType::~SetType() = default;
 
+FuncType::Capture::Capture(detail::IDPtr _id, bool _deep_copy)
+	: id(std::move(_id)), deep_copy(_deep_copy)
+	{
+	is_managed = id ? ZVal::IsManagedType(id->GetType()) : false;
+	}
+
 FuncType::FuncType(RecordTypePtr arg_args, TypePtr arg_yield, FunctionFlavor arg_flavor)
 	: Type(TYPE_FUNC), args(std::move(arg_args)), arg_types(make_intrusive<TypeList>()),
 	  yield(std::move(arg_yield))
diff --git a/src/Type.h b/src/Type.h
index 020ab6e358..38a08a5c7f 100644
--- a/src/Type.h
+++ b/src/Type.h
@@ -511,10 +511,22 @@ public:
 	/**
 	 * A single lambda "capture" (outer variable used in a lambda's body).
 	 */
-	struct Capture
+	class Capture
 		{
+	public:
+		Capture(detail::IDPtr _id, bool _deep_copy);
+
+		auto& Id() const { return id; }
+		bool IsDeepCopy() const { return deep_copy; }
+		bool IsManaged() const { return is_managed; }
+
+		// For script optimization:
+		void SetID(detail::IDPtr new_id) { id = std::move(new_id); }
+
+	private:
 		detail::IDPtr id;
 		bool deep_copy;
+		bool is_managed;
 		};
 
 	using CaptureList = std::vector<Capture>;
diff --git a/src/parse.y b/src/parse.y
index d16fc5042c..2a44660d56 100644
--- a/src/parse.y
+++ b/src/parse.y
@@ -1640,9 +1640,7 @@ capture:
 
 			delete [] $2;
 
-			$$ = new FuncType::Capture;
-			$$->id = id;
-			$$->deep_copy = $1;
+			$$ = new FuncType::Capture(id, $1);
 			}
 	;
 
diff --git a/src/script_opt/CPP/Exprs.cc b/src/script_opt/CPP/Exprs.cc
index c9cde5ab0c..90e7b0bd8d 100644
--- a/src/script_opt/CPP/Exprs.cc
+++ b/src/script_opt/CPP/Exprs.cc
@@ -1301,7 +1301,7 @@ string CPPCompile::GenLambdaClone(const LambdaExpr* l, bool all_deep)
 		if ( captures && ! IsNativeType(id_t) )
 			{
 			for ( const auto& c : *captures )
-				if ( id == c.id && (c.deep_copy || all_deep) )
+				if ( id == c.Id() && (c.IsDeepCopy() || all_deep) )
 					arg = string("cast_intrusive<") + TypeName(id_t) + ">(" + arg + "->Clone())";
 			}