diff --git a/src/BroList.h b/src/BroList.h
index a37f40d84a..d2e77a33ca 100644
--- a/src/BroList.h
+++ b/src/BroList.h
@@ -13,8 +13,8 @@ typedef PList<ID> id_list;
 class Val;
 typedef PList<Val> val_list;
 
-class Stmt;
-typedef PList<Stmt> stmt_list;
+FORWARD_DECLARE_NAMESPACED(Stmt, zeek::detail);
+typedef PList<zeek::detail::Stmt> stmt_list;
 
 class BroType;
 typedef PList<BroType> type_list;
diff --git a/src/Brofiler.cc b/src/Brofiler.cc
index ba7ff1b358..4eeb456380 100644
--- a/src/Brofiler.cc
+++ b/src/Brofiler.cc
@@ -26,7 +26,7 @@ Brofiler::~Brofiler()
 		Unref(s);
 	}
 
-void Brofiler::AddStmt(Stmt* s)
+void Brofiler::AddStmt(zeek::detail::Stmt* s)
 	{
 	if ( ignoring != 0 )
 		return;
@@ -127,7 +127,7 @@ bool Brofiler::WriteStats()
 		return false;
 		}
 
-	for ( list<Stmt*>::const_iterator it = stmts.begin();
+	for ( list<zeek::detail::Stmt*>::const_iterator it = stmts.begin();
 	      it != stmts.end(); ++it )
 		{
 		ODesc location_info;
@@ -154,4 +154,3 @@ bool Brofiler::WriteStats()
 	fclose(f);
 	return true;
 	}
-
diff --git a/src/Brofiler.h b/src/Brofiler.h
index 4d6bb2eaf5..95a0a17c59 100644
--- a/src/Brofiler.h
+++ b/src/Brofiler.h
@@ -5,7 +5,8 @@
 #include <list>
 #include <string>
 
-class Stmt;
+#include "util.h"
+FORWARD_DECLARE_NAMESPACED(Stmt, zeek::detail);
 
 /**
  * A simple class for managing stats of Bro script coverage across Bro runs.
@@ -39,13 +40,13 @@ public:
 	void IncIgnoreDepth() { ignoring++; }
 	void DecIgnoreDepth() { ignoring--; }
 
-	void AddStmt(Stmt* s);
+	void AddStmt(zeek::detail::Stmt* s);
 
 private:
 	/**
 	 * The current, global Brofiler instance creates this list at parse-time.
 	 */
-	std::list<Stmt*> stmts;
+	std::list<zeek::detail::Stmt*> stmts;
 
 	/**
 	 * Indicates whether new statments will not be considered as part of
diff --git a/src/DbgBreakpoint.cc b/src/DbgBreakpoint.cc
index 2ad5d3ef94..990ff070a3 100644
--- a/src/DbgBreakpoint.cc
+++ b/src/DbgBreakpoint.cc
@@ -166,7 +166,7 @@ bool DbgBreakpoint::SetLocation(ParseLocationRec plr, std::string_view loc_str)
 	return true;
 	}
 
-bool DbgBreakpoint::SetLocation(Stmt* stmt)
+bool DbgBreakpoint::SetLocation(zeek::detail::Stmt* stmt)
 	{
 	if ( ! stmt )
 		return false;
@@ -290,7 +290,7 @@ BreakCode DbgBreakpoint::HasHit()
 	return bcHit;
 	}
 
-BreakCode DbgBreakpoint::ShouldBreak(Stmt* s)
+BreakCode DbgBreakpoint::ShouldBreak(zeek::detail::Stmt* s)
 	{
 	if ( ! IsEnabled() )
 		return bcNoHit;
diff --git a/src/DbgBreakpoint.h b/src/DbgBreakpoint.h
index 2e8e59a16c..bdc9f9bf09 100644
--- a/src/DbgBreakpoint.h
+++ b/src/DbgBreakpoint.h
@@ -3,9 +3,11 @@
 #pragma once
 
 #include <string>
+#include "util.h"
 
 struct ParseLocationRec;
-class Stmt;
+
+FORWARD_DECLARE_NAMESPACED(Stmt, zeek::detail);
 
 enum BreakCode { bcNoHit, bcHit, bcHitAndDelete };
 class DbgBreakpoint {
@@ -20,7 +22,7 @@ public:
 
 	// True if breakpoint could be set; false otherwise
 	bool SetLocation(ParseLocationRec plr, std::string_view loc_str);
-	bool SetLocation(Stmt* stmt);
+	bool SetLocation(zeek::detail::Stmt* stmt);
 	bool SetLocation(double time);
 
 	bool Reset();	// cancel and re-apply bpt when restarting execution
@@ -35,7 +37,7 @@ public:
 	//
 	// NOTE: If it returns a hit, the DbgBreakpoint object will take
 	// appropriate action (e.g., resetting counters).
-	BreakCode ShouldBreak(Stmt* s);
+	BreakCode ShouldBreak(zeek::detail::Stmt* s);
 	BreakCode ShouldBreak(double t);
 
 	const std::string& GetCondition() const	{ return condition; }
@@ -70,7 +72,7 @@ protected:
 	bool enabled;	// ### comment this and next
 	bool temporary;
 
-	Stmt* at_stmt;
+	zeek::detail::Stmt* at_stmt;
 	double at_time;	// break when the virtual time is this
 
 	// Support for conditional and N'th time breakpoints.
diff --git a/src/Debug.cc b/src/Debug.cc
index 3637516850..7cbc928943 100644
--- a/src/Debug.cc
+++ b/src/Debug.cc
@@ -135,7 +135,7 @@ int TraceState::LogTrace(const char* fmt, ...)
 	// Prefix includes timestamp and file/line info.
 	fprintf(trace_file, "%.6f ", network_time);
 
-	const Stmt* stmt;
+	const zeek::detail::Stmt* stmt;
 	Location loc;
 	loc.filename = nullptr;
 
@@ -174,7 +174,7 @@ int TraceState::LogTrace(const char* fmt, ...)
 
 
 // Helper functions.
-void get_first_statement(Stmt* list, Stmt*& first, Location& loc)
+void get_first_statement(zeek::detail::Stmt* list, zeek::detail::Stmt*& first, Location& loc)
 	{
 	if ( ! list )
 		{
@@ -231,7 +231,7 @@ static void parse_function_name(vector<ParseLocationRec>& result,
 		return;
 		}
 
-	Stmt* body = nullptr;	// the particular body we care about; 0 = all
+	zeek::detail::Stmt* body = nullptr;	// the particular body we care about; 0 = all
 
 	if ( bodies.size() == 1 )
 		body = bodies[0].stmts.get();
@@ -243,7 +243,7 @@ static void parse_function_name(vector<ParseLocationRec>& result,
 				 "Please choose one of the following options:\n");
 			for ( unsigned int i = 0; i < bodies.size(); ++i )
 				{
-				Stmt* first;
+				zeek::detail::Stmt* first;
 				Location stmt_loc;
 				get_first_statement(bodies[i].stmts.get(), first, stmt_loc);
 				debug_msg("[%d] %s:%d\n", i+1, stmt_loc.filename, stmt_loc.first_line);
@@ -286,7 +286,7 @@ static void parse_function_name(vector<ParseLocationRec>& result,
 	plr.type = plrFunction;
 
 	// Find first atomic (non-STMT_LIST) statement
-	Stmt* first;
+	zeek::detail::Stmt* first;
 	Location stmt_loc;
 
 	if ( body )
@@ -728,7 +728,7 @@ static char* get_prompt(bool reset_counter = false)
 	return prompt;
 	}
 
-string get_context_description(const Stmt* stmt, const Frame* frame)
+string get_context_description(const zeek::detail::Stmt* stmt, const Frame* frame)
 	{
 	ODesc d;
 	const BroFunc* func = frame ? frame->GetFunction() : nullptr;
@@ -776,7 +776,7 @@ int dbg_handle_debug_input()
 	else
 		current_module = GLOBAL_MODULE_NAME;
 
-	const Stmt* stmt = curr_frame->GetNextStmt();
+	const zeek::detail::Stmt* stmt = curr_frame->GetNextStmt();
 	if ( ! stmt )
 		reporter->InternalError("Assertion failed: stmt != 0");
 
@@ -840,7 +840,7 @@ int dbg_handle_debug_input()
 
 
 // Return true to continue execution, false to abort.
-bool pre_execute_stmt(Stmt* stmt, Frame* f)
+bool pre_execute_stmt(zeek::detail::Stmt* stmt, Frame* f)
 	{
 	if ( ! g_policy_debug ||
 	     stmt->Tag() == STMT_LIST || stmt->Tag() == STMT_NULL )
@@ -905,7 +905,7 @@ bool pre_execute_stmt(Stmt* stmt, Frame* f)
 	return true;
 	}
 
-bool post_execute_stmt(Stmt* stmt, Frame* f, Val* result, stmt_flow_type* flow)
+bool post_execute_stmt(zeek::detail::Stmt* stmt, Frame* f, Val* result, stmt_flow_type* flow)
 	{
 	// Handle the case where someone issues a "next" debugger command,
 	// but we're at a return statement, so the next statement is in
diff --git a/src/Debug.h b/src/Debug.h
index 5208e61780..6e07368a1c 100644
--- a/src/Debug.h
+++ b/src/Debug.h
@@ -5,6 +5,7 @@
 #include "Obj.h"
 #include "Queue.h"
 #include "StmtEnums.h"
+#include "util.h"
 
 #include <vector>
 #include <map>
@@ -12,14 +13,15 @@
 
 template <class T> class IntrusivePtr;
 class Val;
-class Stmt;
+
+FORWARD_DECLARE_NAMESPACED(Stmt, zeek::detail);
 
 // This needs to be defined before we do the includes that come after it.
 enum ParseLocationRecType { plrUnknown, plrFileAndLine, plrFunction };
 struct ParseLocationRec {
 	ParseLocationRecType type;
 	int32_t line;
-	Stmt* stmt;
+	zeek::detail::Stmt* stmt;
 	const char* filename;
 };
 
@@ -33,7 +35,7 @@ class DbgDisplay;
 class StmtHashFn;
 
 typedef std::map<int, DbgBreakpoint*> BPIDMapType;
-typedef std::multimap<const Stmt*, DbgBreakpoint*> BPMapType;
+typedef std::multimap<const zeek::detail::Stmt*, DbgBreakpoint*> BPMapType;
 
 extern std::string current_module;
 
@@ -104,15 +106,15 @@ private:
 class StmtLocMapping {
 public:
 	StmtLocMapping()	{ }
-	StmtLocMapping(const Location* l, Stmt* s)	{ loc = *l; stmt = s; }
+	StmtLocMapping(const Location* l, zeek::detail::Stmt* s)	{ loc = *l; stmt = s; }
 
 	bool StartsAfter(const StmtLocMapping* m2);
 	const Location& Loc() const	{ return loc; }
-	Stmt* Statement() const		{ return stmt; }
+	zeek::detail::Stmt* Statement() const		{ return stmt; }
 
 protected:
 	Location loc;
-	Stmt* stmt;
+	zeek::detail::Stmt* stmt;
 };
 
 
@@ -143,8 +145,8 @@ std::vector<ParseLocationRec> parse_location_string(const std::string& s);
 // Debugging hooks.
 
 // Return true to continue execution, false to abort.
-bool pre_execute_stmt(Stmt* stmt, Frame* f);
-bool post_execute_stmt(Stmt* stmt, Frame* f, Val* result, stmt_flow_type* flow);
+bool pre_execute_stmt(zeek::detail::Stmt* stmt, Frame* f);
+bool post_execute_stmt(zeek::detail::Stmt* stmt, Frame* f, Val* result, stmt_flow_type* flow);
 
 // Returns 1 if successful, 0 otherwise.
 // If cmdfile is non-nil, it contains the location of a file of commands
@@ -168,7 +170,7 @@ IntrusivePtr<Val> dbg_eval_expr(const char* expr);
 int dbg_read_internal_state();
 
 // Get line that looks like "In FnFoo(arg = val) at File:Line".
-std::string get_context_description(const Stmt* stmt, const Frame* frame);
+std::string get_context_description(const zeek::detail::Stmt* stmt, const Frame* frame);
 
 extern Frame* g_dbg_locals;	// variables created within debugger context
 
diff --git a/src/DebugCmds.cc b/src/DebugCmds.cc
index e36836e50a..93e1ef9f0e 100644
--- a/src/DebugCmds.cc
+++ b/src/DebugCmds.cc
@@ -216,7 +216,7 @@ static int dbg_backtrace_internal(int start, int end)
 	for ( int i = start; i >= end; --i )
 		{
 		const Frame* f = g_frame_stack[i];
-		const Stmt* stmt = f ? f->GetNextStmt() : nullptr;
+		const zeek::detail::Stmt* stmt = f ? f->GetNextStmt() : nullptr;
 
 		string context = get_context_description(stmt, f);
 		debug_msg("#%d  %s\n",
@@ -333,7 +333,7 @@ int dbg_cmd_frame(DebugCmd cmd, const vector<string>& args)
 
 	// Set the current location to the new frame being looked at
 	// for 'list', 'break', etc.
-	const Stmt* stmt = g_frame_stack[user_frame_number]->GetNextStmt();
+	const zeek::detail::Stmt* stmt = g_frame_stack[user_frame_number]->GetNextStmt();
 	if ( ! stmt )
 		reporter->InternalError("Assertion failed: %s", "stmt != 0");
 
@@ -373,7 +373,7 @@ int dbg_cmd_break(DebugCmd cmd, const vector<string>& args)
 			g_frame_stack.size() - 1 -
 				g_debugger_state.curr_frame_idx;
 
-		Stmt* stmt = g_frame_stack[user_frame_number]->GetNextStmt();
+		zeek::detail::Stmt* stmt = g_frame_stack[user_frame_number]->GetNextStmt();
 		if ( ! stmt )
 			reporter->InternalError("Assertion failed: %s", "stmt != 0");
 
diff --git a/src/Expr.h b/src/Expr.h
index cd09920522..d196a8069b 100644
--- a/src/Expr.h
+++ b/src/Expr.h
@@ -59,7 +59,6 @@ enum BroExprTag : int {
 extern const char* expr_name(BroExprTag t);
 
 template <class T> class IntrusivePtr;
-class Stmt;
 class Frame;
 class Scope;
 class ListExpr;
@@ -71,6 +70,7 @@ class EventExpr;
 
 struct function_ingredients;
 
+FORWARD_DECLARE_NAMESPACED(Stmt, zeek::detail);
 
 class Expr : public BroObj {
 public:
diff --git a/src/File.h b/src/File.h
index edf0b7d0f4..ab7ac5a993 100644
--- a/src/File.h
+++ b/src/File.h
@@ -2,23 +2,26 @@
 
 #pragma once
 
-#include "Obj.h"
-#include "IntrusivePtr.h"
-
 #include <list>
 #include <string>
 #include <utility>
 
 #include <fcntl.h>
 
-# ifdef NEED_KRB5_H
-#  include <krb5.h>
-# endif // NEED_KRB5_H
+#ifdef NEED_KRB5_H
+#include <krb5.h>
+#endif // NEED_KRB5_H
+
+#include "Obj.h"
+#include "IntrusivePtr.h"
+#include "util.h"
 
 class Attributes;
 class BroType;
 class RecordVal;
 
+FORWARD_DECLARE_NAMESPACED(PrintStmt, zeek::detail);
+
 class BroFile final : public BroObj {
 public:
 	explicit BroFile(FILE* arg_f);
@@ -77,7 +80,7 @@ public:
 
 protected:
 
-	friend class PrintStmt;
+	friend class zeek::detail::PrintStmt;
 
 	BroFile()	{ Init(); }
 	void Init();
diff --git a/src/Frame.h b/src/Frame.h
index a85254469c..e203fa17bd 100644
--- a/src/Frame.h
+++ b/src/Frame.h
@@ -118,12 +118,12 @@ public:
 	 *
 	 * @param stmt the statement to set it to.
 	 */
-	void SetNextStmt(Stmt* stmt)	{ next_stmt = stmt; }
+	void SetNextStmt(zeek::detail::Stmt* stmt)	{ next_stmt = stmt; }
 
 	/**
 	 * @return the next statement to be executed in the context of the frame.
 	 */
-	Stmt* GetNextStmt() const	{ return next_stmt; }
+	zeek::detail::Stmt* GetNextStmt() const	{ return next_stmt; }
 
 	/** Used to implement "next" command in debugger. */
 	void BreakBeforeNextStmt(bool should_break)
@@ -319,7 +319,7 @@ private:
 	const zeek::Args* func_args;
 
 	/** The next statement to be evaluted in the context of this frame. */
-	Stmt* next_stmt;
+	zeek::detail::Stmt* next_stmt;
 
 	IntrusivePtr<trigger::Trigger> trigger;
 	const CallExpr* call;
diff --git a/src/Func.cc b/src/Func.cc
index f0cb8e693a..77dbabaea6 100644
--- a/src/Func.cc
+++ b/src/Func.cc
@@ -121,7 +121,7 @@ Func::Func(Kind arg_kind) : kind(arg_kind)
 
 Func::~Func() = default;
 
-void Func::AddBody(IntrusivePtr<Stmt> /* new_body */,
+void Func::AddBody(IntrusivePtr<zeek::detail::Stmt> /* new_body */,
                    const std::vector<IntrusivePtr<ID>>& /* new_inits */,
                    size_t /* new_frame_size */, int /* priority */)
 	{
@@ -268,7 +268,7 @@ void Func::CheckPluginResult(bool handled, const IntrusivePtr<Val>& hook_result,
 	}
 	}
 
-BroFunc::BroFunc(const IntrusivePtr<ID>& arg_id, IntrusivePtr<Stmt> arg_body,
+BroFunc::BroFunc(const IntrusivePtr<ID>& arg_id, IntrusivePtr<zeek::detail::Stmt> arg_body,
                  const std::vector<IntrusivePtr<ID>>& aggr_inits,
                  size_t arg_frame_size, int priority)
 	: Func(BRO_FUNC)
@@ -449,7 +449,7 @@ IntrusivePtr<Val> BroFunc::Invoke(zeek::Args* args, Frame* parent) const
 	return result;
 	}
 
-void BroFunc::AddBody(IntrusivePtr<Stmt> new_body,
+void BroFunc::AddBody(IntrusivePtr<zeek::detail::Stmt> new_body,
                       const std::vector<IntrusivePtr<ID>>& new_inits,
                       size_t new_frame_size, int priority)
 	{
@@ -574,14 +574,14 @@ void BroFunc::Describe(ODesc* d) const
 		}
 	}
 
-IntrusivePtr<Stmt> BroFunc::AddInits(IntrusivePtr<Stmt> body,
-                                     const std::vector<IntrusivePtr<ID>>& inits)
+IntrusivePtr<zeek::detail::Stmt> BroFunc::AddInits(IntrusivePtr<zeek::detail::Stmt> body,
+                                                   const std::vector<IntrusivePtr<ID>>& inits)
 	{
 	if ( inits.empty() )
 		return body;
 
-	auto stmt_series = make_intrusive<StmtList>();
-	stmt_series->Stmts().push_back(new InitStmt(inits));
+	auto stmt_series = make_intrusive<zeek::detail::StmtList>();
+	stmt_series->Stmts().push_back(new zeek::detail::InitStmt(inits));
 	stmt_series->Stmts().push_back(body.release());
 
 	return stmt_series;
@@ -879,7 +879,7 @@ static int get_func_priority(const std::vector<IntrusivePtr<Attr>>& attrs)
 	return priority;
 	}
 
-function_ingredients::function_ingredients(IntrusivePtr<Scope> scope, IntrusivePtr<Stmt> body)
+function_ingredients::function_ingredients(IntrusivePtr<Scope> scope, IntrusivePtr<zeek::detail::Stmt> body)
 	{
 	frame_size = scope->Length();
 	inits = scope->GetInits();
diff --git a/src/Func.h b/src/Func.h
index 5b2ee5eebc..88a805ad5a 100644
--- a/src/Func.h
+++ b/src/Func.h
@@ -22,12 +22,13 @@
 class Val;
 class ListExpr;
 class FuncType;
-class Stmt;
 class Frame;
 class ID;
 class CallExpr;
 class Scope;
 
+FORWARD_DECLARE_NAMESPACED(Stmt, zeek::detail);
+
 class Func : public BroObj {
 public:
 	static inline const IntrusivePtr<Func> nil;
@@ -42,7 +43,7 @@ public:
 	function_flavor Flavor() const	{ return GetType()->Flavor(); }
 
 	struct Body {
-		IntrusivePtr<Stmt> stmts;
+		IntrusivePtr<zeek::detail::Stmt> stmts;
 		int priority;
 		bool operator<(const Body& other) const
 			{ return priority > other.priority; } // reverse sort
@@ -78,7 +79,7 @@ public:
 		}
 
 	// Add a new event handler to an existing function (event).
-	virtual void AddBody(IntrusivePtr<Stmt> new_body,
+	virtual void AddBody(IntrusivePtr<zeek::detail::Stmt> new_body,
 	                     const std::vector<IntrusivePtr<ID>>& new_inits,
 	                     size_t new_frame_size, int priority = 0);
 
@@ -129,7 +130,7 @@ protected:
 
 class BroFunc final : public Func {
 public:
-	BroFunc(const IntrusivePtr<ID>& id, IntrusivePtr<Stmt> body,
+	BroFunc(const IntrusivePtr<ID>& id, IntrusivePtr<zeek::detail::Stmt> body,
 	        const std::vector<IntrusivePtr<ID>>& inits,
 	        size_t frame_size, int priority);
 
@@ -167,7 +168,7 @@ public:
 	 */
 	broker::expected<broker::data> SerializeClosure() const;
 
-	void AddBody(IntrusivePtr<Stmt> new_body,
+	void AddBody(IntrusivePtr<zeek::detail::Stmt> new_body,
 	             const std::vector<IntrusivePtr<ID>>& new_inits,
 	             size_t new_frame_size, int priority) override;
 
@@ -179,8 +180,8 @@ public:
 
 protected:
 	BroFunc() : Func(BRO_FUNC)	{}
-	IntrusivePtr<Stmt> AddInits(IntrusivePtr<Stmt> body,
-	                            const std::vector<IntrusivePtr<ID>>& inits);
+	IntrusivePtr<zeek::detail::Stmt> AddInits(IntrusivePtr<zeek::detail::Stmt> body,
+	                                          const std::vector<IntrusivePtr<ID>>& inits);
 
 	/**
 	 * Clones this function along with its closures.
@@ -267,10 +268,10 @@ struct function_ingredients {
 
 	// Gathers all of the information from a scope and a function body needed
 	// to build a function.
-	function_ingredients(IntrusivePtr<Scope> scope, IntrusivePtr<Stmt> body);
+	function_ingredients(IntrusivePtr<Scope> scope, IntrusivePtr<zeek::detail::Stmt> body);
 
 	IntrusivePtr<ID> id;
-	IntrusivePtr<Stmt> body;
+	IntrusivePtr<zeek::detail::Stmt> body;
 	std::vector<IntrusivePtr<ID>> inits;
 	int frame_size;
 	int priority;
diff --git a/src/Stmt.cc b/src/Stmt.cc
index e30233ccf3..b0ef9c4ab7 100644
--- a/src/Stmt.cc
+++ b/src/Stmt.cc
@@ -2,6 +2,8 @@
 
 #include "zeek-config.h"
 
+#include "Stmt.h"
+
 #include "CompHash.h"
 #include "Expr.h"
 #include "Event.h"
@@ -9,7 +11,6 @@
 #include "File.h"
 #include "Reporter.h"
 #include "NetVar.h"
-#include "Stmt.h"
 #include "Scope.h"
 #include "Var.h"
 #include "Desc.h"
@@ -34,6 +35,8 @@ const char* stmt_name(BroStmtTag t)
 	return stmt_names[int(t)];
 	}
 
+namespace zeek::detail {
+
 Stmt::Stmt(BroStmtTag arg_tag)
 	{
 	tag = arg_tag;
@@ -1833,3 +1836,5 @@ TraversalCode WhenStmt::Traverse(TraversalCallback* cb) const
 	tc = cb->PostStmt(this);
 	HANDLE_TC_STMT_POST(tc);
 	}
+
+}
diff --git a/src/Stmt.h b/src/Stmt.h
index 0cc4e8ae43..55cc919770 100644
--- a/src/Stmt.h
+++ b/src/Stmt.h
@@ -13,13 +13,16 @@
 
 #include "TraverseTypes.h"
 
-class StmtList;
 class CompositeHash;
 class EventExpr;
 class ListExpr;
-class ForStmt;
 class Frame;
 
+namespace zeek::detail {
+
+class StmtList;
+class ForStmt;
+
 class Stmt : public BroObj {
 public:
 	BroStmtTag Tag() const	{ return tag; }
@@ -447,3 +450,27 @@ protected:
 	IntrusivePtr<Expr> timeout;
 	bool is_return;
 };
+
+}
+
+using Stmt [[deprecated("Remove in v4.1. Use zeek::detail::Stmt instead.")]] = zeek::detail::Stmt;
+using ExprListStmt [[deprecated("Remove in v4.1. Use zeek::detail::ExprListStmt instead.")]] = zeek::detail::ExprListStmt;
+using PrintStmt [[deprecated("Remove in v4.1. Use zeek::detail::PrintStmt instead.")]] = zeek::detail::PrintStmt;
+using ExprStmt [[deprecated("Remove in v4.1. Use zeek::detail::ExprStmt instead.")]] = zeek::detail::ExprStmt;
+using IfStmt [[deprecated("Remove in v4.1. Use zeek::detail::IfStmt instead.")]] = zeek::detail::IfStmt;
+using Case [[deprecated("Remove in v4.1. Use zeek::detail::Case instead.")]] = zeek::detail::Case;
+using SwitchStmt [[deprecated("Remove in v4.1. Use zeek::detail::SwitchStmt instead.")]] = zeek::detail::SwitchStmt;
+using AddStmt [[deprecated("Remove in v4.1. Use zeek::detail::AddStmt instead.")]] = zeek::detail::AddStmt;
+using DelStmt [[deprecated("Remove in v4.1. Use zeek::detail::DelStmt instead.")]] = zeek::detail::DelStmt;
+using EventStmt [[deprecated("Remove in v4.1. Use zeek::detail::EventStmt instead.")]] = zeek::detail::EventStmt;
+using WhileStmt [[deprecated("Remove in v4.1. Use zeek::detail::WhileStmt instead.")]] = zeek::detail::WhileStmt;
+using ForStmt [[deprecated("Remove in v4.1. Use zeek::detail::ForStmt instead.")]] = zeek::detail::ForStmt;
+using NextStmt [[deprecated("Remove in v4.1. Use zeek::detail::NextStmt instead.")]] = zeek::detail::NextStmt;
+using BreakStmt [[deprecated("Remove in v4.1. Use zeek::detail::BreakStmt instead.")]] = zeek::detail::BreakStmt;
+using FallthroughStmt [[deprecated("Remove in v4.1. Use zeek::detail::FallthroughStmt instead.")]] = zeek::detail::FallthroughStmt;
+using ReturnStmt [[deprecated("Remove in v4.1. Use zeek::detail::ReturnStmt instead.")]] = zeek::detail::ReturnStmt;
+using StmtList [[deprecated("Remove in v4.1. Use zeek::detail::StmtList instead.")]] = zeek::detail::StmtList;
+using EventBodyList [[deprecated("Remove in v4.1. Use zeek::detail::EventBodyList instead.")]] = zeek::detail::EventBodyList;
+using InitStmt [[deprecated("Remove in v4.1. Use zeek::detail::InitStmt instead.")]] = zeek::detail::InitStmt;
+using NullStmt [[deprecated("Remove in v4.1. Use zeek::detail::NullStmt instead.")]] = zeek::detail::NullStmt;
+using WhenStmt [[deprecated("Remove in v4.1. Use zeek::detail::WhenStmt instead.")]] = zeek::detail::WhenStmt;
diff --git a/src/Traverse.h b/src/Traverse.h
index 2e528905e0..6c01fb88b7 100644
--- a/src/Traverse.h
+++ b/src/Traverse.h
@@ -6,10 +6,11 @@
 
 class Func;
 class Scope;
-class Stmt;
 class Expr;
 class ID;
 
+FORWARD_DECLARE_NAMESPACED(Stmt, zeek::detail);
+
 class TraversalCallback {
 public:
 	TraversalCallback()	{ current_scope = nullptr; }
@@ -18,8 +19,8 @@ public:
 	virtual TraversalCode PreFunction(const Func*) { return TC_CONTINUE; }
 	virtual TraversalCode PostFunction(const Func*) { return TC_CONTINUE; }
 
-	virtual TraversalCode PreStmt(const Stmt*) { return TC_CONTINUE; }
-	virtual TraversalCode PostStmt(const Stmt*) { return TC_CONTINUE; }
+	virtual TraversalCode PreStmt(const zeek::detail::Stmt*) { return TC_CONTINUE; }
+	virtual TraversalCode PostStmt(const zeek::detail::Stmt*) { return TC_CONTINUE; }
 
 	virtual TraversalCode PreExpr(const Expr*) { return TC_CONTINUE; }
 	virtual TraversalCode PostExpr(const Expr*) { return TC_CONTINUE; }
diff --git a/src/Trigger.cc b/src/Trigger.cc
index 18fd850b64..0d26fb70d5 100644
--- a/src/Trigger.cc
+++ b/src/Trigger.cc
@@ -122,7 +122,8 @@ protected:
 
 }
 
-Trigger::Trigger(Expr* arg_cond, Stmt* arg_body, Stmt* arg_timeout_stmts,
+Trigger::Trigger(Expr* arg_cond, zeek::detail::Stmt* arg_body,
+			zeek::detail::Stmt* arg_timeout_stmts,
 			Expr* arg_timeout, Frame* arg_frame,
 			bool arg_is_return, const Location* arg_location)
 	{
diff --git a/src/Trigger.h b/src/Trigger.h
index c26e6e7b05..bc6dcf50fd 100644
--- a/src/Trigger.h
+++ b/src/Trigger.h
@@ -1,21 +1,23 @@
 #pragma once
 
-#include "Obj.h"
-#include "Notifier.h"
-#include "iosource/IOSource.h"
-
 #include <list>
 #include <vector>
 #include <map>
 
+#include "Obj.h"
+#include "Notifier.h"
+#include "iosource/IOSource.h"
+#include "util.h"
+
 class CallExpr;
 class Expr;
-class Stmt;
 class Frame;
 class Val;
 class ID;
 class ODesc;
 
+FORWARD_DECLARE_NAMESPACED(Stmt, zeek::detail);
+
 namespace trigger {
 // Triggers are the heart of "when" statements: expressions that when
 // they become true execute a body of statements.
@@ -29,7 +31,7 @@ public:
 	// instantiation.  Note that if the condition is already true, the
 	// statements are executed immediately and the object is deleted
 	// right away.
-	Trigger(Expr* cond, Stmt* body, Stmt* timeout_stmts, Expr* timeout,
+	Trigger(Expr* cond, zeek::detail::Stmt* body, zeek::detail::Stmt* timeout_stmts, Expr* timeout,
 		Frame* f, bool is_return, const Location* loc);
 	~Trigger() override;
 
@@ -92,8 +94,8 @@ private:
 	void UnregisterAll();
 
 	Expr* cond;
-	Stmt* body;
-	Stmt* timeout_stmts;
+	zeek::detail::Stmt* body;
+	zeek::detail::Stmt* timeout_stmts;
 	Expr* timeout;
 	double timeout_value;
 	Frame* frame;
diff --git a/src/Var.cc b/src/Var.cc
index af1665d92a..6f989174a8 100644
--- a/src/Var.cc
+++ b/src/Var.cc
@@ -316,7 +316,7 @@ void add_global(const IntrusivePtr<ID>& id, IntrusivePtr<BroType> t,
 	make_var(id, std::move(t), c, std::move(init), std::move(attr), dt, true);
 	}
 
-IntrusivePtr<Stmt> add_local(IntrusivePtr<ID> id, IntrusivePtr<BroType> t,
+IntrusivePtr<zeek::detail::Stmt> add_local(IntrusivePtr<ID> id, IntrusivePtr<BroType> t,
                              init_class c, IntrusivePtr<Expr> init,
                              std::unique_ptr<std::vector<IntrusivePtr<Attr>>> attr,
                              decl_type dt)
@@ -336,7 +336,7 @@ IntrusivePtr<Stmt> add_local(IntrusivePtr<ID> id, IntrusivePtr<BroType> t,
 		auto assign_expr = make_intrusive<AssignExpr>(std::move(name_expr),
 		                                              std::move(init), 0,
 		                                              nullptr, id->GetAttrs());
-		auto stmt = make_intrusive<ExprStmt>(std::move(assign_expr));
+		auto stmt = make_intrusive<zeek::detail::ExprStmt>(std::move(assign_expr));
 		stmt->SetLocationInfo(&location);
 		return stmt;
 		}
@@ -344,7 +344,7 @@ IntrusivePtr<Stmt> add_local(IntrusivePtr<ID> id, IntrusivePtr<BroType> t,
 	else
 		{
 		current_scope()->AddInit(std::move(id));
-		return make_intrusive<NullStmt>();
+		return make_intrusive<zeek::detail::NullStmt>();
 		}
 	}
 
@@ -633,7 +633,7 @@ TraversalCode OuterIDBindingFinder::PostExpr(const Expr* expr)
 	return TC_CONTINUE;
 	}
 
-void end_func(IntrusivePtr<Stmt> body)
+void end_func(IntrusivePtr<zeek::detail::Stmt> body)
 	{
 	auto ingredients = std::make_unique<function_ingredients>(pop_scope(), std::move(body));
 
@@ -668,7 +668,7 @@ Val* internal_val(const char* name)
 	return zeek::id::find_val(name).get();
 	}
 
-id_list gather_outer_ids(Scope* scope, Stmt* body)
+id_list gather_outer_ids(Scope* scope, zeek::detail::Stmt* body)
 	{
 	OuterIDBindingFinder cb(scope);
 	body->Traverse(&cb);
diff --git a/src/Var.h b/src/Var.h
index 935e276f86..ba44b8de00 100644
--- a/src/Var.h
+++ b/src/Var.h
@@ -8,13 +8,14 @@
 
 class Expr;
 class FuncType;
-class Stmt;
 class Scope;
 class EventHandlerPtr;
 class StringVal;
 class TableVal;
 class ListVal;
 
+FORWARD_DECLARE_NAMESPACED(Stmt, zeek::detail);
+
 typedef enum { VAR_REGULAR, VAR_CONST, VAR_REDEF, VAR_OPTION, } decl_type;
 
 extern void add_global(const IntrusivePtr<ID>& id,
@@ -24,12 +25,12 @@ extern void add_global(const IntrusivePtr<ID>& id,
                        std::unique_ptr<std::vector<IntrusivePtr<Attr>>> attr,
                        decl_type dt);
 
-extern IntrusivePtr<Stmt> add_local(IntrusivePtr<ID> id,
-                                    IntrusivePtr<BroType> t,
-                                    init_class c,
-                                    IntrusivePtr<Expr> init,
-                                    std::unique_ptr<std::vector<IntrusivePtr<Attr>>> attr,
-                                    decl_type dt);
+extern IntrusivePtr<zeek::detail::Stmt> add_local(IntrusivePtr<ID> id,
+                                                  IntrusivePtr<BroType> t,
+                                                  init_class c,
+                                                  IntrusivePtr<Expr> init,
+                                                  std::unique_ptr<std::vector<IntrusivePtr<Attr>>> attr,
+                                                  decl_type dt);
 
 extern IntrusivePtr<Expr> add_and_assign_local(IntrusivePtr<ID> id,
                                                IntrusivePtr<Expr> init,
@@ -43,10 +44,10 @@ extern void begin_func(IntrusivePtr<ID> id, const char* module_name,
                        IntrusivePtr<FuncType> t,
                        std::unique_ptr<std::vector<IntrusivePtr<Attr>>> attrs = nullptr);
 
-extern void end_func(IntrusivePtr<Stmt> body);
+extern void end_func(IntrusivePtr<zeek::detail::Stmt> body);
 
 // Gather all IDs referenced inside a body that aren't part of a given scope.
-extern id_list gather_outer_ids(Scope* scope, Stmt* body);
+extern id_list gather_outer_ids(Scope* scope, zeek::detail::Stmt* body);
 
 [[deprecated("Remove in v4.1.  Use zeek::id::find_val().")]]
 extern Val* internal_val(const char* name);
diff --git a/src/input.h b/src/input.h
index 70aa75ae28..fa6da97cec 100644
--- a/src/input.h
+++ b/src/input.h
@@ -41,5 +41,5 @@ extern std::vector<std::string> zeek_script_prefixes;	// -p flag
 extern const char* command_line_policy;	// -e flag
 extern std::vector<std::string> params;
 
-class Stmt;
-extern Stmt* stmts;	// global statements
+FORWARD_DECLARE_NAMESPACED(Stmt, zeek::detail);
+extern zeek::detail::Stmt* stmts;	// global statements
diff --git a/src/parse.y b/src/parse.y
index 59b229bdca..5900f7f64c 100644
--- a/src/parse.y
+++ b/src/parse.y
@@ -239,7 +239,7 @@ static bool expr_is_table_type_name(const Expr* expr)
 	RE_Matcher* re;
 	Expr* expr;
 	EventExpr* event_expr;
-	Stmt* stmt;
+	zeek::detail::Stmt* stmt;
 	ListExpr* list;
 	BroType* type;
 	RecordType* record;
@@ -247,8 +247,8 @@ static bool expr_is_table_type_name(const Expr* expr)
 	TypeList* type_l;
 	TypeDecl* type_decl;
 	type_decl_list* type_decl_l;
-	Case* c_case;
-	case_list* case_l;
+	zeek::detail::Case* c_case;
+	zeek::detail::case_list* case_l;
 	Attr* attr;
 	std::vector<IntrusivePtr<Attr>>* attr_l;
 	attr_tag attrtag;
@@ -994,7 +994,7 @@ type:
 			{
 			if ( ! $1 || ! ($$ = $1->IsType() ? $1->GetType().get() : nullptr) )
 				{
-				NullStmt here;
+				zeek::detail::NullStmt here;
 				if ( $1 )
 					$1->Error("not a Zeek type", &here);
 				$$ = error_type()->Ref();
@@ -1413,7 +1413,7 @@ stmt:
 	|	TOK_PRINT expr_list ';' opt_no_test
 			{
 			set_location(@1, @3);
-			$$ = new PrintStmt(IntrusivePtr{AdoptRef{}, $2});
+			$$ = new zeek::detail::PrintStmt(IntrusivePtr{AdoptRef{}, $2});
 			if ( ! $4 )
 			    brofiler.AddStmt($$);
 			}
@@ -1421,7 +1421,7 @@ stmt:
 	|	TOK_EVENT event ';' opt_no_test
 			{
 			set_location(@1, @3);
-			$$ = new EventStmt({AdoptRef{}, $2});
+			$$ = new zeek::detail::EventStmt({AdoptRef{}, $2});
 			if ( ! $4 )
 			    brofiler.AddStmt($$);
 			}
@@ -1429,19 +1429,19 @@ stmt:
 	|	TOK_IF '(' expr ')' stmt
 			{
 			set_location(@1, @4);
-			$$ = new IfStmt({AdoptRef{}, $3}, {AdoptRef{}, $5}, make_intrusive<NullStmt>());
+			$$ = new zeek::detail::IfStmt({AdoptRef{}, $3}, {AdoptRef{}, $5}, make_intrusive<zeek::detail::NullStmt>());
 			}
 
 	|	TOK_IF '(' expr ')' stmt TOK_ELSE stmt
 			{
 			set_location(@1, @4);
-			$$ = new IfStmt({AdoptRef{}, $3}, {AdoptRef{}, $5}, {AdoptRef{}, $7});
+			$$ = new zeek::detail::IfStmt({AdoptRef{}, $3}, {AdoptRef{}, $5}, {AdoptRef{}, $7});
 			}
 
 	|	TOK_SWITCH expr '{' case_list '}'
 			{
 			set_location(@1, @2);
-			$$ = new SwitchStmt({AdoptRef{}, $2}, $4);
+			$$ = new zeek::detail::SwitchStmt({AdoptRef{}, $2}, $4);
 			}
 
 	|	for_head stmt
@@ -1451,13 +1451,13 @@ stmt:
 
 	|	TOK_WHILE '(' expr ')' stmt
 			{
-			$$ = new WhileStmt({AdoptRef{}, $3}, {AdoptRef{}, $5});
+			$$ = new zeek::detail::WhileStmt({AdoptRef{}, $3}, {AdoptRef{}, $5});
 			}
 
 	|	TOK_NEXT ';' opt_no_test
 			{
 			set_location(@1, @2);
-			$$ = new NextStmt;
+			$$ = new zeek::detail::NextStmt;
 			if ( ! $3 )
 			    brofiler.AddStmt($$);
 			}
@@ -1465,7 +1465,7 @@ stmt:
 	|	TOK_BREAK ';' opt_no_test
 			{
 			set_location(@1, @2);
-			$$ = new BreakStmt;
+			$$ = new zeek::detail::BreakStmt;
 			if ( ! $3 )
 			    brofiler.AddStmt($$);
 			}
@@ -1473,7 +1473,7 @@ stmt:
 	|	TOK_FALLTHROUGH ';' opt_no_test
 			{
 			set_location(@1, @2);
-			$$ = new FallthroughStmt;
+			$$ = new zeek::detail::FallthroughStmt;
 			if ( ! $3 )
 				brofiler.AddStmt($$);
 			}
@@ -1481,7 +1481,7 @@ stmt:
 	|	TOK_RETURN ';' opt_no_test
 			{
 			set_location(@1, @2);
-			$$ = new ReturnStmt(0);
+			$$ = new zeek::detail::ReturnStmt(0);
 			if ( ! $3 )
 			    brofiler.AddStmt($$);
 			}
@@ -1489,7 +1489,7 @@ stmt:
 	|	TOK_RETURN expr ';' opt_no_test
 			{
 			set_location(@1, @2);
-			$$ = new ReturnStmt({AdoptRef{}, $2});
+			$$ = new zeek::detail::ReturnStmt({AdoptRef{}, $2});
 			if ( ! $4 )
 			    brofiler.AddStmt($$);
 			}
@@ -1497,7 +1497,7 @@ stmt:
 	|	TOK_ADD expr ';' opt_no_test
 			{
 			set_location(@1, @3);
-			$$ = new AddStmt({AdoptRef{}, $2});
+			$$ = new zeek::detail::AddStmt({AdoptRef{}, $2});
 			if ( ! $4 )
 			    brofiler.AddStmt($$);
 			}
@@ -1505,7 +1505,7 @@ stmt:
 	|	TOK_DELETE expr ';' opt_no_test
 			{
 			set_location(@1, @3);
-			$$ = new DelStmt({AdoptRef{}, $2});
+			$$ = new zeek::detail::DelStmt({AdoptRef{}, $2});
 			if ( ! $4 )
 			    brofiler.AddStmt($$);
 			}
@@ -1535,15 +1535,15 @@ stmt:
 	|	TOK_WHEN '(' expr ')' stmt
 			{
 			set_location(@3, @5);
-			$$ = new WhenStmt({AdoptRef{}, $3}, {AdoptRef{}, $5},
-			                  nullptr, nullptr, false);
+			$$ = new zeek::detail::WhenStmt({AdoptRef{}, $3}, {AdoptRef{}, $5},
+			                                  nullptr, nullptr, false);
 			}
 
 	|	TOK_WHEN '(' expr ')' stmt TOK_TIMEOUT expr '{' opt_no_test_block stmt_list '}'
 			{
 			set_location(@3, @9);
-			$$ = new WhenStmt({AdoptRef{}, $3}, {AdoptRef{}, $5},
-			                  {AdoptRef{}, $10}, {AdoptRef{}, $7}, false);
+			$$ = new zeek::detail::WhenStmt({AdoptRef{}, $3}, {AdoptRef{}, $5},
+			                                  {AdoptRef{}, $10}, {AdoptRef{}, $7}, false);
 			if ( $9 )
 			    brofiler.DecIgnoreDepth();
 			}
@@ -1552,15 +1552,15 @@ stmt:
 	|	TOK_RETURN TOK_WHEN '(' expr ')' stmt
 			{
 			set_location(@4, @6);
-			$$ = new WhenStmt({AdoptRef{}, $4}, {AdoptRef{}, $6}, nullptr,
+			$$ = new zeek::detail::WhenStmt({AdoptRef{}, $4}, {AdoptRef{}, $6}, nullptr,
 			                  nullptr, true);
 			}
 
 	|	TOK_RETURN TOK_WHEN '(' expr ')' stmt TOK_TIMEOUT expr '{' opt_no_test_block stmt_list '}'
 			{
 			set_location(@4, @10);
-			$$ = new WhenStmt({AdoptRef{}, $4}, {AdoptRef{}, $6},
-			                  {AdoptRef{}, $11}, {AdoptRef{}, $8}, true);
+			$$ = new zeek::detail::WhenStmt({AdoptRef{}, $4}, {AdoptRef{}, $6},
+			                                  {AdoptRef{}, $11}, {AdoptRef{}, $8}, true);
 			if ( $10 )
 			    brofiler.DecIgnoreDepth();
 			}
@@ -1568,7 +1568,7 @@ stmt:
 	|	index_slice '=' expr ';' opt_no_test
 			{
 			set_location(@1, @4);
-			$$ = new ExprStmt(get_assign_expr({AdoptRef{}, $1},
+			$$ = new zeek::detail::ExprStmt(get_assign_expr({AdoptRef{}, $1},
 			                                  {AdoptRef{}, $3}, in_init));
 
 			if ( ! $5 )
@@ -1578,7 +1578,7 @@ stmt:
 	|	expr ';' opt_no_test
 			{
 			set_location(@1, @2);
-			$$ = new ExprStmt({AdoptRef{}, $1});
+			$$ = new zeek::detail::ExprStmt({AdoptRef{}, $1});
 			if ( ! $3 )
 			    brofiler.AddStmt($$);
 			}
@@ -1586,11 +1586,11 @@ stmt:
 	|	';'
 			{
 			set_location(@1, @1);
-			$$ = new NullStmt;
+			$$ = new zeek::detail::NullStmt;
 			}
 
 	|	conditional
-			{ $$ = new NullStmt; }
+			{ $$ = new zeek::detail::NullStmt; }
 	;
 
 stmt_list:
@@ -1601,7 +1601,7 @@ stmt_list:
 			$1->UpdateLocationEndInfo(@2);
 			}
 	|
-			{ $$ = new StmtList(); }
+			{ $$ = new zeek::detail::StmtList(); }
 	;
 
 event:
@@ -1630,18 +1630,18 @@ case_list:
 		case_list case
 			{ $1->push_back($2); }
 	|
-			{ $$ = new case_list; }
+			{ $$ = new zeek::detail::case_list; }
 	;
 
 case:
 		TOK_CASE expr_list ':' stmt_list
-			{ $$ = new Case({AdoptRef{}, $2}, 0, {AdoptRef{}, $4}); }
+			{ $$ = new zeek::detail::Case({AdoptRef{}, $2}, 0, {AdoptRef{}, $4}); }
 	|
 		TOK_CASE case_type_list ':' stmt_list
-			{ $$ = new Case(nullptr, $2, {AdoptRef{}, $4}); }
+			{ $$ = new zeek::detail::Case(nullptr, $2, {AdoptRef{}, $4}); }
 	|
 		TOK_DEFAULT ':' stmt_list
-			{ $$ = new Case(nullptr, 0, {AdoptRef{}, $3}); }
+			{ $$ = new zeek::detail::Case(nullptr, 0, {AdoptRef{}, $3}); }
 	;
 
 case_type_list:
@@ -1704,12 +1704,12 @@ for_head:
 			id_list* loop_vars = new id_list;
 			loop_vars->push_back(loop_var.release());
 
-			$$ = new ForStmt(loop_vars, {AdoptRef{}, $5});
+			$$ = new zeek::detail::ForStmt(loop_vars, {AdoptRef{}, $5});
 			}
 	|
 		TOK_FOR '(' '[' local_id_list ']' TOK_IN expr ')'
 			{
-			$$ = new ForStmt($4, {AdoptRef{}, $7});
+			$$ = new zeek::detail::ForStmt($4, {AdoptRef{}, $7});
 			}
 	|
 		TOK_FOR '(' TOK_ID ',' TOK_ID TOK_IN expr ')'
@@ -1742,7 +1742,7 @@ for_head:
 			id_list* loop_vars = new id_list;
 			loop_vars->push_back(key_var.release());
 
-			$$ = new ForStmt(loop_vars, {AdoptRef{}, $7}, std::move(val_var));
+			$$ = new zeek::detail::ForStmt(loop_vars, {AdoptRef{}, $7}, std::move(val_var));
 			}
 	|
 		TOK_FOR '(' '[' local_id_list ']' ',' TOK_ID TOK_IN expr ')'
@@ -1761,7 +1761,7 @@ for_head:
 			else
 				val_var = install_ID($7, module, false, false);
 
-			$$ = new ForStmt($4, {AdoptRef{}, $9}, std::move(val_var));
+			$$ = new zeek::detail::ForStmt($4, {AdoptRef{}, $9}, std::move(val_var));
 			}
 	;
 
diff --git a/src/zeek-setup.cc b/src/zeek-setup.cc
index e204e59b3e..36e970a086 100644
--- a/src/zeek-setup.cc
+++ b/src/zeek-setup.cc
@@ -101,7 +101,7 @@ zeek::Supervisor* zeek::supervisor_mgr = nullptr;
 trigger::Manager* trigger_mgr = nullptr;
 
 std::vector<std::string> zeek_script_prefixes;
-Stmt* stmts;
+zeek::detail::Stmt* stmts;
 RuleMatcher* rule_matcher = nullptr;
 EventRegistry* event_registry = nullptr;
 ProfileLogger* profiling_logger = nullptr;