diff --git a/src/thingdef/thingdef_exp.h b/src/thingdef/thingdef_exp.h
index b692be4ad..e56215b0f 100644
--- a/src/thingdef/thingdef_exp.h
+++ b/src/thingdef/thingdef_exp.h
@@ -997,6 +997,25 @@ public:
 	void SetFunction(VMScriptFunction *func) { MyFunction = func; }
 };
 
+//==========================================================================
+//
+//
+//
+//==========================================================================
+
+class FxNop : public FxExpression
+{
+public:
+	FxNop(const FScriptPosition &p)
+		: FxExpression(p)
+	{
+		isresolved = true;
+	}
+	ExpEmit Emit(VMFunctionBuilder *build)
+	{
+		return ExpEmit();
+	}
+};
 
 FxExpression *ParseExpression (FScanner &sc, PClassActor *cls, bool mustresolve = false);
 
diff --git a/src/thingdef/thingdef_expression.cpp b/src/thingdef/thingdef_expression.cpp
index 1b570c62e..d2ee090e6 100644
--- a/src/thingdef/thingdef_expression.cpp
+++ b/src/thingdef/thingdef_expression.cpp
@@ -3648,6 +3648,7 @@ FxExpression *FxIfStatement::Resolve(FCompileContext &ctx)
 		FxExpression *e = result ? WhenTrue : WhenFalse;
 		delete (result ? WhenFalse : WhenTrue);
 		WhenTrue = WhenFalse = NULL;
+		if (e == NULL) e = new FxNop(ScriptPosition);	// create a dummy if this statement gets completely removed by optimizing out the constant parts.
 		delete this;
 		return e;
 	}