diff --git a/src/dscanner/analysis/unmodified.d b/src/dscanner/analysis/unmodified.d
index 7fcef71..e881d47 100644
--- a/src/dscanner/analysis/unmodified.d
+++ b/src/dscanner/analysis/unmodified.d
@@ -216,7 +216,7 @@ extern (C++) class UnmodifiedFinder(AST) : BaseAnalyzerDmd
 		}
 	}
 
-	@property private extern (D) VarSet currentScope()
+	@property private extern (D) ref VarSet currentScope()
 	{
 		return usedVars[$ - 1];
 	}
diff --git a/src/dscanner/analysis/unused_parameter.d b/src/dscanner/analysis/unused_parameter.d
index fb8b31a..8ed0047 100644
--- a/src/dscanner/analysis/unused_parameter.d
+++ b/src/dscanner/analysis/unused_parameter.d
@@ -137,7 +137,7 @@ extern (C++) class UnusedParameterCheck(AST) : BaseAnalyzerDmd
 		}
 	}
 
-	@property private extern (D) ParamSet currentScope()
+	@property private extern (D) ref ParamSet currentScope()
 	{
 		return usedParams[$ - 1];
 	}
diff --git a/src/dscanner/analysis/unused_variable.d b/src/dscanner/analysis/unused_variable.d
index c136179..31eaef4 100644
--- a/src/dscanner/analysis/unused_variable.d
+++ b/src/dscanner/analysis/unused_variable.d
@@ -241,7 +241,7 @@ extern (C++) class UnusedVariableCheck(AST) : BaseAnalyzerDmd
 		}
 	}
 
-	@property private extern (D) VarSet currentScope()
+	@property private extern (D) ref VarSet currentScope()
 	{
 		return usedVars[$ - 1];
 	}