diff --git a/src/Interpreters/WindowDescription.h b/src/Interpreters/WindowDescription.h
index 1eb4491ad60..faad4649f91 100644
--- a/src/Interpreters/WindowDescription.h
+++ b/src/Interpreters/WindowDescription.h
@@ -17,7 +17,7 @@ class ASTFunction;
 struct WindowFunctionDescription
 {
     std::string column_name;
-    const ASTFunction * function_node;
+    const ASTFunction * function_node = nullptr;
     AggregateFunctionPtr aggregate_function;
     Array function_parameters;
     DataTypes argument_types;
diff --git a/src/Processors/QueryPlan/WindowStep.cpp b/src/Processors/QueryPlan/WindowStep.cpp
index 42834d70b8f..2b824f91b45 100644
--- a/src/Processors/QueryPlan/WindowStep.cpp
+++ b/src/Processors/QueryPlan/WindowStep.cpp
@@ -9,11 +9,6 @@
 namespace DB
 {
 
-namespace ErrorCodes
-{
-    extern const int BAD_ARGUMENTS;
-}
-
 static ITransformingStep::Traits getTraits()
 {
     return ITransformingStep::Traits