diff --git a/velox/expression/tests/ExpressionFuzzer.cpp b/velox/expression/tests/ExpressionFuzzer.cpp
index 9ec67bd4b414..fdd249e658a0 100644
--- a/velox/expression/tests/ExpressionFuzzer.cpp
+++ b/velox/expression/tests/ExpressionFuzzer.cpp
@@ -44,26 +44,22 @@ class DecimalArgGeneratorBase : public ArgGenerator {
       const TypePtr& returnType,
       FuzzerGenerator& rng) override {
     auto inputs = findInputs(returnType, rng);
-    if (inputs.a == nullptr || inputs.b == nullptr) {
-      return {};
+    for (const auto& input : inputs) {
+      if (input == nullptr) {
+        return {};
+      }
     }
-
-    return {std::move(inputs.a), std::move(inputs.b)};
+    return std::move(inputs);
   }
 
  protected:
   // Compute result type for all possible pairs of decimal input types. Store
   // the results in 'inputs_' maps keyed by return type.
   void initialize() {
-    std::vector<TypePtr> allTypes;
-    for (auto p = 1; p < 38; ++p) {
-      for (auto s = 0; s <= p; ++s) {
-        allTypes.push_back(DECIMAL(p, s));
-      }
-    }
-
-    for (auto& a : allTypes) {
-      for (auto& b : allTypes) {
+    // By default, the result type is considered to be calculated from two input
+    // decimal types.
+    for (auto& a : allTypes_) {
+      for (auto& b : allTypes_) {
         auto [p1, s1] = getDecimalPrecisionScale(*a);
         auto [p2, s2] = getDecimalPrecisionScale(*b);
 
@@ -74,10 +70,7 @@ class DecimalArgGeneratorBase : public ArgGenerator {
     }
   }
   
-  struct Inputs {
-    TypePtr a;
-    TypePtr b;
-  };
+  using Inputs = std::vector<TypePtr>;
 
   // Return randomly selected pair of input types that produce the specified
   // result type.
@@ -95,10 +88,22 @@ class DecimalArgGeneratorBase : public ArgGenerator {
 
   // Given precisions and scales of the inputs, return precision and scale of
   // the result.
-  virtual std::optional<std::pair<int, int>>
-  toReturnType(int p1, int s1, int p2, int s2) = 0;
+  virtual std::optional<std::pair<int, int>> toReturnType(...) = 0;
 
   std::map<std::pair<int, int>, std::vector<Inputs>> inputs_;
+
+  static const std::vector<TypePtr> allTypes_ = generateAllTypes();
+
+ private:
+  std::vector<TypePtr> generateAllTypes() {
+    std::vector<TypePtr> allTypes;
+    for (auto p = 1; p < 38; ++p) {
+      for (auto s = 0; s <= p; ++s) {
+        allTypes.push_back(DECIMAL(p, s));
+      }
+    }
+    return allTypes;
+  }
 };
 
 class PlusMinusArgGenerator : public DecimalArgGeneratorBase {
@@ -108,8 +113,15 @@ class PlusMinusArgGenerator : public DecimalArgGeneratorBase {
   }
 
  protected:
-  std::optional<std::pair<int, int>>
-  toReturnType(int p1, int s1, int p2, int s2) override {
+  std::optional<std::pair<int, int>> toReturnType(...) override {
+    va_list args;
+    va_start(args, 4);
+    int p1 = va_arg(args, int);
+    int s1 = va_arg(args, int);
+    int p2 = va_arg(args, int);
+    int s2 = va_arg(args, int);
+    va_end(args);
+
     auto s = std::max(s1, s2);
     auto p = std::min(38, std::max(p1 - s1, p2 - s2) + 1 + s);
     return {{p, s}};
@@ -123,8 +135,15 @@ class MultiplyArgGenerator : public DecimalArgGeneratorBase {
   }
 
  protected:
-  std::optional<std::pair<int, int>>
-  toReturnType(int p1, int s1, int p2, int s2) override {
+  std::optional<std::pair<int, int>> toReturnType(...) override {
+    va_list args;
+    va_start(args, 4);
+    int p1 = va_arg(args, int);
+    int s1 = va_arg(args, int);
+    int p2 = va_arg(args, int);
+    int s2 = va_arg(args, int);
+    va_end(args);
+
     if (s1 + s2 > 38) {
       return std::nullopt;
     }
@@ -142,8 +161,15 @@ class DivideArgGenerator : public DecimalArgGeneratorBase {
   }
 
  protected:
-  std::optional<std::pair<int, int>>
-  toReturnType(int p1, int s1, int p2, int s2) override {
+  std::optional<std::pair<int, int>> toReturnType(...) override {
+    va_list args;
+    va_start(args, 4);
+    int p1 = va_arg(args, int);
+    int s1 = va_arg(args, int);
+    int p2 = va_arg(args, int);
+    int s2 = va_arg(args, int);
+    va_end(args);
+
     if (s1 + s2 > 38) {
       return std::nullopt;
     }
@@ -785,7 +811,7 @@ ExpressionFuzzer::ExpressionFuzzer(
           argTypes = typeFuzzer.argumentTypes();
           if (!isDeterministic(function.first, argTypes)) {
             LOG(WARNING) << "Skipping non-deterministic function: "
-                        << function.first << signature->toString();
+                         << function.first << signature->toString();
             continue;
           }
         }