ValidateInputFieldDefaultValues():

• Let {inputFields} be all input fields across all source schemas
• For each {inputField} in {inputFields}:
  • Let {type} be the type of {inputField}
  • If {IsExposed(inputField)} is true and {inputField} has a default value:
    • Let {defaultValue} be the default value of {inputField}
    • If {ValidateDefaultValue(defaultValue)} is false
      • return false
• return true

{type} is unused.