swagger: "2.0"
info:
  title: Sample API
  description: API description in Markdown.
  version: 1.0.0
host: api.example.com
basePath: /v1
schemes:
  - https
paths:
  /users:
    get:
      summary: Returns a list of users in certain locations.
      description: Optional extended description in Markdown.
      produces:
        - application/json
      responses:
        200:
          description: OK
      parameters:
        - name: locations
          in: query
          type: array
          description: Locations filter
          default: []
          items:
            type: string

$ swagger generate client -f swagger.yml 
2021/03/09 10:04:16 validating spec /tmp/swagger-test/swagger.yml
2021/03/09 10:04:16 preprocessing spec with option:  minimal flattening
2021/03/09 10:04:16 building a plan for generation
2021/03/09 10:04:16 generation target ./
2021/03/09 10:04:16 planning definitions (found: 0)
2021/03/09 10:04:16 planning operations (found: 1)
2021/03/09 10:04:16 grouping operations into packages (packages: 1)
2021/03/09 10:04:16 operations for package packages "operations" (found: 1)
2021/03/09 10:04:16 planning meta data and facades
2021/03/09 10:04:16 rendering 2 templates for operation 
2021/03/09 10:04:16 name field GetUsers
2021/03/09 10:04:16 package field operations
2021/03/09 10:04:16 creating generated file "get_users_parameters.go" in "client/operations" as parameters
2021/03/09 10:04:16 executed template asset:clientParameter
2021/03/09 10:04:16 source formatting failed on template-generated source ("client/operations/get_users_parameters.go" for parameters). Check that your template produces valid code
2021/03/09 10:04:16 unformatted generated source "get_users_parameters.go" has been dumped for template debugging purposes. DO NOT build on this source!
source formatting on generated source "parameters" failed: client/operations/get_users_parameters.go:96:37: expected operand, found ',' (and 10 more errors)

[...]
/ SetDefaults hydrates default values in the get users params (not the query body).
//
// All values with no default are reset to their zero value.
func (o *GetUsersParams) SetDefaults() {
  var (
        locationsDefault = []string{,}

  )
[...]